Investigation of antioxidant, cytotoxic, tyrosinase inhibitory activities, and phenolic profiles of green, white, and black teas

Abstract

Abstract Objectives To determine of antioxidant, cytotoxic and tyrosinase inhibitory (TI) activities, and phenolic profiles with a new high performance liquid chromatography (HPLC) method of green, white and black teas. Methods Antioxidant activities of the teas were examined by means of scavenging of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC). The phenolic contents were investigated by means of HPLC. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the cytotoxic potential of tea extracts in cancer and normal cell lines. TI activity was investigated against diphenolase (DOPA), using kojic acid as a positive control. Results The green tea extract exhibited stronger antioxidant than white and black tea extracts. The green tea contained syringaldehyde, p-coumaric acid, benzoic acid, and quercetin. The white tea extract had the highest tyrosinase inhibitor activity. The extracts exhibited higher cytotoxic potential toward cancer cells than normal cells. The methanol extract of green tea had the highest cytotoxic potential, while the water extracts were less toxic. Conclusion The green, white, and black teas can be regarded as an important in terms of rich antioxidant, tyrosinase inhibitor, and cytotoxic activities in both the pharmaceutical and food industries.