Exposure of newborns to aflatoxin M1 and B1 from mothers’ breast milk in Ankara,Turkey

Aflatoxins (AFs) are important risks for human health due to their widespread presence in foods and environment. However, contamination risk of breast milk with different pollutants including AFs is high in today’s life conditions. Since breast milk is a major nutrient for infants, feeding of infants with safe milk is essential. Therefore, the objective of this study was to determine the levels of AF M₁ and B₁ in breast milk samples collected from 75 mothers in Ankara, Turkey. AF M₁ and B₁ levels were investigated by high performance liquid chromatography (HPLC) with a fluorescence detector following an extraction procedure. The limit of detection was found to be 5 ng/l. Both AFs were detected in diverse degrees in all breast milk samples: The level of AF M₁ were in the ranges of 60.90–299.99 ng/l, and AF B₁ were in the ranges of 94.50–4123.80 ng/l. These results pointed out the exposure of mothers and neonates to AF M₁ and B₁, and the necessity of further research on mycotoxin contamination both in foods and biological fluids as well as protection strategies.     

Occurrence of aflatoxin M1 in some samples of UHT,raw & pasteurized milk from Indian states of Karnataka and Tamilnadu

Aflatoxin M₁ (AFM₁) is a toxic metabolite found in the milk of lactating animals which have consumed feedstuffs contaminated with aflatoxin B₁. Ultra high temperature treated (UHT) milk is a product which is becoming popular in developing countries like India as there is a lack of proper cold storage or refrigeration facilities. In this study, 45 samples of UHT milk of popular brands prevalent in the market were analyzed for the presence of AFM₁ by reversed phase HPLC using fluorescent detector after cleanup of sample with immunoaffinity columns. All samples of plain UHT milk were positive for AFM₁ and 38% of these contained levels more than 0.5 μg/kg, the maximum permitted limit prescribed by the Codex Alimentarius Commission and by the mandatory regulations of the country, the FSSAI Regulations, 2011. In 62.5% of flavored UHT milk, AFM₁ was below detectable levels (0.02 μg L⁻¹). However, 12.5% of these samples also contained levels exceeding the maximum permitted limits. AFM₁ was present in 61.6% of the 52 raw milk samples analyzed from the two states of Karnataka and Tamilnadu with a range of 0.1–3.8 μg L⁻¹. 17.3% of these samples also exceeded the regulatory limits of the country.     

Glycine N-methyltransferase affects the metabolism of aflatoxin B1 and blocks its carcinogenic effect

Previously, we reported that glycine N-methyltransferase (GNMT) knockout mice develop chronic hepatitis and hepatocellular carcinoma (HCC) spontaneously. For this study we used a phosphoenolpyruvate carboxykinase promoter to establish a GNMT transgenic (TG) mouse model. Animals were intraperitoneally inoculated with aflatoxin B₁ (AFB₁) and monitored for 11 months, during which neither male nor female GNMT-TG mice developed HCC. In contrast, 4 of 6 (67%) male wild-type mice developed HCC. Immunofluorescent antibody test showed that GNMT was translocated into nuclei after AFB₁ treatment. Competitive enzyme immunoassays indicated that after AFB₁ treatment, the AFB₁-DNA adducts formed in stable clones expressing GNMT reduced 51.4% compared to the vector control clones. Experiments using recombinant adenoviruses carrying GNMT cDNA (Ad-GNMT) further demonstrated that the GNMT-related inhibition of AFB₁-DNA adducts formation is dose-dependent. HPLC analysis of the metabolites of AFB₁ in the cultural supernatants of cells exposed to AFB₁ showed that the AFM₁ level in the GNMT group was significantly higher than the control group, indicating the presence of GNMT can enhance the detoxification pathway of AFB₁. Cytotoxicity assay showed that the GNMT group had higher survival rate than the control group after they were treated with AFB₁. Automated docking experiments showed that AFB₁ binds to the S-adenosylmethionine binding domain of GNMT. Affinity sensor assay demonstrated that the dissociation constant for GNMT-AFB₁ interaction is 44.9 μM. Therefore, GNMT is a tumor suppressor for HCC and it exerts protective effects in hepatocytes via direct interaction with AFB₁, resulting in reduced AFB₁-DNA adducts formation and cell death.     

