Biological activity and structural characterization of alkaline-soluble polysaccharides from the kernels of Prunus mume Sieb. et Zacc.

The fruits of Prunus mume Sieb. et Zacc. (Japanese name, ume) have been used as a traditional drug and health food. In order to study the active components of P. mume, the polysaccharide fractions were extracted with cold water, hot water and aqueous sodium hydroxide from the kernels of P. mume. We found that some of the polysaccharide fractions exhibited various types of biological activities such as mitogenesis, activation of the alternative pathway of complement and activation of clot formation in human plasma. A polysaccharide, P-1, obtained from the cold 0.5 M NaOH extract was purified by ion-exchange chromatography and gel-filtration, P-1 contained 62.0% neutral sugar as glucose and 38.4% uronic acid (as galacturonic acid), and was free from protein. The neutral sugars of P-1 were arabinose, xylose, rhamnose and galactose in a molar ratio of 9.4:3.4:1.1:1.0, following analysis by gas-liquid chromatography. In addition, galacturonic acid was identified by thin-layer chromatography. The molecular weight of P-1 was found to be more than 2,000,000 by gel-filtration on Toyopearl HW 65F. P-1 showed mitogenic activity towards spleen cells of both C3H/HeN and C3H/HeJ, suggesting that it was free from bacterial endotoxic lipopolysaccharides.