Melanin is a pigment common to a variety of animals, plants and microorganisms. In humans, it resides in the skin, the hair and the iris as well as the retina of the eye. Melanin gives the skin its colour and protects it against the damaging effects of UV sun radiation.
However, in some cases the regular melanin synthesis gets disturbed, causing irregularities in the skin distribution. Possible phenotypic outcomes are an uneven skin tone and local hyperpigmentations caused by an increased melanin production in the form of birthmarks, freckles, age spots, melasma or post-inflammatory hyperpigmentation. Causes for this increased local melanin synthesis may be excessive sun exposure, hormonal changes during pregnancy or due to oral contraceptives, and skin inflammation. The relevance of cosmetic products minimising these local irregularities in the epidermis lies in the perception of consumers and their desire for a more regular skin tone, which was also shown to be perceived as a sign of ageing.1
For many centuries now and in many different cultures a more uniform skin tone without local irregularities in melanin distribution has been a concept of ideal beauty. Cosmetic treatments of the skin were already performed in third century Japan, where women used cloth bags containing rice bran to polish and whiten their skin.2 Even in rural Japan, female rice farmers used the remaining water from cleaning the rice, called Yu-Su-Ru, for washing their hair3 and skin. Today we know that a major bioactive substance responsible for this reported lightening effect of rice bran is phytic acid.
A new naturally-derived lightening agent
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