Tyrosinase Inhibitors from Natural and Synthetic Sources as Skin-lightening Agents

Melanin, a major pigment in mammalian skin, is known to protect the skin against harmful effects of ultraviolet (UV) irradiation, oxidative stress, and DNA damage. The accumulation or over production of melanin can cause esthetic problem as well as serious diseases related to hyperpigmentation. Tyrosinase, is a copper-containing enzyme which catalyses two rate–limiting reactions in melanogenesis: the hydroxylation of monophenols to o-diphenols, and the oxidation of o-diphenols to o-quinones. Therefore, inhibition of tyrosinase, is the prime target for researchers to regulate melanin production. Tyrosinase inhibitors with high efficacy and less adverse side effects, have huge demand in cosmetic and medicinal industries due to their preventive effect on pigmentation disorders as well as skin-whitening effect. In this review, we focus on the recent advances of tyrosinase inhibitors from all sources, including synthesized compounds, natural products, virtual screening and structure-based molecular docking studies; by categorized into two parts, mushroom and human tyrosinase inhibitors.