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Barreira J.C.M.,University of Porto | Barreira J.C.M.,Polytechnic Institute of Braganca | Visnevschi-Necrasov T.,University of Porto | Nunes E.,University of Porto | And 3 more authors.
Phytochemistry | Year: 2015

A high variety of plant species are often proposed as potential natural sources of specific bioactive components, with emphasis in phenolic compounds. However, the ability to produce a determined phytochemical might be variable, even among species with close phylogeny. Furthermore, the metabolic dynamics vary greatly according to phenologic factors. Herein, it was verified whether isoflavone production in Medicago spp. is more associated with phylogenetic or phenologic determinants, to define the optimal productive conditions. Isoflavone profiles were characterized in field-grown Medicago species in three phenologic stages. Isoflavones were extracted by matrix solid-phase dispersion method and analyzed using high-performance liquid chromatography coupled with a diode-array detector. The obtained data were evaluated by a generalized linear model (GLM) and linear discriminant analysis (LDA). Formononetin, genistein and irilone were the most abundant isoflavones, reaching values higher than those present in acknowledged plant sources like soy or red clover. Outputs from GLM and LDA indicate that the phylogenetic factors are the most defining criteria. This study promotes Medicago spp. as potential isoflavone sources, particularly because the effects of these compounds are highly dependent on their type and concentration, with potential application as foodstuff, feedstuff, or in the nutraceutical and pharmaceutical industry. © 2015 Elsevier Ltd.

Visnevschi-Necrasov T.,University of Porto | Barreira J.C.M.,University of Porto | Barreira J.C.M.,Polytechnic Institute of Braganca | Cunha S.C.,University of Porto | And 3 more authors.
Food Research International | Year: 2015

Legumes (Fabaceae) are important crops, known as sources of food, feed for livestock and raw materials for industry. Their ability to capture atmospheric nitrogen during symbiotic processes with soil bacteria reduces the need for expensive chemical fertilizers, improving soil and water quality. Several Fabaceae species are acknowledged for the high levels of secondary metabolites. Isoflavones are among the most well-known examples of these compounds, being recognized for their several types of biological activity. Herein, isoflavone profiles were characterized in nine species of four Fabaceae genera (Biserrula, Lotus, Ornithopus and Scorpiurus). Plants were harvested in the late flower physiological stage to prevent biased results due to naturally occurring variations along the vegetative cycle. Isoflavones were extracted using matrix solid-phase dispersion and analyzed by high performance liquid chromatography/diode-array detection. The detected profiles revealed significant differences, inclusively among species belonging to the same genus, indicating that other factors besides the genotypic features contribute to the expression of these phenolic compounds. The classification of the results by principal component analysis placed species belonging to the same genus in different clustering groups, proving this latter assumption. However, the detected profiles proved to be characteristic of the assayed, as it was proved by the applied linear discriminant analysis. © 2014 Elsevier Ltd.

Visnevschi-Necrasov T.,University of Porto | Barreira J.C.M.,University of Porto | Barreira J.C.M.,Polytechnic Institute of Braganca | Cunha S.C.,University of Porto | And 3 more authors.
Phytochemical Analysis | Year: 2015

Introduction-Analytical methods used in phytochemistry analysis are limited by the sample preparation step, which should ideally be fast, accurate, ecofriendly and achievable using low quantities of the sample. Matrix solid-phase dispersion (MSPD) may be a good alternative for combining extraction and purification procedures, thereby reducing the indicated limitations.Objective-Applying an MSPD extraction procedure coupled to high-performance liquid chromatography diode-array detection (HPLC/DAD) as an alternative methodology to evaluate isoflavone profiles.Methods-Isoflavone profiles were determined for the leaves of nine species of Medicago in the late flower phenological stage (one or more nodes with 50% open flowers, no seed pods). Extraction was performed following MSPD, and isoflavone profiles were characterised using HPLC/DAD. The quantified amounts were compared with previous results in different species commonly recognised as good sources of isoflavones.Results-Formononetin was the major isoflavone in most species, except M. polymorpha and M. truncatula. The isoflavone amounts were significantly different among the assayed species, with M. orbicularis and M. arabica as the major isoflavone sources, while M. rigidula presented the lowest contents. Furthermore, the detected differences allow electing the best species as a primary source of a specific isoflavone.Conclusion-The MSPD allowed good extraction efficiency, reproducibility and recovery. Some of the species showed relevant isoflavone contents, even when compared with acknowledged plant sources such as soy or red clover. To the best of our knowledge the results presented are reported for the first time in these species. Copyright © 2014 John Wiley & Sons, Ltd.

Barreira J.C.M.,University of Porto | Barreira J.C.M.,Polytechnic Institute of Braganca | Visnevschi-Necrasov T.,Polytechnic Institute of Braganca | Visnevschi-Necrasov T.,University of Porto | And 3 more authors.
Food Research International | Year: 2016

There is an increasing trend towards finding alternative sources of valued phytochemicals due to their diverse potentialities in food industry and pharmaceutical applications. Phenolic compounds, in particular, have been the focus of several profiling reports, but isoflavones characterization has been studied in fewer cases and in a very limited group of plant species. Despite their acknowledged bioactivity, there's actually a strict number of plants validated for their isoflavones contents. In a previous report, we have identified nine Leguminosae species (from genera . Biserrula, . Lotus, . Ornithopus and . Scorpiurus) as potential alternative sources of these phenolic compounds. However, the isoflavone profiles are highly modulated by the ontogenic stage. Therefore, the present study was conducted in the same Leguminosae species, but harvested at three sequential vegetative development stages: vegetative elongation, late bud and late flowering, with the main purpose of assessing the evolution of isoflavones content throughout the plant development. In general, the plant species from . Biserrula and . Lotus genera showed the highest potential as new natural sources of isoflavones, especially owing their high levels of biochanin A. Independently of the plant species, it was possible to identify the phenologic stages where each of the quantified isoflavones is maximized. These findings are useful to predict isoflavone yields according to harvesting time, validating the potential use of the studied plants in innovative food formulations. © 2016 Elsevier Ltd.

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