Subterranean Clover and Sulla as Valuable and Complementary Sources of Bioactive Compounds for Rainfed Mediterranean Farming Systems

Mediterranean pasture and forage legumes are important components of sustainable production systems. Subterranean clover and sulla represent key species having proven high agronomic value and traits for production and multiple services. Our research investigated the potential of the abovementioned species as a source of phenolic compounds and antioxidants for contributing to support their full exploitation in the fodder, animal welfare, and nutraceutical sectors. Antioxidant capacity, as well as the content of total phenolic compounds and individual phenolic compounds, was determined in subterranean clover and sulla shoots at the vegetative, flower bud, flowering, and seed ripening phenological stages. The antioxidant capacity and the phenolic content were affected significantly by harvest time. In subterranean clover, 10 individual phenolic compounds were detected, and isoflavones were the most abundant (3.19-18.27 mg·g^-1 DM). Eleven phenolic compounds were identified in sulla shoots, and chlorogenic acid (0.76-3.43 mg·g^-1 DM) and diosmin (3.64-4.94 mg·g^-1 DM) were the most represented compounds at the vegetative and flower bud stage. On the basis of our findings, a complementary utilization of both legume species is suggested; this might ensure the exploitation of all phenolic compounds in view of the potential benefits for animal production and health.

Study of antioxidant activity of fodder grasses using microbial test systems

AIM

To measure biological activities of extracts of fodder grasses Onobrýchis arenária, Galéga orientális and Rhaponticum carthamoides that are commonly planted in Europe, Middle East and eastern Africa.

METHODS AND RESULTS

Microbial test-systems based on E. coli BW25113 that allow measurement of gene expression, growth and survival, biofilm formation in combination with the standard chemical procedures were used. The extracts studied had radical scavenging and metal-chelating activities and induced expression of antioxidant genes via generation of hydrogen peroxide. Although, the extracts did not affect bacterial growth in planktonic cultures but dose-dependently inhibited biofilm formation.

CONCLUSIONS

The most remarkable effects were observed in G. orientalis, a high-yielding crop, rich in crude protein and fibers.

SIGNIFICANCE AND IMPACT OF THE STUDY

Taking into account antibiofilm activities of the extracts, a perspective for decreasing colonization of ruminants' gut with pathogenic bacteria might be suggested in case of feeding with all the grasses studied.

Investigation of the Phytochemical Composition, Antioxidant Activity, and Methylglyoxal Trapping Effect of Galega officinalis L. Herb In Vitro

Galega officinalis L. has been known for centuries as an herbal medicine used to alleviate the symptoms of diabetes, but its comprehensive chemical composition and pharmacological activity are still insufficiently known. The current study involved the qualitative and quantitative phytochemical analysis and in vitro evaluation of the antioxidative and methylglyoxal (MGO) trapping properties of galega herb. Ultra high-performance liquid chromatography coupled with both the electrospray ionization mass spectrometer and diode-array detector (UHPLC-ESI-MS and UHPLC-DAD) were used to investigate the composition and evaluate the anti-MGO capability of extracts and their components. Hot water and aqueous methanol extracts, as well as individual compounds representing phytochemical groups, were also assessed for antioxidant activity using DPPH (2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) assays. Quercetin and metformin were used as a positive control. We confirmed the presence of tricyclic quinazoline alkaloids, guanidines, flavonoids, and hydroxycinnamic acids (HCAs) in galega extracts. The polyphenolic fraction was dominated by mono-, di-, and triglycosylated flavonols, as well as monocaffeoylhexaric acids. The in vitro tests indicated which G. officinalis components exhibit beneficial antioxidative and MGO trapping effects. For galega extracts, flavonols, and HCAs, a potent antiradical activity was observed. The ability to trap MGO was noted for guanidines and flavonoids, whereas HCA esters and quinazoline alkaloids were ineffective. The formation of mono-MGO adducts of galegine, hydroxygalegine, and rutin in the examined water infusion was observed.