Human skin pigmentation is caused by the synthesis of melanin (a natural pigment) and by its distribution in skin and in hair follicles. Melanin synthesis, also called melanogenesis, is an enzymatic process that is mainly catalyzed by tyrosinase, tyrosinase-related protein 1 (TYRP1) and dopachrome tautomerase (DCT). These enzymes allow the biotransformation of tyrosine into melanin within melanocytes, and more particularly in melanosomes, which are lysosomal vesicles.
Melanin plays an essential role in skin tone evenness and in photoprotection against UV-induced DNA damages. Melanin production can be increased by some internal factors (inflammatory or hormonal reactions) or by external factors (sun exposure). This increased melanin production can cause pigmentation damages or hyperpigmentation marks (age spots, melasma, acne lesions, etc.), which require skin care treatment.
The purpose of this assay is to evaluate, via photometric determination, the capacity of compounds (molecules, active ingredients, extracts, etc.) to inhibit melanin production in a model of human epidermal melanocytes stimulated by L-tyrosine.