Trp266 determines the binding specificity of a porcine aflatoxin B1 aldehyde reductase for aflatoxin B1-dialdehyde

Aflatoxin B₁ (AFB₁) is a severe threat to human and animal health. The aflatoxin B₁ aldehyde reductase (AFAR) family specifically catalyzes AFB₁-dialdehyde, a toxic metabolic intermediate of AFB₁, producing a nontoxic dialcohol. Although several AFARs have been found and characterized, the binding specificity of the family for AFB₁-dialdehyde remains unclear. Herein, according to the published sequence, we cloned a porcine AFAR gene. Recombinant porcine AFAR was expressed and purified from Escherichia coli as hexa-histidine tagged fusion protein. Using the cloned porcine AFAR as a model, site-directed mutagenesis combined with high performance liquid chromatography studies revealed that the substitution of Trp266 with Ala resulted in almost complete loss of catalytic activity for AFB₁-dialdehyde. Interestingly, the substitution of Met86 with Ala exhibited an obviously increased activity to the dialdehyde. Based on these results and by using molecular docking simulations, this work provides a structural explanation for why the AFAR family exhibits high specificity for AFB₁-dialdehyde. The Trp266 residue in porcine AFAR plays a critical role in stabilizing the binding of AFB₁-dialdehyde in the active pocket through the hydrophobic interaction of the side-chain indole ring of Trp266 with the fused coumarin rings of the dialdehyde molecule. The enhanced activity of M86A may be attributed to the formed π–π stacking interaction between Trp266 and the dialdehyde. In addition, other hydrophobic residues (e.g. Phe and Trp) around the dialdehyde molecule also stabilize the substrate binding. The findings may contribute to understanding the substrate specificity of the AFAR family for AFB₁-dialdehyde.     

Determination of aflatoxin B(1) levels in deep-red ground pepper (isot) using immunoaffinity column combined with ELISA.

Deep-red ground pepper, a variety of red ground pepper, is a special spices belonging to Sanliurfa and consumed both in Sanliurfa and other provinces of Turkey. The aim of this study was to determine the aflatoxin B(1) (AFB(1)) levels of deep-red ground pepper. For this purpose, 75 samples of deep-red ground pepper (isot) marketed in Sanliurfa (Turkey) were purchased from bazaars and herbal shops. The occurrence and concentration range of AFB(1) in the samples were investigated by microtitre plate Enzyme Linked Immunosorbent Assay (ELISA) method using immunoaffinity columns. Seventy-two of the 75 ground deep-red pepper samples (96%) contained AFB(1) in the range of 0.11-24.7 microg/kg. Eleven (14.7%) samples were above the regulatory limits used in the European Union and in Turkey. More precaution should be taken on hygiene controls in order to prevent microbiological and chemical hazards.     

Screening of Lactobacillus casei strains for their ability to bind aflatoxin B1

It has been proposed that the consumption of lactic acid bacteria capable of binding or degrading foodborne carcinogens would reduce human exposure to these deleterious compounds. In the present study, the ability of eight strains of Lactobacillus casei to bind aflatoxin B₁ in aqueous solution was investigated. Additionally, the effect of addition of bile salts to the growth medium on aflatoxin B₁ binding was assessed. The eight strains tested were obtained from different ecological niches (cheese, corn silage, human feces, fermented beverage). The strains exhibited different degrees of aflatoxin binding; the strain with the highest AFB₁ binding was L. casei L30, which bound 49.2% of the available aflatoxin (4.6 μg/mL). In general, the human isolates bound the most aflatoxin B₁ and the cheese isolates the least. Stability of the bacterial–aflatoxin complex was assessed by repeated washings. Binding was to a limited degree (0.6–9.2% release) reversible; the L. casei 7R1–aflatoxin B₁ complex exhibited the greatest stability. L. casei L30, a human isolate, was the strain least sensitive to the inhibitory effects of bile salts. Exposure of the bacterial cells to bile significant increased aflatoxin B₁ binding and the differences between the strains was reduced.     

