Abstract:

A water-soluble crude polysaccharide was extracted from Truffle (Tuber indicum) by water extraction and alcohol precipitation and then purified by DEAE 52 cellulose and Sephadex G-100 chromatographic column to obtain a major fraction of polysaccharide (TIP-A). The relative molecular weight (Mr) of TIP-A was determined to be 17500 by high performance gel permeation chromatography (HPGPC). In addition, gas chromatography-mass spectrometry (GC-MS) analysis exhibited that TIP-A was a homogeneous heteropolysaccharide consisted of mannose, glucose, galactose and rhamannose with a molar ratio of 7:2:2:2. TIP-A had strong scavenging activity on hydroxyl, superoxide anion, and 1-diphenyl-2-picryldydrazyl (DPPH) free radicals and IC50 values of TIP-A for three kinds of free radicals were 1.06, 1.02 mg/mL and 1.13 mg/mL, respectively. TIP-A could also significantly attenuate PC12 cell damage caused by hydrogen peroxide at the concentration of 300 mmol/L.

Key words: Tuber indicum, polysaccharide, monosaccharide composition, antioxidant activity