There are three major types of tea : green tea which is a non fermented processed tea, black tea which is processed through a fermentation and 'oolong', a partial fermented processed. When extracted, tea yields fractions of polyphenol (tannine) and nontannine. Tannine fraction demonstrates antibacterial effects whereas non tannine has no such activities. It was reported that polyphenol fraction…
A research has been conducted to determine LD-50 green tea extract on mice strain C3H by Thompson-weil methode. The result is 5.7-11.0 g/kg body weight, thus green tea extract has a low toxicity.