UJI AKTIVITAS ANTIBAKTERI EKSTRAK ETANOL 96% BIJI KOPI LIBERIKA (Coffea liberica) PADA BAKTERI STAPHYLOCOCCUS AUREUS DAN ESCHERICHIA COLI

Abstract

Liberica coffee is a plant known to have antibacterial benefits due to its content of alkaloids, flavonoids, and terpenoids. This study aimed to determine the antibacterial activity of a 96% ethanol extract of Liberica coffee beans on the bacteria Staphylococcus aureus and Escherichia coli. The extraction method was maceration with a polar solvent, 96% ethanol. This research used a laboratory experimental method. The antibacterial activity test was performed using the disk diffusion method with four concentrations: 30%, 50%, 70%, and 100%, each repeated three times. The results showed that the 96% ethanol extract of Liberica coffee (Coffea liberica) inhibited the growth of both Staphylococcus aureus and Escherichia coli, as indicated by the formation of an inhibition zone around the disk. Staphylococcus aureus’s largest inhibition zone diameter was 17.0 mm at a 50% concentration, while the smallest was 8.83 mm at a 30% concentration. For Escherichia coli, the largest inhibition zone diameter was 13.0 mm at 50%, while the smallest was 5.75 mm at 100%. Of the two bacteria, the largest inhibition zone was observed for Staphylococcus aureus. This is likely because Staphylococcus aureus is a Gram-positive bacterium with a thick peptidoglycan layer and low lipid content in its cell wall. In contrast, Escherichia coli is a Gram-negative bacterium with a thin peptidoglycan layer and a double outer membrane, which provides better resistance.