Abstract

ABSTRACT
Endophytic fungi associated with the mangrove plant Ceriops tagal are a promising source of antibacterial compounds. This study aimed to isolate and identify endophytic fungi from C. tagal and evaluate the antibacterial activity of their secondary metabolites. Fungi were isolated from roots, branches and leaves using a direct plating method and cultured in potato dextrose broth. Crude extracts were prepared with ethyl acetate and tested against Escherichia coli, Staphylococcus aureus and Candida albicans using the disk diffusion method. Ten isolates were obtained and all inhibited at least one test microorganism with inhibition zones ranging from 6.6 ± 0.55 mm to 19.1 ± 0.05 mm. Three isolates ECT52, ECT57, and ECT63 showed strong activity with inhibition zones above 10 mm. Molecular identification based on ITS and LSU sequences identified them as Neopestalotiopsis saprophytica, Schizophyllum commune and Muyocopron laterale. Extracts of S. commune ECT57 showed the strongest activity against S. aureus with an MIC of 62.5 ± 0.96 µg/mL. LC-HRMS analysis of ECT57 extract revealed the presence of several dominant compounds, especially Cyclo(phenylalanyl-prolyl), 6-Quinolinecarboxylic acid and Caffeic acid. These findings indicate that C. tagal contains endophytic fungi that can synthesize antimicrobial compounds, which may have potential relevance for antibiotic development.

Key words: Ceriops tagal, endophytic fungi, antimicrobial, Neopestalotiopsis saprohytica, Schizophyllum commune, Muyocopron laterale