Antioxidant and Cytotoxic Effects of Aqueous Extract of Iranian Green Tea (Camellia sinensis L.)

Green tea, a common beverage, has several pharmacological effects. In this study, the amounts of phenoliccompounds and epigallocatechin (EGC) were determined in an aqueous extract of green tea planted in Lahijan (acity in the north of Iran) by Folin-Ciocalteu method and HPLC, respectively. Antioxidant activity of the extract wasmeasured by DPPH and the FRAP assays. Furthermore, its cytotoxic effect was investigated on HT-29 (colorectalcancer) and 3T3 (normal fibroblast) cell lines, after 24 and 48 h treatment by MTT method. Trypan blue dye exclusionmeasurement was also done on the HT-29 cells treated with the extract. The results have shown that each gram ofthe dried extract contains 283.6 ± 10.57 mg total phenolic content and 88.44 ± 1.85 mg EGC. The antioxidant activityof the extract measured by DPPH showed an EC50 value of 84.31 ± 4.14 µg/ml. In the FRAP test, the equivalentamount of Iron (Fe) was 4.45 mmol per g of the dried extract. The extract showed toxicity on the HT-29 cell linewith an IC50 value of 82.45 ± 18.39 µg/ml after 48 h treatment. The data were confirmed by trypan blue dye exclusiontest. Based on the results, adding green tea to the diet may have many health benefits.