IN VIVO AND IN VITRO EVALUATION OF EFFICACY OF HUMIC ACID AGAINST AFLATOXINS

Aflatoxins (AFs), a group of closely related, extremely toxic mycotoxins produced by Aspergillus flavus and A. parasiticus, can occur as natural contaminants of food and feeds. AFs have been shown to be hepatotoxic, carcinogenic, mutagenic and teratogenic to different animal species. Therefore reducing their toxicity in vivo is of major interest. The potential of humic acid (HA) was evaluated for affinity to adsorb AFs from aqueous solution in vitro and for reducing the AFs-induced toxicity and oxidative stress in rat. In vitro study, three concentrations of HA (20, 60, and 100 mg/ml aqueous solution) and three concentrations of AFs (20, 60 and 100ppb) at three interaction time (1, 2 and 3hr) were tested. The results indicated that HA had a high capacity of adsorbing AFs at different tested concentrations and adsorption not significantly affected by increasing interaction time. The adsorption affinity was increased by elevation HA concentration and decreasing AFs concentration. The in vivo result indicated that rats administrated orally with 1 and 2mg AFs/ kg body weight (b.w)/once/week for 6 week showed significant dose and time- dependant increase in serum alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transpeptidase (GGT), creatinine, urea, triglycerides, total cholesterol and  lipid peroxidation product (malondialdehyde, MDA) and significant time and dose- dependent reduction of serum albumin and total protein (TP), plasma reduced glutathione (GSH), glutathione -S- transferase (GST), superoxide dismutase (SOD) contents. Hyperglycemia was observed in AFs ingested rats in time and dose dependant manner. While, HA intake at two examined doses (200 and 400mg/kg b.w/daily) did not alter any of measured parameters along experimental periods except plasma GSH which enhanced significantly along experimental periods. The combined treatment showed significant improvement in all tested parameters. This improvement was more pronounced in the groups received the high dose of HA especially low AFs- co treated group. It could be concluded that HA has a potential activity and protective effect against AFs toxicity and this protection was dose dependant.