FLAVONOID 5-GLUCOSIDES FROM PRUNUS-CERASUS BARK AND THEIR CHARACTERISTIC WEAK GLYCOSIDIC BONDING

Pinostrobin 5-glucoside, a novel flavanone glycoside, was isolated from the bark of Prunus cerasus. As it was not found in P. avium, the substance is useful to distinguish these two species. Apigenin 5-glucoside genkwanin 5-glucoside and neosakuranin were also isolated from the bark of P. cerasus. They occur in both species as minor components. These 5-glucosides together with genistein 5-glucoside, prunetin 5-glucoside, sakuranin, tectochrysin 5-glucoside and luteolin 5-glucoside were hydrolysed in malic acid. The isoflavone and flavone 5-glucosides were shown to be hydrolysed more rapidly than the flavanone 5-glucosides, whereas no hydrolysis was observed with the corresponding 7-glucosides under the same conditions. The chalcone 2'-glucoside neosakuranin was transformed at first to the corresponding flavanone 5-glucoside, which was hydrolysed thereafter.