In vitro cytotoxic effects of chemical constituents of Euphorbia grandicornis Blanc against breast cancer cells
- Kemboi, Douglas, Peter, Xolani, Langat, Moses K, Mhlanga, Richwell, Vukea, Nyeleti, de la Mare, Jo-Anne, Siwe-Noundou, Xavier, Krause, Rui W M, Tembu, Vuyelwa J
- Authors: Kemboi, Douglas , Peter, Xolani , Langat, Moses K , Mhlanga, Richwell , Vukea, Nyeleti , de la Mare, Jo-Anne , Siwe-Noundou, Xavier , Krause, Rui W M , Tembu, Vuyelwa J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191747 , vital:45160 , xlink:href="https://doi.org/10.1016/j.sciaf.2021.e01002"
- Description: Euphorbia grandicornis Blanc is widely utilized in traditional medicine for a variety of ailments including body pains associated with skin irritations, inflammation, and snake or scorpion bites. Compounds from E. grandicornis were characterized using spectroscopic techniques, NMR, IR, MS, and melting points and alongside the extracts were evaluated for in vitro anticancer activity against several cancer cell lines. The root extract afforded known, β-glutinol (1), β-amyrin (2), 24-methylenetirucalla-8-en-3β-ol (3), tirucalla-8,25-diene-3β,24R-diol (4), stigmasterol (5), sitosterol (6), and hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) based on their NMR spectroscopic data for the first report in E. grandicornis. The extracts and isolated compounds were evaluated for anticancer activities against hormone receptor-positive breast cancer (MCF-7), triple-negative breast cancer (HCC70), and non-tumorigenic mammary epithelial (MCF-12A) cell lines. The CH2Cl2 extract exhibited potent, cytotoxicity against MCF-7, HCC70, and MCF-12A cells. The aerial extract exhibited IC50 values of 1.03, 0.301, and 1.68 µg/mL, and root extract displayed IC50 values of 0.83, 0.83 and 3.98 µg/mL against MCF-7, HCC70, and MCF-12A cells respectively. The root extract thus showed selectivity for the cancer cell lines over the non-cancerous control cell line (SI = 4.80). Hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) showed significant activity with IC50 values of 23.41, 29.45 and 27.01 µM against MCF-7, HCC70 and MCF-12A cells respectively, suggesting non-specific cytotoxicity.
- Full Text:
- Date Issued: 2021
- Authors: Kemboi, Douglas , Peter, Xolani , Langat, Moses K , Mhlanga, Richwell , Vukea, Nyeleti , de la Mare, Jo-Anne , Siwe-Noundou, Xavier , Krause, Rui W M , Tembu, Vuyelwa J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191747 , vital:45160 , xlink:href="https://doi.org/10.1016/j.sciaf.2021.e01002"
- Description: Euphorbia grandicornis Blanc is widely utilized in traditional medicine for a variety of ailments including body pains associated with skin irritations, inflammation, and snake or scorpion bites. Compounds from E. grandicornis were characterized using spectroscopic techniques, NMR, IR, MS, and melting points and alongside the extracts were evaluated for in vitro anticancer activity against several cancer cell lines. The root extract afforded known, β-glutinol (1), β-amyrin (2), 24-methylenetirucalla-8-en-3β-ol (3), tirucalla-8,25-diene-3β,24R-diol (4), stigmasterol (5), sitosterol (6), and hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) based on their NMR spectroscopic data for the first report in E. grandicornis. The extracts and isolated compounds were evaluated for anticancer activities against hormone receptor-positive breast cancer (MCF-7), triple-negative breast cancer (HCC70), and non-tumorigenic mammary epithelial (MCF-12A) cell lines. The CH2Cl2 extract exhibited potent, cytotoxicity against MCF-7, HCC70, and MCF-12A cells. The aerial extract exhibited IC50 values of 1.03, 0.301, and 1.68 µg/mL, and root extract displayed IC50 values of 0.83, 0.83 and 3.98 µg/mL against MCF-7, HCC70, and MCF-12A cells respectively. The root extract thus showed selectivity for the cancer cell lines over the non-cancerous control cell line (SI = 4.80). Hexyl (E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate (7) showed significant activity with IC50 values of 23.41, 29.45 and 27.01 µM against MCF-7, HCC70 and MCF-12A cells respectively, suggesting non-specific cytotoxicity.
- Full Text:
- Date Issued: 2021
Review of the Traditional Uses, Phytochemistry, and Pharmacological Activities of Rhoicissus Species (Vitaceae)
- Dube, Nondumiso, Siwe-Noundou, Xavier, Krause, Rui W M, Kemboi, Douglas, Tembu, Vuyelwa J, Manicum, Amanda-Lee
- Authors: Dube, Nondumiso , Siwe-Noundou, Xavier , Krause, Rui W M , Kemboi, Douglas , Tembu, Vuyelwa J , Manicum, Amanda-Lee
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191769 , vital:45162 , xlink:href="https://doi.org/10.3390/molecules26082306"
- Description: Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species.
- Full Text:
- Date Issued: 2021
- Authors: Dube, Nondumiso , Siwe-Noundou, Xavier , Krause, Rui W M , Kemboi, Douglas , Tembu, Vuyelwa J , Manicum, Amanda-Lee
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191769 , vital:45162 , xlink:href="https://doi.org/10.3390/molecules26082306"
- Description: Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species.
- Full Text:
- Date Issued: 2021
Unlocking the Diversity of Pyrroloiminoquinones Produced by Latrunculid Sponge Species
- Kalinski, Jarmo-Charles J, Krause, Rui W M, Parker-Nance, Shirley, Waterworth, Samantha C, Dorrington, Rosemary A
- Authors: Kalinski, Jarmo-Charles J , Krause, Rui W M , Parker-Nance, Shirley , Waterworth, Samantha C , Dorrington, Rosemary A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191802 , vital:45165 , xlink:href="https://doi.org/10.3390/md19020068"
- Description: Sponges of the Latrunculiidae family produce bioactive pyrroloiminoquinone alkaloids including makaluvamines, discorhabdins, and tsitsikammamines. The aim of this study was to use LC-ESI-MS/MS-driven molecular networking to characterize the pyrroloiminoquinone secondary metabolites produced by six latrunculid species. These are Tsitsikamma favus, Tsitsikamma pedunculata, Cyclacanthia bellae, and Latrunculia apicalis as well as the recently discovered species, Tsitsikamma nguni and Tsitsikamma michaeli. Organic extracts of 43 sponges were analyzed, revealing distinct species-specific chemical profiles. More than 200 known and unknown putative pyrroloiminoquinones and related compounds were detected, including unprecedented makaluvamine-discorhabdin adducts and hydroxylated discorhabdin I derivatives. The chemical profiles of the new species T. nguni closely resembled those of the known T. favus (chemotype I), but with a higher abundance of tsitsikammamines vs. discorhabdins. T. michaeli sponges displayed two distinct chemical profiles, either producing mostly the same discorhabdins as T. favus (chemotype I) or non- or monobrominated, hydroxylated discorhabdins. C. bellae and L. apicalis produced similar pyrroloiminoquinone chemistry to one another, characterized by sulfur-containing discorhabdins and related adducts and oligomers. This study highlights the variability of pyrroloiminoquinone production by latrunculid species, identifies novel isolation targets, and offers fundamental insights into the collision-induced dissociation of pyrroloiminoquinones.
