One of bioactive constituents of Chinese natural medicines---Hovenia dulcis

Hovenia dulcis, the oriental raisin tree, is a hardy tree found from Asia, over Eastern China and Korea to the Himalayas (up to altitudes of 2,000 m), growing preferably in a sunny position on moist sandy or loamy soils, is one of bioactive constituents of Chinese natural medicines. SourceKyoto Pharmaceutical University in Japan studied the methanol-soluble fraction from a Chinese natural medicine Hoveniae Semen Seu Fructus, the seed and fruit of Hovenia dulcis THUNB. http://www.ebiochem.com/product/hovenia-dulcis-thunb-p-e-10-1-8839

 (Rhamnaceae) was found to show an inhibitory effect on the alcohol-induced muscular relaxation and a protective activity on the D-galactosamine/lipopolysaccharide or carbon tetrachloride-induced liver injury. Through bioassay-guided separation using a traction performance test, three new dihydrofravonols named hovenitins I, II, and III were isolated from Hoveniae Semen Seu Fructus together with four known flavonoids, (+)-ampelopsin, laricetrin, myricetin, and (+)-gallocatechin. The absolute stereostructures of hovenitins I, II, and III were determined on the basis of chemical and physicochemical evidence to be (2R, 3R)-5,7,4',5'-tetrahydroxy-3'-methoxydihydroflavonol,(2R,3S)-5,7,4',5'-tetrahydroxy-3'-methoxy-dihydroflavonol, and (2R, 3S)-5,7,3',4',5'-pentahydroxydihydro-flavonol, respectively. Hovenitin I and (+)-ampelopsin, both of which were principal ingredients of the active fractions from this natural medicine, were found to show an inhibitory activity on the ethanol-induced muscle relaxation in rats. In addition, hovenitin I showed a protective activity on the liver injury induced by D-galactosamine/lipopolysaccharide or carbon tetrachloride in mice.

On the hepatoprotective effects of the fruits of Hovenia dulcis THUNB. on chemically or immunologically induced experimental liver injury models were examined by Research Institute for Wakan-Yaku. The methanol extract showed significant hepatoprotective activity against CCl4-toxicity in rats and D-galactosamine (D-GalN)/lipopolysaccharide-induced liver injury in mice. The methanol extract also significantly protected against CCl4-toxicity in primary cultured rat hepatocytes. Hepatoprotective activity-guided fractionation and chemical analysis led to the isolation of an active constituent, (+)-ampelopsin (1) from the methanol extract.