Abstract Aflatoxin B1 Research Articles

A methanolic extract of Zanthoxylum bungeanum modulates secondary metabolism regulator genes in Aspergillus flavus and shuts down aflatoxin production

Aflatoxin B1 (AFB1) is a food-borne toxin produced by Aspergillus flavus and a few similar fungi. Natural anti-aflatoxigenic compounds are used as alternatives to chemical fungicides to prevent AFB1 accumulation. We found that a methanolic extract of the food additive Zanthoxylum bungeanum shuts down AFB1 production in A. flavus. A methanol sub-fraction (M20) showed the highest total phenolic/flavonoid content and the most potent antioxidant activity. Mass spectrometry analyses identified four flavonoids in M20: quercetin, epicatechin, kaempferol-3-O-rhamnoside, and hyperoside. The anti-aflatoxigenic potency of M20 (IC50: 2–4 µg/mL) was significantly higher than its anti-proliferation potency (IC50: 1800–1900 µg/mL). RNA-seq data indicated that M20 triggers significant transcriptional changes in 18 of 56 secondary metabolite pathways in A. flavus, including repression of the AFB1 biosynthesis pathway. Expression of aflR, the specific activator of the AFB1 pathway, was not changed by M20 treatment, suggesting that repression of the pathway is mediated by global regulators. Consistent with this, the Velvet complex, a prominent regulator of secondary metabolism and fungal development, was downregulated. Decreased expression of the conidial development regulators brlA and Medusa, genes that orchestrate redox responses, and GPCR/oxylipin-based signal transduction further suggests a broad cellular response to M20. Z. bungeanum extracts may facilitate the development of safe AFB1 control strategies.

Preparation of recombinant Kluyveromyces lactis agents for simultaneous degradation of two mycotoxins

Aflatoxin B1 (AFB1) and zearalenone (ZEN) are widely distributed in corns, peanuts, and other cereals, causing serious threat to food safety and human health. As shown by our previous studies, the recombinant yeast strain Kluyveromyces lactis GG799(pKLAC1-ZPF1) had the ability of degrading AFB1 and ZEN simultaneously. In this work, the agent preparation process was optimized for K. lactis GG799(pKLAC1-ZPF1), and the storage conditions of the prepared yeast agents were investigated, for obtaining the products with high storage activities and potent mycotoxin degradation efficiency. The optimal preparation process was as follows: centrifugation at 6000 rpm for 15 min for collection of the yeast cells, spray drying with the ratio of protective compounds to yeast cells at 3:1 (w/w) and then stored at − 20 °C. Simultaneous degradation tests of AFB1 and ZEN were performed using the supernatants of reactivated yeast agents after three months of storage, and the degradation ratios for AFB1 and ZEN in reaction system 1 (70.0 mmol/L malonic buffer, pH 4.5, with 1.0 mmol/L MnSO4, 0.1 mmol/L H2O2, 5.0 μg/mL AFB1 and ZEN, respectively) were 48.2 ± 3.2% and 34.8 ± 2.8%, while that for ZEN in reaction system 2 (50.0 mmol/L Tris–HCl, pH 7.5, with 5.0 μg/mL AFB1 and ZEN, respectively) was 30.1 ± 2.7%. Besides, the supernatants of reactivated yeast agents degraded more than 80% of AFB1 and 55% of ZEN in contaminated peanuts after twice treatments. Results of this work suggested that the optimized process for K. lactis GG799(pKLAC1-ZPF1) was with high value for industrial applications.

