UWCScholar :: Browsing by Author "Johnson, Quinton"

Browsing by Author "Johnson, Quinton"

Now showing 1 - 16 of 16

The antihypertentive effect of aqueous extract O Africana leaves
(University of the Western Cape, 2007) Wang, Xu; Dietrich, Daneel; Johnson, Quinton; Dept. of Medical BioSciences; Faculty of Science
The incidence of cardiovascular diseases, including hypertension, is on the increase worldwide. Medicinal plants played an important role in the treatment of hypertension for centuries. Very few scientific studies have, however, been done to validate the use of these phytotherapies. O africana is on of the many phytotherapies that has been use indigenously for years to treat hypertension. The objectives of this study were to determine the most effective does of O africana aqueous extract which will reduce blood pressure; to determine whether chronic administration of O africana can be used to prevent and treat hypertension; to determine whether O africana exert its effects by modulation of the renin-angiotensin system.
An assessment of carpobrotrn actnacifurmis and cissampelos capensis as potential antimicrobial agents and their effects on animal metabolism
(University of the Western Cape, 2002) Bowie, Andrea; Johnson, Quinton
An assessm entof Carpobrotus acinaciformib and Cissampelos capensis as potential antimicrobialagentsandtheireffectsonanimalmetabolism
An assessment of Carpobrotus acinaciformis and Cissampelos capensis as potential antimicrobial agents and their effects on animal metabolism
(University of the Western Cape, 2002) Bowie, Andrea; Johnson, Quinton
The definition of a medicinal plant (as formulated by the WHO) is a plant that consists of either one or more plant parts with therapeutic properties that can be used in the development of drugs (sofowora lg82). Various medicinal plants have been used over the years for their healing properties, and it can even be said that this is an ancient practice (Cowan 1999). Plant derived medicines have been part of traditional healthcare in most parts of the world for thousands of years @alombo & Semble 2001- Salie 1998))' Presently, approximately l|%of the world population make use of plants and its extracts (salie 1998; Abelson 1990). Despite this widespread use of medicinal plants, only a fraction has been tested. Many plant derived natural products must be investigated for their pharmacological activity (Mendelson & Balick 1998; Gentry 1993)' Hence it is of utmost importance to study medicinal plants for safety and efficacy @loff 1998)' since there is still an infinite number that must be studied and discovered (Abelson 1990; Sofowora 1982). Hippocratus in the late fifth century B.C.) was a physician who strongly believed in herbal remedies to treat many ailments and recorded the use of approximately 300 to 400 medicinal plants (cowan 1999; Sofowora 1982; Schultes 1978). It is also believed that the Egyptians (1500 B.C) made use of medicinal plants as some records excavated from ancient Egyptian tombs stated (Sofowora 1982). The De Materia Medical medicinal plant catalogue of about 600 medicinal plants, was compiled by the Greek Dioscorides (A. D. 60) and was used by Europeans as a standard reference during medieval times (Cowan Lggg,Sofowora lg82). The works of the physician Galen were used in the middle ages but many of his records were destroyed. In spite of these unfortunate circumstances, present allopathic and homeopathic systems have been derived from the works of Galen (Sofowora 1982)'
An assessment of Hypoxis hemerocallidea extracts, and actives as natural antibiotic, and immune modulation phytotherapies
(University of the Western Cape, 2006) Muwanga, Catherine; Johnson, Quinton; South African Herbal Science and Medicine Institute (SAHSMI); Faculty of Science
In South Africa, the crude aqueous extract from Hypoxis hemerocallidea is used by AIDS patients to treat opportunistic infections, such as tuberculosis. The rapid emergence of multidrug-resistant tuberculosis, and extreme drug resistant tuberculosis, in recent years, is a major threat to human health. The treatment of TB, nosocomial bacterial infections, and fungal infections is now a clinical challenge, especially in the immuno-compromised individual. There is a dire need for novel antibiotic alternatives with phytotherapies and plant-derived compounds as potentially promising alternatives. The main objective of this study was to investigate the antimycobacterial activity of Hypoxis hemerocallidea, a South African medicinal plant, using Mycobacterium smegmatis.
