Screening of Antimicrobial and Antioxidant Secondary Metabolites from Endophytic Fungi Isolated from Wheat (triticum Durum)

The emergence of antibiotic-resistant micro-organisms calls for inventive research and development strategies. Inhibition of these pathogenic micro-organisms may be a promising therapeutic approach. The screening of antimicrobial compounds from endophytes is a promising way to meet the increasing threat of drug-resistant strains of human and plant pathogens. In the present study, a total of 20 endophytic fungi and 23 endophytic actinomycetes have been isolated from wheat (Triticum durum). Mohamed Ben Bachir variety collected from Bordj Bou Arreridj region (Algeria) during winter 2010. The isolates were screened and evaluated for their antimicrobial and antioxidant activities. Antimicrobial activity was evaluated for crude ethyl acetate extracts using an agar diffusion assay against twelve pathogenic bacteria, yeast, and two phytopathogenic fungi. All extracts showed inhibitory activity on at least one or more pathogenic microorganisms, with an average zone of inhibition varied between 7 mm to 25 mm, and the largest zone was of 25 and 25.3 mm against candida albicans and Escherichia coli respectively. The antioxidant capacity of the extracts was evaluated by β-carotene/linoleic acid assay. Results showed that 60% of these extracts have antioxidant activity, exhibiting 50, 57% to 78, 96% inhibitions. While the inhibitory activity for oxidation of linoleic acid of 40% of them was less than 50%. From the present work it is possible to conclude that these microorganisms could be promising source of bioactive compounds, and warrant further study.