Autophagy up-regulated by MEK/ERK promotes the repair of DNA damage caused by aflatoxin B1

Aflatoxin B1 (AFB1), a kind of mycotoxin, exerts its cytotoxicity by increasing the oxidative damage of target organs, especially the liver. In vivo and in vitro experiments were carried out to elucidate the toxic mechanism of AFB1. The results of MTT, cloning-formation, flow cytometry, immunocytochemistry, Reverse transcription PCR (RT-PCR) and western blot showed that AFB1 activated NOX2 gp91 phox, inhibited proliferation and migration, and blocked cell cycle at G0/G1 period of HHL-5 cells. Autophagy promoted the repair of NOX2-dependent DNA damage. NOX2/gp91 phox mainly activates MEK/ERK pathway and then up-regulates autophagy. In vivo experiments have shown that AFB1 (0.75 mg/kg daily orally, 4 weeks) had no significant changes in the size and shape of the liver in mice. However, these treatments lead to structural abnormalities of hepatocytes and DNA damage. In summary, AFB1 caused intracellular oxidative stress and DNA damage, NOX2/gp91-phox activates the MEK/ERK pathway, and upregulated autophagy to promote the repair of DNA damage. We concluded that by increasing the level of autophagy, the ability of anti-AFB1 toxicity of liver can be increased.

A kinetic analysis of the aflatoxin detoxification potential of lactic acid bacteria in Terxine (a cereal-based food)

Aflatoxin B1 (AFB1) is a hazardous component that can seriously threaten the public health. Terxine is a component used in traditional soup and found in the western mountainous regions of Iran. Several microorganisms have been reported to bind or degrade aflatoxins (AFs) in foods and feeds. This research aimed to investigate the effect of Terxine fermentation byLactobacillus plantarumstrains AF1 and LU5 on AFB1. Fermentation was carried out, and pH, lactic acid and AFB1 amount and microbial count were further determined. In addition, the kinetic experimental data of AFB1 by L. plantarumAF1 and LU5 (obtained at 37°C) were fitted to the zero-order, first-order and parabolic diffusion models. According to the coefficient of determination (R2) and root mean square of errors (RMSE), the zero-order model best described AF degradation. The growth of Lactobacillus strains was increased by the rise in the fermentation time; in this regard, the number of L. plantarum AF1 increased from 4.2 to 5.1 log cfu/g and that of L. plantarum LU5 increased from 4.1 to 5.2 log cfu/g in the first 8h, reaching 7.2 and 7.4 log cfu/g in the next 8h, respectively. The results also showed that the amount of lactic acid increased whereas the pH value decreased during the 24h fermentation. Both microorganisms reduced the amount of AFB1 while L. plantarum AF1 was more effective. Therefore, L. plantarumstrains AF1 and LU5 can be effectively used to reduce AFB1 in fermented foods.

Aflatoxin B1 Induces Gut-Inflammation-Associated Fecal Lipidome Changes in F344 Rats

Abstract Aflatoxin B1 (AFB1) induced intestinal epithelial damage in rodent models, which indicates that long-term exposure to AFB1 may cause chronic gut disorders. In this study, we tested the hypothesis that AFB1-induced adverse effects on gut is mediated by gut-microbiota, which is partially reflected by the changes of fecal microbiome and metabolome. F344 rats were orally exposed to AFB1 of 0, 5, 25, and 75 µg kg−1 body weight for 4 weeks and fecal samples were collected. An ion-fragmentation-spectrum-based metabolomics approach was developed to investigate the fecal microbiota-associated metabolic changes in fecal samples. We found that AFB1 inhibited the hepatic and intestinal metabolism of bile constituents. As compared with the controls, bile acid synthesis-associated cholesterols in rats treated with 25 µg kg−1 (the middle-dose group) were significantly decreased in the fecal samples, for example, lathosterol (45% reduction), cholesterol ester (21% reduction), chenodeoxycholic acid (20% reduction), dihydroxycholesterol (55% reduction), hydroxycholesterol (20% reduction), and 5-cholestene (29% reduction). Although disease-associated lipids were not detectable in the feces of the control group, they were found in AFB1-treated groups, including diglyceride, monoacylglyceride, 19,20-dihydroxy-docosapentaenoic acid, and phosphatidylethanolamine. Metabolisms of carbohydrates and production of short-chain fatty acids were remarkedly decreased in all treated groups. Moreover, an inflammatory-bowel-disease (IBD)-associated taxonomic structure of fecal microbiota was observed as ∼25% Lachnospiraceae, ∼25% Ruminococcaceae, and <1% Lactobacillales, which was similar to the composition pattern found in IBD patients. These results suggest that AFB1-induced disruption on gut-microbiota, partially reflected by fecal microbiome and metabolome, may play important roles in the pathogenesis of chronic gut disorders.

