Structure analysis and anti-fatigue activity of a polysaccharide from <i>Lepidium meyenii</i> Walp

<p>A polysaccharide was obtained from <i>Lepidium meyenii</i> Walp by hot water extraction and purification by Millipore (100 kD) and Sephadex G-200. The content of polysaccharide was examined to be 89.9% with phenol-sulfuric acid method. Its average molecular weight was estimated to be 2.213 × 10<sup>6</sup> Da by High Performance Gel Permeation Chromatography (HPGPC). Monosaccharide analysis showed that the polysaccharide was composed of arabinose, mannose, glucose and galactose with the molar ratio of 2.134: 1: 2.78: 2.82. After Smith degradation, methylation, infrared spectroscopy and NMR, the primary structure of the polysaccharide was identified. The backbone of the polysaccharide was composed of →4)-β-D-Gal<i>p</i>-(1→ and →4)-α-D-Gal<i>p</i>-(1→, while the branches were comprised of →6)-β-D-Glu<i>p</i>-(1→, →5)- β-D-Ara<i>f</i>-(1→, →3,6)-α-D-Man<i>p</i>-(1→, →3)-α-D-Gal<i>p</i>-(1→, and α-D-Glu<i>p</i>-(1→. The anti-fatigue effect of the polysaccharide was evaluated using exhaustive swimming test and biochemical indexes. The results indicated the polysaccharide has anti-fatigue effect.</p>