AN ALTERNATIVE APPROACH TO DEPIGMENTATION BY SOYBEAN EXTRACT VIA INHIBITION OF THE PAR-2 PATHWAY.

The protease-activated receptor 2, expressed on keratinocytes but not on melanocytes, has been ascribed functional importance in the regulation of pigmentation by phagocytosis of melanosomes. Inhibition of protease-activated receptor 2 activation by synthetic serine protease inhibitors requires keratinocyte-melanocyte contact and results in depigmentation of the dark skinned Yucatan swine, suggesting a new class of depigmenting mechanism and agents. We therefore examined natural agents that could exert their effect via the protease-activated receptor 2 pathway. Here we show that soymilk and the soybean-derived serine protease inhibitors, soybean trypsin inhibitor and Bowman-Birk inhibitor inhibit protease-activated receptor 2 cleavage, affect cytoskeletal and cell surface organization, and reduce keratinocyte phagocytosis. The depigmenting activity of these agents and their capability to prevent ultraviolet-induced pigmentation are demonstrated both in vitro and in vivo. These results imply that inhibition of the protease-activated receptor 2 pathway by soymilk may be used as a natural alternative to skin lightening.

Alternative, BBI, DOPA, Depigmentation, Epidermal equivalents, MelanoDerm, Melanocytes, Melanosomes, PAR-2, Phagocytosis, Protease-activated receptor 2, STI, Skin lightening, Soy milk, Soybean extract, TRP-1, TRP-2, UVB