Mechanisms of butylated hydroxytoluene chemoprevention of aflatoxicosis--inhibition of aflatoxin B1 metabolism

Chemoprevention of toxicoses and/or cancer through the use of nutrients or pharmacologic compounds is the subject of intense study. Among the many compounds examined, food additives such as antioxidants are being considered due to their ability to reduce disease formation by either induction or inhibition of key enzyme systems. One such compound, butylated hydroxytoluene (BHT), has been found to protect against cancer formation caused by exposure to aflatoxin B₁ (AFB₁) in rodents. We have shown that dietary BHT protects against clinical signs of aflatoxicosis in turkeys, a species that is very susceptible to this mycotoxin. In this study, the effect of BHT on AFB₁ metabolism and other cytochrome P450 (CYP)-related enzyme activities in turkey liver microsomes was examined to discern possible mechanisms of BHT-mediated protection against aflatoxicosis. Ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), prototype activities for CYP1A1 and 1A2, respectively, were decreased in the BHT fed (4000 ppm) animals, while oxidation of nifedipine, a prototype activity for CYP3A4, was increased. However, BHT added to microsomal incubations inhibited these CYP activities in a concentration-related manner. Importantly, BHT inhibited conversion of AFB₁ to the reactive intermediate AFB₁-8,-9-epoxide (AFBO), exhibiting Michaelis-Menton competitive inhibition kinetics (Ki = 0.81 μM). Likewise, microsomes prepared from turkeys fed BHT were significantly less active in AFBO formation compared to those from control birds. When turkeys were fed BHT for up to 40 days, residual BHT was present in liver, breast meat, thigh meat and abdominal fat in concentrations substantially below U.S. FDA guidelines for this antioxidant, but in concentrations greater than the Ki, likely sufficient to inhibit bioactivation of AFB₁in vivo. BHT-induced hydropic degeneration in the livers of BHT fed animals was significantly greater in birds that remained on BHT treatment for up to 30 days, but this lesion diminished in animals fed for 40 days or when returned to a control diet. The data indicate that the observed chemopreventive properties of BHT in turkeys may be due, at least in part, to its ability to inhibit hepatic AFB₁ epoxidation and also that the BHT-induced hydropic degeneration is reversible and does not appear to cause long-term effects.     

Occurrence of aflatoxins in mahua (Madhuca indica Gmel.) seeds: Synergistic effect of plant extracts on inhibition of Aspergillus flavus growth and aflatoxin production

Occurrence of aflatoxin in Madhuca indica Gmel. seeds was determined by competitive ELISA. Eighty percent of mahua seed samples were found to be contaminated with aflatoxin. Total aflatoxin content ranged from 115.35 to 400.54 ppb whereas the concentration of AFB₁ was in the range of 86.43 to 382.45 ppb. Mahua oil was extracted by cold press expeller and analysed for contamination of aflatoxin in both the oil and cake samples. Total aflatoxin and aflatoxin B₁ were 220.66 and 201.57 ppb in oil as compared to that in cake samples where it was 87.55 and 74.35 ppb, respectively. Various individual and combined plant extracts were evaluated for their efficacy against growth of Aspergillus flavus and aflatoxin production in vitro. Combination of botanicals were found to be more effective in controlling fungal growth and aflatoxin production than individual extracts. Results of the present study suggests that synergistic effect of plant extracts can be used for control of fungal growth and aflatoxin production. These natural plant products may successfully replace synthetic chemicals and provide an alternative method to protect mahua as well as other agricultural commodities of nutritional significance from toxigenic fungi such as A. flavus and aflatoxin production.     

A longitudinal assessment of aflatoxin M1 excretion in breast milk of selected Egyptian mothers.

Aflatoxins are potent toxins and carcinogens which can be excreted in the milk of exposed lactating mothers mainly in the form of aflatoxin M(1) (AFM(1)). We previously evaluated the level and frequency of AFM(1) in breast milk in a group of Egyptian mothers attending the New El-Qalyub Hospital, Qalyubiyah governorate, Egypt. In this study, fifty of those women who were AFM(1) positive were revisited monthly for 12 months to assess the temporal variation in breast milk AFM(1). AFM(1) was detected in 248 of 443 (56%) samples. In a multilevel model of the data there was a highly significant (p<0.001) effect of month of sampling on the frequency of AFM(1) detection with summer months having the highest frequency (>80%) and winter months the lowest frequency (<20%) of detection. AFM(1) was observed most frequently in June [OR 63, 95% CI (7.6, 522)]. The level of AFM(1) detection also followed this seasonal pattern with highest mean level in July (64 pg/ml milk, range 6.3-497 pg/ml milk) and the lowest mean level in January (8 pg/ml milk, range 4.2-108 pg/ml milk). The duration of lactation [p=0.0035, OR=1.08, 95% CI (1.02, 1.13)], and peanut consumption [p=0.06, OR=1.69, 95% CI (0.9, 2.9)] also contributed to the model. The identification and understanding of factors determining the presence of toxicants in human milk is important and may provide a knowledge driven basis for controlling the transfer of chemicals to infants.     

