Abstract
Background: Nosocomial infection is a hospital-acquired infection that can cause various severe diseases. The main bacteria that causes nosocomial infection is Pseudomonas aeruginosa multiresistant (PAMR). The Rambutan leaf (Nephelium lappaceum) is known to have antibacterial activity because it is suspected to have the content of flavonoids, polyphenols, and tannins. Aims and Objectives: This research was conducted to determine the antibacterial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of the extract and the most active fraction. Materials and Methods: The research was started by extraction and then fractinationed by liquid-liquid extraction to obtain ethyl acetate, water, and n-hexane fraction. After that, antibacterial activity was carried out by the agar diffusion method, and the value of MIC and MBC was determined by the microdilution method. Results: The result showed that ethanol extract, ethyl acetate fraction, and water fraction of the Rambutan leaf had antibacterial activity against PAMR, of which the ethyl acetate fraction was the most active fraction. The value of MIC and MBC of the extract and ethyl acetate fraction was in a concentration 2.5% w/v and 5% w/v against PAMR. Conclusions: The antibacterial activity of this extract and fractions against PAMR was probably derived from flavonoids, polyphenols, saponins, and tannins.