Hcy-thiolactone/creatinine ratio is a novel AMI risk predictor in patients with suspected CAD, independent of traditional risk factors and tHcy, but modified by vitamin B catabolism. These findings lend a support to the hypothesis that Hcy-thiolactone is mechanistically involved in cardiovascular disease.

Context: The main source of bufadienolides is toad venom; however, plants such as members of Kalanchoe Adans. (Crassulaceae) genus may also synthesize these bioactive substances. Objective: This is the first study on antioxidant effects and cytotoxicity of bufadienolide-rich fraction isolated from Kalanchoe daigremontiana Raym.-Hamet & H. Perrier. Materials and methods: The methanolic fraction was extracted from the plant roots and contained 0.48 mg bufadienolides/mg of dry mass (11a,19-dihydroksytelocinobufagin, bersaldegenin-1-acetate, bersaldegenin-1,3,5-orthoacetate, 19-(acetyloxy)-3b,5b,11a,14-tetrahydroxyl-12-oxo-bufa-20,22-dienolide and 19-(acetyloxy)-1b,3b,5b,14-tetrahydroxyl-bufa-20,22-dienolide, mainly). The cytotoxicity of K. daigremontiana fraction was evaluated in an in vitro experimental model of blood platelets. The viability of blood platelets was determined on the basis of a release of lactate dehydrogenase. Results: The fraction scavenged DPPH radicals, with EC 50 of 21.80 lg/mL. Studies on an experimental model of blood plasma under peroxynitrite-induced oxidative stress revealed that the plant preparation had moderate antioxidant properties. Levels of 3-nitrotyrosine and thiol groups indicated that the protective effect of K. daigremontiana was significant mainly for its concentration of 50 lg/mL. No effect was found in prevention of oxidation of low-molecular plasma thiols (glutathione, cysteine and cysteinylglycine). Simultaneously, measurements of lipid hydroperoxides and thiobarbituric acid-reactive substances (TBARS) indicated that the examined fraction might be effective antioxidant at broader concentration range, that is 1-5 and 25-50 lg/mL for hydroperoxides and TBARS generation, respectively. No cytotoxicity was observed at the concentration range of 1-50 lg/mL. Conclusions: Based on the obtained results, we suggest that antioxidant activity may additionally contribute to beneficial properties of K. daigremontiana-derived extracts.ARTICLE HISTORY

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In this work, the use of square-wave adsorptive stripping voltammetry (SWAdSV) in combination with boron-doped diamond electrode modified with multiwalled carbon nanotubes (MWCNTs-BDDE) and β-cyclodextrin (β-CD, β-CD-MWCNTs-BDDE) for the determination of the fungicide carbendazim (Cbz) is described for the first time. Cbz oxidation response was observed in the Britton-Robinson buffer supporting electrolyte in a pH range from 2.3 to 6.0 in potential range from + 1.0 to + 1.3 V vs SCE. The SWAdSV peak current of Cbz oxidation response on β-CD-MWCNTs-BDDE with peak maxima close to + 1.2 V vs SCE at pH 4.0 was linear over the wide linear dynamic range of 6.72 × 10 . The obtained results demonstrated the viability of the proposed methodology for determination of Cbz in river water samples containing low concentrations of Cbz. Moreover, the effect of Cbz on the corrosion properties of an AISI type 316 L stainless steel used to fabricate farming equipment and tools was tested by means of the potentiodynamic method. The characterization and evaluation of the corrosion inhibition effect raised from the use of Cbz was performed using optical microscope.

Gas chromatography–mass spectrometry technique (GC-MS) is mainly recognized as a tool of first choice when volatile compounds are determined. Here, we provide the credible evidence that its application in analysis can be extended to non-volatile sulfur-containing compounds, to which methionine (Met), homocysteine (Hcy), homocysteine thiolactone (HTL), and cysteine (Cys) belong. To prove this point, the first method, based on GC-MS, for the identification and quantification of Met-related compounds in human saliva, has been elaborated. The assay involves simultaneous disulfides reduction with tris(2-carboxyethyl)phosphine (TCEP) and acetonitrile (MeCN) deproteinization, followed by preconcentration by drying under vacuum and treatment of the residue with a derivatizing mixture containing anhydrous pyridine, N-trimethylsilyl-N-methyl trifluoroacetamide (MSTFA), and trimethylchlorosilane (TMCS). The validity of the method was demonstrated based upon US FDA recommendations. The assay linearity was observed over the range of 0.5–20 µmol L−1 for Met, Hcy, Cys, and 1–20 µmol L−1 for HTL in saliva. The limit of quantification (LOQ) equals 0.1 µmol L−1 for Met, Hcy, Cys, while its value for HTL was 0.05 µmol L−1. The method was successfully applied to saliva samples donated by apparently healthy volunteers (n = 10).

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