The present study aim to evaluate the chemical constituents and biological activities of the commercially available green tea sample. High performance liquid chromatography equipped with UV detector was used to quantify the caffeine content in the tea extract. The caffeine content in the green tea sample ranges from 7.18 to 22.90 mg/g DW. Whereas total phenolic, total flavonoids contents varied from 9.19 to 11.41 mg GAE/g DW, 7.03 to 9.25 mg/g DW, respectively. Further, analyzed green tea extract revealed the range of in vitro antioxidant activities measured by DPPH with IC50 values from 53.46 to 64.54 μg/ml. Furthermore, evaluated tea extract were found to be potent alpha amylase inhibitors.
Black tea, green tea, HPLC, caffeine, polyphenols, flavonoids