Metabolism of aflatoxin B1 in turkey liver microsomes: the relative roles of cytochromes P450 1A5 and 3A37

The extreme sensitivity of turkeys to aflatoxin B₁ (AFB₁) is associated with efficient epoxidation by hepatic cytochromes P450 (P450) 1A5 and 3A37 to exo-aflatoxin B₁-8,9-epoxide (exo-AFBO). The combined presence of 1A5 and 3A37, which obey different kinetic models, both of which metabolize AFB₁ to the exo-AFBO and to detoxification products aflatoxin M₁ (AFM₁) and aflatoxin Q₁ (AFQ₁), respectively, complicates the kinetic analysis of AFB₁ in turkey liver microsomes (TLMs). Antisera directed against 1A5 and 3A37, thereby individually removing the catalytic contribution of these enzymes, were used to identify the P450 responsible for epoxidating AFB₁ in TLMs. In control TLMs, AFB₁ was converted to exo-AFBO in addition to AFM₁ and AFQ₁ confirming the presence of functional 1A5 and 3A37. Pretreatment with anti-1A5 inhibited exo-AFBO formation, especially at low, submicromolar (~ 0.1 μM), while anti-3A37, resulted in inhibition of exo-AFBO formation, but at higher (> 50 μM) AFB₁ concentrations. Metabolism in immunoinhibited TLMs resembled that of individual enzymes: 1A5 produced exo-AFBO and AFM₁, conforming to Michaelis-Menten, while 3A37 produced exo-AFBO and AFQ₁ following the kinetic Hill equation. At 0.1 μM AFB₁, close to concentrations in livers of exposed animals, 1A5 contributed to 98% of the total exo-AFBO formation. At this concentration, 1A5 accounted for a higher activation:detoxification (50:1, exo-AFBO: AFM₁) compared to 3A37 (0.15: 1, exo-AFBO: AFQ₁), suggesting that 1A5 is high, while 3A4 is the low affinity enzyme in turkey liver. The data support the conclusion that P450 1A5 is the dominant enzyme responsible for AFB₁ bioactivation and metabolism at environmentally-relevant AFB₁ concentrations in turkey liver.     

Modulation of aflatoxin toxicity and biomarkers by lycopene in F344 rats

Modulation by lycopene of aflatoxin B(1) (AFB(1))-induced toxic effects, metabolism, and metabolic activations was studied in young F344 rats. Animals were pretreated orally with either corn oil (control group) or lycopene [100 mg/kg body weight (b.w.), intervention group] 5 days/week for 2 weeks. Control animals were then treated daily with AFB(1) (250 microg/kg b.w) alone. Intervention animals were administered lycopene (100 mg/kg b.w.) at 1 h following a daily treatment with AFB(1) (250 mug/kg b.w.). Pretreatment and intervention with lycopene significantly reduced the toxic effect caused by AFB(1) and greatly modulated AFB(1) metabolism and metabolic activation. Urinary excretion of AFB(1) phase 1 metabolites, AFM(1), AFQ(1), and AFP(1), was significantly decreased in lycopene-treated animals. Formation of serum AFB(1)-albumin adducts was also significantly reduced. The rate of reduction was from approximately 30% on day 1 (p<0.05) to 67.7% on day 15 (p<0.001). Lycopene intervention also significantly reduced formation of AFB(1)-DNA adducts in liver compared to control animals, with the highest reduction (52.7%) occurring on day 3 (p<0.05). Levels of AFB(1)-N(7)-guanine excreted in urine were also significantly decreased. Urinary excretion of the phase 2 detoxification metabolite, AFB(1)-mecapturic acid, was significantly increased in lycopene-intervened animals. AFB(1)-induced urinary excretion of 8-hydroxydeoxyguanosine was also reduced to 50% on day 7 after lycopene intervention. Collectively, these results suggest that inhibition of phase 1 metabolism and metabolic activation, as well as induction of phase 2 detoxification enzyme activity are the potential mechanisms for the chemopreventive effects of lycopene.     

