Browsing by Author "Mabusela, Wilfred"

Now showing 1 - 6 of 6
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    Medicinal plant use in the Dwarsrivier Valley, Stellenbosch
    (University of the Western Cape, 2013) Arendse, Melissa Liezel; Weitz, F.M; Mabusela, Wilfred
    Plants have been used as medicine since antiquity. Passed on by word of mouth through the generations, this oral tradition is at risk of becoming extinct due to westernization and lack of documentation. The community in the Dwarsrivier valley is one such community who continues to use these medicinal plant remedies on a daily basis. However, these remedies are at risk of becoming extinct due to a lack of interest from the younger generation. The objectives of the study were to identify the plants used for medicinal purposes, provide an inventory and select several plants for elemental analysis and phytochemical screening. Individuals were selected based on their ethnobotanical knowledge and agreed to participate in the study. Over 40 individuals were interviewed from the four communities; Pniel, Lanquedoc, Meerlust and Kylemore. Of the 40 participants interviewed, 25 participants agreed to complete questionnaires. The survey yielded 53 plant species belonging to 31 families of which only 24 are indigenous. Although more exotic plants are used compared to indigenous, the indigenous plants were the more popular choice for medicinal use. Most plants belonged to the Lamiaceae family followed by Asteraceae, Alliaceae, Apiaceae and Rosaceae. The most popular plants in terms of ranking are Agathosma crenulata followed by Artemisia afra and Helichrysum petiolare. This is the first report of Protea cynaroides, Cissus rhombifolia, Canna spp. and Dilatris viscosa used for medicinal purposes.
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    Phytochemical and biological studies of extracts from selected South African indigenous medicinal plants: Bulbine and helichrysum species
    (University of the Western Cape, 2022) Makhaba, Masixole; Mabusela, Wilfred
    Medicinal plants from the Asteraceae and Asphodelaceae families are among the most widely recognized in South African traditional medicine for managing diabetes mellitus. Diabetes mellitus is a universal epidemic, yet there are no permanent treatments for this disease. Three South African indigenous medicinal plants, namely Helichrysum petiolare (Asteraceae), H. splendidum (Asteraceae), and Bulbine frutescens (Asphodelaceae) which have reported ethnobotanical usage in the management of diabetes were investigated in this study. Despite the increasing scientific evidence using the extracts that supports the ethnobotanical claims of these medicinal plants, the active metabolites, or their mechanism of action is not considered.
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    Phytochemical synthesis and antimicrobial application of gold nanoparticles from extract of Artemisia annua
    (University of the Western Cape, 2023) Ntamo, Akhona; Mabusela, Wilfred
    Metallic nanoparticles synthesized using chemical methods and physical methods are considered toxic to the environment due to the use of toxic solvents. The biological synthesis methods such as the use of plant extracts are of interest because they are biocompatible, environmentally friendly, and relatively cost-effective. Gold nanoparticles (AuNPs) have been synthesized using plant aqueous extract as a reducing agent and have shown selective antibacterial activity and good antifungal properties. This study used an aqueous extract of Artemisia annua to synthesize biogenic AuNPs and tested them for antimicrobial activity. The A.annua-AuNPs were characterized using Ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), and High-resolution transmission electron microscopy (HRTEM).
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    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.
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    Secondary metabolites of the uromycladium tepperianum McAlpine epiphytic fungus
    (University of the Western Cape, 2021) Correia, Kelly Luana Viegas; Mabusela, Wilfred
    Research on natural products and medicinal plants has been conducted more with each passing year due to the great interest in isolating bioactive compounds and secondary metabolites from natural products such as plants, fungi, and many other naturally occurring products. To our knowledge, the Uromycladium tepperianum MacAlpine fungus has not been studied in depth before thus, its organic characterization was unknown, but related species have been studied, and these have shown compounds that may be used as medicine and as health benefits. Crude and macerated extracts of the Uromycladium tepperianum fungus have been fractionized using various chromatographic techniques such as solvent-solvent extraction followed by dry column chromatography to achieve the required separations.
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    Studies of chemical constituents on the aerial parts of pelargoniumcapitatum
    (University of the Western Cape, 2017) Mthembu, Zandile Lorraine; Mabusela, Wilfred
    Pelargonium capitatum is a plant that is popular in essential oils. The isolated essential oil constituents from the flowers and leaves of the plant were obtained by hydrodistillation followed by GC-MS analysis. The following essential constituents were obtained in abundance from flowers and leaves 8, 11-octadecadienoic acid and citronellol, caryophyllen, α-cubebene, copaene, azulene, pentacosane, 9, 12- octadecadienoic acid. Crude extracts from Pelargonium capitatum were fractionated through various chromatographic techniques in order to achieve satisfactory separations. Four compounds were characterized and the structural elucidation were unambiguously confirmed by spectroscopic methods including one and two-dimensional nuclear magnetic resonance and high resolution mass spectroscopy. The compounds were isolated from the ethyl acetate (2) and hexane (2) extracts, respectively. The four isolates were identified as quercetin, quercetin xylopyranoside, β-sitosterol and undecaprenol. The isolate and the different extracts were tested for cytotoxicity using brine shrimp lethality test. The results showed that quercetin and the extracts were active with hexane extract showed the highest cytotoxicity level of 1.5μg/ml. To the best of our knowledge quercetin xylopyranoside, β-sitesterol and undecaprenol compounds are reported for the first time from Pelargonium capitatum.