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.

Eight diketopiperazines including five previously unreported derivatives were isolated from an endophytic fungus cultured from the medicinal plant Globularia alypum collected in Algeria. The strain was characterised by means of morphological studies and molecular phylogenetic methods and was found to represent a species of a new genus in the Chaetomiaceae, for which we propose the name Batnamyces globulariicola. The taxonomic position of the new genus, which appears phylogenetically related to Stolonocarpus and Madurella, was evaluated by a multi-locus genealogy and by morphological studies in comparison to DNA sequence data reported in the recent monographs of the family. The culture remained sterile on several culture media despite repeated attempts to induce sporulation, and only some chlamydospores were formed. After fermentation in submerged culture and extraction of the cultures with organic solvents, the major secondary metabolites of B. globulariicola were isolated and their chemical structures were elucidated by extensive spectral analysis including nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionisation mass spectrometry (HRESIMS), and electronic circular dichroism (ECD) measurements. The isolated compounds were tested for their biological activities against various bacteria, fungi, and two mammalian cell lines, but only three of them exhibited weak cytotoxicity against KB3.1 cells, but no antimicrobial effects were observed.

The in vitro antibacterial activity of the endophytic fungus Aspergillus neobridgeri PLR9 (isolated from the plant Pistacia lentiscus) against a wide range of tested bacteria were studied. The maximum inhibitory activity was found on malt extract agar medium with a mean inhibitory zone of 11.3 mm (p<0.05). The ethyl acetate extract showed a significant inhibitory zone of 13.4 mm (p<0.05), followed by dichloromethane 9.1 mm. Whereas, n-hexane extract showed no activity. The largest inhibition zones were observed against Staphylococcus aureus 3, S. aureus 5 and Escherichia coli 1 with 21.0 mm of diameter. The MIC's were ranged between 312.5 and 1,250 μg/mL. The MBC's were ≤2500 μg/mL for most Gram positive bacteria and ≥2500 μg/mL for most Gram negative bacteria. Time kill assay study against the Enterococcus faecium showed a bactericidal effect at 4x MIC and bacteriostatic against Acinetobacter baumannii at different concentrations. Moreover, it is the first report, PLR9 isolated as endophyte and studied for their antimicrobial activity.