Aflatoxin B1 inhibited autophagy flux by inducing lysosomal alkalinization in HepG2 cells

Aflatoxin B1 (AFB1) is a hazard food pollutant and the most toxic one of all the aflatoxins. It is mainly metabolized in the liver and exerts strong hepatotoxicity and carcinogenesis. Autophagy is an important biological process to maintain the homeostasis of intracellular environment. But the role of autophagy in AFB1-exposured hepatotoxicity remains unclear. The objective of this study was to explore the effect of AFB1 on autophagy flux and its potential mechanisms in HepG2 cells. The data showed AFB1 with no-observed adverse effect level (NOAEL) induced the accumulation of autophagosomes by detecting the level of LC3 and MDC staining. Subsequent findings revealed that autophagosome accumulation was caused by the inhibition of autophagy flux by transfection mRFP-GFP-LC3 adenovirus in the presence of autophagy inhibitor 3-MA and CQ. Further, we investigated lysosomal pH by Acridine orange (AO) and Lysotracker Red (LTR) staining and found that AFB1 exposure caused lysosomal alkalinization. These results indicated AFB1 with NOAEL could inhibit autophagy flux by inducing lysosomal alkalinization. Our study was helpful to further explain early hepatotoxicity mechanism of AFB1.

Desarrollo de un nanosensor aptamérico basado en nanotriángulos de oro para la detección de aflatoxina B1 mediante LSPR

La aflatoxina B1 (AFB1) es una micotoxina producida por la especie de hongos Aspergillus que afecta a una gran variedad de productos agrícolas como la kiwicha. La AFB1 es conocida por ser nefrotóxica, hepatotóxica y carcinogénica, lo que ha llevado a una estricta regulación en todo el mundo y a la necesidad de tener nuevos métodos que permitan su detección rápida, sencilla y selectiva. Los nanosensores aptaméricos basados en nanotriángulos de oro (AuNTs) surgen como una alternativa simple y eficaz a los sistemas tradicionales de detección. Por una parte, los aptámeros hacen que el sistema sea estable y muy selectivo debido a su gran afinidad, pero a un bajo costo y, por otro, las excepcionales propiedades ópticas de las nanopartículas de oro permiten implementar el sensor en una técnica analítica sencilla como la espectroscopía UV-Vis-NIR. Esto se debe a la resonancia de plasmón superficial localizado (LSPR), que permite monitorear la interacción entre el aptámero y la toxina y relacionar los cambios espectrales con el contenido de micotoxina. Los nanosensores aptaméricos desarrollados en esta investigación fueron evaluados en diferentes solventes y tampones, siendo el mejor de ellos el de PBS pH 7.5 (R2 = 0.98101) logrando detectar AFB1 en el rango de 0-780 ppbs. Adicionalmente, el análisis multivariante por regresión de mínimos cuadrados parciales (PLS) de los espectros logró obtener un límite de detección de 22 ppbs. Finalmente, los nanosensores han demostrado ser lo suficientemente robustos para obtener buenos resultados aun en matrices complejas como extractos de kiwicha.

Structural dynamics studies on the binding of aflatoxin B1 to chicken egg albumin using spectroscopic techniques and molecular docking

