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Polyphenol content and biological activities of Mesembryanthemum edule organs after fractionation

Falleh, Hanen, Trabelsi, Najla, Bonenfant-Magné, Michèle, Le Floch, Gaëtan, Abdelly, Chedly, Magné, Christian, Ksouri, Riadh
Industrial crops and products 2013 v.42 pp. 145-152
Candida albicans, Carpobrotus edulis, Kloeckera apiculata, Micrococcus luteus, antibacterial properties, antibiotics, antifungal properties, antioxidant activity, antioxidants, bacteria, bacterial infections, foods, fractionation, fungi, growth retardation, halophytes, leaves, metabolites, methanol, roots, stems
Mesembryanthemum edule (Aizoaceae) is an edible halophyte widely used as a traditional remedy against fungal and bacterial infections. This study investigates phenolic contents and biological activities of aqueous methanolic fractions (methanol/acidified water, v/v: 20/80, 40/60 and 60/40) of M. edule leaves, stems and roots. The most phenol-rich fractions were leaf 20%, stem 60%, and root 40% (from 671 to 989mg GAEg−1 DR). The highest ferric reducing power was found in leaf 40% and stem 40% (86 and 94μgml−1, respectively) whereas the highest total antioxidant activity was noted in root 40% (395mg GAEg−1 DR). Concerning the antimicrobial activity, organ extracts were assayed for their activity against food borne bacteria and fungi. The inhibitory percentages ranged from 0 to 94%. Stems showed the strongest antibacterial activity (inhibition of the growth in 6 of the 7 strains tested) especially against Micrococcus luteus (82%) followed by leaves and roots. Regarding fraction polarity, 60% and 20% aqueous methanolic fractions were the most and the less active fractions, respectively. All the organ fractions showed a high antifungal activity, notably against Kloeckera apiculata (85% for leaf 40%) and Candida albicans (77% for stem 40%). Even more, leaf, stem and root fractions were very potent in inhibiting growth of filamentous fungi, with inhibition percentages varying between 23% and 99%. Overall, the fractionation process enabled a better assessment of M. edule antioxidant and antimicrobial activities, which were attributed to various metabolites with different polarities. Our findings also indicate that M. edule organs could be used as a potent source of natural antioxidants and antibiotics.