Ethanol fractionation precipitation and physico-chemical properties of soluble polysaccharides from Prunella vulgaris Linn

The physico -chemical properties of soluble polysaccharides from Prunella Vulgaris Linn were studied. Soluble polysaccharides extracted with hot water and subsequently precipitated with ethanol, were successively fractionated by different gradient concentrations of ethanol (20%, 30%, 40%, 50%, 60% and 70%) into six fractions, named as PVLP -1, PVLP -2, PVLP -3, PVLP -4, PVLP -5 and PVLP -6. Contents of sugar, uronic acid and protein in these fractions were determined , monosaccharide compositions of them were also analyzed by gas chromatography (GC) , UV and IR spectra analysis were run simultaneously to determine their spectroscopy properties . The result showed that all six fractions were acidic polysaccharides , with high protein content . Each of these fractions all contain rhamnose , arabinose , xylose , mannose , glucose and galactose, and xylose and arabinose were the main monosaccharides in them , the content of mannose was lowest, fucose and ribose were not found , but the mol ratios of these monosaccharides in six fractions were different.