Plants as a Promising Reservoir of Tyrosinase Inhibitors

The process of melanogenesis that takes place in the melanocytes of the epidermis, leads to hyperpigmentation. The biosynthetic pathway for the production of melanin involves the enzyme tyrosinase that has been an attractive target for cosmaceutical research. Numerous synthetic, semisynthetic and natural, especially plant-based, inhibitors of tyrosinase have been reported in the literature. In plants, the secondary metabolites like flavonoids, chalcones, stilbenes, tannins, hydroquinone and kojic acid, etc., have been shown to possess anti-tyrosinase activity. In the current review, we have covered the progress in this sphere that would be useful for not only further mechanistic investigations but also for the optimization of the structure of the metabolites for improved activity and selectivity. Thus, the review presents a comprehensive report on tyrosinase inhibitors of plant origin reported in the extract form or as isolated compounds. A huge gap has been found between research and industry due to inconsistent pursual of potent plant-based extracts. There is a need to completely evaluate the extracts for structure optimization using molecular docking and evaluation of the safety in order to benefit the industry with non-toxic biological friendly products through in vivo and ex vivo optimization.