- Full Text:
- Date Issued: 2021
- Authors: Kalinski, Jarmo-Charles J , Krause, Rui W M , Parker-Nance, Shirley , Waterworth, Samantha C , Dorrington, Rosemary A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191802 , vital:45165 , xlink:href="https://doi.org/10.3390/md19020068"
- Description: Sponges of the Latrunculiidae family produce bioactive pyrroloiminoquinone alkaloids including makaluvamines, discorhabdins, and tsitsikammamines. The aim of this study was to use LC-ESI-MS/MS-driven molecular networking to characterize the pyrroloiminoquinone secondary metabolites produced by six latrunculid species. These are Tsitsikamma favus, Tsitsikamma pedunculata, Cyclacanthia bellae, and Latrunculia apicalis as well as the recently discovered species, Tsitsikamma nguni and Tsitsikamma michaeli. Organic extracts of 43 sponges were analyzed, revealing distinct species-specific chemical profiles. More than 200 known and unknown putative pyrroloiminoquinones and related compounds were detected, including unprecedented makaluvamine-discorhabdin adducts and hydroxylated discorhabdin I derivatives. The chemical profiles of the new species T. nguni closely resembled those of the known T. favus (chemotype I), but with a higher abundance of tsitsikammamines vs. discorhabdins. T. michaeli sponges displayed two distinct chemical profiles, either producing mostly the same discorhabdins as T. favus (chemotype I) or non- or monobrominated, hydroxylated discorhabdins. C. bellae and L. apicalis produced similar pyrroloiminoquinone chemistry to one another, characterized by sulfur-containing discorhabdins and related adducts and oligomers. This study highlights the variability of pyrroloiminoquinone production by latrunculid species, identifies novel isolation targets, and offers fundamental insights into the collision-induced dissociation of pyrroloiminoquinones.
- Full Text:
- Date Issued: 2021
A novel dimeric exoglucanase (GH5_38)
- Mafa, Mpho S, Dirr, Heinrich W, Malgas, Samkelo, Krause, Rui W M, Pletschke, Brett I
- Authors: Mafa, Mpho S , Dirr, Heinrich W , Malgas, Samkelo , Krause, Rui W M , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193976 , vital:45412 , xlink:href="https://doi.org/10.3390/molecules25030746"
- Description: An exoglucanase (Exg-D) from the glycoside hydrolase family 5 subfamily 38 (GH5_38) was heterologously expressed and structurally and biochemically characterised at a molecular level for its application in alkyl glycoside synthesis. The purified Exg-D existed in both dimeric and monomeric forms in solution, which showed highest activity on mixed-linked β-glucan (88.0 and 86.7 U/mg protein, respectively) and lichenin (24.5 and 23.7 U/mg protein, respectively). They displayed a broad optimum pH range from 5.5 to 7 and a temperature optimum from 40 to 60 °C. Kinetic studies demonstrated that Exg-D had a higher affinity towards β-glucan, with a Km of 7.9 mg/mL and a kcat of 117.2 s−1, compared to lichenin which had a Km of 21.5 mg/mL and a kcat of 70.0 s−1. The circular dichroism profile of Exg-D showed that its secondary structure consisted of 11% α-helices, 36% β-strands and 53% coils. Exg-D performed transglycosylation using p-nitrophenyl cellobioside as a glycosyl donor and several primary alcohols as acceptors to produce methyl-, ethyl- and propyl-cellobiosides. These products were identified and quantified via thin-layer chromatography (TLC) and liquid chromatography–mass spectrometry (LC-MS). We concluded that Exg-D is a novel and promising oligomeric glycoside hydrolase for the one-step synthesis of alkyl glycosides with more than one monosaccharide unit.
- Full Text:
- Date Issued: 2020
- Authors: Mafa, Mpho S , Dirr, Heinrich W , Malgas, Samkelo , Krause, Rui W M , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193976 , vital:45412 , xlink:href="https://doi.org/10.3390/molecules25030746"
- Description: An exoglucanase (Exg-D) from the glycoside hydrolase family 5 subfamily 38 (GH5_38) was heterologously expressed and structurally and biochemically characterised at a molecular level for its application in alkyl glycoside synthesis. The purified Exg-D existed in both dimeric and monomeric forms in solution, which showed highest activity on mixed-linked β-glucan (88.0 and 86.7 U/mg protein, respectively) and lichenin (24.5 and 23.7 U/mg protein, respectively). They displayed a broad optimum pH range from 5.5 to 7 and a temperature optimum from 40 to 60 °C. Kinetic studies demonstrated that Exg-D had a higher affinity towards β-glucan, with a Km of 7.9 mg/mL and a kcat of 117.2 s−1, compared to lichenin which had a Km of 21.5 mg/mL and a kcat of 70.0 s−1. The circular dichroism profile of Exg-D showed that its secondary structure consisted of 11% α-helices, 36% β-strands and 53% coils. Exg-D performed transglycosylation using p-nitrophenyl cellobioside as a glycosyl donor and several primary alcohols as acceptors to produce methyl-, ethyl- and propyl-cellobiosides. These products were identified and quantified via thin-layer chromatography (TLC) and liquid chromatography–mass spectrometry (LC-MS). We concluded that Exg-D is a novel and promising oligomeric glycoside hydrolase for the one-step synthesis of alkyl glycosides with more than one monosaccharide unit.
- Full Text:
- Date Issued: 2020
Anti-cancer and anti-trypanosomal properties of alkaloids from the root bark of Zanthoxylum leprieurii Guill and Perr
- Eze, Fabian I, Siwe-Noundou, Xavier, Isaacs, Michelle, Patala, Srivinas, Osadebe, Patience O, Krause, Rui W M
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Isaacs, Michelle , Patala, Srivinas , Osadebe, Patience O , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193352 , vital:45324 , xlink:href="http://dx.doi.org/10.4314/tjpr.v19i11.19"
- Description: Purpose: To isolate the anti-cancer and anti-trypanosomal principles of Zanthoxylum leprieurii, a medicinally versatile wild tropical plant used for managing tumours, African trypanosomiasis, and inflammation in southeastern Nigeria. Methods: The pure compounds were isolated using chromatographic methods. The structural elucidation of the pure compounds was based on their NMR (1D and 2D) and mass spectral data as well as chemical test results. Structure-activity relationships were based on the structural differences among the compounds. The cytotoxicity of the extracts and compounds (1, 2, 3, and 4) was evaluated in HeLa (human cervix adenocarcinoma) cell line while the trypanocidal activities were evaluated on Trypanosoma brucei brucei. Results: Two acridone alkaloids, 1-hydroxy-3-methoxy-10-methylacridin-9 (10H)-one, named fabiocinine (1), and 1-hydroxy-2,3-dimethoxy-10-methylacridin-9 (10H)-one (arborinine, 2), together with a furoquinoline alkaloid, skimmianine (3), and a chelerythrine derivative, 6-acetonyl-5,6-dihydrochelerythrine (4) were isolated from the root bark of Zanthoxylum leprieurii. Skimmianine (3) exhibited cytotoxicity and anti-trypanosomal IC50 of 12.8 and 13.2 µg/mL respectively (p less than 0.05). Compound (1) and arborinine (2) were selectively cytotoxic to HeLa cells with cytotoxicity IC50 of 28.49 and 62.71 µg/mL, respectively, while (4) did not show significant activity (p less than 0.05). Conclusion: Zanthoxylum leprieurii root bark contains cytotoxic and trypanocidal compounds, and is thus a potential source of anti-cancer and anti-trypanosomal leads.
