PHYTOCHEMICAL STUDY TO VALIDATE THE ETHNOBOTANICAL IMPORTANCE OF Dioscorea steriscus TUBERS OBTAINED FROM ZIMBABWE

Modern people have embraced plants as a source of useful bioactive compounds. As such, plants with medicinal properties have become essential components in human life. The purpose of this study was to investigate the phytochemical profile of the extract of Dioscorea steriscus tubers obtained from Zimbabwe. Phytochemicals were extracted from tubers of D. steriscus using aqueous acetone. UV-Visible Spectrophotometry, Fourier transform infrared (FTIR) spectrometry and highperformance liquid chromatography (HPLC) techniques were used to determine the phytochemical profile of the tuber extract. The yield of phytochemicals extracted from D. steriscus tubers was found to be 6.38 %. The presence of bioactive compounds possessing phenyl, organic hydroxyl, amine, carboxyl, carbonyl, acyl, alkyl and aromatic functional groups was confirmed using UVVisible and FTIR analysis. The presence of substantial amounts of vanillic acid and kaempferol in D. steriscus tubers was confirmed using HPLC analysis. In support of the ethnobotanical values of Dioscorea species, the study confirmed the presence of potent phytochemicals in the extract of D. steriscus tubers obtained from Zimbabwe

Antibacterial Activity of Tabernaemontana Stapfiana Britten (Apocynaceae) Extracts

Antibacterial and phytochemical screening of methanolic, sequential extracts (hexane, dichloromethane, ethyl acetate and methanol) and alkaloid rich fractions of Tabernaemontana stapfiana Britten was carried out. The phytochemical screening showed the presence of alkaloids, flavonoids, coumarins, tannins and saponins that have been associated with antimicrobial activity. The stem and root bark methanolic extracts showed good activity against the bacterial strains used including the multiple drug resistant Staphylococcus aureus strain with minimum inhibitory concentrations ranging from 15.6 to 500 µg/ml and minimum bactericidal concentrations ranging from 31.25 to 500 µg/ml. The sequential extracts of the root and stem bark had high antimicrobial activity with minimum inhibitory concentrations (MICs) ranging between 3.9 and 250 µg/ml and minimum bactericidal concentrations (MBCs) ranging between 7.8 and 500 µg/ml against the tested microorganisms. The dichloromethane extract of the alkaloid rich fractions however exhibited reduced antibacterial activities as compared to methanol and sequential extracts but the dichloromethane:methanol (4:1) mixture showed high activity with MICs ranging between 15.6 and 250 µg/ml. These antibacterial efficacy studies suggest that Tabernaemontana stapfiana Britten could be a source of antibacterial agents