Aflatoxins hepatotoxicity

Liver cancer can also be a consequence of exposure to hepatotoxic chemicals. Natural hepatocarcinogens include fungal aflatoxins. Synthetic hepato-carcinogens include nitrosoamines, certain chlorinated hydrocarbons, polychlorinated biphenyls (PCBs), chloroform, carbon tetrachloride, dimethyl-benzanthracene, and vinyl chloride.Table 5.15 lists the chemical compounds that induce liver cancer or cirrhosis in experimental animals or... 

Aflatoxins Contaminant (mycotoxin) Produced by Aspergillus flavus, especially grains, corn, and peanuts carcinogenic and hepatotoxic... 

Antihepatotoxic activity. A mixture of the methanol-insoluble fraction of the dried resin, fresh garlic, curcumin, ellagic acid, butylated hydroxytoluene, and butylated hydroxyanisole, administered by gastric intubation to ducklings at a dose of 10 mg/ani-mal, was active vs aflatoxin Bl-induced hepatotoxicity " . ... 

Hepatotoxic, e.g. from Amanita phalloides (death cap mushroom), from Senecio (ragwort) and Crotalatia and from bush teas prepared from these plants in the Caribbean. Aflatoxin, from Aspergillus flavus, a fungus which contaminates foods, is probably a cause of primary liver cancer. 

Acute aflatoxin B1 (AFBl)-induced hepatotoxicity was assessed in vivo in male Sprague-Dawley rats (150-300 g) using MRI. MRI results were compared to serum enzyme levels, histology and electron microscopy. 

Schoental R. Hepatotoxic activity of retrorsine, senkirkine and hydroxysenkirkine in newborn rats, and the role of epoxides in carcinogenesis by pyrrolizidine alkaloids and aflatoxins. Nature 1970 227 401-2. 

Both quantitative and qualitative differences have been reported in the biotransformation of xenobiotics by different animal species (25, 26). Initially, indications for this phenomenon came primarily from toxicity studies with smil laboratory animals, showing species-differences in the sensitivity towards the toxic effects of a compound. In vivo studies have for example revealed a large difference between rats and mice in their sensitivity to the hepatotoxic and carcinogenic properties of aflatoxin (27). More recently, species-related differences in the biotransformation of compounds were shown in studies with isolated cellular fractions from livers of different animal species, including farm animals (28, 29, 30, 31, 32). 

Related to carbon tetrachloride hepatotoxicity, aucubin is active only on in vivo assays [27], but not in vitro [49], This fact also is observed in other iridoids as loganin or catalposide [49], suggesting that the active agent could be a metabolite. The iridoid that has shown most important hepatoprotective activity is picroliv [88-98], and we emphasize that it could be interesting to assay catalpol in the showed assays for picroliv, and study the influence of these radicals on the hepatoprotective activity. Picroliv has been also assayed against aflatoxin Bi [81-87]. 

Maxuitenko, Y. Y, W. G. North, and R. D. Roebuck. 1997. Urine taurine as a noninvasive marker of aflatoxin B1-induced hepatotoxicity Success and failure. Toxicology 118 159-169. 

Eiu YE, Roebuck BD, Yager JD, Groopman JD, Kensler TW. Protection by 5(2-pyrazmyl)-4-methyl-1, 2-dithiol-3-thione (oltipraz) against the hepatotoxicity of aflatoxin B1 in the rat. Toxicol Appl Pharmacol 1988 93 442-451. 

Sterigmatocystin (ST) or dihydrosterigmatocystin (DHST) (Fig.11.1), a related dihydrofuran toxin, is the penultimate precursor of aflatoxins, and is also produced as a final biosynthetic product by a number of species such as Aspergillus versicolor and Aspergillus nidulans. Sterigmatocystin is hepatotoxic, carcinogenic, and mutagenic as well, but is less potent than aflatoxins. The common biochemical... 

Aflatoxins are secondary fungal metabolites produced by A. flavus Link and A. parasiticus Speare and are recognized for their potent hepatotoxic, teratogenic, and carcinogenic effects in some animals (10). 

The toxic effects of aflatoxin in animals includes gross liver damage, development of a necrosis in the periportal zone [246], and haemorrhage in the intestinal tract and peritoneal cavity. Aflatoxins also affect several cell culture systems in vitro [247—249], and cause lesions in chick embryos [249—251 ]. The finding of multiple liver tumours and lung metastases [252] was the first indication of the hepatotoxicity of this group of mycotoxins. This observation has been several times confirmed [253-257] and only 0.005 p.p.m. failed to induce liver tumour in rats [258]. Mice are more resistant [259—261], whereas rainbow trouts are considerably more sensitive to the action of aflatoxins [262—266]. 

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