UNIQUE PHENYL ETHER TYPE BIFLAVONOIDS, ZIZYFLAVOSIDES A AND B WITH BIOMIMETIC SYNTHESIS FOR ZIZYFLAVOSIDE A

摘要

During our investigation of Zizyphus spina-christi (L.) Willd. leaves for anti-inflammatory activity, eight compounds were characterized. Two are new phenyl ether type biflavonoids, which were assigned as zizyflavosides A (1) and B (2). The structures of 1 and 2 were determined by spectroscopic analyses including 1D, 2D NMR and MS spectroscopic and chemical data. The other isolated compounds were known flavonoids kaempferol-3-O-rutinoside (5), quercetin-3-O-rutinoside (6), 3',5'-di-C-p-D-glucosylphloretine (7), quercetin-3-O-[P-D-xylosyl-(→2)-α-L-rhamnoside]-4'-O-α-L-rhamnoside (8), epiafzelechin (9) and quercetin-3-O-[β-D-xylosyl-(1→2)-α-L-rhamnoside] (10). Zizyflavoside A was synthesized from quercetin-3-O-rutinoside and kaempferol-3-O-rutinoside using laccase as an enzyme and this biomimetic synthesis could be indication to its biosynthetic pathway.