桦褐孔菌醇提物抗氧化活性部位的筛选

摘要

目的：比较桦褐孔菌醇提物不同极性部位的抗氧化活性,从中筛选出抗氧化的功能部位。方法采用系统溶剂法分离桦褐孔菌菌核的乙醇提取物,分别得到石油醚相、氯仿相、乙酸乙酯相和乙醇相等4个不同极性部位,以还原力及对2,2-二(4-叔辛基苯基)-1-苦肼基自由基(DPPH·)和羟自由基(·OH)的清除能力作为筛选其抗氧化活性的评价指标,并对4种萃取物所含有的黄酮含量和多酚含量进行测定。结果4种提取物均具有较高的抗氧化活性,还原力及清除 DPPH·和·OH 的活性大小顺序均为：乙醇相>乙酸乙酯相>氯仿相>石油醚相,并与多酚含量和黄酮含量具有很高的相关性。乙醇相的清除率最高,在500µg/mL时,对DPPH·和·OH的清除率分别高达83.13%和52.44%,非常接近于阳性对照抗坏血酸的清除活性。结论乙醇相是主要的抗氧化活性部位,值得进一步开发利用。%Objective To compare the biological activities of different polar parts with each other, in order to screen functional parts of ethanol extract fromInonotus obliquus sclerotia.Methods The systematic solvent extraction was used to extract and separate the ethanol extract by petroleum ether (PE), chloroform (Chl), ethyl acetate (EA) and ethanol (Eth), respectively. Accordingly, 4 extracts were obtained and named PEE, ChlE, EAE and EthE, respectively. Their antioxidant capacitiesin vitro were investigated in terms of reducing power assay and scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and hydroxyl radicals. Furthermore, the flavonoid content and polyphenol content of 4 extracts were determined.ResultsIn general, 4 kinds of extracts exhibited increasing antioxidant activity with increasing concentration at the ranges of tested dosage. The orders of reducing power, DPPH-scavenging capacity and hydroxyl-scavenging activity were all EthE>EAE>PEE>ChlE, which was very relevant to the polyphenol content and flavonoids content. These findings demonstrated that 4 extracts extracted fromI. obliquus, especially EthE, at 500 µg/mL, the scavenging rate on DPPH and OH radicals were 83.13% and 52.44%, respectively, which was near to that of the ascorbic acid that was served as positive control.Conclusion The EthE can be employed as natural ingredients in functional food and pharmaceutical industry to alleviate the oxidative stress.