Abstract: Objective To evaluate the inhibitory action of ethanolic extracts from 196 kinds of Chinese herbs on tyrosinase.Methods Tyrosinase inhibitory activity was determined by the dopachrome method using L-DOPA as the substrate and the amount of dopachrome in the reaction mixture was measured by spectrophotometer.Results Nine Chinese crude extracts[Glycyrrhiza glabra L.,Melaphis chinensis(Bell.)Baker,Cryptotympana atrata Fabricius,Paeonia suffruticosa Andr.,Sophora flavescens Ait.,Spirea thunbegii Sieb.et Bl.,Xanthium sibiricum Patr.,Morus alba L.,Rheum palmatum L.] showed potent inhibitory action on tyrosi-nase compared with positive control arbutin(1mmol/L,P<0.01),and 11 Chinese extracts[Artemisia anomala S.Moore,Hemistepta lyrata Bunge,Lycum chinensis Mill.,Dipsacus asper Wall.,Gastrodia elata Bl.,Forsythia suspensa(Thunb.)Vahl.,Acer ginnala Maxim.,Acer ginnala Maxim.,Glycyrrhiza uralensis Fisch.,Patrinia sabiosaefolia Fisch.,Buxus sinica(Rehd.et Wils.)Ching,Lonicera japonica Thunb.] showed no difference compared with positive control arbutin(1mmol/L,P>0.05).Conclusion The results suggest that 20 kinds of crude extracts from Chinese herbs[Glycyrrhiza glabra L.,Melaphis chinensis(Bell.)Baker,Cryptotympana atrata Fabricius,Paeonia suffruticosa Andr.,Sophora flavescens Ait.,Spirea thunbegii Sieb.et Bl.,Xanthium sibiricum Patr.,Morus alba L.,Rheum palmatum L.,Artemisia anomala S.Moore,Hemistepta lyrata Bunge,Lycium chinensis Mill.,Dipsacus asper wall.,Gastrodia elata Bl.,Forsythia suspensa(Thunb.)Vahl.,Acer gin-nala Maxim.,Glycyrrhiza uralensis Fisch,Patrinia sabiosaefolia Fisch.,Buxus sinica(Rehd.et Wils.)Ching,Lonicera japonica Thunb.,] inhibit tyrosinase and may be used as depigmentaty agents for pigmentary skin diseases caused by abnormal tyrosinase activity.

Key words: Drugs, Chinese herbal, Monophenol monooxygenase, Skin pigmentation