Antimicrobial Potential of Endophytic Fungi Isolated from Wild Plants in the Qassim Region, Saudi Arabia

Objectives Endophytic fungi constitute a vital source of new bioactive chemicals with considerable therapeutic potential. This study examines the antibacterial properties of endophytic fungus isolated from wild medicinal plants indigenous to the Al-Qassim region of Saudi Arabia. Materials and methods Twenty-four Fungal isolates were obtained from various tissues of the selected plant species under sterile conditions and molecularly identified. The total phenolic content of the endophytic fungal strains quantitatively assessed. Antimicrobial activity of these fungal isolates was evaluated by dual culture assay against Candida albicans, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Results according to molecular identification, most of these isolates belonged to Penicillium genus. The total phenolic content showed considerable variation among the fungal isolates. several isolates exhibited significant antimicrobial activity, particularly against Candida albicans and E. coli. In contrast, Staphylococcus aureus demonstrated predominantly mild suppression, while Pseudomonas aeruginosa showed the highest resistance. Conclusion These findings demonstrates that the antimicrobial efficacy of endophytic fungi is significantly strain-dependent and changes with the target pathogen. The endophytic fungal isolates exhibiting a more pronounced antagonistic impact against candida and Gram-negative E. coli than S. aureus and Pseudomonas aeruginosa, highlighting their potential as a source of bioactive antimicrobial compounds.