Evaluation of Antioxidant and Antibacterial Activities, Cytotoxicity of Del Bark Extracts and Isolated Compounds.
Fiche publication
Date publication
mai 2020
Journal
Molecules (Basel, Switzerland)
Auteurs
Membres identifiés du Cancéropôle Est :
Mr RISLER Arnaud
Tous les auteurs :
Elmi A, Spina R, Risler A, Philippot S, Mérito A, Duval RE, Abdoul-Latif FM, Laurain-Mattar D
Lien Pubmed
Résumé
Water extract of bark is used traditionally by the population in Djibouti for its anti-infectious activity. The evaluation of in vitro antibacterial, antioxidant activities and cytotoxicity as well as chemical characterization of bark water and methanolic extracts were presented. The water extract has a toxicity against the MRC-5 cells at 256 μg/mL while the methanolic extract has a weak toxicity at the same concentration. The methanolic extract has a strong antioxidant activity with half maximal inhibitory concentration (IC) of 150 ± 2.2 μg/mL using 1-diphenyl-2-picrylhydrazyl (DPPH) and IC of 27 ± 1.3 μg/mL using 2,2'-azino-bis 3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical methods. For ferric reducing/antioxidant power (FRAP) assay, the result is 45.74 ± 5.96 μg Vitamin C Equivalent (VCE)/g of dry weight (DW). The precipitation of tannins from methanol crude extract decreases the MIC from 64 µg/mL to 32 µg/mL against and . However, the antioxidant activity is higher before tannins precipitation than after (IC = 150 µg/mL for methanolic crude extract and 250 µg/mL after tannins precipitation determined by DPPH method). By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, the results showed that the condensed tannins consist of two types of catechin and gallocatechin-based oligomers. The fractionation led to the identification of three pure compounds: two flavanols catechin and epicatechin; one triterpene as lupeol; and a mixture of three steroids and one fatty acid: campesterol, stigmasterol, clionasterol, and oleamide.
Mots clés
Acacia seyal bark, MALDI-TOF, antioxidant activity, in vitro antibacterial properties, polyphenols, tannins
Référence
Molecules. 2020 May 21;25(10):