STUDIES OF CUTICLE DRUGS FROM NATURAL SOURCES .4. INHIBITORY EFFECTS OF SOME ARCTOSTAPHYLOS PLANTS ON MELANIN BIOSYNTHESIS

The inhibitory effect of 50% ethanol extracts obtained from the leaves of six Arctostaphylos plants (A. patula, A. viscida, A. canescens, A. columbiana, A. nevadensis and A. uva-ursi) (Ericaceae) was tested on melanin biosynthesis. Among them, the extracts of A. patula and A. vis cida showed potent inhibition against tyrosinase. The two extracts not only inhibited the production of melanin from dopachrome by autoxidat ion, but exhibited SOD (superoxide dismutase)-like activity and had a moderate absorbance in the UV-B area. These results suggest that the l eaves of Arctostaphylos plants, especially A. patula and A. viscida ca n be applied to a whitening agent for the skin.