No abstract

Ochratoxin A (OTA) is one of the most widespread mycotoxins, and is produced by several Aspergillus or Penicillium species. Human exposure to OTA is mainly by intake of contaminated food, with cereal products, followed by coffee and red wine as the main sources of OTA. In this study, the OTA production of four ochratoxigenic fungi (two Aspergillus and two Penicillium species) was investigated in four different media, i.e. wheat and coffee model media as food-based media and two standard laboratory media (malt extract glucose agar, MEA and yeast extract sucrose agar, YES). Colony growth was documented and OTA concentrations in cultures were determined at day 2, 4 and 8 of incubation at 25°C by high-performance thin-layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). OTA production clearly depended upon time of incubation, fungal species, and medium composition. On coffee based medium, moderate OTA levels were produced by A. ochraceus BFE635 (9.8 μg/g) and by A. niger BFE632 (10.6 μg/g) on day 8 of incubation. In wheat-based medium, these strains produced much more OTA than in coffee. The highest OTA concentration (83.8 μg/g on day 8) was formed by A. ochraceus BFE635 followed by the other Aspergillus niger BFE632 (49 μg/g). Lower OTA levels were produced by P. verrucosum BFE550 and P. nordicum BFE487, in both wheat and in YES medium, whilst OTA was hardly detectable in coffee and in MEA in case of P. nordicum. Colony growth of the tested strains on different media was not indicative of OTA production. Guttation droplets developed on wheat-based medium with the Aspergillus strains within a week, and this phenomenon coincided with the high OTA amounts formed by these species. Results from this study add to our knowledge on the behaviour of ochratoxigenic fungal species when cultured on food based media.

No abstract

No abstract

A high performance thin-layer chromatographic (HPTLC) method for quantitative analysis of trazodone in human serum has been developed and validated. Trazodone was extracted with n-hexane: isoamyl alcohol (99:1). Chromatographic separation was performed on silica gel 60 F 254 HPTLC plates, with toluene: acetone: ethanol: ammonium (9:7:2:0.5, v/v/v/v) as mobile phase. Densitometric evaluation was carried out at 290 nm. There was no chromatographic interference between trazodone and its major metabolite, m-chlorophenilpiperazine (R f 0.82 and 0.39, respectively). Regression analysis of the calibration plot revealed good linearity (r=0.999) over the range of 20.00 and 200.00 ng/band, corresponding to 0.20 and 2.00 ng/μL of trazodone in human serum after extraction process and applying 10 μL to the chromatographic plates. The % RSD of intra-assay and inter-assay precision, were in the range of 0.98% to 2.97% (n=3) and 1.06% to 3.54% (n=9), respectively. LOD and LOQ were found to be 0.016ng/μL, and 0.048ng/μL, and the recovery values, of trazodone from serum, were between 92.52 % and 96.73 %. This method was successfully applied to quantify trazodone in patient serum samples. In conclusion, the developed method might be useful for the quantitative determination of trazodone in human serum, as a tool to evaluate patient adherence to their pharmacotherapy with this drug.