Antifungal and Antibacterial Activities of

Natural antimicrobial agents are increasingly attracting interest as safer alternatives. Cosmos caudatus Kunth., an edible plant native to tropical regions, contains bioactive compounds such as polyphenols, flavonoids, tannins, saponins, alkaloids, and essential oils, all of which have been reported to exhibit potential as natural antimicrobial food preservatives. This study aimed to evaluate the antibacterial and antifungal activities of C. caudatus leaf essential oil against various foodborne pathogens. The findings showed that the fungal strains were more susceptible to C. caudatus leaf essential oil than the bacterial strains. Moreover, the essential oil exhibited stronger activity against Gram-positive bacteria than Gram- negative bacteria. The minimum inhibitory concentration (MIC) values for A. niger FNCC 6114 and A. flavus FNCC 6181 were 6.25 and 12.5 μL·mL-1, respectively, with both fungi showing minimum fungal concentration (MFC) values of 50 μL·mL-1. For S. aureus ATCC 25923, the MIC and minimum bactericidal concentration (MBC) values were 31.25 and 250 μL·mL-1, respectively. Additionally, P. aeruginosa ATCC 27853 and E. coli ATCC 25922 exhibited MBC and MIC values of 500 and 62.5 μL·mL-1, respectively. These results suggest that C. caudatus leaf essential oil holds promise as a natural antimicrobial agent.