- Full Text:
- Date Issued: 2020
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Isaacs, Michelle , Patala, Srivinas , Osadebe, Patience O , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193352 , vital:45324 , xlink:href="http://dx.doi.org/10.4314/tjpr.v19i11.19"
- Description: Purpose: To isolate the anti-cancer and anti-trypanosomal principles of Zanthoxylum leprieurii, a medicinally versatile wild tropical plant used for managing tumours, African trypanosomiasis, and inflammation in southeastern Nigeria. Methods: The pure compounds were isolated using chromatographic methods. The structural elucidation of the pure compounds was based on their NMR (1D and 2D) and mass spectral data as well as chemical test results. Structure-activity relationships were based on the structural differences among the compounds. The cytotoxicity of the extracts and compounds (1, 2, 3, and 4) was evaluated in HeLa (human cervix adenocarcinoma) cell line while the trypanocidal activities were evaluated on Trypanosoma brucei brucei. Results: Two acridone alkaloids, 1-hydroxy-3-methoxy-10-methylacridin-9 (10H)-one, named fabiocinine (1), and 1-hydroxy-2,3-dimethoxy-10-methylacridin-9 (10H)-one (arborinine, 2), together with a furoquinoline alkaloid, skimmianine (3), and a chelerythrine derivative, 6-acetonyl-5,6-dihydrochelerythrine (4) were isolated from the root bark of Zanthoxylum leprieurii. Skimmianine (3) exhibited cytotoxicity and anti-trypanosomal IC50 of 12.8 and 13.2 µg/mL respectively (p less than 0.05). Compound (1) and arborinine (2) were selectively cytotoxic to HeLa cells with cytotoxicity IC50 of 28.49 and 62.71 µg/mL, respectively, while (4) did not show significant activity (p less than 0.05). Conclusion: Zanthoxylum leprieurii root bark contains cytotoxic and trypanocidal compounds, and is thus a potential source of anti-cancer and anti-trypanosomal leads.
- Full Text:
- Date Issued: 2020
Antiparasitic Constituents of Beilschmiedia louisii and Beilschmiedia obscura and Some Semisynthetic Derivatives
- Waleguele, Christine C, Mba'ning, Brice M, Awantu, Angelbert F, Bankeu, Jean J, Fongang, Yannick S F, Ngouela, Augustin S, Tsamo, Etienne, Sewald, Norbert, Lenta, Bruno N, Krause, Rui W M
- Authors: Waleguele, Christine C , Mba'ning, Brice M , Awantu, Angelbert F , Bankeu, Jean J , Fongang, Yannick S F , Ngouela, Augustin S , Tsamo, Etienne , Sewald, Norbert , Lenta, Bruno N , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193364 , vital:45325 , xlink:href="https://doi.org/10.3390/molecules25122862"
- Description: The MeOH/CH2Cl2 (1:1) extracts of the roots and leaves of Beilschmiedia louisii and B. obscura showed potent antitrypanosomal activity during preliminary screening on Trypanosoma brucei brucei. Phytochemical investigation of these extracts led to the isolation of a mixture of two new endiandric acid derivatives beilschmiedol B (1) and beilschmiedol C (2), and one new phenylalkene obscurene A (3) together with twelve known compounds (4–15). In addition, four new derivatives (11a–11d) were synthesized from compound 11. Their structures were elucidated based on their NMR and MS data. Compounds 5, 6, and 7 were isolated for the first time from the Beilschmiedia genus. Additionally, the NMR data of compound 4 are given here for the first time. The isolates were evaluated for their antitrypanosomal and antimalarial activities against Tb brucei and the Plasmodium falciparum chloroquine-resistant strain Pf3D7 in vitro, respectively. From the tested compounds, the mixture of new compounds 1 and 2 exhibited the most potent antitrypanosomal activity in vitro with IC50 value of 4.91 μM.
- Full Text:
- Date Issued: 2020
- Authors: Waleguele, Christine C , Mba'ning, Brice M , Awantu, Angelbert F , Bankeu, Jean J , Fongang, Yannick S F , Ngouela, Augustin S , Tsamo, Etienne , Sewald, Norbert , Lenta, Bruno N , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193364 , vital:45325 , xlink:href="https://doi.org/10.3390/molecules25122862"
- Description: The MeOH/CH2Cl2 (1:1) extracts of the roots and leaves of Beilschmiedia louisii and B. obscura showed potent antitrypanosomal activity during preliminary screening on Trypanosoma brucei brucei. Phytochemical investigation of these extracts led to the isolation of a mixture of two new endiandric acid derivatives beilschmiedol B (1) and beilschmiedol C (2), and one new phenylalkene obscurene A (3) together with twelve known compounds (4–15). In addition, four new derivatives (11a–11d) were synthesized from compound 11. Their structures were elucidated based on their NMR and MS data. Compounds 5, 6, and 7 were isolated for the first time from the Beilschmiedia genus. Additionally, the NMR data of compound 4 are given here for the first time. The isolates were evaluated for their antitrypanosomal and antimalarial activities against Tb brucei and the Plasmodium falciparum chloroquine-resistant strain Pf3D7 in vitro, respectively. From the tested compounds, the mixture of new compounds 1 and 2 exhibited the most potent antitrypanosomal activity in vitro with IC50 value of 4.91 μM.
- Full Text:
- Date Issued: 2020
Electronic and nonlinear optical properties of 3-(((2-substituted-4-nitrophenyl) imino) methyl) phenol
- Ojo, Nathanael D, Krause, Rui W M, Obi-Egbedi, Nelson O
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
Green synthesis of antimicrobial silver nanoparticles using aqueous leaf extracts from three Congolese plant species (Brillantaisia patula, Crossopteryx febrifuga and Senna siamea)
- Kambale, Espoir K, Nkanga, Christian I, Mutonkole, Blaise-Pascal I, Bapolisi, Alain M, Tassa, Daniel O, Liesse, Jean-Marie I, Krause, Rui W M, Memvanga, Patrick B
- Authors: Kambale, Espoir K , Nkanga, Christian I , Mutonkole, Blaise-Pascal I , Bapolisi, Alain M , Tassa, Daniel O , Liesse, Jean-Marie I , Krause, Rui W M , Memvanga, Patrick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193419 , vital:45330 , xlink:href="https://doi.org/10.1016/j.heliyon.2020.e04493"
- Description: In the present study, silver nanoparticles (AgNPs) were synthesized using aqueous leaf extracts of three Congolese plant species, namely Brillantaisia patula (BR-PA), Crossopteryx febrifuga (CR-FE) and Senna siamea (SE-SI). The obtained AgNPs were studied for their optical, structural, surface morphological and antibacterial properties. The prepared AgNPs were characterized by using UV-Visible spectra, Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray spectroscopy (EDX) and X-ray diffractometer (XRD). The synthesized nanoparticles were spherical shaped and well-dispersed with average sizes ranging from 45 to 110 nm. The AgNPs derived from BR-PA, CR-FE and SE-SI exhibited higher antibacterial activity against three bacterial pathogens of the human skin compared to their respective crude extracts and AgNO3. This indicated that the biomolecules covering the nanoparticles may enhance the biological activity of metal nanoparticles. Hence, our results support that biogenic synthesis of AgNPs from Congolese plants constitutes a potential area of interest for the therapeutic management of microbial diseases such as infectious skin diseases.
- Full Text:
- Date Issued: 2020
- Authors: Kambale, Espoir K , Nkanga, Christian I , Mutonkole, Blaise-Pascal I , Bapolisi, Alain M , Tassa, Daniel O , Liesse, Jean-Marie I , Krause, Rui W M , Memvanga, Patrick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193419 , vital:45330 , xlink:href="https://doi.org/10.1016/j.heliyon.2020.e04493"
- Description: In the present study, silver nanoparticles (AgNPs) were synthesized using aqueous leaf extracts of three Congolese plant species, namely Brillantaisia patula (BR-PA), Crossopteryx febrifuga (CR-FE) and Senna siamea (SE-SI). The obtained AgNPs were studied for their optical, structural, surface morphological and antibacterial properties. The prepared AgNPs were characterized by using UV-Visible spectra, Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray spectroscopy (EDX) and X-ray diffractometer (XRD). The synthesized nanoparticles were spherical shaped and well-dispersed with average sizes ranging from 45 to 110 nm. The AgNPs derived from BR-PA, CR-FE and SE-SI exhibited higher antibacterial activity against three bacterial pathogens of the human skin compared to their respective crude extracts and AgNO3. This indicated that the biomolecules covering the nanoparticles may enhance the biological activity of metal nanoparticles. Hence, our results support that biogenic synthesis of AgNPs from Congolese plants constitutes a potential area of interest for the therapeutic management of microbial diseases such as infectious skin diseases.
