Waru leaves (Hibiscus tiliaceus L.) are used as an alternative treatment for digestive tract infections and contain various compounds that require purification to isolate more specific and pure constituents.This study aims to evaluate the potential antibacterial activity of the purified ethyl acetate extract of waru leaves (PEAEWL) against Escherichia coli and Staphylococcus aureus, and to determine its total flavonoid content.

The powdered waru leaves were first macerated in n-hexane. The residue was dried and then re-macerated with 96% ethanol and concentrated. The thick extract was dissolved in hot water and subjected to liquid-liquid partitioning with ethyl acetate. The ethyl acetate phase was collected and concentrated using a rotary vacuum evaporator. The antibacterial activity of PEAEWL was tested using the disc diffusion method at concentrations of 5, 10, 15, and 25%. DMSO served as a negative control and chloramphenicol (30 µg/disc) as a positive control. Antibacterial activity data were analyzed descriptively. The total flavonoid content was determined using UV-Visible spectrophotometry with quercetin as the standard.

The purified ethyl acetate extract of waru leaves exhibited antibacterial activity against both Escherichia coli and Staphylococcus aureus at all tested concentrations. The total flavonoid content was found to be 1.140 ± 0.006 mgQE/g of extract.