Purpose. The purpose of this study was to evaluate the antibacterial activity of both individual and combined extracts of Cymbopogon citratus and Carica papaya and the antifungal activity of Azadirachta indica against selected microorganisms

Methods. Dried leaves of A. indica, C. citratus and C. papaya were extracted using Soxhlet extraction method and then evaporated to dryness to further concentrate the extract. Both the antimicrobial and antifungal properties were determined using Resazurin Assay method on a 96-well microplate using serial dilution method against S. aureus, S. epidermidis, P. aeruginosa, E. coli, C. albicans, T. rubrum, A. niger and T. mentagrophytes.

Results. Resazurin assay shows the different combined extracts of A. indica, C. citratus, and C. papaya were effective against E. coli. A. indica and C. papaya shows efficacy in inhibiting the growth of S. aureus, while C. citratus needs to increase concentration to have a better efficacy against S. aureus. The combination of the three plants in equal parts are not effective against E. coli, while C. citratus alone has the highest inhibition. On the antifungal activity, the MIC of 0.5 neem, 0.25 papaya and 0.25 lemongrass and 0.5 papaya, 0.25 neem and 0.25 lemongrass has lower efficacy against C. albicans. In inhibiting the growth of A. niger, the most effective combination is 0.5 lemongrass, 0.25 neem and 0.25 papaya. In T. rubrum, the highest potency found was 0.5 neem, 0.25 papaya and 0.25 lemongrass. Against T. mentagrophytes, C. citratus alone has higher potency compared to A. indica and C. papaya alone.

Conclusion. The testing of the three plant extracts has shown effective inhibition against E. coli. While A. indica and C. papaya showed efficacy against S. aureus. In terms of antifungal activity, the most significant result was the efficacy of 0.5 neem, 0.25 papaya and 0.25 lemongrass against T. rubrum. Other concentrations against S. epidermidis, P. aeruginosa, T. mentagrophytes, A. niger and C. albicans showed less inhibitory properties.