Aflatoxin B1, a mycotoxin produced by large number of Aspergillus species including Aspergillus flavus and Aspergillus parasiticus, has been described as the most potent carcinogenic mycotoxin. In this study, we have used a multiple spectroscopic and molecular docking approach to investigate the interaction of aflatoxin B1 (AFB1) with chicken egg albumin (CEA). Fluorescence spectroscopy, UV-Vis spectroscopy, and three-dimensional fluorescence spectroscopic techniques were employed to gain insight into the conformational changes in CEA in the presence of AFB1. Fluorescence spectroscopy revealed ligand-induced quenching in the fluorescence emission spectra of CEA upon binding with AFB1. Hyperchromic effect was observed in case of the ground state complex formation between CEA and AFB1 by UV-Vis spectroscopy. To gain further comprehension into the site of binding of AFB1 to CEA, competitive site marker displacement assay was performed using warfarin site marker. The magnitude of ΔG value calculated from fluorescence-based method was negative which confirmed spontaneous process. The results obtained suggest that the binding is enthalpy driven and van der Waals force and hydrogen bonds are stabilizing the AFB1-CEA complex. Three-dimensional fluorescence studies also confirmed the quenching in the fluorescence intensity around tryptophan residues in CEA. Circular dichroism assessment revealed reduction in the alpha helical content of CEA in the presence of AFB1. Molecular docking studies showed hydrophobic interaction, van der Waals forces, and hydrogen bonds as major forces present in interaction between CEA and AFB1. The overall study confirms conformational and structural alteration in the protein due to binding of AFB1.Communicated by Ramaswamy H. Sarma

Aflatoxin M1 and B1 in Colombian milk powder and estimated risk exposure

ABSTRACTAflatoxin M1 (AFM1) and aflatoxin B1 (AFB1) were determined in 51 milk powder samples purchased from different grocery stores located in the Caribbean region of Colombia. Analysis was conducted using QuEChERS extraction and high-performance liquid chromatography with fluorescence detection. Results from the analytical method showed recovery ranges from 65% to 110% and relative standard deviations lower than 20%. AFM1 was detected in 100% of the milk samples (0.20–1.19 µg/kg) and 55% exceeded the maximum level in milk (0.5 µg/kg) set by the Colombian and European regulations. AFB1 was not detected in any of the analysed samples. Considering the measured contamination the maximum AFM1 level that can be ingested by consumption of milk powder is 0.007–0.013 µg/person/day. These values are above the average dietary intake estimated in Latin America according to the Joint FAO/WHO Expert Committee, which is 0.0035 µg/person/day.

Measures against aflatoxin B1: a brief review about the use of flavonoids and clays

http://dx.doi.org/10.5007/2175-7925.2017v30n1p1A aflatoxina B1 (AFB1) é uma das micotoxinas mais abundantes e tóxicas produzidas por cepas toxigênicas. Esta substância afeta a viabilidade celular, sendo capaz de induzir a morte, tanto de células humanas, quanto de células animais. Medidas vêm sendo adotadas para minimizar os danos causados pela AFB1, incluindo a utilização de flavonoides (compostos polifenólicos extraídos de plantas) e bentonitas (um tipo de argila). Nesta revisão, as características físico-químicas da AFB1 e seus efeitos em diferentes tipos de células, in vitro e in vivo, foram abordados. Além disso, a capacidade de proteção celular a partir de substâncias e materiais naturais, tais como flavonoides e bentonita, foi brevemente descrita. Também relatamos os efeitos econômicos causados pelas micotoxinas e sugerimos alternativas (flavonoides e bentonita) para novas abordagens terapêuticas visando combater a toxicidade causada por estas substâncias (AFB1).

Short communication: Inhibitory effects of dietary aflatoxin B1 on cytokines expression and T-cell subsets in the cecal tonsil of broiler chickens

Aflatoxin B1 (AFB1) is the most toxic form among the mycotoxins. Cytokines are important mediators of the immune system. T-cell subsets play a crucial role in cell-mediated immunity. The aim of present study was to evaluate the effects of dietary AFB1 on the cytokines expression and T-cell subsets in the cecal tonsil of broiler chickens throughout a 21-day experimental period. One hundred and fifty six one-day-old broiler chickens were randomly divided into control group (0 mg AFB1/kg feed) and AFB1 group (0.6 mg pure AFB1/kg feed). At 7, 14 and 21 days of age, the levels of seven cytokines (IL-2, IL-4, IL-6, IL-10, IL-17, IFN-γ and TNF-α) mRNA expression as well as the proportions of T-cell subsets (CD3+, CD3+CD4+, CD3+CD8+) by qRT-PCR and flow cytometry methods were assessed in the cecal tonsils. The levels of the seven cytokines mRNA expression and the percentages of T-cell subsets significantly decreased at 14 and 21 days of age in the AFB1 group compared with the control group. However, the CD4+/CD8+ ratio was not significantly changed. These results demonstrate that 0.6 mg/kg AFB1 dietary exposure reduced the levels of cytokines mRNA expression and the percentages of T-cell subsets in the cecal tonsils of broiler chickens, suggesting that the cell-mediated immunity of cecal tonsils might be impaired in broilers.

