苦瓜多糖的分子修饰及抗氧化活性研究

Modification of polysaccharide from Momordica charantia L. and its antioxidant activities

中文关键词:  苦瓜多糖  金属络合  羧甲基化  抗氧化作用

英文关键词:Momordica polysaccharide  metal complexation  carboxy methylation  antioxidant activity

中文摘要:

      目的 通过羧甲基化及金属络合对苦瓜多糖进行分子修饰, 比较不同修饰方法对其抗氧化活性产生的影响。方法 采用水提醇沉法分离制备苦瓜粗多糖(Momordica charantia polysaccharide , MCP), 以DEAE-52离子交换层析梯度洗脱获得4种苦瓜多糖组分(MCPⅠ, MCPⅡ, MCPⅢ, MCPⅣ)。将其中活性较高组分MCPⅡ进行羧甲基化及金属络合获得苦瓜多糖衍生物CMMCPⅡ、MCPⅡ-Ca(Ⅱ), 并以Fenton法检测其?OH清除率。结果 苦瓜多糖活性组分MCPⅡ及其衍生物MCPⅡ-Ca(Ⅱ) 、CMMCPⅡ均具有抗氧化活性, 在质量浓度为0.7 mg/mL时, 其对?OH的清除率分别为58%、82% 和 93%, SC50值均在0.6 mg/mL以下, 其中, 苦瓜多糖羧甲基化衍生物的抗氧化活性最高。结论 通过羧甲基化及金属络合可增强苦瓜多糖生物活性。

英文摘要:

      Objective To investigate the antioxidant activities of modified polysaccharides, which was embellished by carboxy methylated and metal ions. Methods Water soluble crude polysaccharide was extracted from Momordica charantia L. with hot water and precipitated by ethanol, then purified by DEAE-cellulose ion-exchange chromatography with NaCl gradient elution to obtain 4 kinds of polysaccharide components (MCPⅠ, MCPⅡ, MCPⅢ, MCPⅣ). The antioxidant activities of MCPⅡ were tested by determining scavenging rates of the fraction on ?OH in vitro. The calcium-polysaccharide complex was synthesized when chelated with Ca2+ , coded as MCPⅡ- Ca(Ⅱ) . The carboxy methylated polysaccharide was named as CMMCPⅡ. Results The MCPⅡ, MCPⅡ-Ca(Ⅱ) and CMMCPⅡ showed obvious antioxidant activities to ?OH. Their scavenging rates were 58%, 82% and 93% at a mass concentration of 0.7 mg/mL, respectively. The SC50 values in the study were less than 0.6 mg/mL. Furthermore, CMCPⅡ exhibited the strongest antioxidant activities among them. Conclusion The current study suggests that carboxy methylated and metal ions can improve polysaccharide bearing excellent antioxidant activities.