Aflawless complexion is without doubt a desirable attribute across many cultures. Especially in Asia, the obsession with whiter skin has greatly evolved, shifting from beauty to a sign of social class and representing sophistication, innocence, femininity and higher social stature. To achieve this lightening effect, product developers leverage active ingredients such as vitamin C, or L-ascorbic acid, which is not only a septicemia inhibitor, but also an effective reducing agent that can momentarily retard the melanin-biosynthesis pathway in skin. Vitamin C is also known to protect skin from ultraviolet B (UVB) damage and enhance collagen synthesis, therefore it is widely used in cosmetics as a whitening ingredient, especially in Asia. Due to its instability, however, several derivatives of it have been developed for cosmetic application; for example, ethyl ascorbic acid, magnesium L-ascorbyl-2-phosphate, L-ascorbic acid 2-glucoside and sodium ascorbyl phosphate.
3-O-Ethyl ascorbic acid, shown in Figure 1, is a derivative consisting of vitamin C with an ethyl group bound to the third carbon position. With its reducing ability, this structure helps to increase the stability of the compound when used in cosmetic products. The present article explores the function and efficacy of this material to determine its mechanism of action and potential for application against melanin biosynthesis.
To understand the potential mechanisms of skin lightening, it is helpful to review the melanin biosynthesis process. In brief, after exposure to sunlight, melanin is produced by melanocytes through melanogensis, a biological process that helps to protect human DNA from harmful UV rays. The amount of melanin produced by melanocytes embedded in the basal layer of the epidermis defines the skin color, but it is interesting to note that all individuals from different countries and climates tend to have the same number of melanocytes.