Antioxidant and antibacterial activities of various extracts and fractions of fresh tea leaves and green tea

Abstract

Polyphenol content, polyphenol yield, antioxidant and antibacterial activities of methanol, ethanol and water extracts and their crude, ethyl acetate and water fractions derived from fresh tea leaves (FTL) and green tea (GT) were evaluated. Ethyl acetate fractions of ethanolic extracts contained the highest polyphenol content in FTL and GT samples (680.2 and 560.8 mg gallic acid equivalent g-1 dry extract, respectively). For each of 3 extraction solvents, ethyl acetate fractions always had highest polyphenol content, for both teas. Ethyl acetate fractions of water extracts of FTL and GT had highest antioxidant activity (80.8 and 78.6 g ascorbic acid 100g-1 dry extract). A rather high correlation coefficient (R2 = 0.9376 for FTL and 0.9783 for GT) was obtained between antioxidant activity to total polyphenol content for both tea. Ethyl acetate fractions of extracts showed antibacterial activity on S. aureus and B. cereus. Crude extract of FTL were also effective on S. aureus.