Anti-melanogenic activity of steamed and freeze-dried mature silkworm powder

Silkworms, Bombyx mori L., have been traditionally used as an oriental medicine to manage diverse pathological conditions including dermatological problems in East Asia, in addition to the use of their cocoons for making fabrics. The mature silkworms of B. mori have recently been regarded as a potential health supplement due to gaining their edibility for humans by a newly-developed steaming method. Therefore, the present study was conducted to investigate the effects of steamed and freeze-dried mature silkworm powder (SMSP) on skin pigmentation and melanogenesis. For elucidating the hypo-pigmenting activity, lightness of a designated site on the murine dorsal skin was measured in vivo. During the experiment, hyper-pigmentation was induced on the skin by cumulative exposure to ultraviolet B (UVB) irradiation. At the end of the experiment, melanin production on the skin was visualized by Fontana-Masson staining. Orally administered SMSP significantly and dose-dependently reduced abnormal pigmentation caused by UVB on the murine dorsal skin. SMSP also showed a potential antimelanogenic efficacy in modulating UVB-induced melanogenesis. Taken together, SMSP was identified for the first time as a potential candidate for a novel anti-melanogenic agent, which showed hypo-pigmenting efficacy against UVB-induced melanogenesis in vivo when administered orally.