An assessment of Hypoxis hemerocallidea extracts, and actives as natural antibiotic, and immune modulation phytotherapies
(University of the Western Cape, 2006) Muwanga, Catherine; Johnson, Quinton; South African Herbal Science and Medicine Institute (SAHSMI); Faculty of Science
In South Africa, the crude aqueous extract from Hypoxis hemerocallidea is used by AIDS patients to treat opportunistic infections, such as tuberculosis. The rapid emergence of multidrug-resistant tuberculosis, and extreme drug resistant tuberculosis, in recent years, is a major threat to human health. The treatment of TB, nosocomial bacterial infections, and fungal infections is now a clinical challenge, especially in the immuno-compromised individual. There is a dire need for novel antibiotic alternatives with phytotherapies and plant-derived compounds as potentially promising alternatives. The main objective of this study was to investigate the antimycobacterial activity of Hypoxis hemerocallidea, a South African medicinal plant, using Mycobacterium smegmatis.
Brine shrimp lethality test and acetylcholine esterase inhibition studies on selected South African medicinal plants
(University of the Western Cape, 2012) Jooste, Clarese Staley; Mabusela, Thozamile Wilfred; Johnson, Quinton
Research into traditional medicines is often conducted in a multidisciplinary approach as motivated by a desire to understand them in as complete a manner as possible,realizing their chemistry, biology and pharmacology. One biological approach involves monitoring the cytotoxicity of the extracts of subfractions against the nauplii,Artemia salina (brine shrimp). Organic and aqueous extracts of seven South African medicinal plants was investigated for biological activity. Selected plant extracts was also evaluated for AChE inhibitory activity. The objectives of this study was to look for any correlation between known biological activities of the investigated plants and BSLT lethality data and also to look for any correlation between AChEI activity and BSLT lethality data for selected plant extracts. The most active of the plants was the n-hex extract of T.alliacea, followed by the aqueous extract of C.mellei and the MeOH extract of C.quadrifidus; the MeOH and the DCM extracts of A.afra; the DCM extract of P.undulatum and the EtOAc extract of A.annua. The results from this study show a good correlation with antitumor, antimicrobial and anti-trypanocidal activity.The various plants extracts investigated showed good inhibitory activity towards AChE using the TLC bioautography method. The results obtained from this study indicate that this type of activity is not only subject to plants containing alkaloids, but rather a diverse class of compounds may exhibit this kind of activity. The extracts that showed good AChE inhibitory activity also showed good cytotoxicity towards brine shrimp nauplii.
The effects of Elytropappus rhinocerotis Cass and Pelargonium triste (L.) L'Hèrit on animal health and metabolism
(University of the Western Cape, 2003) Duarte, Nazeema; Johnson, Quinton; Weitz, Frans M.
Many South Africans use cultural traditions and practices in the management of their health. Elytropappus rhinocerotis is an important medicinal plant, which is widely distributed in regions of South Africa. The objective of this study was to evaluate the anti-microbial characteristics of Elytropappus rhinocerotis extracts and to assess its effects on animal and metabolism. Elemental analyses were done on the plant and soil samples to determine the concentrations of selected elements within the plant. The leaves were sectioned using freeze-microtomy. Elytropappus rhinocerotic was screened using a MeOH extract and the disc diffusion method against Staphylococcus aureus (ATCC2gzl3), Mycobacterium smegmatis, Pseudomonas aeruginosa (ATCC27853) and dandida albicans (ATCC1023I). The positive control for the bacteria was Ciprofloxacin and Amphotericin B for the fungal yeast. Elytropappus rhinocerotic aqueous extract was administered to female mice (NMRI strain), which were divided into two groups of 10 each. The mice were given lgllO0mykddz1 of the plant extract for a period of 6 weeks. Various metabolic parameters were assessed over time and included the mice mass, stool production and selected elemental analyses, and water and food consumption. A variety of blood parameters and selected tissue samples were analysed after the animals were sacrificed. There was no significant difference between the plant and soil analyses. The trichomes are anti-herbivory or iridescent techniques of the plant. The sclereids around the vascular bundle are part of the desiccation prevention methods of the plant. The plant extracts had no effect on the microbial pathogens. Furthermore, there were no significant differences in metabolic parameters between the plant medicine and placebo group, except for the following: The mass of the Elytropappus rhinocerotic group was significantly higher (PS 0.05) at week two when compared to the placebo controls. On the other hand, the Elytropappus rhinocerotis group excreted less (P< 0.05) Cu at week 4 compared with the control group. The haematology indicated that the Elytropappus rhinocerotis group had elevated immune surveillance in that these animals had significantly higher (PS 0.05) levels of white blood cells, Neutrophils and Lymphocytes. The red blood cell parameters remained largely unaffected, except for mean cell haemoglobin concentration, which was higher (PS 0.05), and the mean cell volume, which was lower (P< 0.05) in the Elytropappus rhinocerotis group compared to the placebo. Moreover, there were no differences between the tissue architecture of both groups. This investigation has shown that Elytropappus rhinocerotic had no direct effect on microbial growth but significantly improved immune cell numbers, with minimal physiologically important effects on red blood cell parameters. These outcomes compel us to further study Elytropappus rhinocerotic as a potential anti-infective indigenous phytotherapy that may exert its effects via immune enhancement, especially when we consider its favorable safety profile.
