Biogenic synthesis of Silver nanoparticles (AgNPs) and its effects on Zebrafish (Danio rerio)
- Authors: Siguba, Busiswa
- Date: 2019
- Subjects: Biogenic synthesis -- Zebrafish , Nanoparticles – Silver , Zebrafish
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1339 , vital:32260
- Description: The increase in use and production of engineered nanoparticles in recent years points towards their inevitable release into freshwater ecosystems. Subsequently, exposure to organisms in freshwater ecosystems is to be expected. The aim of this dissertation was to synthesize silver nanoparticles (AgNPs) using silver nitrate, gelatine and maltose as precursor, capping and reducing agent respectively. Cytotoxic effects of the as-synthesized AgNPs was evaluated at concentrations of 0.031 μg/L, 0.250 μg/L and 5.000 μg/L on selected target organs in zebrafish (Danio rerio ) after 96 hr of exposure, under a 24 hr static renewal system. Formation of AgNPs was investigated by UV-Vis spectrophotometry, which displayed absorption maxima peak characteristic of plasmon resonance band for silver at 419 nm. From transmission electron microscopy, AgNPs was found to be small, well dispersed and spherical in shape with a narrow size distribution, and an average particle size of3.76 ± 1.00 nm. Histopathological alterations following exposure to AgNPs was noticed in the gills, epidermis, muscle tissue and kidney. Secondary lamellae hypertrophy, oedema and epithelial lifting was observed in all experimental groups. Curling and clubbed tips of secondary lamellae were observed at the lowest concentration (0.031 μg/L). Hyperplasia and lamellae fusion was most common at the median concentration (0.250 μg/L) of AgNP exposure. Hypertrophy of endothelial cells along with blood vessel congestion was also observed. Reduced secondary lamellar length, lamellar erosion and thinning were observed at the highest concentration (5.000 μg/L).AgNP exposure also altered the shape of alarm cells. In addition, hyperplasia and hypertrophy of goblet cells were observed at the highest concentration (5.000 μg/L) at 96 hr. At 5.000 μg/L of AgNP, PAS reaction was intense (deep purple), while the number and size of these cells decreased. Staining with AB pH 2.5 demonstrated an intense deep purple staining at the lowest and at the median concentration (24 hr). Moderate staining was seen at the higher concentrations. Muscle bundles with severe oedema, their thickening and separation were more pronounced in all treated groups. Histopathological tubular deformation and mononuclear cell infiltration were observed in kidney tissues. In addition; an increase in melano‐macrophage aggregation intensity was identified on the 48 hr in the treated groups. An increase in tubular epithelial cell regeneration/ proliferation, resulting in production of new epithelial cells which was indicative of recovering of kidney tissues from AgNP induced injury at 96 hr of exposure. Results presented here shows that fish respond to the presence of AgNPs.
