Twenty-three flavonoids have been identified in the aerial parts of barrel medic, and their structures were established by spectrometric and spectroscopic (ESI-MS/MS and NMR) techniques. Eight of the identified compounds, including apigenin 7-O-beta-D-glucuronopyranosyl-(1-->3)-O-beta-D-glucuronopyranosyl-(1-->2)-O-beta-D-glucuronopyranoside, apigenin 7-O-[2'-O-sinapoyl-beta-D-glucuronopyranosyl-(1-->2)-O-beta-D-glucuronopyranoside], apigenin 7-O-{2-O-feruloyl-[beta-D-glucuronopyranosyl-(1-->3)]-O-beta-D-glucuronopyranosyl-(1-->2)-O-beta-D-glucopyranoside}, chrysoeriol 7-O-[beta-D-glucuronopyranosyl-(1-->2)-O-beta-D-glucuronopyranoside, chrysoeriol 7-O-{2'-O-p-coumaroyl-[beta-D-glucuronopyranosyl-(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside}, tricin 7-O-beta-D-glucuronopyranosyl-4'-O-glucopyranoside, tricin 7-O-[2'-O-feruloyl-beta-D-glucuronopyranosyl-(1-->2)-O-beta-D-glucopyranoside], and tricin 7-O-{2'-O-p-coumaroyl-[beta-D-glucuronopyranosyl-(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside}, have not been reported before in the plant kingdom. Additionally, the presence of two luteolin, three apigenin, one chrysoeriol, and six tricin glycosides, previously identified in alfalfa (Medicago sativa), was confirmed in M. truncatula. Moreover, besides the above flavones, the aerial parts of this species contained three flavonols including rutin, laricitrin 3,7,5'-triglucoside, and laricitrin 3,5'-diglucoside.

The aim of this study was to assess the phenolic composition and nutraceutical potential of tinctures from fruits in two stages of maturity (F3, younger; F25, older), green husks (GH), and leaves (L) of Juglans regia L. In all extracts gallic, protocatechuic, 3-caffeoylquinic, 3-ρ-coumaroylquinic, 4-caffeoylquinic, 4-ρ-coumaroylquinic, and ρ-coumaric acids and quercetin-3-O-deoxyhexoside were detected using UPLC-MS technique. Caffeic acid hexoside I and quercetin-3-O-deoxyhexoside I have been identified in GH tincture. The highest ability to chelate Fe2+ was observed for GH tincture (EC50 = 71.01 ± 3.55 mg FM/mL), whereas the lowest was observed (EC50 = 131.06 ± 6.55 mg FM/mL) for F3 tincture. The highest reducing power was found for F3 and F25 (EC50 = 32.47 ± 1.53 and 36.07 ± 1.72 mg FM/mL, resp.). Ability of tinctures to prevent lipids against oxidation was relatively low. The highest activity (EC50 = 126.49 ± 6.32 mg FM/mL) was determined for F25. Tested tinctures showed relatively high antiradical activity—EC50 values ranged from 100.56 ± 5.03 to 129.04 ± 6.45 mg FM/mL for L and F25, respectively. The results obtained suggest that J. regia can be a source of bioactive compounds with antioxidant properties.

Context: Clovers were chosen on the basis of traditional medicine recommendations, agricultural value, or available information on their promising chemical profiles.Objective: This study evaluates and compares free radical scavenging and antioxidant properties of six clover species: Trifolium alexandrinum L. (Leguminosae), Trifolium fragiferum L., Trifolium hybridum L., Trifolium incarnatum L., Trifolium resupinatum var. majus Boiss., and Trifolium resupinatum var. resupinatum L. Materials and methods: Free radical scavenging activity of the extracts (1.5-50 mg/ml) was estimated by reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH ) and 2,2 0 -azino-bis(3-ethylbenzthiazoline-6-sulphonic) acid (ABTS ) radicals. The Trifolium extract effects on total antioxidant capacity of blood plasma were determined by the reduction of ABTS + and DPPH radicals, as well as with the use of the ferric reducing ability of plasma (FRAP) assay. Results: The UPLC analysis of chemical profiles of the examined extracts showed the presence of three or four groups of phenolic substances, including phenolic acids, clovamides, isoflavones, and other flavonoids. The measurements of free radical scavenging and ferric reducing ability of the examined clover extracts revealed the strongest effect for T. alexandrinum. Furthermore, antioxidant activity assays in human plasma have shown protective effects of all extracts against peroxynitrite-induced reduction of total antioxidant capacity. Conclusions: Trifolium plants may be a rich source of bioactive substances with antioxidant properties. The examined extracts displayed free radical scavenging action and partly protected blood plasma against peroxynitrite-induced oxidative stress; however, the beneficial effects of T. alexandrinum and T. incarnatum seem to be slightly higher.

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A simple, rapid and reliable TLC-DPPH˙ test with image processing has been developed enabling comparison of free radical scavenging activity of plant polyphenols. The influence of different structural features on the observed activity was measured successfully.

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For the first time Trifolium scabrum L. was researched for its phenolic profile. Sixteen phenolics (isoflavones and flavonoids) were isolated and identified in the aerial parts of T. scabrum L. Their structures were established by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) techniques. Quantitative analysis of individual phenolics performed by means of ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) was based on calibration curves obtained for previously isolated standard compounds. Additionally, the free radical scavenging potential of these substances was assessed by means of a simple benchtop thin-layer chromatography-2,2-diphenyl-1-picrylhydrazyl radical (TLC-DPPH(•)) bioassay. Thus, T. scabrum L. can be regarded as a potential source of estrogenic and antioxidant compounds, both of significance in the pharmaceutical as well as the food industry. The results show that T. scabrum L. can be considered as a natural and very good commercial source of phenolic compounds (mainly isoflavones).