Ethnobotanical survey of medicinal plants used to manage High Blood Pressure and Type 2 Diabetes Mellitus in Bitterfontein, Western Cape Province, South Africa
(Elsevier, 2016) Davids, Denver; Gibson, Diana; Johnson, Quinton
ETHNOPHARMACOLOGICAL RELEVANCE: The aim of this study was to identify and document medicinal plants used to manage High Blood Pressure and Type 2 Diabetes Mellitus in Bitterfontein, Western Cape Province, South Africa. METHODS: One hundred and twelve (112) respondents were interviewed between August 2014 and September 2015 through semi-structured surveys to gather data on the percentage of people who had been diagnosed with High Blood Pressure and/or Type 2 Diabetes Mellitus and to determine the frequency of medicinal plant and allopathic medicine use. Twelve (12) key respondents were subsequently selected, using a non-probability snowball sampling method. They were interviewed in-depth concerning their plant practices and assisted with plant collection. RESULTS: Twenty-four plant (24) species belonging to 15 families were identified for the management of High Blood Pressure and Type 2 Diabetes Mellitus. The most frequently reported families were Asteraceae (20.8%), Lamiaceae (16.67%), Crassulaceae (8.33%) and Aizoaceae (8.33%). The remaining (45.54%) were evenly split over eleven families- Fabaceae, Amaryllidaceae, Anacardiaceae, Capparaceae, Geraniaceae, Apiaceae, Convolvulaceae, Apocynaceae, Rutaceae, Asphodelaceae and Thymelaeaceae. The most commonly used plant species overall was Lessertia frutescens (96.55%). The most frequently used plant parts included leaves (57.63%) roots/bulbs (15.25%) and stems (11.86%), mostly prepared as infusions or decoctions for oral administration. CONCLUSIONS: Medicinal plants are widely used by High Blood Pressure and Type 2 Diabetes Mellitus sufferers. They employ diverse plant species to manage both conditions. In addition, some sufferers often use prescribed allopathic medication, as well as medicinal plants, but at different intervals. Despite high usage the plants identified are not currently threatened (Red Data list status: least concern).
An evaluation of the biopesticidal characteristics of Helichrysum marifolium and Helichrysum patulum and their effects on animal metabolism
(University of the Western Cape, 2002) Speelman, Abigail; Johnson, Quinton
There are a number of pesticides that are suspected to be endocrine disrupters Many of these pesticides are man-made. Endocrine disrupters are chemicals that can lead to an increase in birth defects, sexual abnormalities, and reproductive failure. Marine animals seem to be the most vulnerable to the effects of pesticides since the ocean is the final sink for many pollutants. Endocrine disrupters can exert their effects in many ways. They can either bind to the hormone's receptor and mimic the hormone, or block the action of the hormone' An experiment done of newborn female rats injected with 1mg DDT/day on days 2-4 after birth had early onset of puberty and accelerated loss of fertility. In another experiment, vinclozolin (also a pesticide) at dosage levels of 3mg/kg/day resulted in feminized male rats in the womb, and an abnormal number of nipples were observed (11). Pesticides can be absorbed through the skin, by inhalation or oral ingestion. There are, however, important quantitative differences between the various derivatives. The skin poorly absorbs DDT in solution, whereas dieldrin absorption by the skin is very efficient. The major effects of insecticides in humans are qualitatively similar and cause effects on the central nervous system (9). Endocrine disrupters encompass more than just environmental estrogens and include any agent that adversely affects any aspect of the entire endocrine system. Endocrine disrupters are usually either natural products or synthetic chemicals that mimic, enhance, or inhibit the action of natural hormones (5). Low levels of many endocrine-disrupting chemicals can lead to high levels in the body tissues of animals and humans. This is due to the fact that many endocrine disrupters are stored in fat tissues through biomagnifications (2).