- Full Text:
- Date Issued: 2019
- Authors: Siguba, Busiswa
- Date: 2019
- Subjects: Biogenic synthesis -- Zebrafish , Nanoparticles – Silver , Zebrafish
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1339 , vital:32260
- Description: The increase in use and production of engineered nanoparticles in recent years points towards their inevitable release into freshwater ecosystems. Subsequently, exposure to organisms in freshwater ecosystems is to be expected. The aim of this dissertation was to synthesize silver nanoparticles (AgNPs) using silver nitrate, gelatine and maltose as precursor, capping and reducing agent respectively. Cytotoxic effects of the as-synthesized AgNPs was evaluated at concentrations of 0.031 μg/L, 0.250 μg/L and 5.000 μg/L on selected target organs in zebrafish (Danio rerio ) after 96 hr of exposure, under a 24 hr static renewal system. Formation of AgNPs was investigated by UV-Vis spectrophotometry, which displayed absorption maxima peak characteristic of plasmon resonance band for silver at 419 nm. From transmission electron microscopy, AgNPs was found to be small, well dispersed and spherical in shape with a narrow size distribution, and an average particle size of3.76 ± 1.00 nm. Histopathological alterations following exposure to AgNPs was noticed in the gills, epidermis, muscle tissue and kidney. Secondary lamellae hypertrophy, oedema and epithelial lifting was observed in all experimental groups. Curling and clubbed tips of secondary lamellae were observed at the lowest concentration (0.031 μg/L). Hyperplasia and lamellae fusion was most common at the median concentration (0.250 μg/L) of AgNP exposure. Hypertrophy of endothelial cells along with blood vessel congestion was also observed. Reduced secondary lamellar length, lamellar erosion and thinning were observed at the highest concentration (5.000 μg/L).AgNP exposure also altered the shape of alarm cells. In addition, hyperplasia and hypertrophy of goblet cells were observed at the highest concentration (5.000 μg/L) at 96 hr. At 5.000 μg/L of AgNP, PAS reaction was intense (deep purple), while the number and size of these cells decreased. Staining with AB pH 2.5 demonstrated an intense deep purple staining at the lowest and at the median concentration (24 hr). Moderate staining was seen at the higher concentrations. Muscle bundles with severe oedema, their thickening and separation were more pronounced in all treated groups. Histopathological tubular deformation and mononuclear cell infiltration were observed in kidney tissues. In addition; an increase in melano‐macrophage aggregation intensity was identified on the 48 hr in the treated groups. An increase in tubular epithelial cell regeneration/ proliferation, resulting in production of new epithelial cells which was indicative of recovering of kidney tissues from AgNP induced injury at 96 hr of exposure. Results presented here shows that fish respond to the presence of AgNPs.
- Full Text:
- Date Issued: 2019
Comparative study of phytochemical composition and insecticidal properties of Lemon species from Eastern Cape and KwaZulu-Natal
- Authors: Nodola, Phumelele
- Date: 2019
- Subjects: Phytochemical -- Insecticidal properties Lemon - - Species – Eastern Cape - - South Africa Citrus limon
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1348 , vital:32261
- Description: Citrus limon commonly known as lemon is the third most cultivated citrus genus in South Africa mainly cultivated for its juice. This study aims at analysing the chemical composition of Citrus limon waste (leaf and peel) and evaluation of their insecticidal properties. Leaves and peels of Eureka lemons were collected from three South African citrus farms (Addo, Riverside and Mystic), while Lisbon lemons were only collected from two citrus farms (Addo and Riverside) in 2017 and 2018. A total of 36 essential oils were extracted using the Clevenger like apparatus. Analyses of these oils were done using GCMS. An infusion extract of C. limon was prepared according to the standard method and subjected for phytochemical screening to detect and quantify secondary metabolites present. D-Limonene was the major compound identified in all the 36 oils from Eureka and Lisbon peels and leaves (27.9-74.8%). Other dominant compounds identified in Eureka leaf and peel oils were -pinene (5.8-13.2%), -terpinene (4.8-6.7%), geranial (4.0-15.4%), z-citral (6.7-11.7%), sabinene (4.5-6.3%), nerol (4.0-5.4%) and neryl acetate (6.3-9.5%). Some compounds were however present only in some oil such caryophyllene (6.5%) in Mystic dry leaf oil, geraniol (8.0%) in Addo dry leaf oil, as significant compounds. Lisbon leaf and peel essential oils -pinene (4.4- 11.8%), p-cymene (4.2-6.3%), -terpinene (4.4-6.9%), geranial (8.6-17.3%), z-citral (7.1-13.6%), neryl acetate (4.7-9.1%) (5.4-5.9%) were the other prominent peaks identified in the oils. These C. limon essential oils were further tested for insecticidal activities against maize weevils by conducting repellent assay, fumigant assay and contact toxicity; also plant viii powder was used against maize weevils. In general, for all the bioassay, mortality of the insect increased as the contact days with the oil increased. Contact toxicity assays of C. limon peel essential oils were most effective against S. zeamais in which all weevils were dead by day 3 (100% mortality) at 300 μL, while at other concentrations (50, 100, 200 μL) over 50% mortality was observed. The fumigant potential was high with the peel oil with over 50% mortality at 32 and 40 μL in day 4. The oil had moderate repellent effect on the maize weevil. Riverside Eureka dried powder peel was the most effect in all. These results unveil the medicinal potential of South African citrus waste in post-harvest crop protection and good sources of some chemical compounds which are of medicinal value. Furthermore, this study also reveals the economic potential of these wastes in job creation.
