EVALUATION DE L’ACTIVITE ANTIOXYDANTE ET L’EFFET ANTIMICROBIEN DES COMPOSES PHENOLIQUES EXTRAITS DU LICHEN «Xanthoria parietina » DE LA REGION DE BOUMERDES

Abstract

Lichens are symbiotic organisms with different biological activities due to their various secondary metabolites. The objective of this work is to identify and characterize the lichen Xanthoria parietina harvested from two sites, forest and agglomeration of the Wilaya of Boumerdes, as well as the evaluation of the antioxidant and antimicrobial activity of its methanolic and acetonic extracts. Phytochemical characterization indicates the presence of parietin and barbatic acid. The highest extraction yield is that of extracts from the agglomeration site whose values for methanolic and acetonic extract are respectively 43% and 34% unlike extracts from forest lichens whose yield is around by 12% and 11%. The determination of total ployphenols reveals a high content for the extract of forest lichens. The values are 0.139 mgEAG / g and 0.126 mgEAG / g respectively for the methanolic and acetonic extract whereas, the extract of agglomeration lichens has values of 0.087 mgEAG / g and 0.044 mgEAG / g. The evaluation of the antioxidant activity of the lichenic extract from the agglomeration site revealed a greater value for the methanolic extract (2.06 mgEAA / g) than that of acetone (1.38 mgEAA / g). The evaluation of antimicrobial activity highlighted the sensitivity of 4 bacterial strains (Bacillus sp, A.boumannii, E.faecalis and E.cloacea) and 5 fungal strains (A.fumigatus, A.flavus, yeast of Malassezia, T.glabrum, C. parapsilosis) with acetonic and methanolic extracts from the two sites studied. It emerges from this study that the methanolic and acetonic extracts of the lichen Xanthoria parietina have a greater spectrum of action on fungi than bacteria.