Uji Daya Hambat Antibakteri Kombinasi Ekstrak Daun Sente (Alocasia macrorrhizos) dan Daun Jambu Biji (Psidium guajava L.) Terhadap Pertumbuhan Bakteri Escherichia coli

Abstract

The increasing resistance of pathogenic bacteria, particularly Escherichia coli, to antibiotics has become a serious public health concern, highlighting the need for alternative antibacterial agents derived from natural sources that are considered safer and more economical. Sente leaves (Alocasia macrorrhizos) and guava leaves (Psidium guajava L.) contain secondary metabolites, including flavonoids, saponins, and tannins, which have potential antibacterial properties. However, studies on the potential synergistic effects of combining these two leaf extracts against E. coli remain limited. This study aimed to evaluate the antibacterial inhibitory activity of combined sente and guava leaf extracts against the growth of E. coli. A laboratory experimental study was conducted using a Completely Randomized Design (CRD). The extracts were prepared by maceration using 70% ethanol, followed by an antibacterial activity assay using the well diffusion method on Nutrient Agar (NA) medium. The extract combinations consisted of ratios of 1:1, 1:2, and 2:1 at concentrations of 100%, 75%, 50%, and 25%. The inhibition zone diameters were analyzed using ANOVA to determine significant differences among treatments. The results showed that all extract combinations effectively inhibited E. coli growth, with inhibition categorized as strong to very strong. Higher extract concentrations resulted in larger inhibition zones. The optimal formulation was the 2:1 ratio, consisting of two parts guava leaf extract and one part sente leaf extract, at 100%, producing the highest mean inhibition zone of 23.52 mm. In conclusion, the combined extracts have potential as antibacterial agents against E. coli, particularly formulations dominated by guava leaf extract.