Purification of Potential Antimicrobial Metabolites from Endophytic Fusarium oxysporum Isolated from Myrtus communis

• DOI: 10.1007/s12010-024-05016-z
• Publication Date: 2024-07-31T11:14:16Z
• Authors: Saeed Ullah Khattak; Mansoor Ahmad; Jamshaid Ahmad; Saima Ikram; Sajjad Ahmad; Fahad M. Alshabrmi; Eid A. Alatawi

Abstract The rise of microbial resistance and emerging infections pose significant health threats. Natural products from endophytic fungi offer a promising source of novel compounds with potential as major drug leads. This research aims to screen Myrtus communis and Moringa oleifera for endophytic fungi and screen their metabolites for antibacterial and antifungal potential. Six endophytic fungal strains were isolated using Potato Dextrose Agar (PDA) medium. The M. communis isolates were designated MC1, MC2, MC3, and the M. oleifera isolates were named MO1, MO2, MO3. Preliminary bioactivity testing revealed that the MC3 isolate exhibited significant growth inhibition against multidrug-resistant bacterial and fungal pathogens, including Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and Candida glabrata. The MC3 isolate was identified as Fusarium oxysporum through morphological and microscopic methods. For metabolite production, the fungal strain was cultured in Potato Dextrose Broth (PDB) medium at 28 °C for 14 days in a shaking incubator. The metabolites were purified using various chromatographic techniques, HPLC and GC-MS. The GC-MS analysis of F. oxysporum revealed multiple compounds at different retention times using the NIST-20 Library. Based on RSI values and probability indices, two compounds were targeted for further purification. Structure elucidation was performed using 1D and 2D Nuclear Magnetic Resonance (NMR) experiments on a Varian 500 NMR machine. The compounds identified were Ethyl isoallocholate (C26H44O5, exact mass 436.32) and 1-Monolinoleoyl glycerol trimethylsilyl ether (C27H56O4Si2, exact mass 500.37). The MS (NIST-20) library facilitated the investigation of the insilico antimicrobial activity of these compounds against alpha-N-acetylgalactosaminidase and elastase virulence proteins of P. aeruginosa and E. faecalis. Aspartic protease from Candida albicans was used to evaluate the insilico antifungal potential. All ligands and proteins were docked using the Glide Induced Fit Docking (IFD) algorithm. The compounds showed binding scores of -7.7 and -7.9 Kcal mol-1 against alpha-N-acetylgalactosaminidase, -7.3 and -6.5 Kcal mol-1 against elastase, and -7.6 and -7.2 Kcal mol-1 against aspartic protease. Invitro studies confirmed the inhibitory activity of these compounds against multidrug-resistant P. aeruginosa and E. faecalis. Ethyl isoallocholate exhibited higher bioactivity against P. aeruginosa with inhibition rates of 41%, 27%, and 35% at concentrations of 1000, 500, and 250 μg mL-1, respectively. These results suggest that bioactive compounds from F. oxysporum have potential as antimicrobial agents, warranting further research.