Effect of p53 Arg72Pro polymorphism on the induction of micronucleus by aflatoxin B1 in in vitro in human blood lymphocytes

Aflatoxin B1 (AFB1) is a class 1 carcinogen produced by Aspergillus flavus and Aspergillus parasiticus that can contaminate a variety of food substances, the liver being its target organ. A common p53 Arg72Pro polymorphism resulting in the substitution of an arginine amino acid by proline amino acid in the transactivating domain has been demonstrated to affect p53 function. The aim of this study is to investigate association between p53 Arg72Pro polymorphism and the frequencies of spontaneous and AFB1-induced DNA damage in peripheral blood lymphocytes from 100 healthy individuals in Turkish population. In vitro cytokinesis-blocked micronucleus (CBMN) assay was used to detect the spontaneous and AFB1-induced DNA damage whereas, genotyping of p53 Arg72Pro polymorphism was carried out by using a polymerase chain reaction restriction fragment length polymorphism assay. During 68 h incubation time, lymphocytes treated with AFB1 (1.56 μg/mL) and S9 mix for a total of 3 h (48–51 h). Treatment of the lymphocytes with AFB1significantly increased the overall frequencies of micronucleus (MN) when compared to untreated cultures (1.23 ± 0.05 versus 0.55 ± 0.02; p < 0.001). Moreover, genotype analysis revealed a statistically significant association between Pro/Pro genotype of p53 Arg72Pro polymorphism and increased frequencies of MN both spontaneous and AFB1-induced cultures when compared Arg/Arg genotype (0.69 ± 0.19 versus 0.46 ± 0.13, p < 0.001; 1.59 ± 0.65 versus 1.01 ± 0.41 p < 0.001; respectively). Our data indicate that p53 Arg72Pro polymorphism plays a significant role in human sensitivity to the genotoxic effects of AFB1. Further investigations in larger sample size and with different ethnic origins as well as including more functional single nucleotide polymorphisms might lead to the identification of novel genetic factors responsible for susceptibility to human carcinogens such as AFB1.

Expression of V(H)-linker-V(L) orientation-dependent single-chain Fv antibody fragment derived from hybridoma 2E6 against aflatoxin B1 in Escherichia coli.

Aflatoxin B1 (AFB1) is a toxic secondary metabolic product, which threatens human and animal health. Antibody is a key factor for immunoassay against toxic stuff like AFB1, and single-chain Fv antibody fragment (scFv) has become a popular format of genetically engineered antibody. In this study, four hybridoma cell lines against AFB1 were obtained, and then scFvs 2E6 derived from hybridoma cell line 2E6 were constructed in different V(H)/V(L) orientations. Subsequently, scFvs 2E6 were expressed in E. coli BL21(DE3) mainly in the form of inclusion body. SDS-PAGE, Western blot and ELISA were employed to characterize scFvs 2E6. The results revealed that the yield of inclusion body of scFvs 2E6 in either V(H)/V(L) orientation was similar; however, only the scFv in V(H)-linker-V(L) orientation showed anti-AFB1 bioactivity after refolding. The present study underscores the importance of choosing optimal V(H)/V(L) orientation for scFv construction, and scFv may be favorable for immunoassays in food industry.

