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”.
