Antimicrobial and Cytotoxic Activities of Nigrospora oryzae Endophytic Fungi Isolated from Moringa oleifera

Abstract

Background: Endophytic fungi are known to produce bioactive compounds with potential therapeutic applications. Objective: This study investigated the antimicrobial and cytotoxic activities of Nigrospora oryzae, an endophytic fungus, isolated from Moringa oleifera. Methodology: Nigrospora oryzae was cultured, and its secondary metabolites were extracted and screened for antimicrobial efficacy against a range of pathogenic microorganisms, including Bacillus subtilis ATCC 6051, Escherichia coli ATCC 8739, Klebsiella pneumoniae NCTC 13465, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10231. Results: The results demonstrated that extracts from Nigrospora oryzae exhibited high antimicrobial activity against Staphylococcus aureus and Candida albicans compared to other microorganisms. The cytotoxicity assays revealed a dose-dependent inhibition of cell proliferation in MDA-MB-231 cell lines, suggesting potential anticancer properties. IC50 values indicating moderate cytotoxicity for DCM extract (44.66 µg/ml) and superior efficacy for Doxorubicin (40.79 µg/m). In silico docking validation of AutoDock Vina showed reliable RMSD values for DNA Gyrase B, DNA Topoisomerase 4, and PARP3, supporting the in vitro results. Among the identified compounds, Aurofusarin demonstrated the most promising inhibitory potential, with high binding affinities across all tested proteins (-11.44 to DNA Gyrase B, -8.40 to DNA Topoisomerase 4, and -11.55 to PARP3). While Mellein and Nigrospin showed lower activity, Aurofusarin's strong binding suggests significant pharmacological potential. Conclusion: This study highlights the antimicrobial and anticancer potential of Nigrospora oryzae extracts, particularly Aurofusarin, as a less toxic alternative to chemotherapy drugs like Doxorubicin. Further research should focus on its mechanisms of action and potential use in oncological therapies.