高效液相色谱-荧光检测法测定沉香中黄曲霉毒素B1、B2、G1、G2

目的建立高效液相色谱–光化学衍生–荧光检测法测定沉香药材中黄曲霉毒素B1、B2、G1、G2。方法采用高效液相色谱法,通过免疫亲和柱提取和净化,荧光检测器检测。Agilent Zorbax Ecilpse Plus C18色谱柱(250 mm×4.6 mm,5μm);流动相:甲醇–水(45∶55);体积流量:0.8 m L/min;柱温:30℃;进样盘温度:4℃;荧光激发波长为360 nm,发射波长为450 nm。结果黄曲霉毒素B1、B2、G1、G2分别在9.3~74.4、3.0~24.0、9.3~74.4、3.5~28.0 pg线性关系良好,r均大于0.998 0;检测限分别为1.86、0.60、1.86、0.70 pg,定量限分别为7.44、2.40、7.44、2.80 pg。平均回收率分别为78%、92%、82%、99%,RSD值分别为4.4%、3.0%、4.3%、2.8%。结论所建立的方法结果准确、重复性、稳定性均良好,可用于沉香药材中黄曲霉毒素的质量控制。     

高效液相色谱-光化学衍生法测定湖南产莲子中黄曲霉毒素G1、G2、B1、B2

目的对不同来源的湖南产莲子中黄曲霉毒素G_1、G_2、B_2、B_1进行高效液相色谱-光化学衍生法测定。方法采用高效液相色谱–光化学衍生法,采用岛津GL Inertsil ODS-3色谱柱(250 mm×4.6 mm,5μm),流动相为甲醇–乙腈–水(35∶13∶52),柱温35℃;光化学衍生器(254 nm)激发波长λ_(ex)=360 nm,发射波长λ_(ex)=450 nm。结果黄曲霉毒素G_1、G_2、B_2、B_1分别在6.7～33.3、11.4～56.8、10.3～51.5、4.1～20.3 pg线性关系良好;平均回收率分别为98.07%、97.72%、96.11%、99.52%,RSD值分别为1.69%、1.40%、2.72%、1.34%(n=6)。9批莲子样品中,有6批未检出黄曲霉毒素,来自于农贸市场农户自存的2批次检出黄曲霉毒素B_1,实验室塑料袋包装储存1年的1批检出黄曲霉毒素B_1、B_2,但质量分数均低于法定标准限量。结论不同来源湖南产莲子中黄曲霉毒素质量分数均低于《中国药典》2020年版规定限量。该法测定结果准确、重复性良好,可为完善莲子安全性控制和质量标准提升提供实验依据。     

Aflatoxin B1 and fumonisin B1 affect the oxidative status of bovine peripheral blood mononuclear cells

Mycotoxins are secondary metabolites having a high cytotoxic potential. They are produced by molds and released in food and feed. To date, the mechanisms underlying the mycotoxin-induced cytotoxicity have not been fully clarified. The induction of oxidative stress, as a possible mechanism, has been postulated. This in vitro study was focused on the effect of two widely occurring mycotoxins, aflatoxin B₁ (AFB₁) and fumonisin B₁ (FB₁), on the oxidative status of bovine peripheral blood mononuclear cells (PBMC) incubated for 2 and 7 days at different levels of AFB₁ (0, 5 and 20 μg/ml) and FB₁ (0, 35 and 70 μg/ml). Reactive oxygen metabolites (ROM), intracellular thiols (SH), malondialdehyde (MDA) and gene expression of cytoplasmic superoxide dismutase (SOD) and glutathione peroxidase (GSHPX-1) were measured on PBMC after incubation. The highest concentration of AFB₁ and all concentrations of FB₁ caused an increase (p < 0.05) of intracellular ROM without any time dependent effect. Intracellular SH decreased with 20 μgAFB₁/ml (p < 0.05) and the effect was particularly marked after 7 days of exposure. Intracellular SH were not affected by FB₁ even though a lower (p < 0.05) SH level after 2 days exposure than after 7 days was observed. MDA increased (p < 0.05) in AFB₁ or FB₁ treated PBMC. The exposure to FB₁ for 7 days increased MDA (p < 0.05) only in cells treated with 70 μg/ml. Exposure of PBMC to AFB₁ reduced SOD mRNA while FB₁ decreased both SOD and GSHPX-1 mRNA abundance. These results demonstrate that, even though by different mechanisms, AFB₁ and FB₁ may induce cytotoxicity through an impairment of the oxidative status of PBMC.     

