Inhibitory effects of phenylpropionamides from the hemp seed husk on tyrosinase.

Tyrosinase is an enzyme involved in melanin production. To identify inhibitors of this enzyme in natural products, extracts and fractions of hemp seed husk were screened for tyrosinase inhibition. Phenylpropionamides 1-9, which were isolated from the ethyl acetate fraction, had inhibitory effects; compounds 3 and 4 had the greatest inhibitory effects. Cannabisin A (3) was a non-competitive and cannabisin B (4) was a competitive inhibitor. The binding sites and interactions of each inhibitor on tyrosinase were calculated by computational chemistry. Potential inhibitor 3 decreased the melanin content and tyrosinase activity in B16F10 melanoma cells. Therefore, cannabisin A (3) has potential as a tyrosinase inhibitor.