Influence of climate variation on phenolic composition and antioxidant capacity of Medicago minima populations

Souhir Kabtni,Neila Trifi-Farah,Dorra Sdouga,Marie-Laure Fauconnier,Mattew Save,Ines Bettaib Rebey,Sonia Marghali

doi:10.1038/s41598-020-65160-4

Abstract

Medicago minima is a pasture legume that grows almost all over the world. In Tunisia, it occupies various climatic environments and is considered the most abundant annual Medicago plant. However, this species is unconsumed and unused by humans. This study aimed to explore the phytochemical characteristics of Medicago minima selected from different provenances in Tunisia and subsequently investigate the influence of environmental factors on their phenolic composition and antioxidant activity. Therefore, a calorimetric method and DPPH tests provided the total phenolic and total flavonoid contents and antioxidant potential in roots, stems, leaves and seeds. High performance liquid chromatography (HPLC) identified and quantified four phenolic acids and three flavonoids in the studied organs. Roots and leaves showed the greatest phenolic compound content and had high antioxidant activity. Rutin and syringic acid (leaves) represent a characteristic for this species. For each organ, principal component analysis of phenolic profiles showed that the root’s phenolic composition could be an indication of the plant adaptation to even small changes in its environments. Plants originating from a cold climate, higher altitude or semi-arid environment had the highest phenolic compound contents in their organs. Our findings provide useful information for the exploitation of the phenolic compounds in these weeds for the development of environmental sustainability.

Highlights

Medicago minima is a pasture legume that grows almost all over the world
These results demonstrated that leaf and seed extracts have the highest Total phenolic contents (TPC), respectively, with 16.65 mg GAE/g dry matter (DM) and 15.97 mg GAE/g DM (Fig. 1a), whereas both root and stem extracts have the lowest contents
The TPC, Total flavonoid contents (TFC) and antioxidant capacity measured in M. minima roots, stems, leaves and seeds highlight their phenolic potential

Summary

Introduction

In Tunisia, it occupies various climatic environments and is considered the most abundant annual Medicago plant This species is unconsumed and unused by humans. The Medicago genus belongs to the Leguminosae family and presents a wide range of interesting species for foods and feeds These species are reported in many studies as sources of phytochemical compounds, including carotenoids, saponins, flavonoids and phytoestrogens[1,2,3]. It is necessary to note that the extensive uses of these active composites may have toxic effects[22] For this purpose, many studies have been interested in identifying these natural active compounds in plants and determine their contents and their spectrum of functional properties. We aimed to discriminate twelve M. minima populations selected from different Tunisian climatic environments according to their phenolic profiles

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Conclusion