用气相色谱和红外光谱对羧甲基化南瓜多糖结构的研究

Determination of Molecular Structure of Carboxymethyl Pumpkin Polysaccharide by Gas Chromatography and IR Spectroscopy

采用超声辅助法提取南瓜多糖并对其进行分离和羧甲基化;邻苯三酚自氧化法测定羧甲基南瓜多糖对超氧阴离子自由基的清除作用;气相色谱法、红外光谱对南瓜粗多糖及其组分AP1的化学结构进行了分析。结果表明,羧甲基南瓜多糖能有效清除超氧阴离子自由基,并随着浓度的增加清除作用增强。该结果提示羧甲基南瓜多糖具有抗氧化性。气相色谱证明南瓜多糖由阿拉伯糖、鼠李糖、核糖、甘露糖、果糖、半乳糖、葡萄糖组成。南瓜AP1多糖由阿拉伯糖、鼠李糖、核糖、果糖、半乳糖、葡萄糖组成。红外光谱分析证实南瓜多糖具有糖类物质的特征吸收峰,同时存在呋喃环和吡喃环。

The pumpkin polysaccharide was extracted by ultrasonic method. The pumpkin AP1 polysaccharide was obtained from the precipitate with cetyltrim-ethlammonium bromide （CTAB）. The pumpkin polysaccharide was carboxymethylated by C1CH2COOH in NaOH aqueous solution. The method of antoxidation reaction system of pyrogallol was performed to investigate the scavenging action of pumpkin polysaccharide on superoxide radical. The composition was identified through hydrolyzing with acid and analyzed by GC and IR. The carboxymethyl pumpkin polysaccharide had the ability to scavenge superoxide radical. The scavenging effects increased with the increasing of concentration. The carboxymethyl pumpkin polysaccharide had antioxidative property. The pumpkin polysaccharides was composed of arabinose, rhamnose, ribose, mannose, fructose, galactose and glucose. The pumpkin AP1 polysaccharides was composed of arabinose ,rhamnose,ribose fructose, galactose and glucose. The analysis result of FT-IR spectra of pumpkin polysaccharide showed that there were characteristic absorption bands of polysaccharide, The monosaecharides in the polysaccharide existed as pyranoide and furanoide.