Publications by authors named "Andrej Smidovnik"

Coenzyme Q10 (CoQ10) is an essential cofactor in the mitochondrial electron transport pathway, and is also the only known endogenously synthesized lipid-soluble antioxidant. The aim of the present study was to determine, for the first time, endogenous plasma CoQ10 concentration and its correlation with plasma total antioxidant capacity (TAC) and serum total cholesterol (TC) in a population of healthy untrained horses. Thirty-one horses were included in the study.

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The present paper demonstrates that electrochemical detection (ECD) coupled to ion chromatography and electrospray ionization tandem mass spectrometry (IC-ECD-ESI/MS/MS) can be used to rapidly estimate some indications of the health status of organisms. The lactulose to mannitol ratio (L/M) is used as a non-invasive assay to investigate small intestinal absorption pathways and mucosal integrity. In the present study, an evaluation of the negative effects of nonsteroidal anti-inflammatory drug meloxicam perorally administrated to a group of dogs was carried out by determining the lactulose/mannitol index using the IC-ECD-ESI/MS/MS hyphenated technique.

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The development of some sensitive assays for quantitative nutritional analysis with an emphasis on selected hyphenated analytical techniques is reviewed in the present paper. The majority of work is dedicated to reviewing the development of analytical tools for routine analysis of carbohydrates and lipids in biological samples, many of them introduced in our laboratory. Handling biological matrices, where endogenous compounds can mask the analyte of interest or where the occurrence of the coelution effect of several compounds present in different amounts hinders the analyte's peak integration, is a major challenge.

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This article deals with the oxidation problems of food caused by atmospheric oxygen. Two approaches to overcome these problems are involved: (i) by reducing the double bonds in unsaturated fatty acids in lipids, the so-called hydrogenation; and (ii) by introduction of some antioxidants, modified by cyclodextrins, in order to protect food against the oxidation processes. In the area of hydrogenation, an alternative method of hydrogenation was presented, catalytic transfer hydrogenation of edible oils, using sodium formate as a hydrogen donor.

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The mass spectrometric characterization of aqueous solutions of alpha- and beta-cyclodextrins (CDs) and o-, m- and p-coumaric acids (CAs) by negative ion electrospray ionization (ESI) indicates that the [CD+CA](-) ions were sourced from the inclusion complex present in solution and from the anion attached to CD molecules formed in the spray processes. The anion adducts formed in the spray process contribute significantly to the signal intensity of an ionized inclusion complex thus overestimating the calculated stability constant (K) of solution-phase complexes by one to two orders of magnitude. The relative intensities of anion adducts in mass spectra depend on the concentration ratio of the anion and the CD in spray droplets, while the relative intensity of the ionized inclusion complex depends on CD and CA concentrations in solutions and the value of K.

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Background: Coenzyme Q10 (CoQ10) is a naturally occurring compound that plays a fundamental role in cellular bioenergetics and is an effective antioxidant. Numerous health benefits of CoQ10 supplementation have been reported, resulting in growing demands for its use in fortifying food. Due to its insolubility in water, the enrichment of most food products is not easily achievable and its in vivo bioavailability is known to be poor.

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The bioavailability of a novel water-soluble inclusion complex of CoQ10, prepared in our laboratory was determined and compared with the bioavailability of commercially available oil-based form of CoQ10. Experimental work consisted of single dose comparative bioavailability study on seven beagle dogs, with a 14-day washout period between treatments. Identification and quantification of CoQ10 was done with HPLC-MS method using positive APCI ionization and SIM mode, M+ m/z 863.

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