<![CDATA[This study evaluated the antibacterial activity of 70% ethanol extract of jackfruit leaves (Artocarpus heterophyllus Lam.) against Bacillus subtilis and Pseudomonas aeruginosa. Jackfruit leaves collected from Jambi, Indonesia, were processed into simplicia and extracted by maceration using 70% ethanol, producing an extract yield of 7.2%. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, saponins, steroids, and triterpenoids. Fourier-transform infrared spectroscopy (FTIR) analysis indicated the presence of hydroxyl, aliphatic C–H, carbonyl/aromatic C=C, C–O, and aromatic C–H functional groups, supporting the presence of bioactive secondary metabolites. Antibacterial activity was evaluated using the disc diffusion method at extract concentrations of 20%, 40%, 60%, 80%, and 100%, with chloramphenicol as the positive control and 10% dimethyl sulfoxide as the negative control. The extract produced inhibition zones against both test bacteria, with the highest inhibition observed at 100% concentration. The minimum bactericidal concentration (MBC) assay showed no bacterial growth at 100% extract concentration in all replications for both bacteria, indicating bactericidal activity at the highest concentration tested. However, the minimum inhibitory concentration (MIC) could not be conclusively determined from the current optical density data because the inhibition pattern was not consistently concentration-dependent. These findings suggest that jackfruit leaf extract has potential as a natural antibacterial agent, although further studies are required to confirm MIC values, isolate active compounds, standardize extract quality, evaluate safety, and develop suitable formulations.]]>