- Full Text:
- Date Issued: 2019
- Authors: Nodola, Phumelele
- Date: 2019
- Subjects: Phytochemical -- Insecticidal properties Lemon - - Species – Eastern Cape - - South Africa Citrus limon
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1348 , vital:32261
- Description: Citrus limon commonly known as lemon is the third most cultivated citrus genus in South Africa mainly cultivated for its juice. This study aims at analysing the chemical composition of Citrus limon waste (leaf and peel) and evaluation of their insecticidal properties. Leaves and peels of Eureka lemons were collected from three South African citrus farms (Addo, Riverside and Mystic), while Lisbon lemons were only collected from two citrus farms (Addo and Riverside) in 2017 and 2018. A total of 36 essential oils were extracted using the Clevenger like apparatus. Analyses of these oils were done using GCMS. An infusion extract of C. limon was prepared according to the standard method and subjected for phytochemical screening to detect and quantify secondary metabolites present. D-Limonene was the major compound identified in all the 36 oils from Eureka and Lisbon peels and leaves (27.9-74.8%). Other dominant compounds identified in Eureka leaf and peel oils were -pinene (5.8-13.2%), -terpinene (4.8-6.7%), geranial (4.0-15.4%), z-citral (6.7-11.7%), sabinene (4.5-6.3%), nerol (4.0-5.4%) and neryl acetate (6.3-9.5%). Some compounds were however present only in some oil such caryophyllene (6.5%) in Mystic dry leaf oil, geraniol (8.0%) in Addo dry leaf oil, as significant compounds. Lisbon leaf and peel essential oils -pinene (4.4- 11.8%), p-cymene (4.2-6.3%), -terpinene (4.4-6.9%), geranial (8.6-17.3%), z-citral (7.1-13.6%), neryl acetate (4.7-9.1%) (5.4-5.9%) were the other prominent peaks identified in the oils. These C. limon essential oils were further tested for insecticidal activities against maize weevils by conducting repellent assay, fumigant assay and contact toxicity; also plant viii powder was used against maize weevils. In general, for all the bioassay, mortality of the insect increased as the contact days with the oil increased. Contact toxicity assays of C. limon peel essential oils were most effective against S. zeamais in which all weevils were dead by day 3 (100% mortality) at 300 μL, while at other concentrations (50, 100, 200 μL) over 50% mortality was observed. The fumigant potential was high with the peel oil with over 50% mortality at 32 and 40 μL in day 4. The oil had moderate repellent effect on the maize weevil. Riverside Eureka dried powder peel was the most effect in all. These results unveil the medicinal potential of South African citrus waste in post-harvest crop protection and good sources of some chemical compounds which are of medicinal value. Furthermore, this study also reveals the economic potential of these wastes in job creation.
