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

peer reviewedMedicago 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 diferent provenances in Tunisia and subsequently investigate the infuence of environmental factors on their phenolic composition and antioxidant activity. Therefore, a calorimetric method and DPPH tests provided the total phenolic and totalfavonoid contents and antioxidant potential in roots, stems, leaves and seeds. High performance liquid chromatography (HPLC) identifed and quantifed four phenolic acids and three favonoids 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 profles 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 fndings provide useful information for the exploitation of the phenolic compounds in these weeds for the development of environmental sustainability

Integrated analysis for identifying <i>Portulaca oleracea</i> and its sub-species based on chloroplastic and nuclear DNA barcoding

<p>The taxonomy of <i>Portulaca oleracea</i> has been considered as being complex since the aggregate is composed of many subspecies or a group of micro-species based on seed-coat characters, seed size, and chromosome number. In order to enlarge the background of the extent of genetic variability between and within Tunisian <i>P. oleracea</i> accessions, a combined morphological and molecular approach was adapted, in the present survey. The morphological analyses of the spontaneous Tunis population display high intra population variability characterized by two distinct morphotypes corresponding to the botanical forms (wild and cultivated plant). Furthermore, the molecular approach based on sequences data related to chloroplastic and ribosomal DNA, was used to understand this variability. The obtained results highlighted the greater molecular variability of this plant and allowed to segregate between morphotypes and genotypes of <i>Portulaca</i>. Mostly, this work shows the important contribution of DNA barcoding approach in resolving low-level-taxonomy problems to distinguish between natural populations and varieties.</p