An evaluation of the biopesticidal characteristics of Helichrysum marifolium and Hetichrysum patulum and their effects on animal metabolism
(University of the Western Cape, 2002) Speelman, Abigail; Johnson, Quinton
There ate a number of pesticides that are suspected to be endocrine disrupters' Many of these pesticides are man-made. Endocrine disrupters are chemicals that can lead to an increase in birth defects, sexual abnormalities, and reproductive failure. Marine animals seem to be the most vulnerable to the effects of pesticides since the ocean is the final sink for many pollutants. Endocrine disrupters can exert their effects in many ways. They can either bind to the hormone's receptor and mimic the hormone, or block the action of the hormone' An experiment done of newborn female rats injected with 1mg DDT/day on days 2-4 after birth had early onset of puberty and accelerated loss of fertility. ln another experiment, vinclozolin (also a pesticide) at dosage levels of 3mg/kg/day resulted in feminised male rats in the womb and an abnormal number of nipples were observed (11). Pesticides can be absorbed through the skin, by inhalation or oral ingestion. There are, however, important quantitative differences between the various derivatives. The skin poorly absorbs DDT in solution, whereas dieldrin absorption by the skin is very efficient. The major effects of insecticides in humans are qualitatively similar and cause effects on the central nervous system (9). Endocrine disrupters encompass more than just environmental estrogens and include any agent that adversely affects any aspect of the entire endocrine system. Endocrine disrupters are usually either natural products or synthetic chemicals that mimic, enhance or inhibit the action natural hormones (5). Low levels of many endocrine disrupting chemicals can lead to high levels in body tissues of animals and humans. This is due to the fact that many endocrine disrupters are stored in fat$ tissues through biomagnifications (2). The greatest exposure to endocrine-disrupting chemicals is from food intake and since many are fat-solubte, the highest levels occur in the higher trophic levels' particularly meat, fish, and dairy products. The groups of organisms for which there is substantial evidence of endocrine disruption include snails, oysters, fish, alligators, and other reptiles, and birds such as seagulls and eagles' Many endocrine disrupting chemicals have become widespread contaminants across the globe. This is not due to their vast usage on a worldwide scale, but because some of the pesticides can be transported for thousands of kilometres on air currents (2).