- Full Text:
- Date Issued: 2019
Phytochemical Analysis and Biological potential of leaves and peels of three Eastern Cape Citrus Species
- Authors: Matuka, Thandiswa
- Date: 2019
- Subjects: Phytochemical -- Analysis Biology -- Leaves and peels Citrus species -- Eastern Cape -- South Africa
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1362 , vital:32263
- Description: Citrus sinensis, Citrus reticulata and Citrus clementine are citrus species that belong to a large family Rutaceae. Citrus leaves and peels are often regarded as waste products. In view of the environment pollution impact, the search for end use of citrus waste products for economic value and medicinal purposes was sort after. The aim of this study was to investigate chemical composition of citrus waste products (leaves and peels) essential oils and determine biological active volatile compounds from Citrus sinensis, Citrus reticulata and Citrus clementine Leaves and peels of Citrus sinensis, Citrus reticulata and Citrus clementine collected twice from citrus farm were extracted for essential oils using hydrodistillation method and analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) for plant samples collected in 2016 and, gas chromatography (GC) and gas chromatography-triple quadrupole-mass spectrometry (GC-MSMS) for plant samples collected in 2017. The oil yield for Citrus sinensis was 0.19 - 0.85 %v/w for fresh and dried leaf and peels for samples collected in 2016 and 0.26 – 0.87% v/w for those collected in 2017. Analysis of the essential oils analyses identified sabinene (20.4% GCMS, 22.6% GCMSMS), terpinen-4-ol (13.2% GCMS, 6.8% GCMSMS) and linalool (7.6% GCMS, 19.3% GCMSMS) as major compounds in fresh leaves essential oils while β-elemene (16.3% GCMS, 21.4% GCMSMS) and sabinene (10.7% GCMS, 20.8% GCMSMS) were major compounds characterized in dried leaves essential oils. Fresh and dried peels essential oils had limonene as the major constituent (49.6% GCMS, 87.1% GCMSMS) and (73.6% GCMS, 88.3% GCMSMS) respectively. Citrus reticulata essential oils percentage yield range between 0.44-0.80% v/w for fresh and dried leaf and peel oils. Analyses of the GCMS and GCMSMS chromatogram of the volatile oils analyses revealed linalool (33.4% GCMS, 19.6% GCMSMS), (+)-spathulenol (15.2% GCMS, 10.1% GCMSMS) and terpinene-4-ol (4.5% GCMS, 11.9% GCMSMS) as major compounds in fresh leaf essential oils while, sabinene (20.8% GCMS, 32.5% GCMSMS) and linalool (17.2% GCMS, 20.4% GCMSMS) were the major compounds found in dried leaf essential oils. Limonene (55.2%, 75.4% GCMS; 39.5%, 80.8% GCMSMS) was the major prominent compound identified in the C. reticulata peel essential oils in fresh and dried peels respectively, followed by linalool (12.8%, 2.9% GCMS; 48.4%, 7.4% GCMSMS). Percentage yields for the essential oils from C. clementine fresh and dried leaves and peels ranges from 0.40-0.62% v/w for. Fresh and dried leaves volatile oils had sabinene (22.7-27.1%) for GCMS and GCMSMS respectively), linalool (18.5- 20.9% GCMS and GCMSMS) and terpinene-4-ol (6.5- 11.8% GCMS and GCMSMS) as main compounds while fresh and dried peels oils were dominated by limonene (38.9- 86.5% GCMS and GCMSMS). Phytochemical screening experiment of the three citrus species leaves and peels aqueous extract reveal the prominent presence of flavonoids and phenolic compounds in high concentrations. C. reticulata and C. clementine peels and leaves volatile oils exhibited higher antioxidant activity as DPPH free radical scavengers and Ferric reducing power (FRAP) ability, when compared to C. sinensis essential oils which exhibited minimum antioxidant activity. Antioxidant activity of leaves and peels essential oils maybe due to the presence of oxygenated monoterpenes and high limonene content. C. sinensis peels oils showed non-toxic to extremely very low toxicity effect at highest dose 2000 mg/kg. C. reticulata and C. clementine peels oils showed toxicity effect in mice at high dose levels. It is suggested that citrus volatile oils could be safe to use at lower dose levels. Citrus species peels and leaves volatile compounds limonene linalool and sabinene exhibited antiinflammatory activity by significantly reducing rats paw oedema size induced by fresh egg albumin. The study suggests the use of Citrus waste products (leaves and peels) as natural antioxidants with antiinflammatory properties for medicinal value and volatile oils compounds for aroma in beverages and cosmetic industries.
