Synthesis and reactions of [1]benzofuro[3,2-c]pyridine

(E)-3-(1-Benzofuran-2-yl)propenoic acid (I) was prepared from 1-benzofuran-2-carbaldehyde under the Doebner’s conditions. The obtained acid was converted to the corresponding azide II, which was cyclized by heating in diphenyl ether to [1]benzofuro[3,2-c]pyridin-1(2H)-one (III). This compound was aromatized with phosphorus oxychloride to chloroderivative IV which was reduced with zinc and acetic acid to the title compound V. [1]Benzofuro[3,2-c]pyridin-2-oxide (VI) was synthesized by reaction of V with 3-chloroperoxybenzoic acid in dichloromethane. Treatment VI with benzoyl chloride and potassium cyanide (Reissert-Henze reaction) was shown to produce the corresponding [1]benzofuro[3,2-c]pyridin-1-carbonitrile (VII). The title compound was used for preparation of complex compounds VIII, IX

Effect of Hexane Extracts of Chromolaena odorata (Linn.) on Hematotoxicity Induced by Cyanide in Male Albino Wistar Rats

Aim: To investigate the effect of Hexane extract of Chromolaena odorata (HECO) on cyanide induced hematotoxicity in male Albino Wistar rats. Methodology: Thirty-five (35) male albino rats weighing between 100g and 150g were distributed randomly into 7 groups of 5 rats each. Group 1 which comprised of normal rats received distilled water and served as the normal control, while groups 2-7 comprised of rats exposed to Potassium cyanide (KCN) (3 mg/kg). Group 2 received no treatment and served as the negative control. Groups 3, 4 and 5 received 100, 150 and 200 mg/kg of HECO respectively. Group 6 received 200 mg/kg HECO and 200 mg/kg sodium thiosulphate while group 7 was treated with a sodium thiosulphate (200 mg/kg), an established antidote, and served as the positive control. All administrations were done via the oral route and lasted for 14 days. Complete blood count was conducted after the experimental period. Data were analyzed using one-way analysis of variance, followed by Tukeys multiple comparisons test and P < .05 was considered significant. Results: Results obtained indicate Red cell indices and white blood cell and differential were all significantly raised (P < .05) in treated rats relative to the negative control rats. Platelet value and Mean corpuscular volume were raised and lowered respectively during induction by the treatments, however, no statistical significance (P < .05) was observed. The results therefore suggest that C. odorata could be valuable in the management of the hematological changes induced by cyanide. Conclusion: HECO reversed the adverse hematological changes in rats induced by cyanide at 100, 150 and 200 doses, with the 200 mg dose being more effective.

Rhodaneses Enzyme Addition Could Reduce Cyanide Concentration and Enhance Fiber Digestibility via In Vitro Fermentation Study

The use of cyanide-containing feed (HCN) is restricted because it causes prussic acid poisoning in animals. The objective of this study was to see how adding rhodanese enzyme to an HCN-containing diet affected gas dynamics, in vitro ruminal fermentation, HCN concentration reduction, and nutrient digestibility. A 3×4 factorial arrangement in a completely randomized design was used for the experiment. Factor A was the three levels of potassium cyanide (KCN) at 300, 450, and 600 ppm. Factor B was the four doses of rhodanese enzyme at 0, 0.65, 1, and 1.35 mg/104 ppm KCN, respectively. At 96 h of incubation, gas production from an insoluble fraction (b), potential extent (omit gas) (a + b), and cumulative gas were similar between KCN additions of 300 to 450 ppm (p > 0.05), whereas increasing KCN to 600 ppm significantly decreased those kinetics of gas (p < 0.05). Supplementation of rhodanese enzymes at 1.0 to 1.35 mg/104 ppm KCN enhanced cumulative gas when compared to the control group (p < 0.05). Increasing the dose of rhodanese up to 1.0 mg/104 ppm KCN significantly increased the rate of ruminal HCN degradation efficiency (DE) by 70% (p < 0.05). However, no further between the two factors was detected on ruminal fermentation and in vitro digestibility (p > 0.05). The concentration of ammonia-nitrogen (NH3-N) increased with increasing doses of KCN (p < 0.05), but remained unchanged with varying levels of rhodanese enzymes (p > 0.05). The in vitro dry matter digestibility (IVDMD) was suppressed when increasing doses of KCH were administered at 600 ppm, whereas supplementation of rhodanese enzymes at 1.0–1.35 mg/104 ppm KCN enhanced IVDMD (p < 0.05). Increasing doses of KCN affected reduced total volatile fatty acids (TVFA) concentration, which was lowest when 600 ppm was added (p < 0.05). Nevertheless, the concentration of TVFAs increased when rhodanese enzymes were included by 1.0–1.35 mg/104 ppm KCN (p < 0.05). Based on this study, it could be concluded that supplementation of rhodaneses enzyme at 1.0–1.35 mg/104 ppm KCN could enhance cumulative gas, digestibility, and TVAF, as well as lowering ruminal HCN concentration.