Protective effects of sodium selenite against aflatoxin B1on haemoglobin content, erythrocyte count, and immune adherence function in broilers

Aflatoxin B1 (AFB1), commonly found in feed stuffs causes hepatocellular carcinoma and immunosuppression. Selenium (Se) is mainly known as an important antioxidant and immunostimulant. To evaluate the protective effects of dietary sodium selenite against AFB1_induced erythocytic toxicology, one hundred male Avian broilers were randomly divided into five groups viz. : fed with basal diet (control group), 0.3mg/kg AFB1 (AFB1 group), 0.3mg/kg AFB1+0.2mg/kg Se (+Se group ‘!), 0.3mg/kg AFB1+0.4mg/kg Se (+Se group a!) and 0.3mg/kg AFB1+0.6mg/kg Se (+Se group b!), respectively. At 7, 14 and 21 days of the experiment, the red blood cells (RBC count), content of hemoglobin (Hb) and the immune adherence function were determined. Compared with control group, the number of RBC in AFB1 group was increased, while the content of Hb and erythrocyte rosette rates in AFB1 group were decreased significantly. Dietary sodium selenite, however, could decrease the number of RBC; increase the content of Hb and erythrocyte rosette rate significantly. It was indicated that sodium selenite in the diets could exert protective effects against AFB1-induced damage on the red blood cells, and the transport capacity and immune adherence function of erythocyte could be maintained.

Aflatoxin B1 in betel nuts (Areca catechu L.) imported to Pakistan from different regions of South Asia

Aflatoxin B1 (AFB1) levels were evaluated in betel nuts (Areca catechu L.) being imported to Pakistan during 2010–2011. In total, 278 betel nut samples (India = 21, Indonesia = 51, Sri-Lanka = 34 and Thailand = 172) were received from the Department of Customs and were analysed by thin layer chromatography (TLC). All Indian origin betel nuts showed AFB1 contamination ranging from 11.7–262.0 µg kg−1 with a mean of 92.5 µg kg−1. Among Indonesian and Sri Lankan shipments, 80.4% and 73.5% betel nuts were contaminated with AFB1 ranging between 3.3–39.2 and 6.5–103.4 µg kg−1 with a mean of 11.6 and 35.0 µg kg−1, respectively. However, only 30.2% of Thailand origin samples showed AFB1 contamination ranging 3.3–77.0 µg kg−1 with a mean of 6.6 µg kg−1. The widespread occurrence of AFB1 increases the hazard associated with betel nuts. Thus, strict control is a pre-requisite for the production and import/export of psychoactive substances as betel nuts.

In vitro study of AFB1 and AFM1 effects on human lymphoblastoid Jurkat T-cell model

Aflatoxin B1 (AFB1) is a mycotoxin produced by Aspergillus spp. that can occur as a natural contaminant in foods and feeds of vegetable origin. Post-ingestion, AFB1 can be metabolized in the liver of mammals into hydroxylated aflatoxin M1 (AFM1) that is excreted with milk. Although several studies have been carried out to evaluate effects of AFB1 on the immune system, studies regarding AFM1 are moreover lacking. The aim of the current study was to investigate effects of AFB1 and AFM1 on immune function using a lymphoblastoid Jurkat T-cell line as an experimental model. Both AFB1 and AFM1 produced significant decreases in Jurkat cell proliferation, whereas only minor effects were noted on interleukin (IL)-2 and interferon (IFN)-γ cytokines mRNA expression in stimulated cells that had been pre-incubated with AFB1 and AFM1. Particularly, AFB1, but not AFM1, at the highest concentration (50 µM) induced a marked increase in IL-8 mRNA expression. The results of the current study suggested the existence of a concentration threshold for AFB1 and AFM1 needed to exert biological activity on cell viability and innate immunity.

