Brassica rapa hairy root extracts promote skin depigmentation by modulating melanin production and distribution

Skin whitening products, used for ages by Asian people for cultural and esthetic purposes, are very popular nowadays in Western countries as well, where the need to inhibit skin spots after sun exposure has become not only a cosmetic but also a health-related issue. Thus, the development of effective and safe depigmenting agents derived from natural products gets continuous attention by cosmetic brands and consumers.

The aim of this study was to determine the effects of two preparations, obtained from the hairy root cultures of the species Brassica rapa, on melanogenesis and the expression of the extracellular matrix proteins involved in a correct pigment distribution.

The two preparations, obtained by water-ethanol extraction and by digestion of cell-wall glycoproteins of the root cells, were chemically characterized and tested on skin cell cultures and on human skin explants to investigate on their dermatological activities.

Both the extracts were able to decrease melanin synthesis pathway in melanocytes and modulate the expression of genes involved in melanin distribution. One of the extracts was also effective in inducing the expression of laminin-5 and collagen IV, involved into the maintenance of tissue integrity. The two extracts, when tested together on human skin explants, demonstrated a good synergic hypopigmenting activity.

Taken together, the results indicate that the extracts from B. rapa root cultures can be employed as cosmetic active ingredients in skin whitening products and as potential therapeutic agents for treating pigmentation disorders.