细脚拟青霉代谢产物清除自由基和抑制单胺氧化酶活性的研究

用二苯代苦味肼基自由基(DPPH)-TLC法和酶标仪法对一株细脚拟青霉RCEF0394发酵液甲醇提取物的清除自由基活性进行了定性和定量测定,发现该提取物具有较强的清除自由基活性,在浓度为5.0mg/mL,于37℃下保温10min时,它对0.4mg/mL的DPPH自由基的清除率可达75.4%。以大鼠肝脏线粒体单胺氧化酶为靶标的体外实验发现供试细脚拟青霉发酵液有较强的抑制单胺氧化酶活性,且其活性和浓度呈量效关系。该发酵液冻干品对单胺氧化酶的半数抑制浓度IC50为118.1μg/mL。其三氯甲烷提取物对单胺氧化酶的抑制活性明显强于发酵液冻干品,表明该抑制剂可能为极性较低的化合物。进一步的分型试验表明该三氯甲烷提取物对A型单胺氧化酶呈混合抑制,对B型呈竞争性抑制,其Km值分别为0.44mg/L,0.34mg/L。

Study on scavenging and monoamine oxidase inhibitory activities of the metabolite of Paecilomyces tenuipes

A DPPH-TLC and DPPH-mcroplate assay were made to determine the free radical scavenging activity of methanol extract from fermentation broth of Paecilomyces tenuipes RCEF0394. The results revealed that the extract has strong free radical scavenging activity. At the concentration of 5.0 mg/mL it can decrease 75.4 percent 0.4 mg/mL DPPH radicals after incubated at 37℃ for 10 minutes . A rat liver monoamine oxidase assay showed that the dried fermentation broth of Paecilomyces tenuipes has also strong MAO inhibitory activity. It has a dose-dependent manner with IC50 of 118.1 μg/mL. The chloroform extract of the dried fermentation broth exhibited stronger MAO inhibitory activity. This indicated that the polarity of the inhibitor might be not so high. Further tests reveal that the inhibitory type of the chloroform extracts on MAO-A was mixed and on MAO-B competitive, and the Km values were 0.44mg/L and 0.34mg/L respectively.