Cytotoxicity of aflatoxin B1 and its chemically synthesised epoxide derivative on the A549 human epithelioid lung cell line

Aflatoxin B-1 (AFB(1)) is a carcinogenic mycotoxin found in feeds and in airborne grain dusts. Aflatoxin B-1 requires biotransformation to the AFB(1)-8,9 epoxide (AFBO) by a bioactivation system and subsequent covalent binding to DNA or proteins, to exert its carcinogenic potential. The lung contains cytochrome P-450, prostaglandin-H-synthase, lipoxygenase, epoxide hydrolase and other bioactivation enzymes, and is thus a potential target for the effects of AFB(1) via the routes of inhalation and ingestion. The A549 human epithelioid lung cell line and the methylthiazol tetrazolium (MTT) bioassay were used to investigate the cytotoxicity of AFB(1) and its chemically synthesised epoxide (AFBO) in vitro. Statistical analysis of the MTT results indicated that there were overall significant differences between the control and both the AFB(1)-treated (p < 0.0001) and AFBO-treated cells (p = 0.00 2). However, there was no significant difference between AFB(1) and AFBO-treated cells, when the entire range of concentrations were assessed against each other (p = 0.2877). When analysed at each concentration, only at 0.01 mM was there a significant difference between the effects of AFB(1) and AFBO (p = 0.0358). The results of this investigation show that AFB(1) and AFBO are both cytotoxic in the A549 cell line.