In living organisms, melanin can be formed by enzymatic reaction of tyrosinase with certain substrates such as L-3,4-dihydroxyphenylalanine (L-dopa). The objective of this study was to determine the inhibitory effects of seed and peel ethanol extracts from kyoho grape and red globe grape on tyrosinase activity. Ethanol extracts of grape cells derived from Vitis vinifera L.Gamayreaux callus and red globe grape seed were also tested to evaluate the potential of using grape as the source for skin care. The activity of tyrosinase was defined as the reactive rate to hydrolyze L-dopa into dopachrome, which can be detected at OD475. The results indicated that both the extracts from grape seed and peel showed inhibitory effect on the activity of mushroom tyrosinase. The inhibitory influence was not significant between the extracts from kyoho grape seed and peel; however, the influence was significantly higher in grape seed extract than grape peel extract in red globe grape. Therefore, ethanol extract from kyoho grape was considered to have higher inhibitory effect toward mushroom tyrosinase than ethanol extract from red globe grape. Ethanol extracts from the grape cells showed slight influence on mushroom tyrosinase activity, the inhibition rate was only 9-31%. Analysis of enzyme kinetics revealed that all the extracts showed mixed-type inhibition toward mushroom tyrosinase activity.
