Exposure to aflatoxins in the adult Malaysian diet was estimated by analysing aflatoxins in 236 food composites prepared as "ready for consumption". Dietary exposure to aflatoxin B1 (AFB1) ranged from 24.3 to 34.00 ng/kg b.w./day (lower to upper bound), with peanuts being the main contributor. Estimated liver cancer risk from this exposure was 0.61-0.85 cancers/100,000 population/year, contributing 12.4%-17.3% of the liver cancer cases. Excluding AFB1 occurrence data higher than 15 µg/kg reduced exposure by 65%-91% to 2.27-11.99 ng/kg b.w./day, reducing the cancer risk to 0.06-0.30 cancers/100,000 population/year (contributing 1.2%-6.1% liver cancer cases). Reducing further the ML of AFB1 from 15 to 5 µg/kg yielded 3%-7% greater drop in the exposure to 0.47-10.26 ng/kg b.w./day with an estimated risk of 0.01-0.26 cancers/100,000 population/year (0.2%-5.1% liver cancer cases attributed to dietary AFB1). These findings indicate that current MLs are adequate in protecting Malaysians' health.
The effect of ovariectomy and sex hormone/s replacement in female rats was investigated by the determination of the tumour marker enzymes gamma-glutamyltranspeptidase (GGT) and alkaline phosphatase (ALP). This was compared to ovariectomized rats receiving sex hormone replacement and treated with carcinogen. Ovariectomy significantly increased the activity of plasma GGT. Plasma and microsomal ALP and microsomal GGT were unchanged. When replacements of estrogen (E), or progesterone (Prog), or combinations of both estrogen and progesterone were given to ovariectomized rats, the activity of plasma GGT was brought to the level of normal intact females. Treatment with carcinogen increased the PGGT activities in intact rats. In ovariectomized rats receiving carcinogen, the PGGT activities were significantly lower than in intact females and rats receiving both hormone replacement and carcinogen (p < 0.01). Carcinogen treatment in case of estrogen or progesterone replacement, either individually or in combination, showed GGT activities comparable to intact females receiving carcinogen. Both plasma and microsomal ALP were not affected by carcinogen administration. These results showed that ovariectomy reduced the severity of hepatocarcinogenesis while sex hormone replacement worsened the process.
Methyl eugenol (ME), is converted into two major phenylpropanoids, 2-allyl-4,5-dimethoxyphenol and trans-coniferyl alcohol, following consumption by the male fruit fly Bactrocera papayae. Chemical analysis of wild male B. papayae rectal glands, where the compounds are sequestered, revealed the presence of ME metabolites in varying quantities. These phenylpropanoids are shown to be involved in the fruit fly defense both in no-choice and choice feeding tests against the Malayan spiny gecko, Gekko monarchus. After being acclimatized to feeding on fruit flies, geckos consumed significantly fewer ME-fed male flies than controls that consumed all the ME-deprived male flies offered throughout a two-week period. Diagnosis of dissected livers from geckos that consumed ME-fed male flies revealed various abnormalities. These included discoloration and hardening of liver tissue, whitening of the gallbladder, or presence of tumor-like growths in all geckos that consumed ME-fed male flies. Control geckos fed on ME-deprived male flies had healthy livers. When given an alternative prey, geckos preferred to eat untreated house flies, Musca domestica to avoid preying on ME-fed fruit flies.
The effects of long-term administration of tocotrienol on hepatocarcinogenesis in rats induced by diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) were investigated by determining the activities of gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), glutathione S-transferases (GSTs), and glutathione (GSH) levels in blood and liver. Twenty-eight male 7- to 8-wk-old Rattus norwegicus rats, weighing 120-160 g, were used in this study. The rats were divided into four treatment groups: a control group on a basal diet, a group fed a basal diet supplemented with tocotrienol (30 mg/kg food), a group treated with DEN/AAF, and a group treated with DEN/AAF and fed a diet supplemented with tocotrienol (30 mg/kg food). Blood was collected monthly, and GGT, ALP, and GSH levels were determined. The rats were killed after 9 mo, and the livers were examined morphologically. Grayish white nodules (2/liver) were found in all the DEN/AAF-treated rats (n = 10), but only one of the rats treated with DEN/AAF and supplemented with tocotrienol (n = 6) had liver nodules. A significant increase in the level of blood and liver GSH, ALP, and GGT activities was observed in the DEN/AAF-treated rats. Liver GSTs were similarly increased with DEN/AAF treatment. Tocotrienol supplementation attenuated the impact of the carcinogens in the rats.
Brewers' rice, which is known locally as temukut, is a mixture of broken rice, rice bran, and rice germ. Our present study was designed to identify the effect of brewers' rice on the attenuation of liver and kidney damage induced by azoxymethane (AOM). Alanine transaminase (ALT), alkaline phosphatase (ALP), aspartate transaminase (AST), creatinine, and urea were evaluated to understand potential hepatoprotective effects and the ability of brewers' rice to attenuate kidney pathology induced by AOM treatment. Liver and kidney tissues were evaluated by hematoxylin and eosin (H&E) staining. Overall analyses revealed that brewers' rice improved the levels of serum markers in a manner associated with better histopathological outcomes, which indicated that brewers' rice could enhance recovery from hepatocyte and kidney damage. Taken together, these results suggest that brewers' rice could be used in future applications to combat liver and kidney disease.
Zerumbone (ZER), a monosesquiterpene found in the subtropical ginger (Zingiber zerumbet Smith), possesses antiproliferative properties to several cancer cells lines, including the cervical, skin and colon cancers. In this study, the antitumourigenic effects of ZER were assessed in rats induced to develop liver cancer with a single intraperitoneal injection of diethylnitrosamine (DEN, 200 mg/kg) and dietary 2-acetylaminofluorene (AAF) (0.02%). The rats also received intraperitoneal ZER injections at 15, 30 or 60 mg/kg body wt. twice a week for 11 weeks, beginning week four post-DEN injection. The hepatocytes of positive control (DEN/AAF) rats were smaller with larger hyperchromatic nuclei than normal, showing cytoplasmic granulation and intracytoplasmic violaceous material, which were characteristics of hepatocarcinogenesis. Histopathological evaluations showed that ZER protects the rat liver from the carcinogenic effects of DEN and AAF. Serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (AP) and alpha-fetoprotein (AFP) were significantly lower (P<0.05) in ZER-treated than untreated rats with liver cancer. The liver malondialdehyde (MDA) concentrations significantly (P<0.05) increased in the untreated DEN/AAF rats indicating hepatic lipid peroxidation. There was also significant (P<0.05) reduction in the hepatic tissue glutathione (GSH) concentrations. The liver sections of untreated DEN/AAF rats also showed abundant proliferating cell nuclear antigen (PCNA), while in ZER-treated rats the expression of this antigen was significantly (P<0.05) lowered. By the TUNEL assay, there were significantly (P<0.05) higher numbers of apoptotic cells in DEN/AAF rats treated with ZER than those untreated. Zerumbone treatment had also increased Bax and decreased Bcl-2 protein expression in the livers of DEN/AAF rats, which suggested increased apoptosis. Even after 11 weeks of ZER treatment, there was no evidence of abnormality in the liver of normal rats. This study suggests that ZER reduces oxidative stress, inhibits proliferation, induces mitochondria-regulated apoptosis, thus minimising DEN/AAF-induced carcinogenesis in rat liver. Therefore, ZER has great potential in the treatment of liver cancers.