No abstract

No abstract

No abstract

The objective of this study was to determine the concentrations of isoflavones in the cultivars and ecotypes of red clover (Trifolium pratense L.) in a whole above ground part of a plant and separately in stems, leaves and flowers at flowering stage. Isoflavones were extracted using acidified aqueous methanol and subsequent analyses of the extracts were carried out by ultra-performance liquid chromatography coupled with a photodiode array detector. Red clover accumulated the highest concentrations of formononetin (51%) and biochanin A (40%) at flowering stage.

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.

Approaching switchgrass (Panicum virgatum L.) as a multifunctional energy plant, it is important to comprehensively study the composition and partitioning of organic substances in the biomass. The character of carbohydrates and lignin concentration variation was assessed in switchgrass biomass cut at two maturity stages (heading and seed filling) in the first and second harvest years. Quality components partitioning in the biomass of aboveground plant parts was examined in leaves, stems and panicles of the most productive switchgrass accessions cut at seed filling. The concentrations of lignocellulose (NDF), cellulose (Cel), sum of structural carbohydrates (holocellulose -HoCel), sum of nonstructural and structural carbohydrates (ΣCH 2 O) and lignin in switchgrass biomass of both plant development stages in the second harvest year were significantly higher, whereas an average hemicellulose (HCel) concentration was significantly lower compared with the respective parameters in the first harvest year. The concentrations of nonstructural carbohydrates (NSC) and their individual fractions (water soluble carbohydrates (WSC) and starch) in biomass were similar both in the first and second harvest years. The concentrations of NDF, Cel, HoCel and ΣCH 2 O and particularly lignin at seed filling were significantly higher compared with the respective data at heading in both harvest years. High lignin concentration (105 g kg -1 dry matter (DM)) in switchgrass biomass at seed filling in the second harvest year showed its great suitability for solid biofuel production. Considerable amount of ΣCH 2 O (693-742 g kg -1 DM) indicated that switchgrass biomass at this stage fits for the second-generation bioethanol production. At heading, switchgrass in the second harvest year produced quite a high NSC yield (an average 28.4 g plant -1 ) and low lignin output (an average 19.3 g plant -1 ), which is a favourable feature of feedstock for biogas production, biomass at seed filling is less suitable for that than at heading. Switchgrass plant part significantly (P < 0.01) affected the concentration of all biomass quality attributes tested, but did not affect HCel concentration. Accessions' DM yield correlated positively with NDF (r = 0.781, P < 0.05), Cel (r = 0.882, P < 0.01) and lignin (r = 0.517) and negatively with WSC and NSC (r = −0.982, −0.959; P < 0.01).

No abstract

A deeper understanding of the phytochemical composition of perennial legumes is important for animal nutrition as well as for the development of pharmaceuticals. The present study is an assessment of perennial legumes including clovers (Trifolium pratense L. and T. medium L.), medics (Medicago sativa L. and M. lupulina L.), sainfoin (Onobrychis viciifolia Scop.) and milkvetches (Astragalus glycyphyllos L. and A. cicer L.) as potential sources of bioactive compounds. Whole aerial parts of plants at stem elongation and full-flowering stages as well as morphological parts of fully flowering plants (leaves, stems and flowers) were analysed for four isoflavones (biochanin A, daidzein, formononetin, and genistein), coumestrol, condensed tannins and triterpene saponins. According to total concentration of the four isoflavones in plants, the species were ranked as follows: T. medium (23.2–28.7 mg g–1 DM) > T. pratense > A. glycyphyllos = A. cicer = O. viciifolia = M. sativa = M. lupulina (0.054–0.212 mg g–1 DM). Young plants were 1.2–5.6-fold richer in isoflavones than fully flowering plants. Quantifiable concentrations of coumestrol and saponins were found in the Medicago species and tannins in O. viciifolia. In general, leaves contained the highest concentrations of the phytochemicals. These findings suggest considerable potential to improve legume-based forage quality through appropriate exploitation of species- or cultivar-specific phytochemicals and manipulation of the content of phytochemicals by management of production including growth stage at harvest and selection of plant species.