Flavonoids from the Leaves of Loranthus kaoi (Chao) Kiu

JER-HUEI LIN* AND YA-TZE LIN

 National Laboratories of Foods and Drugs, Department of Health, Executive Yuan, 161-2, Kuen Yang Street, Nankang, Taipei, Taiwan, R.O.C.

ABSTRACT

   In continuing a chemical examination of Loranthaceous plants, this study isolated eight flavonoids from the fresh leaves of Loranthus kaoi, an endemic parasitic shrub found only at median altitudes in the central part of Taiwan. These compounds were a mixture of (+)- and (-)-catechin (1), (-)-epi-catechin (2), 2',4',6'-trihydroxydihydrochalcone 4'-O-β-D-glucoside (3), pinocembrin 7-O-β-D-glucoside (4), kaempferol 3-O-α-D-rhamnoside (5), kaempferol 3,7-di-O-β-D-glucoside (6), quercetin 3-O-α-D-rhamnoside (7) and quercetin 3-O-β-D-glucoside (8). The structures of compounds 1-8 were established on the basis of their physical properties and spectroscopic evidence.

Key words: Loranthus kaoi, Loranthaceae, leaves, flavonoid