Sapindus saponins inhibits tyrosinase & Glutathione-induced melanin deposition by obstructing DOPA and cysteyl derivatives transformation pathways

Background/Objective: The ancient Chinese book, the Compendium of Materia Medica, records that the peel of Sapindus whitens and protects the skin. This study focused on the removal of melanin by Sapindus saponins and determining the involvement of TYR & GSH pathways. Methods: The inhibition rate of Sapindus saponins on TYR activity was measured in vitro. SOD, MDA, TYR and GSH levels in mice were measured, and the amount of melanocytes and melanin in the epidermal cells were analyzed microscopically to evaluate the scavenging effect of Sapindus saponins on melanin in vivo. The expression of TYR, TRP-1, and TRP-2 was examined by western blot. Results: Higher inhibition rate (48.69%) was achieved by PIVb and 40% TYR inhibition rate by SA and SB at 1 mg.mL-1. The SOD content could be significantly enhanced and the MDA, TYR and GSH content were decreased by PIVb, SA, and SB. The melanin in PIVb, SA, and SB-treated groups showed a trend of desalination following epidermal cell analysis. In the expression of TYR, TRP-1 and TRP-2, PIVB also played the very important role to reduce the proteins levels. Conclusions: PIVb, SA, and SB in Sapindus saponins exerted effects of melanin clearance and TRY inhibition evidenced by the amount of melanocytes and melanin in the epidermal cells, alleviation of TYR & GSH pathways-mediated melanin deposition, while PIVb had a stronger effect than SA and SB, showing potential as a good candidate for treating melanosis.