- Full Text:
- Date Issued: 2019
- Authors: Matuka, Thandiswa
- Date: 2019
- Subjects: Phytochemical -- Analysis Biology -- Leaves and peels Citrus species -- Eastern Cape -- South Africa
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1362 , vital:32263
- Description: Citrus sinensis, Citrus reticulata and Citrus clementine are citrus species that belong to a large family Rutaceae. Citrus leaves and peels are often regarded as waste products. In view of the environment pollution impact, the search for end use of citrus waste products for economic value and medicinal purposes was sort after. The aim of this study was to investigate chemical composition of citrus waste products (leaves and peels) essential oils and determine biological active volatile compounds from Citrus sinensis, Citrus reticulata and Citrus clementine Leaves and peels of Citrus sinensis, Citrus reticulata and Citrus clementine collected twice from citrus farm were extracted for essential oils using hydrodistillation method and analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) for plant samples collected in 2016 and, gas chromatography (GC) and gas chromatography-triple quadrupole-mass spectrometry (GC-MSMS) for plant samples collected in 2017. The oil yield for Citrus sinensis was 0.19 - 0.85 %v/w for fresh and dried leaf and peels for samples collected in 2016 and 0.26 – 0.87% v/w for those collected in 2017. Analysis of the essential oils analyses identified sabinene (20.4% GCMS, 22.6% GCMSMS), terpinen-4-ol (13.2% GCMS, 6.8% GCMSMS) and linalool (7.6% GCMS, 19.3% GCMSMS) as major compounds in fresh leaves essential oils while β-elemene (16.3% GCMS, 21.4% GCMSMS) and sabinene (10.7% GCMS, 20.8% GCMSMS) were major compounds characterized in dried leaves essential oils. Fresh and dried peels essential oils had limonene as the major constituent (49.6% GCMS, 87.1% GCMSMS) and (73.6% GCMS, 88.3% GCMSMS) respectively. Citrus reticulata essential oils percentage yield range between 0.44-0.80% v/w for fresh and dried leaf and peel oils. Analyses of the GCMS and GCMSMS chromatogram of the volatile oils analyses revealed linalool (33.4% GCMS, 19.6% GCMSMS), (+)-spathulenol (15.2% GCMS, 10.1% GCMSMS) and terpinene-4-ol (4.5% GCMS, 11.9% GCMSMS) as major compounds in fresh leaf essential oils while, sabinene (20.8% GCMS, 32.5% GCMSMS) and linalool (17.2% GCMS, 20.4% GCMSMS) were the major compounds found in dried leaf essential oils. Limonene (55.2%, 75.4% GCMS; 39.5%, 80.8% GCMSMS) was the major prominent compound identified in the C. reticulata peel essential oils in fresh and dried peels respectively, followed by linalool (12.8%, 2.9% GCMS; 48.4%, 7.4% GCMSMS). Percentage yields for the essential oils from C. clementine fresh and dried leaves and peels ranges from 0.40-0.62% v/w for. Fresh and dried leaves volatile oils had sabinene (22.7-27.1%) for GCMS and GCMSMS respectively), linalool (18.5- 20.9% GCMS and GCMSMS) and terpinene-4-ol (6.5- 11.8% GCMS and GCMSMS) as main compounds while fresh and dried peels oils were dominated by limonene (38.9- 86.5% GCMS and GCMSMS). Phytochemical screening experiment of the three citrus species leaves and peels aqueous extract reveal the prominent presence of flavonoids and phenolic compounds in high concentrations. C. reticulata and C. clementine peels and leaves volatile oils exhibited higher antioxidant activity as DPPH free radical scavengers and Ferric reducing power (FRAP) ability, when compared to C. sinensis essential oils which exhibited minimum antioxidant activity. Antioxidant activity of leaves and peels essential oils maybe due to the presence of oxygenated monoterpenes and high limonene content. C. sinensis peels oils showed non-toxic to extremely very low toxicity effect at highest dose 2000 mg/kg. C. reticulata and C. clementine peels oils showed toxicity effect in mice at high dose levels. It is suggested that citrus volatile oils could be safe to use at lower dose levels. Citrus species peels and leaves volatile compounds limonene linalool and sabinene exhibited antiinflammatory activity by significantly reducing rats paw oedema size induced by fresh egg albumin. The study suggests the use of Citrus waste products (leaves and peels) as natural antioxidants with antiinflammatory properties for medicinal value and volatile oils compounds for aroma in beverages and cosmetic industries.
