The efficacy of tea extracts in inhibition of two strains of Staphylococcus aureus, and a preliminary phytochemical analysis

Abstract

Tea is a hot water infusion of the leaves from the Camellia sinensis. It is the most widely consumed drink worldwide. There are many different types of tea and among the most common types are black tea and green tea. In Sri Lanka, apart from these two types, people consume so called “factory discarded tea”. The objective of this study was to screen the antibacterial effects of black, green and “factory discarded tea” against two Staphylococcus aureus strains. These strains are human pathogenic and antibiotic-resistant bacteria. The other objective was to characterization of chemical components which are responsible for antibacterial activity. Hot water infusions of black, green and “factory discarded tea” were used. Hot water infusion of “factory discarded tea” contained alkaloids, steroids and flavanoids. However, hot water infusion of both black and green tea showed the presence of cardiac glucosides as well apart from the above. None of the samples contained saponins. For the analysis of active ingredients of each tea, Soxhlet extracts were prepared using hexane, dichloromethane, ethyl acetate, methanol, and water as solvents. Phytochemical screening of Soxhlet extracts of “factory discarded tea”, black and green tea in methanol showed the presence of alkaloids, steroids, cardiac glucosides and flavanoids. According to the preliminary screening of antibacterial activity against the two bacteria tested showed the highest inhibition for green tea followed by the black tea. The least inhibition was shown by the “factory discarded tea”.