Polyphenol Content,Antioxidative and Anti-α-amylase Activities of Four Tea Extracts

In order to provide scientific basis for the health benefits and guidance for the industrial development of Xinhui Ganpu tea,the composition and biologic function of Xinhui Ganpu tea with Pu'er,Maojian,and Dianhong were carried out in this study.The polyphenol contents were determined by folin-phenol colorimetry method using gallic acid as a reference.The DPPH and ABTS radical scavenging activities of ethanol extracts of four kinds of tea were determined by spectrophotometry method,evaluating the antioxidant activity of the four samples in vitro.Using acarbose as a positive control,the inhibitory effect of tea ethanol extract on the activity ofα-amylase was measured by spectrophotometry,and the hypoglycemic activity of four teas was evaluated initially.Results showed that the polyphenol contents of four samples from the highest to the lowest were Maojian(369.5mg/g),Dianhong(237.0 mg/g),Pu'er(200.5 mg/g) and Ganpu(194.8 mg/g).The DPPH radicals scavenging activities of four samples from the strongest to the weakest were Maojian(IC₅₀=4μg/mL),Dianhong(IC₅₀=6μg/mL),Pu'er(IC₅₀=15μg/mL) and Ganpu(IC₅₀=18μg/mL).The ABTS radicals scavenging activities of four samples from the strongest to the weakest were Maojian(IC₅₀=2μg/mL),Dianhong(IC₅₀==3μg/mL),Pu'er and Ganpu(IC₅₀=7μg/mL).Using acarbose as positive control,four samples had obvious effect on inhibitingα-amylase,and they were Maojian(IC₅₀=12.9 mg/mL),Dianhong(IC₅₀=19.0 mg/mL),Pu'er(IC₅₀=21.0 mg/mL) and Ganpu(IC₅₀=24.9 mg/mL).Four samples have good anti-oxidative andα-amylase inhibitory activities,and the two physiological activities are positively related to polyphenol content.Four samples have great potential in the research and development of functional food.