Aflatoxins in selected Thai commodities

Aflatoxin (AF) B1, B2, G1 and G2 were determined in 120 samples of selected Thai commodities including unpolished rice, unpolished glutinous rice, chilli powder, whole dried chilli pods and raw peanut. The mean concentrations of the total AFs for analysed samples were 0.16, 25.43, 14.18, 6.62 and 1.43 µg kg−1 with positive incidences of 4%, 20%, 97%, 37% and 30%, respectively. Quantitative analysis was performed using HPLC equipped with post-column derivatisation and fluorescence detection. Sample clean-up was carried out using immunoaffinity columns for selective enrichment of AFs. The method was validated by using certified reference material, which showed recoveries over 85%. The limit of detections (LODs) and limit of quantifications (LOQs) were in a range between 0.01–0.11 µg kg−1 and 0.03–0.38 µg kg−1, respectively. The results clearly demonstrated that AFs were detectable in different matrices. Chilli powder was found to have the highest level of AFs contamination followed by chilli pods, peanut and rice, respectively. However, among the selected commodities, unpolished rice contained only trace levels of AFB1 and AFB2. With regard to the fact that AFs are a natural contaminant in commodities, this report calls to attention the regular monitoring and effective control of food commodities to prevent health hazards.

Reduction in the urinary aflatoxin M1 biomarker as an early indicator of the efficacy of dietary interventions to reduce exposure to aflatoxins

Aflatoxin B1 is a persistent public health issue in Ghana. Assessment of AFB1 intervention efficacy is currently dependent on long-term biomarkers. This study was designed to determine whether daily AFM1 biomarker levels could be utilized as an early detection method for intervention efficacy. Participants were treated with a refined calcium montmorillonite clay (UPSN) or a placebo (calcium carbonate) in a crossover study. Urine samples were assessed for AFM1 levels daily. UPSN treatment reduced AFM1 biomarkers by 55% compared to the placebo. This is the first study to show that daily urinary AFM1 levels can be used as a biomarker of internal aflatoxin B1 exposure in short-term intervention trials to determine efficacy.

Screening and Identification of an Aflatoxin B&lt;sub&gt;1&lt;/sub&gt;-Degradation Strain from Moldy Cereals

Aflatoxin B1(AFB1), as a kind of mycotoxin produced by Aspergillus spp., is a highly toxic substance and widely distributed in food matrix. Cumarin was used first as the only carbon and energy source to screen the strains which were separated from different kinds of food. The strains selected were then added into nutrient agar and broth media to assess the ability to deplete AFB1. Results showed that a strain isolated from mustiness foodstuff was able to degrade AFB1 in nutrient broth, with a degradation rate of 26.3% after 48h fermentation. The microorganism was identified as a strain of Aspergillus niger, with analysis of phylogenetic tree based on 18S rDNA. This provides a potential solution for biological degradation of AFB1.

Chemical Profile, Antioxidant, Antifungal and Antiaflatoxigenic Activity of Parsley and Ginger Volatile and Non-Volatile Extracts

Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Natural products refer that aromatic components of spices can control the production of aflatoxins. With a view to controlling aflatoxin production, the volatile and nonvolatile extracts from parsley and ginger were obtained by hydrodistillation and ethanol extraction. Antifungal activities of the extracts were studied with special reference to the inhibition of Aspergillus flavus growth and aflatoxin production. Minimal inhibitory (MIC) and minimal fungicidal concentrations of the extracts were determined. Parsley essential oil showed a stronger inhibitory effect than ginger on the growth of A. flavus. On the contrary, ginger ethanolic extract has superior inhibition for aflatoxin production at 20000 ppm (92.93 %). The essential oils of parsley and ginger analyzed by GC-MS) comprised 19.17 % and 8.67 % monoterpenes, 59.74 % and 82.8 % sesquiterpenes, 1.99 % and 3.18 % oxygenated monoterpenes, and 18.98 % and 3.93 % oxygenated sesquiterpenes, respectively and the major volatile compounds in the parsley were myristicin (44%), apiole (16.8%), copaene (13.39%) and β-pinene (6.91%), where as zingibrine (37.65 %), δ-amorphene (19.76%) and α-curcumin (11.32 %) in ginger oil. The antioxidant activity (IC50) of parsley extracts, as compared with that of TBHQ were superior to ginger extracts in DPPH and β-carotene/bleaching assays. It is concluded that both the essential oils could be safely used as preservative materials for some kinds of foods to protect them from toxigenic fungal infections and highlight the potential of this food plants for their possible clinical uses.