Extraction, purification and structural elucidation of the main water-soluble polysaccharide isolated from Acanthophyllum glandulosum roots

A new water-soluble polysaccharide with molecular weight of 35.2 KDa and a specific optical rotation of ힿ.5° was extract by hot water (80°C) from the roots of Acanthophyllum glandulosum. The polysaccharide purified through DEAE-cellulose and Sephadex G-50 columns and the main fraction was collected and freeze-dried. Total yields of purified polysaccharide were 3.4% and %2.3 respectively. The purified polysaccharide had no absorption at 280 nm (Detected by UV spectrum), indicating the absence of protein and nucleic acid. Total carbohydrate content of purified polysaccharide was 98.2%. Monosaccharide analysis by GC revealed that polysaccharide was composed of Glucose, Galactose, Arabinose and Mannose with a relative molar ratio of 2.9:6.1:0.9:1.0 respectively. Its structural features were elucidated by a combination of chemical and analytical methods such as Methylation, Periodate Oxidation and Smith degradation, Partial acid hydrolysis, FT-IR and 13C and 1H NMR Spectroscopy. The data obtained indicate that purified polysaccharide possessed a backbone of α-(1→6)-linked Galactose with branched attached to O-2 by α-1→linked Mannose and at O-3 by α-(1→3)-linked Glucose and α-(1→3)-linked Arabinose.