Integrated proteome and HPLC analysis revealed quercetin-mediated inhibition of aflatoxin B1 biosynthesis in Aspergillus flavus.

The contamination of aflatoxins in maize or maize-related products synthesized by Aspergillus flavus causes severe economical loss and threat to human health. Use of eco-friendly phytochemicals has shown potential to inhibit secondary metabolites in Aspergillus species. Thus, A. flavus cultured in corn flour (CF) and corn flour with quercetin (CFQ) was used for protein extraction for proteome analysis using nLC-Q-TOF mass spectrometer. Proteome analysis revealed the expressions of 705 and 843 proteins in CFQ and CF, respectively. Gene Ontology Slim Categories (GOSC) of CF exhibited major transcriptional factors; involved in acetylation and deacetylation of histone proteins, carbohydrate metabolism, and hydrolase activity, whereas GOSC analysis of CFQ showed membrane transport activity, including both influx and efflux proteins. cAMP/PKA signaling pathway was observed in CFQ, whereas MAPK pathway in CF. To quantify biosynthesis of aflatoxin B1 (AFB1) in CF and CFQ, HPLC analysis at 7, 12, 24 and 48 h was carried out which showed decrease in AFB1 (1%) at 7-24 h in CFQ. However, remarkable decrease in AFB1 biosynthesis (51%) at 48 h time point was observed. Thus, the present study provided an insight into the mechanism of quercetin-mediated inhibition of aflatoxin biosynthesis in A. flavus and raises the possibility to use quercetin as an anti-aflatoxigenic agent.