Biphenyl glycosides from the fruit of Pyracantha fortuneana.

Five new biphenyl glycosides, fortuneanosides A (1), B (2), C (3), D (4), and E (5), were isolated from the fruit of Pyracantha fortuneana. Their structures were established as 3,3'-dihydroxy-5'-methoxy-(1,1'-biphenyl)-4-O-beta-d-glucoside, 4'-hydroxy-2,3',5'-trimethoxy-(1,1'-biphenyl)-2'-O-beta-d-glucoside, 4'-hydroxy-3',5'-dimethoxy-(1,1'-biphenyl)-2-O-beta-d-glucoside, 2,4'-dihydroxy-3',5'-dimethoxy-(1,1'-biphenyl)-3-O-beta-d-glucoside, and 3,4'-dihydroxy-3',5'-dimethoxy-(1,1'-biphenyl)-4-O-beta-d-glucoside by spectroscopic analysis. All compounds were evaluated for inhibitory activity against tyrosinase. Compared with arbutin (IC(50) = 0.23 mM), fortuneanoside D possessed more potency, with an IC(50) value of 0.07 mM.