Abstract
M.Tech. (Biotechnology)
Globally medicinal plants play a very significant role in health-promotion and the reduction of disease burden in our communities. Over 80,000 species of such plants and their secondary metabolites including tannins, terpenoids, alkaloids, terpenes, phenolic compounds, glycosides and flavonoids have demonstrated excellent antimicrobial properties in vitro. Phytochemicals constitute over 25 – 50% of all pharmaceutical drugs prescribed globally. In addition, most phytochemicals have antioxidant and anti-carcinogenic properties which are beneficial to humans. Furthermore, the vitamins and other substances in plants play a significant role in protecting the human body against diabetes and heart diseases. Many plants have been the source of many pharmacologically active principles that are now used in medicine, for example, vincristine and vinblastine found in Catharanthus roseus are prescribed for hypertension and can also act as chemotherapeutic drugs against leukemia, Hodgkin’s disease, etc. Nature has provided us with a variety of very useful and important compounds but these have somehow been over looked in recent times and more research attention needs to be given to natural products to explore their many positive therapeutic attributes which is the purpose of this study on Rhoicissus tomentosa. R. tomentosa is a medicinal plant indigenous to Southern Africa. It is a vigorous, evergreen tendril climber with ornamental, vine-like leaves and bunches of purple grape-like fruits. The plant is mainly used by traditional healers to treat fertility related ailments. The rhizomes Rhoicissus tomentosa were analyzed in this study. The dry powdered plant material was first screened for the presence of phytochemicals and the findings revealed the presence of alkaloids, flavonoids, saponins, steroids, reducing sugars and tannins. The ground plant material was subsequently extracted using 100% ethyl acetate and methanol/chloroform (1:1) and pressurized hot water extraction (PHWE) technique. The extracts were analyzed for antimicrobial activity against 14 common human bacterial pathogens using the disc diffusion method and the micro titer plate method and the findings revealed that the extracts showed moderate to high inhibitory activity against most of the test organisms. While different bacterial species were investigated, the most susceptible ones to the rhizome organic solvent extracts were Staphylococcus aureus (MIC 0.063 mg/mL) and Bacillus subtilis (MIC 0.125 mg/mL) and the ones most susceptible to the PHWE extract were Staphylococcus aureus (MIC 1.0 mg/mL) and...