乌龙茶多糖的化学修饰及其理化性质和活性研究

目的对乌龙茶多糖进行硫酸化和乙酰化的化学修饰。探讨不同的结构修饰对乌龙茶多糖理化性质和活性的影响。方法通过对乌龙茶多糖进行硫酸化和乙酰化,应用红外、紫外光谱分析和原子力显微镜观察对两种衍生化的多糖和未衍生化的多糖进行结构分析。为检测乌龙茶多糖的物理性质变化,进行了溶解度变化的检测。通过还原力实验和脂质过氧化抑制试验模型研究比较乌龙茶多糖的体外抗氧化活性变化。结果通过红外光谱和紫外光谱证实了在衍生化多糖中硫酸基和乙酰基的存在。通过原子力显微镜观察发现,与未衍生化的乌龙茶多糖相比,乙酰化的多糖平面图由圆棒形变成长棒形。硫酸化多糖的平面图呈大小不一的圆岛状,高度图显示尺寸分布较窄。经过乙酰化和硫酸化衍生后的样品,溶解性明显改善。活性分析显示在铁还原力模型实验下,乙酰化后的多糖活性明显升高。在抑制脂质过氧化实验中,硫酸化后多糖的抑制能力极显著增强(P0.01)。结论对多糖进行衍生化有利于其活性的提高。

Physicochemical properties and bioactivity of chemical modified Oolong tea polysaccharide

Objective Oolong tea polysaccharide was subjected to acetylated and sulfated Modification and comparison studies were processed between the derivatives. Methods IR and UV spectrum and AFM were used to analyze the structure of the polysaccharide and its derivatives. The measurement of solubility was used to determine the physicochemical property changes of polysaccharide. The activities were compared using the reducing power and inhibition effects on liposome peroxidation assays. Result The results showed that sulfonic acid and acetyl were existed in the derivatives. Through AFM, compared with oolong polysaccharide, the planar graph of acetylated polysaccharide was exhibited as sticks while sulfated polysaccharide was presented as round islands. Solubility of polysaccharide was notably increased after acetylated and sulfated. Activity studies indicated that in reducing power assay, acetylated polysaccharide exhibited a stronger antioxidant activity. The activity of sulfated polysaccharide was notably increased in the liposome peroxiation assay. Conclusion Chemical modification was benefit for the increase of polysaccharide activity.