Anti-melanogenic compounds in Rubus croceacanthus

Abstract

BACKGROUND: Rubus croceacanthus is a wild berry grown in Okinawa, Japan, and is consumed fresh because of its sweetness. In addition, this fruit is processed into jam and jelly, and used in food such as doughnuts in Okinawa. In our anti-melanogenesis screening program, the methanol extract of R. croceacanthus showed the whitening activity on B16 mouse melanoma cells. OBJECTIVE: The aim of this study was to evaluate anti-melanogenetic activity of the extract of R. croceacanthus and find the active components in it. METHOD: The anti-melanogenetic activity was examined using B16 cells. To reveal the mechanism underlying the anti-melanogenic activity, the inhibition of tyrosinase which is the key enzyme in melanogenesis was measured. Furthermore, we analyzed the constituents of R. croceacanthus to investigate the active compounds. RESULTS: The extract of R. croceacanthus had an anti-melanogenic effect in B16 cells. We found that this effect was caused by cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside due to inhibit tyrosinase activity, resulting in decreasing melanin content in B16 cells. We also identified two ellagitannins, lambertianin C and sanguiin H-6, which may contribute to the anti-melanogenic effect. CONCLUSIONS: The fruit of R. croceacanthus has the anti-melanogenic activity and potential to be utilized as a skin-whitening agent.