板蓝根多糖结构修饰及抗氧化、抗炎活性研究

Structural modification, antioxidant and anti-inflammatoryactivities of radix isatidis polysaccharides

目的:以板蓝根为原料,优化板蓝根多糖乙酸酐法修饰工艺,制得乙酰化板蓝根多糖,并研究其修饰前后体外抗氧化和抗炎活性。方法:采用乙酸酐法修饰制备乙酰化板蓝根多糖,以乙酰基取代度为评价指标,结合单因素和响应面方法对其乙酰化修饰工艺条件进行优化,采用体外化学模型法评估多糖对DPPH、ABTS^(+)、羟基自由基的清除能力,并通过细胞活力实验检测其抗炎能力。结果:通过红外光谱分析结果,显示乙酰化板蓝根多糖修饰成功,并未改变多糖基本结构骨架。其最佳工艺条件为反应温度39℃,反应时间5.6 h,料液比1:19 g·mL^(-1),取代度可达到0.3889。在抗氧化实验中发现,板蓝根多糖乙酰化修饰前后对DPPH自由基、ABTS^(+)自由基和羟基自由基均具有较好的清除能力,并呈现出剂量依赖关系,其中乙酰化板蓝根多糖抗氧化活性更强,同时可以有效降低炎症细胞的活力,显示出较显著的抗炎活性。结论:板蓝根多糖经乙酰化修饰后,可显著提高体外抗氧化和抗炎活性,为板蓝根多糖的进一步开发与利用提供理论依据和数据参考。

Objective:Using radix isatidis as raw material,radix isatidis polysaccharides(RIP)was acetylated by acetic anhydride method and this was optimized to produce acetylated radix isatidis polysaccharides(Ac-RIP),and the in vitro antioxidant and anti-inflammatory activities of RIP and Ac-RIP were measured.Methods:Ac-RIP were prepared by acetic anhydride method.Acetyl substitution degree was used as evaluation index,combined with single factor and response surface,the process conditions of acetylation modification were optimized.And the scavenging ability of RIP and Ac-RIP against DPPH,ABTS^(+),and hydroxyl radicals were assessed by in vitro chemical modeling method,and theirs anti-inflammatory ability was detected by cell viability method.Results:The results were analyzed by Fourier-transform infrared spectroscopy,which showed that the Ac-RIP was successfully modified and did not change the basic structural backbone of the polysaccharide.The results showed that the optimum process conditions of acetylation modification of RIP were as follows:reaction temperature 39℃,reaction time 5.6 h,liquid-material ratio of acetic anhydride to polysaccharide 19:1 g·mL^(-1).Under these conditions,the substitution degree of substitution of Ac-RIP was 0.3889.In antioxidant experiments,it was found that RIP and Ac-RIP showed a stronger scavenging ability against DPPH radicals,ABTS^(+)radicals and hydroxyl radicals in a dose-dependent relationship,in which the Ac-RIP had stronger antioxidant activity,and at the same time,it could effectively reduce the viability of the inflammatory cells,exhibiting a stronger anti-inflammatory efficacy in the interim.Conclusion:The acetylation modification of RIP significantly improved the in vitro antioxidant and anti-inflammatory activities,which provides theoretical basis and data reference for further utilization of Radix Isatidis polysaccharides.