ANTIMICROBIAL ACTIVITY OF COMPOUNDS ISOLATED FROM MANGROVE-DERIVED ENDOPHYTIC FUNGUS Actinomucor elegan AGAINST Xanthomonas axonopodis pv. passiflorae

This study investigated bioactive compounds isolated from the mangrove endophytic fungus Actinomucor elegans AcCC18.1A for the control of Xanthomonas axonopodis pv. passiflorae (Xap), the causal agent of bacterial spot disease in passion fruit. Through classical chromatographic techniques, we isolated four phenolic compounds: tyrosol (1), 4-hydroxyphenylacetic acid (2), 4-formylphenyl-2-phenylacetate (3), and phenylacetic acid (4), with their structures elucidated through nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Among the isolated compounds, compound 3 was characterized as a new natural product. Antimicrobial assays were performed using the broth microdilution method against four Xap strains (Xap1-Xap4), with amoxicillin (3.9 µg mL–1) and tetracycline (3.9 µg mL–1) as positive controls. All compounds exhibited inhibitory activity, with compound 2 showing the highest efficacy (7.8 µg mL–1). These results underscore the biotechnological potential of mangrove endophytic fungi as sources of bioactive molecules against agricultural phytopathogens, offering new insights for developing sustainable strategies to control bacterial spot in passion fruit cultivation.