PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL STUDIES OF GREEN, ORTHODOX AND BLACK KENYAN TEA

Abstract

This study evaluated the phytochemical and antimicrobial

activities of green, orthodox and black Kenyan tea onfive microorganisms with the possible purpose of determining their pharmacological significance/ medicinal value.The in vitro antimicrobial activities of three extracts of tea was done using humanly isolated strains ofStaphylococcus aureus, Salmonella typhimurium, Escherichia coli, Streptococcus faecalis, and, Candida albicans.The assays were carried out by agar well diffusion. Streptomycin and cefadroxil served as the control drugs. Theaqueous tea extract were found to be more effective against the tested bacteria than fungi at high concentration.Orthodox tea had no antimicrobial activity against Salmonella typhimurium and Candida albicans. Extracts ofgreen tea, orthodox and black tea showed activity on Staphylococcus aureus at concentrations ranging from 100-150mgml-1 having comparable diameters of zones of inhibition of 10.0±0.0 20.0±0.0, 4±0.2- 8.0 ±0.0 and 6.5±0.0,7.4 ±0.2 respectively. The first two tea extracts demonstrated activities on Escherichia coli and Streptococcusfaecalis at concentrations ranging from 100-400mgml-1 with relatively close diameters of zones of inhibition. Onlyblack tea inhibition the growth Candida albicans at the MIC of 100mgml-1 whereas, Salmonella typhimurium wasinhibited by green tea and black tea extracts at the MIC of 200mgml-1. Black tea also inhibited growth of E. Coli,but at concentration ranging from 200-400mgml-1 with diameter zones of inhibition from 3.5±0.0- 4.0±0.0 and aMIC of 150mgml-1. Phytoscreening of the three extracts of tea showed the presence of cardiacglycosides,alkaloids, saponins, flavanoids, terpenes and tannins.