An evaluation of the biopesticidal characteristics of Hetichrysum marifolium and Helichrysum patulum and their effects on animal metabolism
(University of the Western Cape, 2002) Speelman, Abigail; Johnson, Quinton
There ate a number of pesticides that are suspected to be endocrine disrupters' Many of these pesticides are man-made. Endocrine disrupters are chemicals that can lead to an increase in birth defects, sexual abnormalities, and reproductive failure. Marine animals seem to be the most vulnerable to the effects of pesticides since the ocean is the final sink for many pollutants. Endocrine disrupters can exert their effects in many ways. They can either bind to the hormone's receptor and mimic the hormone, or block the action of the hormone' An experiment done of newborn female rats injected with 1mg DDT/day on days 2-4 after birth had early onset of puberty and accelerated loss of fertility. ln another experiment, vinclozolin (also a pesticide) at dosage levels of 3mg/kg/day resulted in feminised male rats in the womb and an abnormal number of nipples were observed (11). Pesticides can be absorbed through the skin, by inhalation or oral ingestion. There are, however, important quantitative differences between the various derivatives. The skin poorly absorbs DDT in solution, whereas dieldrin absorption by the skin is very efficient. The major effects of insecticides in humans are qualitatively similar and cause effects on the central nervous system (9). Endocrine disrupters encompass more than just environmental estrogens and include any agent that adversely affects any aspect of the entire endocrine system. Endocrine disrupters are usually either natural products or synthetic chemicals that mimic, enhance or inhibit the action natural hormones (5). Low levels of many endocrine disrupting chemicals can lead to high levels in body tissues of animals and humans. This is due to the fact that many endocrine disrupters are stored in fat$ tissues through biomagnifications
Higher education and democracy: A study of students' and student leaders' attitudes towards democracy in Tanzania
(University of the Western Cape, 2002) Speelman, 2002; Johnson, Quinton
Students in African universities have a long history of political involvement at the institutional level and in national politics. The present study investigates the political opinions of students in Tanzania with respect to (1) their attitudes towards democracy and how these attitudes could be explained, (2) student satisfaction with the way their university and their country, Tanzania, are governed, and (3) whether student leaders (SL) have more democratic attitudes than students who are not in formal student leadership positions (SNL) and if there are other relevant groups that can be identified whose political attitudes differ significantly from those of other groups. The study draws on the work of Bratton, Mattes and Gyimah-Boadi (2005) and employs a survey questionnaire adapted from the Afrobarometer. Using survey data collected at the University of Dar es Salaam in Tanzania, a number of questions are investigated, and related hypotheses are tested in order to determine the extent to which students understand and demand democracy, how they perceive the supply of democracy, and what their attitudes are towards university governance and national politics in general. Overall, the study has found that students clearly understand what democracy is and are very supportive of democracy. This support, however, is opined within a context where they are dissatisfied with the way governance operates within the university as well as at national level in Tanzania. Democracy is therefore seen as an ideal which is not fully realised in the current situation. It is significant that, firstly, students have a good understanding of democracy in a wider perspective by conceptualising democracy mostly in procedural rather than substantive terms and by rejecting non-democratic alternatives, and they support popular representation at all levels of decision-making. Secondly, students are not satisfied with the way student representation and governance operates in their university; they demand more democracy in the University Students' Representative Council (USRC) elections; they support representative university governance and demand more accountability from student leaders and university management. Lastly, it is seen that between SL and SNL there are no significant differences in their respective conceptualisation of, and support for, democracy, and both groups show equal dissatisfaction with the way democracy operates in Tanzania.
An investigation into the medicinal properties of Tulbaghia alliacea phytotherapy
(University of the Western Cape, 2009) Thamburan, Samantha; Johnson, Quinton; School of Pharmacy; Faculty of Science
The reproductive health of individuals is severely compromised by HIV infection, with candidiasis being the most prevalent oral complication in patients. Although not usually associated with severe morbidity, oropharyngeal candidiasis can be clinically significant, as it can interfere with the administration of medications and adequate nutritional intake, and may spread to the esophagus. Azole antifungal agents are commonly prescribed for the treatment and prophylaxis of candidal infections. However, the emergence of drug resistant strains and dose limiting toxic effects have complicated the treatment of candidiasis. Consequently, safe and effective and affordable medicine is required to combat this fungus. Commercial garlic (Allium sativum) has been used time since immemorial as a natural antibiotic, however very little is known about the antifungal properties of two indigenous South African species of garlic, namely Tulbaghia alliacea and Tulbaghia violacea, that are used as folk medicines for a variety of infections. This study compares the in vitro anti-candidal activity of Tulbaghia alliacea, Tulbaghia violacea and Allium sativum extracts. It was found that the greatest concentrations of inhibitory components were extracted by chloroform or water. The IC50 concentrations of Tulbaghia alliacea were between 0.007 - 0.038% (w/v). Assays using S. cerevisiae revealed that the T. alliacea extract was fungicidal, with a killing half-life of approximately 2 hours. This inhibitory effect of the T. alliacea extracts was observed via TLC, and may be due to an active compound called Marasmicin, that was identified using NMR. This investigation confirms that extracts of T.alliacea exhibit anti-infective activity against candida species in vitro.
