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Potent Inhibitors of Tyrosinase Activity and Melanin Biosynthesis from Rheum officinale

1995; Thieme Medical Publishers (Germany); Volume: 61; Issue: 05 Linguagem: Inglês

10.1055/s-2006-958129

1439-0221

Koichi Iida, Koji Hase, Kenji Shimomura, Syu Sudo, Shigetoshi KADOTA, Tsuneo Namba,

Phytochemicals and Antioxidant Activities

Thirty-three crude drug extracts were screened for their tyrosinase inhibitory activity. Among them, the acetone extract of the rhizomes of Rheum officinale Baillon showed the strongest inhibitory activity. Tyrosinase inhibitory activity-guided fractionation and chemical analysis led to the isolation of two potent compounds, 3,4',5-trihydroxystilbene-4'-O-beta-D-(2"-O-galloyl)glucopyr anoside (1) and 3,4',5-trihydroxystilbene-4'-O-beta-D-(6"-O-galloyl)glucopyr anoside (2). These compounds showed a competitive inhibition against tyrosinase and also inhibited the melanin biosynthesis.