- Full Text:
- Date Issued: 2020
Synthesis and biological evaluation of bis-N2, N2′-(4-hydroxycoumarin-3-yl) ethylidene]-2, 3-dihydroxysuccinodihydrazides
- Manyeruke, Meloddy H, Tshiwawa, Tendamudzimu, Hoppe, Heinrich C, Isaacs, Michelle, Seldon, Ronnett, Warner, Digby F, Krause, Rui W M, Kaye, Perry T
- Authors: Manyeruke, Meloddy H , Tshiwawa, Tendamudzimu , Hoppe, Heinrich C , Isaacs, Michelle , Seldon, Ronnett , Warner, Digby F , Krause, Rui W M , Kaye, Perry T
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193430 , vital:45331 , xlink:href="https://doi.org/10.1016/j.bmcl.2019.126911"
- Description: A series of N2,N2′-bis[4-hydroxycoumarin-3-yl)ethylidene]-2,3-dihydroxysuccino-hydrazides, containing 4-hydroxycoumarin, hydrazine and tartaric acid moieties, have been prepared and examined for possible biological activity. Several of these compounds exhibit promising HIV-1 integrase inhibition (IC50 = 3.5 μM), and anti-T. brucei (32% viability) and anti-mycobacterial (Visual MIC90 = 15.63 μM) activity.
- Full Text:
- Date Issued: 2020
- Authors: Manyeruke, Meloddy H , Tshiwawa, Tendamudzimu , Hoppe, Heinrich C , Isaacs, Michelle , Seldon, Ronnett , Warner, Digby F , Krause, Rui W M , Kaye, Perry T
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193430 , vital:45331 , xlink:href="https://doi.org/10.1016/j.bmcl.2019.126911"
- Description: A series of N2,N2′-bis[4-hydroxycoumarin-3-yl)ethylidene]-2,3-dihydroxysuccino-hydrazides, containing 4-hydroxycoumarin, hydrazine and tartaric acid moieties, have been prepared and examined for possible biological activity. Several of these compounds exhibit promising HIV-1 integrase inhibition (IC50 = 3.5 μM), and anti-T. brucei (32% viability) and anti-mycobacterial (Visual MIC90 = 15.63 μM) activity.
- Full Text:
- Date Issued: 2020
Antiplasmodial Activity of the n-Hexane Extract from Pleurotus ostreatus (Jacq. ex. Fr) P. Kumm
- Afieroho, Ozadheoghene E, Siwe-Noundou, Xavier, Onyia, Chiazor P, Festus, Osamuyi H, Chukwu, Elizabeth C, Adedokun, Olutayo M, Isaacs, Michelle, Hoppe, Heinrich C, Krause, Rui W M, Abo, Kio A
- Authors: Afieroho, Ozadheoghene E , Siwe-Noundou, Xavier , Onyia, Chiazor P , Festus, Osamuyi H , Chukwu, Elizabeth C , Adedokun, Olutayo M , Isaacs, Michelle , Hoppe, Heinrich C , Krause, Rui W M , Abo, Kio A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194981 , vital:45516 , xlink:href="https://doi.org/10.4274/tjps.18894"
- Description: Objectives: Several mushrooms species have been reported to be nematophagous and antiprotozoan. This study reported the antiplasmodial and cytotoxic properties of the n-hexane extract from the edible mushroom Pleurotus ostreatus and the isolation of a sterol from the extract. Materials and Methods: Antiplasmodial and cytotoxicity assays were done in vitro using the plasmodium lactate dehydrogenase assay and human HeLa cervical cell lines, respectively. The structure of the isolated compound from the n-hexane extract was elucidated using spectroscopic techniques. Results: The n-hexane extract (yield: 0.93% w/w) showed dose dependent antiplasmodial activity with the trend in parasite inhibition of: chloroquine (IC50=0.016 μg/mL) > n-hexane extract (IC50=25.18 μg/mL). It also showed mild cytotoxicity (IC50>100 μg/mL; selectivity index >4) compared to the reference drug emetine (IC50=0.013 μg/mL). The known sterol, ergostan-5,7,22-trien-3-ol, was isolated and characterized from the extract. Conclusion: This study reporting for the first time the antiplasmodial activity of P. ostreatus revealed its nutraceutical potential in the management of malaria.
- Full Text:
- Date Issued: 2019
- Authors: Afieroho, Ozadheoghene E , Siwe-Noundou, Xavier , Onyia, Chiazor P , Festus, Osamuyi H , Chukwu, Elizabeth C , Adedokun, Olutayo M , Isaacs, Michelle , Hoppe, Heinrich C , Krause, Rui W M , Abo, Kio A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194981 , vital:45516 , xlink:href="https://doi.org/10.4274/tjps.18894"
- Description: Objectives: Several mushrooms species have been reported to be nematophagous and antiprotozoan. This study reported the antiplasmodial and cytotoxic properties of the n-hexane extract from the edible mushroom Pleurotus ostreatus and the isolation of a sterol from the extract. Materials and Methods: Antiplasmodial and cytotoxicity assays were done in vitro using the plasmodium lactate dehydrogenase assay and human HeLa cervical cell lines, respectively. The structure of the isolated compound from the n-hexane extract was elucidated using spectroscopic techniques. Results: The n-hexane extract (yield: 0.93% w/w) showed dose dependent antiplasmodial activity with the trend in parasite inhibition of: chloroquine (IC50=0.016 μg/mL) > n-hexane extract (IC50=25.18 μg/mL). It also showed mild cytotoxicity (IC50>100 μg/mL; selectivity index >4) compared to the reference drug emetine (IC50=0.013 μg/mL). The known sterol, ergostan-5,7,22-trien-3-ol, was isolated and characterized from the extract. Conclusion: This study reporting for the first time the antiplasmodial activity of P. ostreatus revealed its nutraceutical potential in the management of malaria.
- Full Text:
- Date Issued: 2019
Cordidepsine is A Potential New Anti-HIV Depsidone from Cordia millenii
- Zeukang, Rostanie D, Siwe-Noundou, Xavier, Fotsing, Maurice T, Mbafor, Joseph T, Krause, Rui W M, Choudhary, Muhammad I, Atchade, Alex de Theodore
- Authors: Zeukang, Rostanie D , Siwe-Noundou, Xavier , Fotsing, Maurice T , Mbafor, Joseph T , Krause, Rui W M , Choudhary, Muhammad I , Atchade, Alex de Theodore
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193988 , vital:45413 , xlink:href="https://doi.org/10.3390/molecules24173202"
- Description: Chemical investigation of Cordia millenii, Baker resulted in the isolation of a new depsidone, cordidepsine (1), along with twelve known compounds including cyclooctasulfur (2), lup-20(29)-en-3-triacontanoate (3), 1-(26-hydroxyhexacosanoyl)glycerol (4), glyceryl-1-hexacosanoate (5) betulinic acid (6), lupenone (7), β-amyrone (8), lupeol (9), β-amyrin (10), allantoin (11), 2′-(4-hydroxyphenyl)ethylpropanoate (12) and stigmasterol glycoside (13). Hemi-synthetic reactions were carried out on two isolated compounds (5 and 6) to afford two new derivatives, that is, cordicerol A (14) and cordicerol B (15), respectively. The chemical structures of all the compounds were established based on analysis and interpretation of spectroscopic data such as electron ionization mass spectrometry (EI–MS), high resolution electrospray ionization mass spectrometry (HR-ESI–MS), fast atom bombardment mass spectrometry (FAB–MS), one dimension and two dimension nuclear magnetic resonance (1D and 2D-NMR) spectral data as well as X-ray crystallography (XRC). Lupeol ester derivatives [Lup-20(29)-en-3-triacontanoate (3)], monoglycerol derivatives [1-(26-hydroxyhexacosanoyl)glycerol (4) and glyceryl-1 hexacosanoate (5)] were isolated for the first time from Cordia genus while sulfur allotrope [cyclooctasulfur (2)] was isolated for the first time from plant origin. Biological assays cordidepsine (1) exhibited significant anti-HIV integrase activity with IC50 = 4.65 μM; EtOAc extract of stem barks, EtOAc fraction of roots and leaves were not toxic against 3T3 cells.
