To obtain the subject inhibitor useful in the fields of medicines, cosmetics, foods, etc. by including sericin.
This tyrosinase activity inhibitor contains sericin (preferably natural sericin, which is obtained e.g. by partially hydrolyzing cocoon or silk with an acid, an alkali or an enzyme, extracting the hydrolysate, adjusting the pH of the obtained aqueous solution to 3-5 with an organic acid or an inorganic acid, adding an organic coagulant or an inorganic coagulant to deposit the sericin, filtering out the sericin and subsequently drying the sericin. The inhibitor has high safety for human bodies and high heat stability, and can advantageously be produced. The inhibitor is added to cosmetics, medicines, etc., in an amount of about 0.1-50 wt.%, preferably 0.5-5 wt.%, or to foods in an amount of 0.1-100 wt.%, preferably 0.5-50 wt.%. The inhibitor is administered as a medicine at a daily dose of e.g. about 10-100 g.
FUWA YORIKIYO
NOMURA MASAKAZU