- Full Text:
- Date Issued: 2019
Evaluation of pharmacological properties and anti-neoplastic potentials of pelargonium iquinans and opuntia stricta extracts using acute leukemia cell lines
- Authors: Izuegbuna, Ogochukwu Osita
- Date: 2018
- Subjects: Pelargoniums Medicinal plants
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/10353/10372 , vital:35442
- Description: Leukaemia like other cancers is a public health issue, and coupled with the issue of drug resistance, toxicity and refractory disease novel treatments both as definitive and supportive care become necessary. The dissertation was designed to evaluate two medicinal plants (Opuntia stricta and Pelargonium inquinans) and their antineoplastic potentials. The phytochemicals analyses were done using standard methods with three different solvents (acetone, aqueous and ethanol). Vitamins analyses was also done using standard methods. The result revealed that vitamin A,C and E were present in the plants. Cell based anti-inflammatory activity were carried out using RAW264.7 macrophages cell, and COX-2 and NO expression as inflammatory markers. Cell based cytotoxicity and antineoplastic activity was investigated using RAW 264.7 macrophages cell, U937 and Jurkat cells. The results of the phytochemical analyses using GC/MS showed that phenols, flavonoids, flavonol, tannin, proanthocyanidin, saponin, alkaloids and phytate were present in these plants. In vitro antioxidant activity was carried out using nitric oxide (NO), alpha, alpha-diphenyl- β-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2), phosphomolybdenum activity, and iron reducing power (FRAP) techniques. The results of the antioxidant activity showed both plants had antioxidant properties that can be attributed to the phytochemical and vitamins contents. The results showed that both plants had anti-inflammatory properties which can also be attributed to their phytochemicals. The GC-MS analysis of the essential oils of both plants showed the presence of monoterpenes, sesquiterpenes, fatty acids, and esters. The results showed that O. stricta extracts have mild cytotoxicity, while P. inquinans have strong cytotoxicity. The cell cycle analysis showed Pelargonium inquinans extracts induced G0/G1 phase arrest and cleaved caspase-3. This study has shown the antineoplastic potential of P. inquinans which may be attributed to some phytochemicals in it such as carophyllene, humulene, beta myrcene and beta pinene.
- Full Text:
- Date Issued: 2018
- Authors: Izuegbuna, Ogochukwu Osita
- Date: 2018
- Subjects: Pelargoniums Medicinal plants
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/10353/10372 , vital:35442
- Description: Leukaemia like other cancers is a public health issue, and coupled with the issue of drug resistance, toxicity and refractory disease novel treatments both as definitive and supportive care become necessary. The dissertation was designed to evaluate two medicinal plants (Opuntia stricta and Pelargonium inquinans) and their antineoplastic potentials. The phytochemicals analyses were done using standard methods with three different solvents (acetone, aqueous and ethanol). Vitamins analyses was also done using standard methods. The result revealed that vitamin A,C and E were present in the plants. Cell based anti-inflammatory activity were carried out using RAW264.7 macrophages cell, and COX-2 and NO expression as inflammatory markers. Cell based cytotoxicity and antineoplastic activity was investigated using RAW 264.7 macrophages cell, U937 and Jurkat cells. The results of the phytochemical analyses using GC/MS showed that phenols, flavonoids, flavonol, tannin, proanthocyanidin, saponin, alkaloids and phytate were present in these plants. In vitro antioxidant activity was carried out using nitric oxide (NO), alpha, alpha-diphenyl- β-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2), phosphomolybdenum activity, and iron reducing power (FRAP) techniques. The results of the antioxidant activity showed both plants had antioxidant properties that can be attributed to the phytochemical and vitamins contents. The results showed that both plants had anti-inflammatory properties which can also be attributed to their phytochemicals. The GC-MS analysis of the essential oils of both plants showed the presence of monoterpenes, sesquiterpenes, fatty acids, and esters. The results showed that O. stricta extracts have mild cytotoxicity, while P. inquinans have strong cytotoxicity. The cell cycle analysis showed Pelargonium inquinans extracts induced G0/G1 phase arrest and cleaved caspase-3. This study has shown the antineoplastic potential of P. inquinans which may be attributed to some phytochemicals in it such as carophyllene, humulene, beta myrcene and beta pinene.
