Molecular Mechanisms of Lipoic Acid Protection against Aflatoxin B1-Induced Liver Oxidative Damage and Inflammatory Responses in Broilers

Alpha-lipoic acid (α-LA) was evaluated in this study for its molecular mechanisms against liver oxidative damage and inflammatory responses induced by aflatoxin B₁ (AFB₁). Birds were randomly allocated into four groups with different diets for three weeks: a basal diet, a 300 mg/kg α-LA supplementation in a basal diet, a diet containing 74 μg/kg AFB₁, and 300 mg/kg α-LA supplementation in a diet containing 74 μg/kg AFB₁. In the AFB₁ group, the expression of GSH-P_X mRNA was down-regulated (p < 0.05), and the levels of lipid peroxide and nitric oxide were increased (p < 0.05) in the chicken livers compared to those of the control group. Additionally, the mRNA level of the pro-inflammatory factor interleukin-6 was up-regulated significantly (p < 0.05), the protein expressions of both the nuclear factor kappa B (NF-κB) p65 and the inducible nitric oxide synthase were enhanced significantly (p < 0.05) in the AFB₁ group. All of these negative effects were inhibited by α-LA. These results indicate that α-LA may be effective in preventing hepatic oxidative stress, down-regulating the expression of hepatic pro-inflammatory cytokines, as well as inhibiting NF-κB expression.     

Nation-Based Occurrence and Endogenous Biological Reduction of Mycotoxins in Medicinal Herbs and Spices

Medicinal herbs have been increasingly used for therapeutic purposes against a diverse range of human diseases worldwide. Moreover, the health benefits of spices have been extensively recognized in recent studies. However, inevitable contaminants, including mycotoxins, in medicinal herbs and spices can cause serious problems for humans in spite of their health benefits. Along with the different nation-based occurrences of mycotoxins, the ultimate exposure and toxicities can be diversely influenced by the endogenous food components in different commodities of the medicinal herbs and spices. The phytochemicals in these food stuffs can influence mold growth, mycotoxin production and biological action of the mycotoxins in exposed crops, as well as in animal and human bodies. The present review focuses on the occurrence of mycotoxins in medicinal herbs and spices and the biological interaction between mold, mycotoxin and herbal components. These networks will provide insights into the methods of mycotoxin reduction and toxicological risk assessment of mycotoxin-contaminated medicinal food components in the environment and biological organisms.     

Bioaccessibility Study of Aflatoxin B1 and Ochratoxin A in Bread Enriched with Fermented Milk Whey and/or Pumpkin

The presence of mycotoxins in cereals and cereal products remains a significant issue. The use of natural ingredients such as pumpkin and whey, which contain bioactive compounds, could be a strategy to reduce the use of conventional chemical preservatives. The aim of the present work was to study the bioaccessibility of aflatoxin B₁ (AFB1) and ochratoxin (OTA) in bread, as well as to evaluate the effect of milk whey (with and without lactic acid bacteria fermentation) and pumpkin on reducing mycotoxins bioaccessibility. Different bread typologies were prepared and subjected to an in vitro digestion model. Gastric and intestinal extracts were analyzed by HPLC–MS/qTOF and mycotoxins bioaccessibility was calculated. All the tested ingredients but one significantly reduced mycotoxin intestinal bioaccessibility. Pumpkin powder demonstrated to be the most effective ingredient showing significant reductions of AFB1 and OTA bioaccessibility up to 74% and 34%, respectively. Whey, fermented whey, and the combination of pumpkin-fermented whey showed intestinal bioaccessibility reductions between 57–68% for AFB1, and between 11–20% for OTA. These results pointed to pumpkin and milk whey as potential bioactive ingredients that may have promising applications in the bakery industry.     

Levels of Aflatoxin M1 in Breast Milk of Lactating Mothers in Monterrey,Mexico: Exposure and Health Risk Assessment of Newborns

The present study aimed to determine the presence of the aflatoxin M1 (AFM1) in breast milk samples from 123 nursing women and the degree of exposure of infants to this toxin, in the metropolitan area of Monterrey, Nuevo Leon state (northeast Mexico). Upon analysis, 100% of the samples were found to be contaminated with the toxin at an average concentration of 17.04 ng/L, with a range of 5.00 to 66.23 ng/L. A total of 13.01% of the breast milk samples exceeded the regulatory limit of 25 ng/L for AFM1 concentration, set by the European Union. The estimated daily intake for AFM1 and the carcinogenic risk index were also determined in the 0- to 6-, 7- to 12-, 13- to 24-, and 25- to 36-month-old age groups. The AFM1 intake through breast milk ranged from 1.09 to 20.17 ng/kg weight/day, and was higher than the tolerable daily intake, indicating a carcinogenic risk for infants in the age groups of 0- to 24-months old. This evidence demonstrates a susceptibility of breast milk to AFM1 contamination that may suggest a carcinogenic risk for the breastfed infants in Monterrey city, Nuevo Leon state, and the need to control the presence of aflatoxins in foods eaten by nursing mothers.     

