Investigation of the production of B1, B2, G1 & G2 aflatoxins in some species of Aspergillus with high performance liquid chromatography (HPLC) methods

Aflatoxins are very toxic secondary metabolites of some، Aspergilluss sp. that are produced when these fungi grow on different agricultural products under special environmental circumstances. In this study aflatoxinsB1، B2، G1 and G2 in some species of Aspergillus were investigated. These fungi included A. terreus، A. ustus، A. candidus، A. carneus، A. ostianus، A. auricomus، A. niveus، A. niger، A. fumigates، A. parasiticus، A. caespitosus، A. awamori and A. sclerotiorumthat were grown in potato dextrose broth (PDB) and aflatoxins thereof were measured using high performance liquid chromatography (HPLC) methods. Pure cultures of the aspergilli were prepared and identified to species، and then each species was cultured for 22 days in 50 ml flask containing PDB at 26 0C، 80% humidity and in darkness، conditions similar to natural habitat. Fungal exudates in the broth cultures were extracted with 10 ml chloroform، the organic solvent was evaporated and the precipitate was dissolved in 3ml methanol. After filtration through 0. 2 µm milipore filter، the final solute was injected into HPLC instrument. Maximum amount of aflatoxins was secreted by A. parasiticus while aflatoxin G1 was not produced in A. terreus، A. carneus، A. fumigatus، A. niveus، A. parasiticus، A. caespitosus، A. ostianus and A. niger. As well، A. niveus، A. ostianus، A. niger and A. sclerotiorum did not produce aflatoxin G2. No aflatoxin B2 was detected in A. sclerotiorum and A. carneus and no aflatoxin B1 was detected in A. ostianus. Among the four type of aflatoxins (B1، B2، G1 and G2)، B1 and G1 had respectively the maximum and minimum amount of secreted aflatoxins in A. parasiticus.