Effect of ethanol on the in vivo covalent binding and in vitro metabolism of aflatoxin B1 in rats

Protective effects of curcumin against aflatoxicosis: A comprehensive review

Aflatoxicosis is a deleterious medical condition that results from aflatoxins (AFs) or ochratoxins (OTs). Contamination with these toxins exerts detrimental effects on the liver, kidneys, reproductive organs, and also on immunological and cardiovascular systems. Aflatoxicosis is closely associated with overproduction of reactive oxygen species (ROS) as key contributors to oxidative and nitrosative stress responses, and subsequent damages to lipids, proteins, RNA, and DNA. The main target organ for AF toxicity is the liver, where DNA adducts, degranulation of endoplasmic reticulum, increased hepatic lipid peroxide, GSH depletion, mitochondrial dysfunction, and reduction of enzymatic and non-enzymatic antioxidants are manifestations of aflatoxicosis. Curcuma longa L. (turmeric) is a medicinal plant widely utilized all over the world for culinary and phytomedical purposes. Considering the antioxidant characteristic of curcumin, the main active component of turmeric, this review is intended to critically summarize the available evidence supporting possible effectiveness of curcumin against aflatoxicosis. Curcumin can serve as a promising candidate for attenuation of the adverse consequences of aflatoxicosis, acting mainly through intrinsic antioxidant effects aroused from its structure, modulation of the immune system as reflected by interleukin-1β and transforming growth factor-β, and interfering with AF's biotransformation by cytochrome P450 isoenzymes CYP1A, CYP3A, CYP2A, CYP2B, and CYP2C.

Role of aflatoxin B1 as a risk for primary liver cancer in north Indian population

OBJECTIVES

The present study was designed to determine whether aflatoxin B1 (AFB1) exposure has any role to play in hepatocellular carcinoma (HCC) patients from northern India.

DESIGN AND METHODS

A total of 266 HCC patients and 251 patients of chronic liver disease without-HCC were enrolled into the study. All samples were screened for serological markers for hepatitis B and C infections and levels of AFB1 in food and urine samples.

RESULTS

A threefold (OR=3.43) and five-fold (OR=5.47) increased risk of HCC was observed amongst HBV infection and AFB1-levels in food and urine samples, respectively. However, a non-significant risk was observed with respect to HCV infection (OR=1.27) and alcohol consumption (OR=1.18). A threefold (OR=3.15) increased risk of HCC was observed amongst cases of non-viral etiology with respect to urinary AFB1.

CONCLUSION

The data provides an exposure and disease risk information for establishing intervention studies to diminish the impact of aflatoxin exposure in Indian population.

Enhanced hepatotoxicity of aflatoxin B1 in the rat by ethanol: ultrastructural changes

The effect of ethanol pretreatment on aflatoxin B1 (AFB1)-induced ultrastructural alteration in hepatocytes was investigated in male Wistar rats. Pretreatment with 4 oral doses of ethanol (4.0 g/kg body wt. each) at 48, 45, 24 and 21 h prior to a single intraperitoneal administration of AFB1 (2.0 mg/kg body wt.) produced an alteration of fine structure more extensive than that observed after administration of AFB1 or ethanol alone. The organelles most affected were the mitochondria, endoplasmic reticulum and nucleus. The degree of nuclear edema, rough endoplasmic reticulum dilatation and mitochondrial swelling in hepatocytes from rats treated with ethanol and AFB1 was much greater than that of hepatocytes from rats treated with AFB1 or ethanol alone. Thus, ethanol may play a specific role in the potentiation of hepatic injury induced by AFB1 at the mitochondrial, endoplasmic reticular and nuclear level.

Time-course effects of ethanol pretreatment on hepatic necrosis and fat accumulation induced by aflatoxin B1 in the rat

Effect of ethanol pretreatment on acute hepatotoxicity and hepatic fat accumulation induced by aflatoxin B1 (AFB1) was followed up to 120 h in male Wistar rats. Pretreatment with 4 oral doses of ethanol (4.0 g/kg body wt. each) at 48, 45, 24 and 21 h prior to AFB1 (2.0 mg/kg body wt.) single intraperitoneal administration caused a significant increase in the activity of plasma glutamic oxaloacetic transaminase (PGOT, 2.4-fold), plasma glutamic pyruvic transaminase (PGPT, 2.8-fold), liver triglycerides (2.3-fold) and the severity of liver necrosis at 72 h after AFB1 administration. The effect of ethanol pretreatment on an increase in the accumulation of liver cholesterol and cholesterol esters induced by AFB1 is additive in nature. In a time-course study, it was shown that liver necrosis and triglyceride, cholesterol and cholesterol ester accumulation occurred simultaneously in both groups of rats treated with AFB1 and ethanol-AFB1. These results suggest that fat accumulation per se is not a primary cause of liver necrosis induced by AFB1 and ethanol-AFB1.

Enhancing effect of ethanol on aflatoxin B1-induced hepatocarcinogenesis in male ACI/N rats

The modifying effect of ethanol (EtOH) on aflatoxin B1 (AFB1)-induced hepatocarcinogenesis was examined in male ACI/N rats by chronic treatment at the post-initiation phase. Rats received an ip injection of AFB1 (1.5 mg/kg) twice a week for 10 weeks (a total of 20 doses). Following a week of acclimation, they were given 10% EtOH as drinking water for 56 weeks. The effect of EtOH on the hepatocarcinogenesis was evaluated in terms of the incidence of altered hepatocellular foci and neoplasms at the end of the experiment. Exposure to AFB1 alone induced a substantial number of altered foci (6.98 iron-excluding foci/cm2) in rats. The number of altered liver cell foci in rats receiving AFB1 followed by EtOH was significantly increased (26.39 iron-excluding foci/cm2). In the rats given EtOH after AFB1, the total area and mean diameter of both iron-excluding foci and altered foci identified in hematoxylin and eosin-stained sections were significantly higher than in the rats exposed to AFB1 alone. The incidence of liver cell tumors of the group given AFB1 and EtOH (3/15, 20%) was higher than that of the group treated with AFB1 alone (0/14, 0%). Treatment with EtOH alone for 56 weeks did not induce either. These results indicate an enhancing effect of EtOH on AFB1-induced hepatocarcinogenesis when it is given in the promotion phase.

Enhanced ethanol-induced changes in disposition and toxic response to dietary aflatoxin B1 due to Sacoglottis gabonensis bark extract, a Nigerian alcoholic beverage additive

The disposition of, and toxic response, to, dietary aflatoxin B1 (AFB1) was investigated in rats ingesting small doses of Sacoglottis gabonensis bark extract, ethanol, or both, in the drinking-water. Ingestion of ethanol alone or with the bark extract for 8 days resulted in a significant reduction in the level of AFB1 bound to serum albumin, but the level of unbound aflatoxin in the serum was significantly depressed only by concurrent ingestion of ethanol and the bark extract. In contrast, the bark extract alone or with ethanol significantly enhanced AFB1 binding to hepatic DNA. As with serum aflatoxin, concurrent ingestion of ethanol and the extract caused the most pronounced effect, suggesting synergism. All three treatments interfered with both the daily excretion pattern, and level, of aflatoxin in the urine. All three treatments enhanced AFB1-induction of liver gamma-glutamyltranspeptidase activity, suggesting potentiation of toxic response to AFB1. These data suggest that addition of the bark extract to alcoholic beverages may affect the biological response to dietary AFB1.