- Full Text:
- Date Issued: 2019
- Authors: Zeukang, Rostanie D , Siwe-Noundou, Xavier , Fotsing, Maurice T , Mbafor, Joseph T , Krause, Rui W M , Choudhary, Muhammad I , Atchade, Alex de Theodore
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193988 , vital:45413 , xlink:href="https://doi.org/10.3390/molecules24173202"
- Description: Chemical investigation of Cordia millenii, Baker resulted in the isolation of a new depsidone, cordidepsine (1), along with twelve known compounds including cyclooctasulfur (2), lup-20(29)-en-3-triacontanoate (3), 1-(26-hydroxyhexacosanoyl)glycerol (4), glyceryl-1-hexacosanoate (5) betulinic acid (6), lupenone (7), β-amyrone (8), lupeol (9), β-amyrin (10), allantoin (11), 2′-(4-hydroxyphenyl)ethylpropanoate (12) and stigmasterol glycoside (13). Hemi-synthetic reactions were carried out on two isolated compounds (5 and 6) to afford two new derivatives, that is, cordicerol A (14) and cordicerol B (15), respectively. The chemical structures of all the compounds were established based on analysis and interpretation of spectroscopic data such as electron ionization mass spectrometry (EI–MS), high resolution electrospray ionization mass spectrometry (HR-ESI–MS), fast atom bombardment mass spectrometry (FAB–MS), one dimension and two dimension nuclear magnetic resonance (1D and 2D-NMR) spectral data as well as X-ray crystallography (XRC). Lupeol ester derivatives [Lup-20(29)-en-3-triacontanoate (3)], monoglycerol derivatives [1-(26-hydroxyhexacosanoyl)glycerol (4) and glyceryl-1 hexacosanoate (5)] were isolated for the first time from Cordia genus while sulfur allotrope [cyclooctasulfur (2)] was isolated for the first time from plant origin. Biological assays cordidepsine (1) exhibited significant anti-HIV integrase activity with IC50 = 4.65 μM; EtOAc extract of stem barks, EtOAc fraction of roots and leaves were not toxic against 3T3 cells.
- Full Text:
- Date Issued: 2019
Green synthesis of zinc oxide nanoparticles using Solanum torvum (L) leaf extract and evaluation of the toxicological profile of the ZnO nanoparticles–hydrogel composite in Wistar albino rats
- Ezealisiji, Kenneth E, Siwe-Noundou, Xavier, Maduelosi, Blessing, Nwachukwu, Nkemakolam, Krause, Rui W M
- Authors: Ezealisiji, Kenneth E , Siwe-Noundou, Xavier , Maduelosi, Blessing , Nwachukwu, Nkemakolam , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194015 , vital:45416 , xlink:href="https://doi.org/10.1007/s40089-018-0263-1"
- Description: Current study reports a simple and one-pot synthesis of zinc oxide nanoparticles (ZnONPs) using an aqueous extract of Solanum torvum and evaluation of its toxicological profile (0.5% w/w and 1.0% w/w) in Wistar albino rats with respect to the biochemical index. The nanoparticles were characterized using ultraviolet–visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction technique. Dynamic light scattering (DLS) and zeta potential of synthesized nanoparticles were analyzed to know the average size and stability of particles. Synthesized nanoparticles were stable, discreet, and mostly spherical, and size of particles was within the nanometre range. Biochemical markers of hepatic and renal functions were measured. Zinc oxide nanoparticles significantly decreased serum uric acid level (p less than 0.001) in a dose-dependent manner, while the serum alkaline phosphatase level was increased at the two test doses. The level of alanine transaminase was increased after exposure for 28 days (p less than 0.05). This study concludes that biogenic zinc oxide nanoparticles-infused hydrogel applied dermatologically could affect hepatic and renal performance in rats, and there was an observed cumulative toxicological effect with time of exposure.
- Full Text:
- Date Issued: 2019
- Authors: Ezealisiji, Kenneth E , Siwe-Noundou, Xavier , Maduelosi, Blessing , Nwachukwu, Nkemakolam , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194015 , vital:45416 , xlink:href="https://doi.org/10.1007/s40089-018-0263-1"
- Description: Current study reports a simple and one-pot synthesis of zinc oxide nanoparticles (ZnONPs) using an aqueous extract of Solanum torvum and evaluation of its toxicological profile (0.5% w/w and 1.0% w/w) in Wistar albino rats with respect to the biochemical index. The nanoparticles were characterized using ultraviolet–visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction technique. Dynamic light scattering (DLS) and zeta potential of synthesized nanoparticles were analyzed to know the average size and stability of particles. Synthesized nanoparticles were stable, discreet, and mostly spherical, and size of particles was within the nanometre range. Biochemical markers of hepatic and renal functions were measured. Zinc oxide nanoparticles significantly decreased serum uric acid level (p less than 0.001) in a dose-dependent manner, while the serum alkaline phosphatase level was increased at the two test doses. The level of alanine transaminase was increased after exposure for 28 days (p less than 0.05). This study concludes that biogenic zinc oxide nanoparticles-infused hydrogel applied dermatologically could affect hepatic and renal performance in rats, and there was an observed cumulative toxicological effect with time of exposure.
- Full Text:
- Date Issued: 2019
In vitro antimalarial, antitrypanosomal and HIV-1 integrase inhibitory activities of two Cameroonian medicinal plants
- Fouokeng, Yannick, Feumo Feusso, H M, Mbosso Teinkela, Jean E, Siwe-Noundou, Xavier, Wintjens, René T, Isaacs, Michelle, Hoppe, Heinrich C, Krause, Rui W M, Azébazé, Anatole G B, Vardamides, Juliette C
- Authors: Fouokeng, Yannick , Feumo Feusso, H M , Mbosso Teinkela, Jean E , Siwe-Noundou, Xavier , Wintjens, René T , Isaacs, Michelle , Hoppe, Heinrich C , Krause, Rui W M , Azébazé, Anatole G B , Vardamides, Juliette C
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195014 , vital:45519 , xlink:href="https://doi.org/10.1016/j.sajb.2018.10.008"
- Description: Antiplasmodial, antitrypanosomal and anti-HIV-1 activities of crude extracts, fractions and some isolated compounds from two Cameroonian medicinal plants: Antrocaryon klaineanum Pierre (Anacardiaceae) and Diospyros conocarpa Gürke ex K. Schum. (Ebenaceae) were assessed. The phytochemical studies led to the isolation of eight compounds (1–8) from Diospyros conocarpa and six compounds (6, 9–13) from Antrocaryon klaineanum. These compounds were identified as mangiferolic acid (1), 3β, 22(S)-dihydroxycycloart-24E-en-26-oic acid (2), lupeol (3), aridanin (4), betulin (5), betulinic acid (6), bergenin (7), D-quercitol(8), entilin C(9), entilin A(10), antrocarine A(11), 7R,20(S)-dihydroxy-4,24(28)-ergostadien-3-one(12) and stigmasterol glucoside (13). The criteria for activity were set as follows: an IC50 value more than 10 μg/mL for crude extracts and more than 1 μg/mL for pure compounds. The hexane/ethyl acetate (1:1) fraction of A.klaineanum root bark (AKERF1) and the hexane/ethyl acetate (1:1) fraction of A.klaineanum trunk bark (AKETF1) presented the strongest antiplasmodial activities with IC50 values of 0.4 and 4.4 μg/mL, respectively. Aridanin (4) and antrocarine A(11), as well as the crude extract of D.conocarpa roots (EDCR), AKERF1 and AKETF1 showed moderate trypanocidal effects. The crude extract of A.klaineanum root bark (AKER) and AKETF1 exhibited attractive activities on HIV-1 integrase with IC50 values of 1.96 and 24.04 μg/mL, respectively. The results provide baseline information on the use of A.klaineanum and D.conocarpa extracts, as well as certain components, as sources of new antiplasmodial, antitrypanosomal and anti-HIV drugs.
