Inhibitory and Eliminating Effects of Yeast-extracted Melanoston on Pigmentation and Preexisting Pigmentation, Respectively / 대한피부과학회지

BACKGROUND: Melanoston is a new melanogenesis inhibitor isolated from yeast. However, little is known about the mechanism of this agent in melanogenesis and also its clinical effectiveness on hyperpigmented lesions. OBJECTIVE: The purpose of this study was to examine the inhibitory effect of melanoston on in vivo activity of tyrosinase. METHODS: We assessed tyrosinase activity, which participates in the synthesis of melanin pigment and resides in melanocytes of guinea pig's epidermis, using immunohistochemical methods after application of 0.1% and 0.01% melanoston on the skin of guinea pigs. We also conducted an 8-week clinical trial on 30 women volunteers to determine the clinical efficacy and safety of melanoston. Participants were instructed to apply melanoston and vehicle on 7 small areas of skin on both forearms for 8 weeks, before and after UVB exposure, and they were examined daily for the first week, then weekly thereafter. RESULTS: The lowest level of tyrosinase activity was observed at the 3rd week after application of 0.1% and 0.01% melanoston on the skin of guinea pigs, and melanoston had a relatively strong inhibitory effect on tyrosinase, as compared with vehicle and arbutin. Differences in the degree of pigmentation between areas treated with 0.5% melanoston and application of vehicle only, and between before and after UVB exposure were considered to be significant (p<0.001, on each time). CONCLUSION: We conclude that melanoston has an inhibitory effect on melanogenesis and some eliminating effect on preexisting pigmentation.

Immunohistochemical and Electron Microscopic Study on the Depigmentation Effect of Melanoston / 체질인류학회지

The present study was designed to address whether melanoston which was extracted from yeast was able to induce depigmentation of the skin in guinea pigs. The activity of tyrosinase which participates in the synthesis of melanin pigment residing in melanocytes of guinea pig's epidermis was assessed using immunohistochemical staining methods with anti-tyrosinase antibody. To determine whether melanoston affects the processes of melanin synthesis in melanosome of melanocytes, melanoston-applied skin was examined by electron microscopy following immunogold tagging methods. We obtained results as follows: 1. The activity of tyrosinase was the lowest 3 weeks after application of 0.1 and 0.01% melanoston on the skin of guinea pigs. 2. The frequency of immunogold particles distributed in melanocytes and keratinocytes was lowest 3-4 weeks after application of 0.5 and 0.1% melanoston. Thus, these results suggest that melanoston has a potential to inhibit synthesis and distribution of melanin in the epidermis.