Materials and Methods Materials Assam fresh leaves and green tea were supplied from Doi Wawee, Chiang Rai, Thailand. Standards of gallic acid, tannic acid, caffeine anhydrous and L-theanine were purchased from Sigma Chemical Co.
Materials and MethodsMaterialsAssam fresh leaves and green tea were supplied from Doi Wawee, Chiang Rai, Thailand. Standards ofgallic acid, tannic acid, caffeine anhydrous and L-theanine were purchased from Sigma Chemical Co.