- Full Text:
- Date Issued: 2019
- Authors: Fouokeng, Yannick , Feumo Feusso, H M , Mbosso Teinkela, Jean E , Siwe-Noundou, Xavier , Wintjens, René T , Isaacs, Michelle , Hoppe, Heinrich C , Krause, Rui W M , Azébazé, Anatole G B , Vardamides, Juliette C
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195014 , vital:45519 , xlink:href="https://doi.org/10.1016/j.sajb.2018.10.008"
- Description: Antiplasmodial, antitrypanosomal and anti-HIV-1 activities of crude extracts, fractions and some isolated compounds from two Cameroonian medicinal plants: Antrocaryon klaineanum Pierre (Anacardiaceae) and Diospyros conocarpa Gürke ex K. Schum. (Ebenaceae) were assessed. The phytochemical studies led to the isolation of eight compounds (1–8) from Diospyros conocarpa and six compounds (6, 9–13) from Antrocaryon klaineanum. These compounds were identified as mangiferolic acid (1), 3β, 22(S)-dihydroxycycloart-24E-en-26-oic acid (2), lupeol (3), aridanin (4), betulin (5), betulinic acid (6), bergenin (7), D-quercitol(8), entilin C(9), entilin A(10), antrocarine A(11), 7R,20(S)-dihydroxy-4,24(28)-ergostadien-3-one(12) and stigmasterol glucoside (13). The criteria for activity were set as follows: an IC50 value more than 10 μg/mL for crude extracts and more than 1 μg/mL for pure compounds. The hexane/ethyl acetate (1:1) fraction of A.klaineanum root bark (AKERF1) and the hexane/ethyl acetate (1:1) fraction of A.klaineanum trunk bark (AKETF1) presented the strongest antiplasmodial activities with IC50 values of 0.4 and 4.4 μg/mL, respectively. Aridanin (4) and antrocarine A(11), as well as the crude extract of D.conocarpa roots (EDCR), AKERF1 and AKETF1 showed moderate trypanocidal effects. The crude extract of A.klaineanum root bark (AKER) and AKETF1 exhibited attractive activities on HIV-1 integrase with IC50 values of 1.96 and 24.04 μg/mL, respectively. The results provide baseline information on the use of A.klaineanum and D.conocarpa extracts, as well as certain components, as sources of new antiplasmodial, antitrypanosomal and anti-HIV drugs.
- Full Text:
- Date Issued: 2019
Molecular Networking Reveals Two Distinct Chemotypes in Pyrroloiminoquinone-Producing Tsitsikamma favus Sponges
- Kalinski, Jarmo-Charles J, Waterworth, Samantha C, Noundou, Xavier S, Jiwaji, Meesbah, Parker-Nance, Shirley, Krause, Rui W M, McPhail, Kerry L, Dorrington, Rosemary A
- Authors: Kalinski, Jarmo-Charles J , Waterworth, Samantha C , Noundou, Xavier S , Jiwaji, Meesbah , Parker-Nance, Shirley , Krause, Rui W M , McPhail, Kerry L , Dorrington, Rosemary A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131618 , vital:36673 , https://doi.org/10.3390/md17010060
- Description: The temperate marine sponge, Tsitsikamma favus, produces pyrroloiminoquinone alkaloids with potential as anticancer drug leads. We profiled the secondary metabolite reservoir of T. favus sponges using HR-ESI-LC-MS/MS-based molecular networking analysis followed by preparative purification efforts to map the diversity of new and known pyrroloiminoquinones and related compounds in extracts of seven specimens. Molecular taxonomic identification confirmed all sponges as T. favus and five specimens (chemotype I) were found to produce mainly discorhabdins and tsitsikammamines. Remarkably, however, two specimens (chemotype II) exhibited distinct morphological and chemical characteristics: the absence of discorhabdins, only trace levels of tsitsikammamines and, instead, an abundance of unbranched and halogenated makaluvamines. Targeted chromatographic isolation provided the new makaluvamine Q, the known makaluvamines A and I, tsitsikammamine B, 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C, and the related pyrrolo-ortho-quinones makaluvamine O and makaluvone. Purified compounds displayed different activity profiles in assays for topoisomerase I inhibition, DNA intercalation and antimetabolic activity against human cell lines. This is the first report of makaluvamines from a Tsitsikamma sponge species, and the first description of distinct chemotypes within a species of the Latrunculiidae family. This study sheds new light on the putative pyrroloiminoquinone biosynthetic pathway of latrunculid sponges
- Full Text:
- Date Issued: 2019
- Authors: Kalinski, Jarmo-Charles J , Waterworth, Samantha C , Noundou, Xavier S , Jiwaji, Meesbah , Parker-Nance, Shirley , Krause, Rui W M , McPhail, Kerry L , Dorrington, Rosemary A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131618 , vital:36673 , https://doi.org/10.3390/md17010060
- Description: The temperate marine sponge, Tsitsikamma favus, produces pyrroloiminoquinone alkaloids with potential as anticancer drug leads. We profiled the secondary metabolite reservoir of T. favus sponges using HR-ESI-LC-MS/MS-based molecular networking analysis followed by preparative purification efforts to map the diversity of new and known pyrroloiminoquinones and related compounds in extracts of seven specimens. Molecular taxonomic identification confirmed all sponges as T. favus and five specimens (chemotype I) were found to produce mainly discorhabdins and tsitsikammamines. Remarkably, however, two specimens (chemotype II) exhibited distinct morphological and chemical characteristics: the absence of discorhabdins, only trace levels of tsitsikammamines and, instead, an abundance of unbranched and halogenated makaluvamines. Targeted chromatographic isolation provided the new makaluvamine Q, the known makaluvamines A and I, tsitsikammamine B, 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C, and the related pyrrolo-ortho-quinones makaluvamine O and makaluvone. Purified compounds displayed different activity profiles in assays for topoisomerase I inhibition, DNA intercalation and antimetabolic activity against human cell lines. This is the first report of makaluvamines from a Tsitsikamma sponge species, and the first description of distinct chemotypes within a species of the Latrunculiidae family. This study sheds new light on the putative pyrroloiminoquinone biosynthetic pathway of latrunculid sponges
- Full Text:
- Date Issued: 2019
Beneficial effects of medicinal plants in fish diseases
- Stratev, Deyan, Zhelyazkov, Georgi, Noundou, Xavier S, Krause, Rui W M
- Authors: Stratev, Deyan , Zhelyazkov, Georgi , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126177 , vital:35856 , https://doi.org/10.1007/s10499-017-0219-x
- Description: Fish are constantly in contact with pathogens inhabiting water. High populationdensity as well as poor hydrodynamic conditions and feeding lead to an increased sensitivitytowards infections. In order to prevent major economic losses due to diseases, variousmedications are used for treatment and prevention of infections. The use of antimicrobialdrugs in aquacultures could lead to emergence of resistance in pathogenic microorganisms.Alternatives are being sought over the last few years to replace antibiotics, and medicinalplants are one of available options for this purpose. These plants are rich in secondarymetabolites and phytochemical compounds, which have an effect against viral, bacterial, andparasitic diseases in fish. Their main advantage is their natural origin and most of these plantsdo not represent threat for human health, the fish, and the environment. The goal of this reviewis to present information on the treatment of viral, bacterial, and parasitic diseases in fishthrough medicinal plants, with focus on the mechanisms of action of the identified secondarymetabolites, fractions, or plant extracts.
