Young herbaceous legumes – a natural reserve of bioactive compounds and antioxidants for healthy food and supplements

Young plants of clover (Trifolium pratense L. and T. medium L.), medick (Medicago sativa L. and M. lupulina L.), sainfoin (Onobrychis viciifolia Scop.) and milkvetch (Astragalus glycyphyllos L. and A. cicer L.), were investigated for total contents of phenolics, flavonoids, isoflavones, condensed tannins and triterpene saponins as well as their extracts for antiradical and ferrous ion chelating activity. The impact of two sample drying methods on the aforementioned characters was compared. The phytochemical concentrations were higher in the freeze-dried legumes; however, antioxidant activities were generally higher of oven-dried samples. Both the composition of health promoting phytochemicals and antioxidant properties were strongly species-dependent. Among the species tested, Trifolium spp. were most abundant in isoflavones, Medicago spp. – in saponins and O. viciifolia – in tannins. Plants of T. medium and O. viciifolia were rich in TPC. The extracts of T. pratense, O. viciifolia and A. cicer possessed significant antiradical activity; the extracts from Astragalus spp. proved to be promising chelators of ferrous ion. We concluded that young perennial legumes could be considered as potential candidates for the development of nutraceuticals and functional food ingredients to accommodate the need for a particular bioactive component or property

Ultra performance liquid chromatography-tandem mass spectrometry for the determination of 5-nitroimidazoles and their metabolites in egg

An ultra performance liquid chromatography (UPLC) coupled to tandem mass spectrometry (MS/MS) procedure was developed for the determination of five 5-nitroimidazoles (dimetridazole, ipronidazole, metronidazole, ronidazole and ternidazole) and three of their metabolites (1-methyl-2-hydroxymethyl-5-nitroimidazole, 1-(2-hydroxyethyl)-2-hydroxymethyl-5-nitroimidazole and 1-methyl-2-(2‘-hydroxyisopropyl)-5-nitroimidazole) in egg matrices. Conditions for UPLC separation and electrospray ionization MS/MS in the positive ion mode were optimized. Samples were prepared by liquid-liquid extraction with buffered aqueous 2.5% trichloroacetic acid followed by solid-phase extraction on a Strata-X-C cartridge with reversed-phase and cation-exchange functionalities. The method’s performance was evaluated in accordance with Commission Decision 2002/657/EC, applying the alternative matrix-comprehensive in-house validation approach using specially designed InterVal software. The method was robust against different sample matrix and SPE cartridges, operator change, and changes in sample extract storage. Acceptable apparent recoveries (76 to 109%) were obtained for all analytes. The decision limits (CCα) and detection capabilities (CCβ) were within the ranges of 0.19 – 2.62 and 0.26 – 4.29 μg kg-1. For all compounds the calibration curve linearity was good with correlation coefficients greater than 0.99. Fifteen eggs and ten whole egg powder samples obtained commercially in Lithuania were analyzed by UPLC–MS/MS; none were found contaminated by 5-nitroimidazoles or their metabolites

Tiocianato nustatymas jonų porų chromatografijos metodu

A simple and rapid ion pair chromatographic method has been developed for the determination of thiocyanate. Separation was carried out on a 25 cm × 4.6 mm Ascentis C18 column (5 μm particle size) with a mobile phase containing 2 mmol/l tetrabutylammonium (TBA)-phosphate (pH 6.5) in 40 (v/v) % acetonitrile at a flow rate of 0.5 ml/min. Detection was performed by direct UV absorption at 210 nm. This study investigated the effect of various experimental factors, such as acetonitrile content, pH, and ion-pairing cation concentration in the mobile phase on the retention behaviour of anions. Under optimized conditions, four anions (Br-, NO3 - , I- and SCN-) were effectively separated within 8 minutes. The calibration curve was linear in the thiocyanate concentration range from 5×10-6 to 5×10-4 mol/l with an excellent correlation coefficient of more than 0.999. The limit of detection was 1.5×10-6 mol/l (signal / noise = 3). The method was applied for determination of thiocyanate ions in human saliva. Saliva sample preparation involved only centrifugation and appropriate dilution

Enantioselective Determination of Protein Amino Acids in Fertilizers by Liquid Chromatography–Tandem Mass Spectrometry on Chiral Teicoplanin Stationary Phase

High-performance liquid chromatography on a glycopeptide antibiotic teicoplanin-based chiral stationary phase coupled with tandem mass spectrometry was developed for fast and reliable enantioseparation and determination of protein amino acids in hydrolyzed fertilizer samples. The effect of the mobile phase parameters (type and content of organic modifier and pH) and the column temperature on the enantioselectivity was investigated. Under optimized conditions, the majority (15 of 19) of d/l-amino acid pairs were resolved with a resolution factor (<i>R</i>_s) higher than 1.5 with a run time of 15 min. A triple quadrupole tandem mass spectrometer operating in multiple reaction monitoring mode with an electrospray ionization (ESI) ion source was employed for detection. The method was validated in terms of linearity, limits of detection, limits of quantitation, precision, and accuracy. Linear responses were obtained with determination coefficients higher than 0.998 for all analytes, and limits of detection were from 0.04 to 0.24 μg/mL. Sample spike/recovery experiments gave recovery values ranging from 73% for d-threonine to 116% for l-tryptophan. Relative standard deviations for inter- and intraday precision experiments were lower than 21.7%. The developed method was successfully applied for determination of the free amino acid enantiomers in five commercially available hydrolyzed protein fertilizer samples

Mineral and Phytochemical Profiles and Antioxidant Activity of Herbal Material from Two Temperate Astragalus Species

Only a few species of the large Astragalus genus, widely used for medicinal purposes, have been thoroughly studied for phytochemical composition. The aim of our research was to investigate the rarely studied species A. glycyphyllos L. and A. cicer L. for the distribution of mineral elements and phytochemicals in whole plants at two growth stages and in morphological fractions. We also investigated the capacity of the plant extracts to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and to chelate ferrous ions. Chemical composition and antioxidant properties depended on species, maturity, and plant part. Herbal material of A. glycyphyllos was richer in Fe, total phenolics, and flavonoids, whereas extracts of A. cicer showed a higher antioxidant activity. Young plants had more isoflavones, showed greater quenching of DPPH radicals, and exhibited better mineral profiles than flowering plants. Among plant parts, leaves were the most valuable plant material according to most characteristics investigated. Isoflavone concentration in flowers was lower than in leaves and stems. None of the Astragalus samples contained detectable amounts of the alkaloid swainsonine. The study demonstrates the potential of plant material from two Astragalus species as a valuable source of iron, phenolic substances including isoflavones, free-radical scavengers, and Fe2+ chelators for pharmaceutical use