A novel procedure for stabilization of azide in biological samples and method for its determination (HS-GC-FID/FID)

Sodium azide is an old poison with toxicity comparable to potassium cyanide. It would seem to be completely forgotten however, between 2000 and 2020, the number of intentional ingestions and murders committed with sodium azide significantly increased. Furthermore, due to its extreme instability, sodium azide is difficult to detect, which poses an additional risk when used to commit a crime. In this study, the epidemiology of sodium azide exposures between 1920 and 2020 was investigated. For the determination the azide concentration in biological samples, a simple, precise and selective headspace gas chromatography method (HS-GC-FID/FID) was developed and fully validated. The limit of quantification was 0.65 µg/mL; and the limit of detection was 0.35 µg/mL; precision and accuracy did not exceed 20%. The stability study was conducted for various biological fluids (urine, bile, blood, gastric content) for 91 days in the refrigerator (4 °C) and the method for stabilization of azide was presented. The addition of a mixture of borax and sodium fluoride (w/w 3:1) to the test tubes can stabilize this poison. The described unique technique of collecting the biological samples poses a great potential for azide detection in clinical and toxicology laboratories even long time after human exposure to this substance.

Structural and Biochemical Characterization of a Dye-Decolorizing Peroxidase from Dictyostelium discoideum

A novel cytoplasmic dye-decolorizing peroxidase from Dictyostelium discoideum was investigated that oxidizes anthraquinone dyes, lignin model compounds, and general peroxidase substrates such as ABTS efficiently. Unlike related enzymes, an aspartate residue replaces the first glycine of the conserved GXXDG motif in Dictyostelium DyPA. In solution, Dictyostelium DyPA exists as a stable dimer with the side chain of Asp146 contributing to the stabilization of the dimer interface by extending the hydrogen bond network connecting two monomers. To gain mechanistic insights, we solved the Dictyostelium DyPA structures in the absence of substrate as well as in the presence of potassium cyanide and veratryl alcohol to 1.7, 1.85, and 1.6 Å resolution, respectively. The active site of Dictyostelium DyPA has a hexa-coordinated heme iron with a histidine residue at the proximal axial position and either an activated oxygen or CN− molecule at the distal axial position. Asp149 is in an optimal conformation to accept a proton from H2O2 during the formation of compound I. Two potential distal solvent channels and a conserved shallow pocket leading to the heme molecule were found in Dictyostelium DyPA. Further, we identified two substrate-binding pockets per monomer in Dictyostelium DyPA at the dimer interface. Long-range electron transfer pathways associated with a hydrogen-bonding network that connects the substrate-binding sites with the heme moiety are described.

Structural and Biochemical Characterization of a Dye Decolorizing Peroxidase from Dictyostelium discoideum

A novel cytoplasmic dye decolorizing peroxidase from Dictyostelium discoideum was investigated that oxidizes anthraquinone dyes, lignin model compounds and general peroxidase substrates like ABTS efficiently. Unlike related enzymes, an aspartate residue replaces the first glycine of the conserved GXXDG motif in Dictyostelium DyPA. In solution, Dictyostelium DyPA exists as a stable dimer with the side chain of Asp146 contributing to the stabilization of the dimer interface by extending the hydrogen bond network connecting two monomers. To gain mechanistic insights, we solved the Dictyostelium DyPA structures in the absence of substrate as well as in the presence of potassium cyanide and veratryl alcohol to 1.7, 1.85, and 1.6 &Aring; resolution, respectively. The active site of Dictyostelium DyPA has a hexa-coordinated heme iron with a histidine residue at the proximal axial position and either an activated oxygen or CN- molecule at the distal axial position. Asp149 is in an optimal conformation to accept a proton from H2O2 during the formation of compound I. Two potential distal solvent channels and a conserved shallow pocket leading to the heme molecule were found in Dictyostelium DyPA. Further, we identified two substrate-binding pockets per monomer in Dictyostelium DyPA at the dimer interface. Long-range electron transfer pathways associated with a hydrogen-bonding network that connects the substrate-binding sites with the heme moiety are described.