夏枯草水溶性多糖体外抗氧化活性研究

目的研究夏枯草水溶性多糖乙醇分级组分的抗氧化活性。方法采用水提醇沉法得到夏枯草水溶性粗多糖,再经不同体积分数(20%、30%、40%、50%、60%、70%,v/v)的乙醇溶液逐级沉淀,依次得到不同分子量的六个夏枯草多糖组分(依次记为PVLP-1、PVLP-2、PVLP-3、PVLP-4、PVLP-5、PVLP-6)。进一步测定了其中四个组分(PVLP-2、PVLP-3、PVLP-4、PVLP-5)对DPPH、O~(2-)·和·OH的清除效率。结果从夏枯草中得到的PVLP-2、PVLP-3、PVLP-4、PVLP-5四个多糖组分对DPPH自由基清除效果最明显,在质量浓度为3.2mg/mL时,清除率依次为98.09%、90.05%、88.56%和87.71%。各组分对O~(2-)·以及·OH自由基的清除作用相对较差些,除PVLP-4清除·OH自由基的EC_(50)值为13.24 mg/mL外,其余均小于10 mg/mL。四个多糖组分中,PVLP-2的总体抗氧化效果优于其他各个组分。结论乙醇分级可以作为一种简便易行的分离纯化方法,制备具有良好抗氧化效果的水溶性夏枯草多糖。

Antioxidant activities of soluble polysaccharides from Prunella vulgaris Linn

Objective To investigate the antioxidant activities of soluble polysaccharides fractionated with ethanol. Methods Water soluble crude polysaccharide was extracted from Prunella vulgaris Linn with hot water and precipitated by ethanol, and subsequently separated by ethanol solutions with different concentrations (20%, 30%, 40%, 50%, 60%, 70%, v/v) into six fractions (PVLP-1, PVLP-2, PVLP-3, PVLP-4, PVLP-5, PVLP-6) with different molecular weights. The antioxidant activities of four fractions (PVLP-2, PVLP-3, PVLP-4, PVLP-5) were tested by determining scavenging rates of the fractions on DPPH, O2-? and ?OH in vitro. Results The four fractions showed obvious antioxidant activities to DPPH radicals. Their scavenging rates were 98.09%, 90.05%, 88.56% and 87.71% at a mass concentration of 3.2 mg/mL, respectively. The four fractions showed relatively lower scavenging rates to O2-? and ?OH radicals. The EC50 values in the study were less than 10 mg/mL except for that of PVLP-4 for ?OH free radicals, which was 13.24 mg/mL. Furthermore, PVLP-2 exhibited the strongest antioxidant activities among all the fractions. Conclusion The current study suggested that ethanol solutions with different concentrations would be a good method to isolate water soluble polysaccharides from Prunella vulgaris Linn bearing excellent antioxidant activities.