The Effect of Tannic Acid as Antimicrobial Agent on Pseudomonas aeruginosa Using In-vitro Diffusion Method

Background: Bacterial infection is a health problem that has long been attention in the world of health. Various antimicrobials have been discovered and developed by researchers to solve pathogenic bacterial infections. Pseudomonas aeruginosa is a pathogenic bacteria that is often of concern to researchers because it has the potential to become resistant to a number of antibiotics. Tannic acid is known to have potential antibacterial activity against pathogenic bacteria. The antibacterial activity of tannic acid is interesting to study considering its great potential as an antimicrobial agent for pathogenic bacterial infections.

Aims: To find out the antibacterial potential of tannic acid compounds against Pseudomonas aeruginosa In-vitro using the disc diffusion method.

Methodology: This research is quantitative research with experimental methods. This research was carried out at the Pharmacy Laboratory of Kusuma Husada Surakarta University, Indonesia between April and May 2023. The sample for this study was a certified bacterial culture of Pseudomonas aeruginosa ATCC 27853 originating from a stock culture from the laboratory. We use certified tannic acid from Merck Millipore. The tannic acid in powder form was dissolved in a 1% DMSO solution. The sample solution containing tannic acid in 1% DMSO was dropped on a Kirby-Bauer disk and placed on an agar plate inoculated with bacteria. One petri dish contains five discs with different samples placed at adequate distances. There were 0.5% tannic acid solution, 1% tannic acid solution, and 2% tannic acid solution, negative control 1% DMSO solution and positive control ciprofloxacin 5 µg/ml. Replication was carried out five times.

Results: Tannic acid with a concentration of 0.5% has an average inhibitory zone of 102 mm. A 1% concentration of tannic acid has an average inhibitory zone of 121 mm. A 2% concentration of tannic acid has an average inhibitory zone of 150 mm. The positive control used, namely the antibiotic ciprofloxacin, obtained an average inhibitory zone of 350 mm. The negative control used, namely 1% DMSO solution, had no inhibitory zone at all. Statistical tests using the Kruskal-Wallis test showed that there was a significant difference with a value of p = 0.000.

Conclusion: The tannic acid compound is an active compound that has antimicrobial activity against Pseudomonas aeruginosa ATCC 27853 and its application in health can be considered.