淮河沉积物来源黄柄曲霉BMC-28次级代谢产物分离鉴定及其抗氧化活性OA

Objective To isolate and identify the secondary metabolites of the fungus Aspergillus flavipes BMC-28 derived from Huaihe River sediment,and evaluate their antioxidant activity.Methods The monomeric compounds were separated and purified by multiple chromatographic techniques such as normal and reversed-phase silica gel column chromatography.The structural identifica-tion of the compounds was performed by spectroscopic techniques such as nuclear magnetic resonance(NMR)and mass spectrometry(MS).The antioxidant activities of the identified compounds were evaluated using the 1,1-Diphenyl-2-picrylhydrazyl(DPPH)method.Results Fifteen known compounds were isolated and identified from the rice fermentation culture of Aspergillus flavipes BMC-28,including sulochrin(1),2-(3'-hydroxy-2'-(methoxycarbonyl)-5'-methylphenoxy)-4-hydroxy-6-methoxybenzoic acid(2),methyl chloroasterrate(3),asterric acid(4),monomethylosoic acid(5),iizukine B(6),epicoccone(7),epicoccolide B(8),N-ben-zoylphenylalaninyl-N-benzoylphenylalaninate(9),questin(10),(2E,2'E)-[6,6'-dihydroxy[1,1'-biphenyl]-3,3'-diyl]bis[prop-2-enoic acid](11),auranticin A(12),2,6-Dihydroxy-3,4-dimethylbenzoic acid(13),4-Methylorcinol(14),4,5,6-Trimethylbenzene-1,3-diol(15).Among them,compounds 11 and 12 were isolated from the genus Aspergillus for the first time.The in vitro antioxidant experiment results revealed that compounds 6,7 and 8 exhibited strong DPPH radical scavenging activity with half-maximal inhibitory concentration(IC50)of 1.53-3.68 μmol/L,significantly superior to the positive control vitamin C.Structure-activity relationship analysis results indicated that the presence of multiple phenolic hydroxyl substitutions in the molecular structure was an important structural feature for compound to exhibit strong antioxidant activity.Conclusion Fifteen known compounds are successfully isolated and identified from Aspergillus flavipes BMC-28 derived from Huaihe River sediment,among which compounds 6,7,and 8 possess strong antioxidant activity,significantly superior to vitamin C,and compounds 11,12 are reported for the first time.This study provides a theoretical basis and scientific reference for the further study of natural antioxidant lead compounds and the subsequent development and utiliza-tion of freshwater fungal resources.