5种枸杞多糖生物活性的比较研究

Comparison on biological activities of Lycium barbarum polysaccharides extracted with five methods

枸杞多糖(Lycium barbarum polysaccharides, LBPs)作为枸杞子中重要的活性成分,其理化性质和生物活性的研究具有重要意义。该研究采用前期通过不同提取方法(冷水浸提、冷水浸提后的滤渣沸水回流提取、50%乙醇超声提取、50%乙醇提取后的滤渣25%乙醇超声提取、热水浸提)得到的5种LBPs(LBP-1、LBP-2、LBP-3、LBP-4、LBP-5)为研究对象,利用紫外光谱、热重分析、扫描电镜对LBPs的结构进行了表征,并比较了其体外生物活性(抗氧化、降血脂、抑制亚硝化反应、抑制乙酰胆碱酯酶和抑制酪氨酸酶活性)。结果表明,高温提取会破坏多糖的结构,而超声辅助提取保证了多糖主要结构的完整;5种LBPs的热稳定性和降解行为存在差异,但5种LBPs的紫外光谱分析结果并无显著差异,都显示蛋白质的特征吸收峰。生物活性结果表明,LBP-3和LBP-4表现出良好的抗氧化活性,而LBP-3降血脂活性最好。此外,LBP-3对亚硝化反应和乙酰胆碱酯酶的抑制作用也显著优于其他组分。相反,LBP-2对酪氨酸酶的抑制能力最为出色。该文探讨了不同提取方法对枸杞多糖的理化性质和生物活性的影响,以期为选择合适的提取方法以获得具有理想生物活性的枸杞多糖提供科学依据。

Studying the physicochemical properties and biological activities of Lycium barbarum polysaccharides(LBPs) is of great significance. The previous study had extracted LBPs(LBP-1, LBP-2, LBP-3, LBP-4, and LBP-5) by five different methods(cold water extraction, boiling water reflux extraction of the residue after cold water extraction, ultrasonic extraction with 50% ethanol, ultrasonic extraction with 25% ethanol of the residue after 50% ethanol extraction, and hot water extraction). In this study, the structures of the obtained five LBPs were characterized by UV spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Furthermore, the antioxidant, blood lipid-lowering, nitrosation-inhibting, acetylcholinesterase-inhibiting, and tyrosinase-inhibiting activities of the five LBPs were measured in vitro. The results showed that high-temperature extraction destroyed the polysaccharide structure, while ultrasound-assisted extraction ensured the structural integrity. The thermal stability and degradation behaviors differed among the five LBPs. However, the UV spectroscopic results of the five LBPs did not show significant differences, and all of the five LBPs showed the characteristic absorption peaks of proteins. LBP-3 and LBP-4 exhibited strong antioxidant activity, while LBP-3 had the strongest blood lipid-lowering activity. In addition, LBP-3 outperformed other LBPs in inhibiting nitrosation and acetylcholineste-rase, and LBP-2 showed the strongest inhibitory effect on tyrosinase. This study explored the effects of different extraction methods on the physicochemical properties and biological activities of LBPs, with a view to providing a basis for the selection of suitable extraction methods to obtain LBPs with ideal biological activities.