- Full Text:
- Date Issued: 2018
- Authors: Stratev, Deyan , Zhelyazkov, Georgi , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126177 , vital:35856 , https://doi.org/10.1007/s10499-017-0219-x
- Description: Fish are constantly in contact with pathogens inhabiting water. High populationdensity as well as poor hydrodynamic conditions and feeding lead to an increased sensitivitytowards infections. In order to prevent major economic losses due to diseases, variousmedications are used for treatment and prevention of infections. The use of antimicrobialdrugs in aquacultures could lead to emergence of resistance in pathogenic microorganisms.Alternatives are being sought over the last few years to replace antibiotics, and medicinalplants are one of available options for this purpose. These plants are rich in secondarymetabolites and phytochemical compounds, which have an effect against viral, bacterial, andparasitic diseases in fish. Their main advantage is their natural origin and most of these plantsdo not represent threat for human health, the fish, and the environment. The goal of this reviewis to present information on the treatment of viral, bacterial, and parasitic diseases in fishthrough medicinal plants, with focus on the mechanisms of action of the identified secondarymetabolites, fractions, or plant extracts.
- Full Text:
- Date Issued: 2018
Current trend in synthesis, Post-Synthetic modifications and biological applications of Nanometal-Organic frameworks (NMOFs)
- Baa, Ebenezer, Watkins, Gary M, Krause, Rui W M, Tantoh, Derek N
- Authors: Baa, Ebenezer , Watkins, Gary M , Krause, Rui W M , Tantoh, Derek N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127042 , vital:35946 , https://doi.org/10.1002/cjoc.201800407
- Description: Since the early reports of MOFs and their interesting properties, research involving these materials has grown wide in scope and applications. Various synthetic approaches have ensued in view of obtaining materials with optimised properties, the extensive scope of application spanning from energy, gas sorption, catalysis biological applications has meant exponentially evolved over the years. The far‐reaching synthetic and PSM approaches and porosity control possibilities have continued to serve as a motivation for research on these materials. With respect to the biological applications, MOFs have shown promise as good candidates in applications involving drug delivery, BioMOFs, sensing, imaging amongst others. Despite being a while away from successful entry into the market, observed results in sensing, drug delivery, and imaging put these materials on the spot light as candidates poised to usher in a revolution in biology. In this regard, this review article focuses current approaches in synthesis, post functionalization and biological applications of these materials with particular attention on drug delivery, imaging, sensing and BioMOFs.
- Full Text:
- Date Issued: 2018
- Authors: Baa, Ebenezer , Watkins, Gary M , Krause, Rui W M , Tantoh, Derek N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127042 , vital:35946 , https://doi.org/10.1002/cjoc.201800407
- Description: Since the early reports of MOFs and their interesting properties, research involving these materials has grown wide in scope and applications. Various synthetic approaches have ensued in view of obtaining materials with optimised properties, the extensive scope of application spanning from energy, gas sorption, catalysis biological applications has meant exponentially evolved over the years. The far‐reaching synthetic and PSM approaches and porosity control possibilities have continued to serve as a motivation for research on these materials. With respect to the biological applications, MOFs have shown promise as good candidates in applications involving drug delivery, BioMOFs, sensing, imaging amongst others. Despite being a while away from successful entry into the market, observed results in sensing, drug delivery, and imaging put these materials on the spot light as candidates poised to usher in a revolution in biology. In this regard, this review article focuses current approaches in synthesis, post functionalization and biological applications of these materials with particular attention on drug delivery, imaging, sensing and BioMOFs.
- Full Text:
- Date Issued: 2018
In vitro antimalarial, antitrypanosomal and HIV-1 integrase inhibitory activities of two Cameroonian medicinal plants: Antrocaryon klaineanum (Anacardiaceae) and Diospyros conocarpa (Ebenaceae)
- Fouokeng, Y, Feusso, H M Feumo, Noundou, Xavier S, Krause, Rui W M, Teinkela, Jean E Mb, Wintjens, R, Hoppe, Heinrich C, Azebaze, Anatole G B, Vardamides, Juliette C, Isaacs, Michelle
- Authors: Fouokeng, Y , Feusso, H M Feumo , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E Mb , Wintjens, R , Hoppe, Heinrich C , Azebaze, Anatole G B , Vardamides, Juliette C , Isaacs, Michelle
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126653 , vital:35908 , https://doi.org/10.1016/j.sajb.2018.10.008
- Description: Antiplasmodial, antitrypanosomal and anti-HIV-1 activities of crude extracts, fractions and some isolated compounds from two Cameroonian medicinal plants: Antrocaryon klaineanum Pierre (Anacardiaceae) and Diospyros conocarpa Gürke ex K. Schum. (Ebenaceae) were assessed. The phytochemical studies led to the isolation of eight compounds (1–8) from Diospyros conocarpa and six compounds (6, 9–13) from Antrocaryon klaineanum. These compounds were identified as mangiferolic acid (1), 3β, 22(S)-dihydroxycycloart-24E-en-26-oic acid (2), lupeol (3), aridanin (4), betulin (5), betulinic acid (6), bergenin (7), D-quercitol(8), entilin C(9), entilin A(10), antrocarine A(11), 7R,20(S)-dihydroxy-4,24(28)-ergostadien-3-one(12) and stigmasterol glucoside (13). The criteria for activity were set as follows: an IC50 value
- Full Text:
- Date Issued: 2018
- Authors: Fouokeng, Y , Feusso, H M Feumo , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E Mb , Wintjens, R , Hoppe, Heinrich C , Azebaze, Anatole G B , Vardamides, Juliette C , Isaacs, Michelle
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126653 , vital:35908 , https://doi.org/10.1016/j.sajb.2018.10.008
- Description: Antiplasmodial, antitrypanosomal and anti-HIV-1 activities of crude extracts, fractions and some isolated compounds from two Cameroonian medicinal plants: Antrocaryon klaineanum Pierre (Anacardiaceae) and Diospyros conocarpa Gürke ex K. Schum. (Ebenaceae) were assessed. The phytochemical studies led to the isolation of eight compounds (1–8) from Diospyros conocarpa and six compounds (6, 9–13) from Antrocaryon klaineanum. These compounds were identified as mangiferolic acid (1), 3β, 22(S)-dihydroxycycloart-24E-en-26-oic acid (2), lupeol (3), aridanin (4), betulin (5), betulinic acid (6), bergenin (7), D-quercitol(8), entilin C(9), entilin A(10), antrocarine A(11), 7R,20(S)-dihydroxy-4,24(28)-ergostadien-3-one(12) and stigmasterol glucoside (13). The criteria for activity were set as follows: an IC50 value
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- Date Issued: 2018
Isolation and Characterisation of Stigmasterol and β–Sitosterol from Anthocleista djalonensis A. Chev.
- Okoro, Ijeoma S, Tor-Anyiin, Terrumun A, Igoli, John O, Noundou, Xavier S, Krause, Rui W M
- Authors: Okoro, Ijeoma S , Tor-Anyiin, Terrumun A , Igoli, John O , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126191 , vital:35857 , https://doi.org/10.9734/AJOCS/2017/37147
- Description: Aim: Anthocleista djalonensis A. Chev. is a plant with several chemical constituents whichaccounts for its ethno-pharmacological uses. The present study is aimed at identifying and characterizing the active principles from the roots of the plant. Place and Duration of Study: The study was carried out at the Department of Organic Chemistry,Rhodes University, Grahamstown, South Africa between March and July 2016. Methodology: The root powder was subjected to maceration with methanol to obtain the crude extract. The methanol extract was fractionated using hexane, ethyl acetate and acetone successively. The acetone extract was thereafter subjected to column chromatography to isolate any pure components. Results: White needle-like crystals were obtained which on spectral analysis(IR, 1H NMR, 13C NMR, 2D- NMR, and ESI-MS ) were identified as a mixture of stigmasterol and β-sitosterol. Conclusion: The compounds isolated were identified as stigmasterol and β-sitosterol.
