INHIBITION OF TYROSINASE ACTIVITY BY GRAPE LEAF EXTRACT VITIS VINIFERA L. (VITACEAE)

Abstract

Arbutin and kojic acid are known as tyrosinase inhibitors commonly used in skin-lightening products. However, kojic acid causes skin sensitization, while arbutin is potentially cytotoxic. Researching natural-origin tyrosinase inhibitors is of great interest. This study aimed to evaluate the inhibitory effect of tyrosinase on grape leaf extract, Vitis vinifera L. The total extract of grape leaf was extracted by soaking 96^o alcohol, chloroform, and water. The tyrosinase inhibitory effect of the grape leaf was evaluated through the reaction with L-DOPA (3,4-dihydroxy-L-phenylalanine), from which IC50 was calculated (concentration value capable of inhibiting 50% of the tyrosinase activity of the high potency). The results showed that all of the investigated extracts had tyrosinase inhibitory activity; the green grape leaf and red grape leaf extract in 96^o alcohol showed the most obvious tyrosinase inhibitory effect. The red grape leaf extract in 96^o alcohol had the strongest activity with IC50 = 0.197 mg/mL compared with 0.072 mg/mL of kojic acid.