虫草及其发酵制品抗氧化能力研究

目的：考察天然冬虫夏草、蛹虫草及其发酵制品水和乙醇提取物体外抗氧化活性。方法：测定样品的6个抗氧化指标：抑制亚油酸氧化的能力；清除DPPH自由基、羟自由基、过氧化氢和超氧阴离子的活性以及螯合金属离子(Fe²⁺)的效果。结果：各样品具有不同程度的抗氧化能力,没有一种提取物在所有测试中均显示出很强的活性,但可以认为天然蛹虫草水提物的抗氧化能力为8个样品中最高,它在抑制亚油酸氧化,螯合金属离子以及清除DPPH自由基和羟自由基的实验中都显示了很高的活性。研究同时表明天然及发酵虫草水和醇提物中多酚类的含量差异很大。结论：虫草及其发酵制品可作为一种潜在的天然抗氧化剂,发酵培养能够影响虫草制品的抗氧化活性,而天然与发酵虫草的抗氧化能力与其含有的多酚类的量没有显著相联。

Antioxidant activity of natural and cultured Cordyceps sp.

Objective: Investigating the antioxidant activities of water and ethanol extracts of natural Cordyceps sinensis and Cordyceps militaris and their fermentation preparations. Method: The samples were tested through 6 assays: inhibition ability of linoleic acid oxidation; scavenging activity of DPPH, hydrogen peroxide, hydroxyl radical and superoxide anion; and metal chelating activity. Result: Samples showed different antioxidant ability, and there was not an extract that exhibited high activity in all assays; however, water extract of natural C. militaris could be regarded as the most powerful antioxidant among 8 samples. It had high activity in inhibition of linoleic acid oxidation, chelating metal ions, and scavenging DPPH and hydroxyl radical. The research also indicated that the contents of phenolic compounds in water and ethanol extracts of natural and cultured Cordyceps sp. had huge difference. Conclusion: Natural Cordyceps sp. and its fermentation preparations could be used as potential natural antioxidants. The fermented process affected the antioxidant ability of cultured Cordyceps sp., and the antioxidant activity of both natural and cultured Cordyceps sp. did not significantly related with the quantity of phenolics.