Skin whitening and toning is an important segment of the anti-aging skin care industry. Skin whitening refers to the process by which discoloration, such as “age spots,” is reduced or removed. Today, skin toning products are available in the form of creams, pills, soaps or lotions. The mechanism of permanent whitening is usually by the melanin pigmentation inhibition by enzymes or reducing agents.
- Melanin pigmentation inhibition: cellular investigation
Melanin is essential in protecting human skin against UV radiation, but overproduction of melanin is also a major consequence of UV damage and aging process that induces pigmentation disorders such as freckles and senile lentigo (i.e., age spots). Excessive melanin has also been viewed as melanoma precursor. Melanin inhibition is a desirable effect sought in various fronts of cosmetic industry to achieve skin whitening, lessen aging appearance, and prevent melanoma.
Cellular melanin inhibition analysis evaluates the impact of a test material on melanin production in melanocytes (melanin-producing cells). The degree of melanin production inhibition in melanocytes treated with and without test materials is assessed and compared to determine the pigmentation inhibition function of the material.
- Tyrosinase Inhibition Analysis
The tyrosinase inhibition assay assesses a material’s effect on tyrosinase reduction and skin-whitening. The color of mammalian skin is determined by many factors, one of which is the production and distribution of melanin pigmentation. In melanin biosynthesis process, tyrosinase is the key enzyme that catalyzes the first step of melanogenesis. Substantial studies have shown that melanin reduction and skin-whitening can be achieved, at least partially, by deactivating of tyrosinase. Therefore, tyrosinase inhibitors have become increasingly important in cosmetic and medicinal products used in the prevention of hyperpigmentaion. Many compounds, such as hydroquinone, kojic acid, and benzaldehyde-O-alkyloximes have been reported as tyrosinase inhibitors. Tyrosinase inhibition assay assesses the tyrosinase inhibition potential of a test material. The maximum degree of inhibition and concentration used will be reported. EC50 (effective concentration at 50% of maximal inhibition) will also be reported if available.