- Full Text:
- Date Issued: 2018
Vulnerabilities of Coastal Tourism destinations to climate change related incidents: a case study selected holiday resorts along the wildcoast, Eastern Cape, South Africa
- Authors: Van Der Byl, Athina
- Date: 2018
- Subjects: Coastal Tourism destinations -- Wildcoast Wildcoast -- Holiday resorts -- South Africa -- Eastern Cape Climate change -- Tourism
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1337 , vital:32259
- Description: Climate change is a global phenomenon with major impacts on coastlines, leaving coastal areas vulnerable to conditions such as sea level rise, flooding as well as storm surges, which results in increased damage to or loss of coastal property and infrastructure. The study examined the vulnerability of the Eastern Cape’s Wild Coast resorts to climate change related impacts. Both qualitative and quantitative methods aided by questionnaires and GIS mapping were used to identify vulnerable settlements as well as their impacts. A meta analysis of the identified vulnerabilities was studied and strategies employed to reduce the impacts was also done. Results indicated that almost 80% of the Wild Coast resorts occur within the low-lying areas of the coast and these areas were mostly affected by impacts such as sea level rise, heavy rainfall and floods accompanied by storm surges. Another alarming challenge faced by the King Sabata Dalindyebo Municipality was controlling unplanned developments within these low-lying zones of the coast. Therefore, it is recommended that relevant departments provide awareness through various platforms such as workshops, programmes and campaigns to ensure that people understand the risk of climate change on low-lying areas as well as mainstreaming climate change in long term development planning. This study highlights a need for monitoring of coastal environments vulnerable to the impact of climate change along a South African coastline.
- Full Text:
- Date Issued: 2018
- Authors: Van Der Byl, Athina
- Date: 2018
- Subjects: Coastal Tourism destinations -- Wildcoast Wildcoast -- Holiday resorts -- South Africa -- Eastern Cape Climate change -- Tourism
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1337 , vital:32259
- Description: Climate change is a global phenomenon with major impacts on coastlines, leaving coastal areas vulnerable to conditions such as sea level rise, flooding as well as storm surges, which results in increased damage to or loss of coastal property and infrastructure. The study examined the vulnerability of the Eastern Cape’s Wild Coast resorts to climate change related impacts. Both qualitative and quantitative methods aided by questionnaires and GIS mapping were used to identify vulnerable settlements as well as their impacts. A meta analysis of the identified vulnerabilities was studied and strategies employed to reduce the impacts was also done. Results indicated that almost 80% of the Wild Coast resorts occur within the low-lying areas of the coast and these areas were mostly affected by impacts such as sea level rise, heavy rainfall and floods accompanied by storm surges. Another alarming challenge faced by the King Sabata Dalindyebo Municipality was controlling unplanned developments within these low-lying zones of the coast. Therefore, it is recommended that relevant departments provide awareness through various platforms such as workshops, programmes and campaigns to ensure that people understand the risk of climate change on low-lying areas as well as mainstreaming climate change in long term development planning. This study highlights a need for monitoring of coastal environments vulnerable to the impact of climate change along a South African coastline.
