https://dthujs.vn/index.php/dthujs Tạp chí Khoa học Đại học Đồng Tháp Dong Thap University Journal of Science vi-VN Tạp chí Khoa học Đại học Đồng Tháp 0866-7675 https://dthujs.vn/index.php/dthujs/article/view/2933 Oldenlandia corymbosa (family Rubiaceae) has been long used in traditional medicine for the treatment of various ailments such as fever, hepatitis, gastrointestinal disorders, cancer, and other inflammatory conditions. Numerous compounds isolated from this species have been reported to exhibit notable pharmacological activities, including anti-inflammatory, antioxidant, anticancer, immunomodulatory, and neuroprotective effects. In the present study, the antibacterial activity of different solvent fractions of O. corymbosa was evaluated to identify promising extracts for further phytochemical investigation. The ethyl acetate fraction showed the strongest inhibitions against Vibrio sp. and Aeromonas caviae, with particularly high inhibition against Vibrio sp. (86.78 ± 0.24 mm at 5.000 mg/mL). Chemical analysis of the ethyl acetate fraction was performed using silica gel column chromatography, and the chemical structures were elucidated by NMR spectroscopy through comparison with reference data, leading to the identification of three compounds: geniposide (1), rutin (2), and quercetin (3). These findings highlight the potential of O. corymbosa as a promising natural source of antibacterial agents. TS. Le Thi Bach Nguyen Minh Nhut Le Tan Tai TS Le Thi Thanh Xuan Nguyen Tien Phong Le Nguyen Hong Phuoc Do Hoang Phi Nguyen Tran Nhat Anh To Thi Hoai Thu Nguyen Viet Hoang Nguyen Van Dat Copyright (c) 2026 Tạp chí Khoa học Đại học Đồng Tháp https://creativecommons.org/licenses/by-nc/4.0 Online First 1 10 10.52714/dthu.ns.2933.1879