UJI AKTIVITAS ANTIBAKTERI EKSTRAK ETANOL DAUN Psidium guajava L. TERHADAP PERTUMBUHAN BAKTERI Escherichia coli

Abstract

Guava leaves are known to contain bioactive compounds such as flavonoids, tannins, saponins, and alkaloids which possess antibacterial activity. This study aims to determine the effectiveness of guava leaf ethanol extract (Psidium guajava L .) on the growth of Escherichia coli bacteria. The research was conducted experimentally using a Completely Randomized Design (CRD) with three extract concentrations (25%, 35%, and 45%), along with a positive control (chloramphenicol) and a negative control (10%DMSO). The method used was the disk diffusion method (Kirby-Bauer) on Eosin Methylene Blue Agar (EMBA) media. The obtained data were analyzed descriptively and quantitatively based on the diameter of the inhibition zone formed around the disk. The results showed that an increase in extract concentration was directly proportional to an increase in the inhibitory effect on E. coli, with average inhibition zone diameters of 3.356 mm at a concentration of 25%, 4.553 mm at 35%, and 5.183 mm at 45%. Statistical analysis using one-way ANOVA showed no significant difference between treatments (p < 0.05). It was concluded that in this study, all three concentrations possessed antibacterial activity classified as weak, as they were only able to inhibit bacterial growth (bacteriostatic) without showing a significant killing effect.