- Full Text:
- Date Issued: 2018
- Authors: Okoro, Ijeoma S , Tor-Anyiin, Terrumun A , Igoli, John O , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126191 , vital:35857 , https://doi.org/10.9734/AJOCS/2017/37147
- Description: Aim: Anthocleista djalonensis A. Chev. is a plant with several chemical constituents whichaccounts for its ethno-pharmacological uses. The present study is aimed at identifying and characterizing the active principles from the roots of the plant. Place and Duration of Study: The study was carried out at the Department of Organic Chemistry,Rhodes University, Grahamstown, South Africa between March and July 2016. Methodology: The root powder was subjected to maceration with methanol to obtain the crude extract. The methanol extract was fractionated using hexane, ethyl acetate and acetone successively. The acetone extract was thereafter subjected to column chromatography to isolate any pure components. Results: White needle-like crystals were obtained which on spectral analysis(IR, 1H NMR, 13C NMR, 2D- NMR, and ESI-MS ) were identified as a mixture of stigmasterol and β-sitosterol. Conclusion: The compounds isolated were identified as stigmasterol and β-sitosterol.
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- Date Issued: 2018
pH-Dependent release of isoniazid from isonicotinic acid (4-hydroxy-benzylidene)-hydrazide loaded liposomes
- Nkanga, Christian I, Tor-Anyiin, Terrumun A, Igoli, John O, Noundou, Xavier S, Krause, Rui W M
- Authors: Nkanga, Christian I , Tor-Anyiin, Terrumun A , Igoli, John O , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126427 , vital:35884 , https://doi.org/10.9734/AJOCS/2017/37147
- Description: Liposomes are considered as potential vehicles for the delivery of anti-tuberculosis drugs (ATBD) due to their rapid uptake by alveolar macrophages, where the mycobacterium often resides. This may provide macrophage-targeting effects that would be key to site specific ATBD delivery using pH-sensitive liposomes, considering the pH-gradient found in the phagocytotic pathway. In this study, isoniazid (INH) was conjugated to 4-hydroxy-benzaldehyde via a hydrazone bond to yield isonicotinic acid (4-hydroxy-benzylidene)-hydrazide (INH-HB). This conjugate was encapsulated in crude soybean lecithin liposomes using film hydration method. INH-HB loaded liposomes (IHL) were characterized by means of dynamic light scattering, transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. The release of INH from IHL was evaluated in media of different pH using a dialysis method. The particle size, Zeta Potential and encapsulation efficiency of IHL were about 945 nm, −62 mV and 89% respectively. In media of pH 7.4, 6.4, 5.4 and 4.4; the IHL exhibited respectively 22, 69, 83 and 100% of release over 12 h. In addition to possible targeted delivery, this pH-dependent release behavior may be suitable for minimizing the loss of INH by leakage from liposomes. The characteristics of IHL are promising for potential site-specific delivery of ATBD.
- Full Text:
- Date Issued: 2018
- Authors: Nkanga, Christian I , Tor-Anyiin, Terrumun A , Igoli, John O , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126427 , vital:35884 , https://doi.org/10.9734/AJOCS/2017/37147
- Description: Liposomes are considered as potential vehicles for the delivery of anti-tuberculosis drugs (ATBD) due to their rapid uptake by alveolar macrophages, where the mycobacterium often resides. This may provide macrophage-targeting effects that would be key to site specific ATBD delivery using pH-sensitive liposomes, considering the pH-gradient found in the phagocytotic pathway. In this study, isoniazid (INH) was conjugated to 4-hydroxy-benzaldehyde via a hydrazone bond to yield isonicotinic acid (4-hydroxy-benzylidene)-hydrazide (INH-HB). This conjugate was encapsulated in crude soybean lecithin liposomes using film hydration method. INH-HB loaded liposomes (IHL) were characterized by means of dynamic light scattering, transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. The release of INH from IHL was evaluated in media of different pH using a dialysis method. The particle size, Zeta Potential and encapsulation efficiency of IHL were about 945 nm, −62 mV and 89% respectively. In media of pH 7.4, 6.4, 5.4 and 4.4; the IHL exhibited respectively 22, 69, 83 and 100% of release over 12 h. In addition to possible targeted delivery, this pH-dependent release behavior may be suitable for minimizing the loss of INH by leakage from liposomes. The characteristics of IHL are promising for potential site-specific delivery of ATBD.
- Full Text:
- Date Issued: 2018
Three new pentacyclic triterpenoids from twigs of Manniophyton fulvum (Euphorbiaceae)
- Mbeunkeu, Ahri B D, Noundou, Xavier S, Krause, Rui W M, Teinkela, Jean E M, Laatsch, Hartmut, Azebaze, Anatole G B, Vardamides, Juliette C, Tala, Michel F
- Authors: Mbeunkeu, Ahri B D , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E M , Laatsch, Hartmut , Azebaze, Anatole G B , Vardamides, Juliette C , Tala, Michel F
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126782 , vital:35922 , https://doi.org/10.1016/j.phytol.2018.06.019
- Description: Phytochemical investigation of the methanol extracts of the twigs of Manniophyton fulvum has led to the isolation and characterization of three new pentacyclic triterpenoids, designated as 3α,28-dihydroxyfriedelan-1-one (1), manniotaraxerol A (3) and manniotaraxerol B (4), along with fourteen known compounds, 3α-hydroxy-1-oxofriedelane (2), betulinic acid (5), friedelin (S1), taraxerol (S2), a mixture of stigmasterol (S3) and β-sitosterol (S4), herranone (S5), docosanoic acid (S6), ursolic acid (S7), nasutin B (S8), bergenin (S9), stigmasterol-3-O-β-Dglucopyranoside (S10), 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-D-quinovopyranosyl)glycerol (S11), and aridanin (S12). The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR, EI and ESI-MS). 3α,28-Dihydroxyfriedelan-1-one (1), 3α-hydroxy-1-oxofriedelane (2), manniotaraxerol A (3), manniotaraxerol B (4), and betulinic acid (5) were evaluated against HeLa (human cervix adenocarcinoma) cancer cells. Manniotaraxerol A (3) showed weak in vitro cytotoxicity with a cell viability value of 49.3%. Betulinic acid (5) also showed significant cytotoxicity against HeLa cell with a cell viability value of 4.0%; the other compounds were inactive in this test.
- Full Text:
- Date Issued: 2018
- Authors: Mbeunkeu, Ahri B D , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E M , Laatsch, Hartmut , Azebaze, Anatole G B , Vardamides, Juliette C , Tala, Michel F
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126782 , vital:35922 , https://doi.org/10.1016/j.phytol.2018.06.019
- Description: Phytochemical investigation of the methanol extracts of the twigs of Manniophyton fulvum has led to the isolation and characterization of three new pentacyclic triterpenoids, designated as 3α,28-dihydroxyfriedelan-1-one (1), manniotaraxerol A (3) and manniotaraxerol B (4), along with fourteen known compounds, 3α-hydroxy-1-oxofriedelane (2), betulinic acid (5), friedelin (S1), taraxerol (S2), a mixture of stigmasterol (S3) and β-sitosterol (S4), herranone (S5), docosanoic acid (S6), ursolic acid (S7), nasutin B (S8), bergenin (S9), stigmasterol-3-O-β-Dglucopyranoside (S10), 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-D-quinovopyranosyl)glycerol (S11), and aridanin (S12). The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR, EI and ESI-MS). 3α,28-Dihydroxyfriedelan-1-one (1), 3α-hydroxy-1-oxofriedelane (2), manniotaraxerol A (3), manniotaraxerol B (4), and betulinic acid (5) were evaluated against HeLa (human cervix adenocarcinoma) cancer cells. Manniotaraxerol A (3) showed weak in vitro cytotoxicity with a cell viability value of 49.3%. Betulinic acid (5) also showed significant cytotoxicity against HeLa cell with a cell viability value of 4.0%; the other compounds were inactive in this test.
- Full Text:
- Date Issued: 2018