Application of pressurized liquid extraction in the analysis of aflatoxins B1, B2, G1 and G2 in nuts
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Aflatoxins (AFs) B(1), B(2), G(1) and G(2) were extracted from nuts by using pressurized liquid extraction (PLE) and the PLE extracts were analyzed using HPLC with fluorescence detection using photochemical post-column derivatization without further cleanup procedures. Several extraction parameters such as temperature (25, 40, 60 and 80 degrees C), pressure (500, 1000, 1500 and 2000 psi), solvent extraction mixture (acetone, acetonitrile, ethyl acetate and methanol), number of cycles (1 and 2), use of dispersing agents and cell size (5 and 11 mL) were investigated for their effects on the extraction performance. The results showed 60 degrees C, 1500 psi, acetonitrile, one cycle and a cell size of 5 mL as most favorable PLE operating conditions. The proposed analytical method provides LODs below the maximum levels established by European Union regulations and the recoveries of the four AFs were between 77 and 93% at spiking levels of 4, 2 and 0.5 microg/kg for AFB(1) and AFG(1) and 1, 0.5 and 0.13 microg/kg for AFB(2) and AFG(2). Validation was carried out using certified reference materials. PLE has been applied for the first time to the analysis of AFs in nuts and offers the possibility for fast simple and accurate quantitative determination of studied mycotoxins.Aspergillus parasiticus
Food contaminant
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Aspergillus parasiticus
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Aspergillus parasiticus
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Extract of Vernonia condensata (Asteraceae = Compositae) leaves has different uses in Brazilian folk medicine, which includes analgesic and antiinflamatory agent. The aim of this study was to apply a modified simplex-centroid mixture design to evaluate the best extractor system for the antinociceptive activity, evaluated by writhing test. Different solvents (acetone, dichloromethane, ethanol and ethyl acetate) as well as their binary, ternary and quaternary mixtures were used. For comparison, aqueous extract was also evaluated. LD50 was estimated and qualitative phytochemical screening, conducted. The extracts with antinociceptive activity were: aqueous, acetone, dicloromethane (DCM), ethanol (ETOH), acetone-DCM, acetone-ETOH, acetone-ethyl acetate, ETOH-ethyl acetate, acetone-DCM-ethyl acetate, acetone-ETOH-ethyl acetate and DCM-ETOH-ethyl acetate. The higher margin of safety (LD50/ED50) was for acetone > acetone-ETOH-ethyl acetate > aqueous > ETOH = acetone-ETOH > DCM > acetone-ethyl acetate > DCM-ETOH-ethyl acetate > acetone-DCM > acetone-DCM-ethyl acetate. Phytochemical screening showed that all the extracts contained alkaloids, phenolic compounds, flavonoids, tannins and saponins. In conclusion, the extractor system influences both the pharmacological activity and acute toxicity of leaves from V. condensata. Acetone and the ternary mixture, acetone-ETOH-ethyl acetate extracts showed higher margin of safety than aqueous extract.
Phytochemical
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Water extraction
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It is well known that cattle ingesting aflatoxin B1 contaminated feed commodities excrete aflatoxin M1 into their milk. As aflatoxin M1 originates from hepatic metabolism, measures to prevent aflatoxin M1 formation need to be directed to either the immobilization of aflatoxin B1 in the gastrointestinal tract or the modification of hepatic metabolism of aflatoxin B1. Here we studied the influence of oltipraz and a second dithiolthione, (1,2) dithiolo (4,3-c)-1,2-dithiole-3,6 dithione (DDD) on bovine hepatic aflatoxin B1 biotransformation. Oltipraz inhibited aflatoxin B1 metabolism as no aflatoxin M1 and no aflatoxin B1-dihydrodiol, the second metabolite found in bovine hepatocytes, was formed. DDD did not significantly inhibit aflatoxin B1 metabolism. It could be demonstrated that the inhibition of aflatoxin B1 metabolism was due to the inhibition of several cytochrome P450 enzyme activities by oltipraz. In contrast, DDD inhibited only ethoxyresorufin O-deethylation activity. These findings suggest a high efficacy of oltipraz in inhibiting aflatoxin M1 contamination of milk from dairy cows exposed to aflatoxin B1 contaminated feeds.
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In this study, a sensitive and accurate immunoaffinity columns coupled with high-performance liquid chromatography method was established to monitor the presence of aflatoxins-aflatoxin B1 , aflatoxin B2 , aflatoxin G1 , and aflatoxin G2 -in different medicinal herbs. The proposed method was found to be suitable for the detection of aflatoxins in eight kinds of herbs and their corresponding granules. Two batches of Arecae semen were positive for aflatoxins, with high residue levels of different aflatoxins. To better understand the presence and transfer of aflatoxins during the formulation of dispensing granules from the herbs, the aflatoxins-free herbs were artificially inoculated with Aspergillus flavus to explore aflatoxins production. Both aflatoxin B1 and aflatoxin B2 were detected in all inoculated samples, while aflatoxin G2 was only detected in Astragali radix samples. Additionally, the presence of aflatoxin B1 was extremely high compared to other aflatoxins. More specifically, the transfer rate of the aflatoxin B1 and the total aflatoxins from original herbs to granules were both approximately 40%. These findings indicated that the preparation of herbs into dispensing granules reduced the content of aflatoxins. The high-level presence of aflatoxins in inoculated herbs indicated that attention is needed to the safety of A. flavus-contaminated herbs.
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Mycotoxins are toxic secondary metabolites and most mycotoxins produced by filamentous fungi can grow on food, especially before harvest and in storage. When humans and animals eaten, inhaled or absorbed through the skin mycotoxins, it can cause illness or death to humans and animals. There are 20 groups of secondary metabolites of fungal aflatoxins but only four identified aflatoxin in foods that aflatoxin B1 (AFB1), Aflatoxin B2 (FB2), Aflatoxin G1 (AFG1) and Aflatoxin G2 (AFG2) (Polychronaki et al., 2008: Liu, Y., and Wu, F.2010) A COMPARATIVE
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