An investigation into the medicinal properties of Tulbaghia alliacea phytotherapy
(University of the Western Cape, 2009) Thamburan, Samantha; Johnson, Quinton
The reproductive health of individuals is severely compromised by HIV infection, with candidiasis being the most prevalent oral complication in patients. Although not usually associated with severe morbidity, oropharyngeal candidiasis can be clinically significant, as it can interfere with the administration of medications and adequate nutritional intake, and may spread to the esophagus. Azole antifungal agents are commonly prescribed for the treatment and prophylaxis of candidal infections. However, the emergence of drug resistant strains and dose limiting toxic effects have complicated the treatment of candidiasis. Consequently, safe and effective and affordable medicine is required to combat this fungus. Commercial garlic (Allium sativum) has been used time since immemorial as a natural antibiotic, however very little is known about the antifungal properties of two indigenous South African species of garlic, namely Tulbaghia alliacea and Tulbaghia violacea, that are used as folk medicines for a variety of infections. This study compares the in vitro anti-candidal activity of Tulbaghia alliacea, Tulbaghia violacea and Allium sativum extracts. It was found that the greatest concentrations of inhibitory components were extracted by chloroform or water. The IC50 concentrations of Tulbaghia alliacea were between 0.007 – 0.038% (w/v). Assays using S. cerevisiae revealed that the T. alliacea extract was fungicidal, with a killing half-life of approximately 2 hours. This inhibitory effect of the T. alliacea extracts was observed via TLC, and may be due to an active compound called Marasmicin, that was identified using NMR. This investigation confirms that extracts of T.alliacea exhibit anti-infective activity against candida species in vitro.
Polysaccharides from the South African medicinal plant Artemisia afra: Structure and activity studies
(Elsevier, 2018) Braunlich, Paula Marie; Inngjerdingen, Kari Tvete; Inngjerdingen, Marit; Johnson, Quinton; Paulsen, Berit Smestad; Mabusela, Wilfred
Artemisia afra (Jacq. Ex. Willd), is an indigenous plant in South Africa and other parts of the African continent, where it is used as traditional medicine mostly for respiratory conditions. The objective of this study was to investigate the structural features of the polysaccharides from the leaves of this plant, as well as the biological activities of the polysaccharide fractions against the complement assay. Leaves of Artemisia afra were extracted sequentially with organic solvents (dichloromethane and methanol), 50% aqueous ethanol, and water at 50 and 100 °C respectively. The polysaccharide extracts were fractionated by ion exchange chromatography and the resulting fractions were tested for biological activity against the complement fixation assay. Active fractions were further fractionated using gel filtration. Monosaccharide compositions and linkage analyses were determined for the relevant fractions. Polysaccharides were shown to be of the pectin type, and largely contain arabinogalactan, rhamnogalacturonan and homogalacturonan structural features. The presence of arabinogalactan type II features as suggested by methylation analysis was further confirmed by the ready precipitation of the relevant polysaccharides with the Yariv reagent. An unusual feature of some of these polysaccharides was the presence of relatively high levels of xylose as one of its monosaccharide constituents. Purified polysaccharide fractions were shown to possess higher biological activity than the selected standard in the complement assay. Digestion of these polysaccharides with an endo-polygalacturonase enzyme resulted in polymers with lower molecular weights as expected, but still with biological activity which exceeded that of the standard. Thus on the basis of these studies it may be suggested that immunomodulating properties probably contribute significantly to the health-promoting effects of this medicinal plant.
Studies on some biologically active natural products from Tulbaghia Alliacea
(University of the Western Cape, 2005) Maoela, Manki Sarah; Mabusela, Wilfred Thozamile; Johnson, Quinton; Dept. of Chemistry; Faculty of Science
It is believed that early humans had knowledge of how to use traditional medicinal plants, but the knowledge has been partially lost as society underwent various changes leading to new civilizations. The aim of this study was to isolate and identify natural product constituents from Tulbaghia Alliacea. There has not yet been any scientifically conducted investigation on the plant. Tulbaghia Alliacea is used for fever and colds, asthma, pulmonary tuberculosis and stomach problems.

Browsing by Author "Johnson, Quinton"

Results Per Page

Sort Options