Antimicrobial Activities of Tea-Derived Flavonoids Against Skin \u3cem\u3eStaphylococci\u3c/em\u3e

This thesis investigates the antimicrobial activities of tea-derived flavonoids against skin Staphylococci. Four hypotheses were tested: (1) Teas that contain high polyphenolic contents possess higher antimicrobial activity against skin bacteria (e.g. S. aureus and S. epidermidis); (2) Different tea infusions and tea-derived individual catechins show differential inhibition of S. aureus and S. epidermidis; (3) Different tea infusions and tea-derived individual catechins show differential inhibition of S. aureus isolated from individuals with and without chronic atopic dermatitis; (4) EGCg, the most abundant polyphenols found in tea, possess the highest anti-staphylococcal activity. We employed multiple methods such as Folin-Ciocalteau colorimetric method, selective media, Gram staining, the Kirby-Bauer test, and Broth dilution susceptibility test to test our hypotheses. An unpaired t-test was used for statistical analyses. The study strongly supported the first hypothesis: teas with high polyphenolic contents possessed higher antimicrobial activity against skin microbes. However, the study was not able to determine differential inhibition of S. aureus and S. epidermidis, and of S. aureus isolated from volunteers with and without chronic atopic dermatitis. Finally, EGC, and not EGCg, possess the highest anti-staphylococcal activity. We discuss the implications of our findings to the potential utilization of tea-derived catechins in the management of skin microflora in health and disease