Catechol-containing imidazolium (four) and benzimidazolium chlorides (eight) were synthesized to evaluate their antimicrobial properties. All the compounds were fully characterized using 1 H and 13 C nuclear magnetic resonance, liquid chromatography-mass spectrometry, infrared spectroscopic methods, and elemental analyses. Antimicrobial activities of the compounds were tested against the bacteria Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Enterococcus faecalis, and the fungal strains Candida albicans and Candida glabrata , and promising results were achieved. The two most important benzyl-substituted benzimidazolium chlorides, 3l and 3k, showed comparable activity to vancomycin against MRSA.

Due to increasing infections caused by microbes, there is an urgent need for the development of new effective antimicrobial agents. Silver-

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Aims: Endophytes are microorganisms residing in the living tissues of the host plant and may contribute to their host plant by producing a plethora of bioactive compounds that provide survival value to the plant. This study aimed to evaluate the antimicrobial activity of Aspergillus sp. IBRL MP15 CCL, an endophytic fungus isolated from Swietenia macrophylla leaf. Methodology and results: The antimicrobial activity was evaluated with disc diffusion and a colorimetric broth microdilution test against 15 organisms comprising of 4 Gram-positive bacteria and 4 Gram-negative bacteria, 4 fungi and 3 yeast. On disc diffusion assay, the fungal extract was shown to inhibit the growth of 7 test bacteria and 3 test yeast. The antibacterial activity was more pronounced with extract from fungal culture with host plant extract supplementation with significantly larger inhibition zones on all susceptible test microorganisms. The minimal inhibitory concentration of the extract ranged from 250 to 4000 µg/mL indicating different level of susceptibility of the tested pathogens against the fungal extract. The killing kinetic study shows that antimicrobial activity of the fungal extract is concentration dependent and it can act as bactericidal at higher concentration. Conclusion, significance and impact of study:The findings of this study suggest that Aspergillus sp. IBRL MP15 CCL can be a promising source of antimicrobial agent to be further studied and developed.