Chemoprevention of liver cancer by plant polyphenols

Primary liver cancer or hepatocellular carcinoma (HCC) is one of the most frequent tumors representing the fifth commonest malignancy worldwide and the third cause of mortality from cancer. Currently, the treatments for HCC are not so effective and new strategies are needed for its fight. Chemoprevention, the use of natural or synthetic chemical agents to reverse, suppress or prevent carcinogenesis is considered an important way for confronting HCC. Many of the chemopreventive agents are phytochemicals, namely non-nutritive plant chemicals with protective or disease preventive properties. In this review, we focus on plant polyphenols, one of the most important classes of phytochemicals, their chemopreventive properties against HCC and discuss the molecular mechanisms accounting for this activity.     

Urinary biomarkers of aflatoxin exposure in young children from Egypt and Guinea.

Aflatoxins are a major risk factor for hepatocellular carcinoma (HCC), and thus understanding the pattern of aflatoxin exposure in different regions is important in order to develop targeted intervention strategies. Given the early onset of HCC in many countries early life exposures may be important. This study investigated aflatoxin exposure in Egyptian children (n=50, aged 1-2.5 years) by assessing urinary aflatoxin metabolite (AFM(1), AFB(1), AFB(2), AFG(1), AFG(2)) levels. Samples from Guinean children (n=50, aged 2-4 years) were analyzed in parallel providing a comparison to a region of established frequent aflatoxin exposure. Aflatoxins were isolated from urine using C18-cartridges followed by immunoaffinity clean-up, and quantified by HPLC with fluorescence detection. Overall aflatoxins were less frequently present in Egyptian (38%) than Guinean urine samples (86%) (p<0.001), which was particularly related to differences in detection rates of AFM(1) (8% compared to 64%, respectively, (p<0.001)). For AFM(1) the geometric mean level in Guinea (16.3 pg/ml; 95% CI: 10.1, 26.6 pg/ml) was 6-fold higher (p<0.001) than in Egypt (2.7 pg/ml; 95% CI: 2.5, 2.8 pg/ml). Urinary aflatoxins from healthy children in these two regions have not previously been reported, and exposure appears modest in Egypt compared to Guinea. These data suggest that measures to reduce aflatoxin exposure in both regions are important, though particularly in Guinea.     

Elevation of 8-hydroxydeoxyguanosine in DNA from isolated mouse lung cells following in vivo treatment with aflatoxin B(1).

Aflatoxin B(1) (AFB(1)) is a mycotoxin produced by some strains of Aspergillus and is a recognized pulmonary and hepatic carcinogen. The most widely accepted mechanism of AFB(1) carcinogenicity involves bioactivation to AFB(1)-8,9-exo-epoxide and binding to DNA to form AFB(1)-N(7)-guanine. Another potential cause of DNA damage is AFB(1)-mediated stimulation of reactive oxygen species formation, leading to oxidation of DNA bases. The objective of this study was to determine the ability of AFB(1) to cause oxidative DNA damage in lung cell types of the A/J mouse. The formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in freshly isolated mouse lung alveolar macrophages, alveolar type II cells, and nonciliated bronchial epithelial (Clara) cells was assessed by high-performance liquid chromatography with electrochemical detection. An approximately 3-fold increase in 8-OHdG formation occurred in both alveolar macrophage and Clara cell preparations isolated from A/J mice 2 h following treatment with a single tumorigenic dose of 50 mg/kg AFB(1) ip (n = 3, p < 0.05). Prior treatment with 300 kU/kg polyethylene glycol-conjugated catalase prevented the AFB(1)-induced increase in 8-OHdG levels in all mouse lung cell preparations (n = 3, p < 0.05). These results support the possibility that oxidative DNA damage in mouse lung cells contributes to AFB(1) carcinogenicity.     

中药中黄曲霉毒素检测概况

介绍了近10年来中药污染黄曲霉毒素检测概况,早期研究主要采用TLC和ELISA法均发现部分中药污染了黄曲霉素,但实验报告结果差异很大,而且尚未形成公认的标准方法。评述了TLC、ELISA和IAC-衍生化HPLC荧光检测法。认为ELISA法可能发展成为样品的快速检测方法,而IAC-HPLC检测法是最有前途的方法,目前国内外在食品检测中采用的多种衍生物方法均可引入用于中药检测。     

黄曲霉毒素高危区肝细胞癌患者微粒体环氧化物水解酶基因检测

目的 :探讨微粒体环氧化物水解酶 (microsomalepoxidehydrolase ,mEH)低活性基因型与肝细胞癌 (hepatocellularcarcinoma ,HCC)的相关性。方法 :应用PCR RFLP和PCR方法检测 5 2例HCC患者和5 6例健康成人中微粒体环氧化物水解酶及谷胱甘肽硫转移酶M1和T1基因型频率的分布。结果 :发现mEH第 3外显子 113纯合组氨酸型和第 4外显子 139纯合组氨酸型都是低活性基因型 ,在HCC组和对照组分别占 5 7 1% (30 /5 2 )、4 8 2 % (2 7/5 6 ) ,82 7% (4 3/5 2 )、73 2 % (4 1/5 6 ) ,两组比较差异无显著意义 ,P >0 0 5。然而 ,mEH低活性型联合谷胱甘肽硫转移酶 (glutathiones transferase ,GST)M1和T1基因缺失型 ,差异有显著意义 ,P <0 0 5。结论 :mEH处于低活性基因型可能是地区性易感HCC的原因之一 ,但单一种解毒酶不起决定作用 ,多种解毒酶联合作用 ,可增加HCC危险性