Study of the Ochratoxin A effect on Aspergillus parasiticus growth and aflatoxin B1 production

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species. Ochratoxin A (OTA) is a metabolite of Aspergillus ochraceus and Penicillium verrucosum. AFB1 and OTA are amongst the most frequent combinations of mycotoxins found in plant products. Thus, synergistic effects or interactions between the two mycotoxins could be taking place. The aim of the present study was to investigate the effect of OTA on Aspergillus parasiticus growth and AFB1 production in yeast extract sucrose (YES) medium at concentrations of 0.16, 1.6 and 16 ng OTA flask(-1). The AFB1 extracted from cultures and purified with immunoaffinity columns was then quantitated by HPLC. The recovery and detection limit of the method were 95.3% and 0.02 ng AFB1 mL(-1), respectively. Maximum AFB1 productions in cultures with OTA were observed from 9 to 12 days (76.09-82.52 ng AFB1 flask(-1)) while in control cultures (without OTA) maximum production (197.2 ng AFB1 flask(-1)) was observed on 14th day. Maximum AFB1 levels in cultures with OTA were reduced by a percentage of 58-61% compared to control cultures. Furthermore AFB1 levels in cultures with OTA were practically (92%) degraded after 18 days of incubation. Conclusively when OTA is present the production of AFB1 by A. parasiticus in YES medium is inhibited.     

Effects of aflatoxin B(1) and fumonisin B(1) on blood biochemical parameters in broilers

The individual and combined effects of dietary aflatoxin B(1 )(AFB(1)) and fumonisin B(1) (FB(1)) on liver pathology, serum levels of aspartate amino-transferase (AST) and plasma total protein (TP) of broilers were evaluated from 8 to 41 days of age. Dietary treatments included a 3 × 3 factorial arrangement with three levels of AFB(1 )(0, 50 and 200 μg AFB(1)/kg), and three levels of FB(1 )(0, 50 and 200 mg FB(1)/kg). At 33 days post feeding, with the exception of birds fed 50 mg FB(1 )only, concentrations of AST were higher (p < 0.05) in all other treatment groups when compared with controls. Plasma TP was lower (p < 0.05) at six days post feeding in groups fed 200 μg AFB(1)/kg alone or in combination with FB(1). At day 33 days post feeding, with the exception of birds fed the highest combination of AFB(1 )and FB(1 )which had higher plasma TP than control birds(, )plasma TP of birds fed other dietary treatments were similar to controls. Broilers receiving the highest levels of AFB(1) and FB(1) had bile duct proliferation and trabecular disorder in liver samples. AFB(1) singly or in combination with FB at the levels studied, caused liver damage and an increase in serum levels of AST.     

Toxicity,biochemical effects and residue of aflatoxin B1 in marine water-reared sea bass (Dicentrarchus labrax L.)

Aflatoxicosis and resulting epizootic hepatoma have been reported among a wide range of fish where Aspergillus species-contaminated foodstuffs are incorporated into the diet. Aflatoxin B₁ (AFB₁) is among the most potent known hepatotoxins and carcinogens. Therefore, it is an important potential toxicant to the most of the popularly cultured fish species. The present study was undertaken to assess the susceptibility and toxicity of AFB₁ to sea bass (Dicentrarchus labrax L.), by behavioral and biochemical evaluations. The estimated oral acute median lethal concentration (96 h LC₅₀) of AFB₁ for sea bass was 0.18 mg/kg bwt. The abnormal behavioral responses and signs of toxicity were described. The prolonged oral administration of 0.018 mg/kg bwt AFB₁ to sea bass for 42 successive days induced a significant increase in serum transaminases and alkaline phosphatase activities, and significant decrease in plasma proteins. Residual AFB₁ was detected at high levels (≈5 ppb) in fish musculature at the end of the experimental period. We conclude that marine water sea bass is a species highly sensitive to AFB₁. In addition, consumption of sea bass reared on AFB₁-contaminated diet could have a negative health impact on human health.     

红参中总皂苷及人参皂苷Rg1、Re、Rb1

目的测定不同产地的26批红参药材中总皂苷及人参皂苷Rg₁、Re、Rb₁的含量。方法采用紫外可见分光光度法测定红参中总皂苷的含量,高效液相色谱法测定红参中人参皂苷Rg 1、Re、Rb 1的含量。结果26批红参药材中总皂苷含量为1.2%~3.0%,人参皂苷Rg₁、Re含量之和为0.17%~0.61%,人参皂苷Rb₁含量为0.21%~0.81%。结论不同产地的红参药材总皂苷及人参皂苷Rg₁、Re、Rb₁的含量存在差异,提示应进一步规范红参药材的种植、加工炮制及标准的建立。     

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.