The depigmenting effect and mechanism S of Kuwanon O and Sanggenon T from the roots of Morus australis

Abstract

Kuwanon O and sanggenon T, two resorcinol-type polyphenols from the root extract of Morus australis, were found to reveal significant depigmenting effects in both murine b16f10 and melan-a cell lines. But their depigmenting mechanisms are slightly different in two cell systems. In b16 cells, kuwanon O and sanggenon T, together with other two phenolics, induced post-transcriptional degradations of MITF without suppressing its mRNA expression, leading to significant decreases of TRP-1 and TRP-2 production. While in melan-a cells, the levels of tyrosinase families were suppressed via MITF downregulation at both transcription and translation level by them, with kuwanon O inducing the greatest suppression. Further evaluations in artificial skin model demonstrated the outstanding depigmenting effects of kuwanon O and sanggenon T. Meanwhile, according to the structure-activity relationship study of theses compounds, to screen or synthesize resorcinol flavonone derivatives with isoprenyl group in the Diels-Alder substituent might be a new direction for the search of potent hypopigmenting agents.