- Full Text:
- Date Issued: 2018
The Anti-hypertensive Properties of T. officinale on L-Name-induced Hypertensive Rats
- Aremu, Olukayode Olasunkanmi
- Authors: Aremu, Olukayode Olasunkanmi
- Date: 2016
- Subjects: Hypertension Anti-hypertensive
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1045 , vital:30434
- Description: Medicinal plants have long been used in folkloric medicine in various parts of the world. Presence of phenolic compounds has been attributed to their medicinal properties. Despite various medicinal uses, scientific claims of anti-hypertensive activities are still deficient. Therefore, hydroethanolic (70% ethanol) extracts of the leaf and root parts of T. officinale (TOL and TOR respectively) were investigated for anti-hypertensive antioxidant, diuretic activities, and effects on lipid profile in L-Name-induced hypertensive Wistar rats. Phytochemical screening of TOL and TOR was assessed by known standardized method. Acute toxicity profile of the plant was also evaluated by Lorke’s method. Total phenolic and flavonoid contents were assessed using Folin Ciocalteau and Aluminium chloride colorimetric methods; while, 2, 2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2’–azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS)and ferric antioxidant reducing power (FRAP) protocols were used for their radical scavenging and total antioxidant capacities respectively. Spontaneously hypertensive rats were used for acute antihypertensive study while for the 21 days antihypertensive study, hypertension was induced by administering L-Name (40 mg/kg) for 4 weeks and, CODA 8 Non-invasive tail cuff machine was used to measure blood pressure. With the aid of a semi-auto chemistry analyzer, lipid profile of Taraxacum officinale (TO) was determined using Biosinol reagents. TOL and TOR also significantly reduced systolic, diastolic and mean arterial blood pressures up until 4 hours with the leaf part most active in single dose study using SHR model. TOL and TOR also significantly lowered systolic, diastolic and mean arterial blood pressures with the leaf part most active in 21 days study using and L-Name-induced HTN models. However, these plant extracts did not have a diuretic effect, but seems to exert its antihypertensive effects by modulating NO production and possibly bioavailability, by acting via an endothelium-dependent pathway. This study validates the traditional use of the leaf part of the plant as an antihypertensive agent.
- Full Text:
- Date Issued: 2016
- Authors: Aremu, Olukayode Olasunkanmi
- Date: 2016
- Subjects: Hypertension Anti-hypertensive
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1045 , vital:30434
- Description: Medicinal plants have long been used in folkloric medicine in various parts of the world. Presence of phenolic compounds has been attributed to their medicinal properties. Despite various medicinal uses, scientific claims of anti-hypertensive activities are still deficient. Therefore, hydroethanolic (70% ethanol) extracts of the leaf and root parts of T. officinale (TOL and TOR respectively) were investigated for anti-hypertensive antioxidant, diuretic activities, and effects on lipid profile in L-Name-induced hypertensive Wistar rats. Phytochemical screening of TOL and TOR was assessed by known standardized method. Acute toxicity profile of the plant was also evaluated by Lorke’s method. Total phenolic and flavonoid contents were assessed using Folin Ciocalteau and Aluminium chloride colorimetric methods; while, 2, 2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2’–azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS)and ferric antioxidant reducing power (FRAP) protocols were used for their radical scavenging and total antioxidant capacities respectively. Spontaneously hypertensive rats were used for acute antihypertensive study while for the 21 days antihypertensive study, hypertension was induced by administering L-Name (40 mg/kg) for 4 weeks and, CODA 8 Non-invasive tail cuff machine was used to measure blood pressure. With the aid of a semi-auto chemistry analyzer, lipid profile of Taraxacum officinale (TO) was determined using Biosinol reagents. TOL and TOR also significantly reduced systolic, diastolic and mean arterial blood pressures up until 4 hours with the leaf part most active in single dose study using SHR model. TOL and TOR also significantly lowered systolic, diastolic and mean arterial blood pressures with the leaf part most active in 21 days study using and L-Name-induced HTN models. However, these plant extracts did not have a diuretic effect, but seems to exert its antihypertensive effects by modulating NO production and possibly bioavailability, by acting via an endothelium-dependent pathway. This study validates the traditional use of the leaf part of the plant as an antihypertensive agent.
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- Date Issued: 2016
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