Molecular networking-guided isolation of compounds from Keetia venosa (Oliv.) Hiern leaves and their antibacterial activities

The global incidence of antibacterial resistance represents a significant public health challenge, with an estimated number of 4.95 million deaths in 2019, predominantly in developing countries [ 1 ]. This emphasises the urgent necessity to identify novel molecules with antibacterial properties to address this concern. Medicinal plants have been identified as playing a crucial role due to their rich chemical diversity and bioactivity [ 2 ]. Nonetheless, the conventional approach to natural product isolation remains challenging, as evidenced by the technical limitations associated with in-depth screening of biomaterials. In this study, we have employed a molecular networking-guided approach aiming at the in-depth chemical profiling and isolation of new potential antibacterial compounds from a medicinal plant Keetia venosa leaves. These plants are used in traditional medicine to treat bacterial and parasitic infections. This applied method led to the isolation and characterisation of 18 compounds, including 4 previously undescribed. The structures of these compounds were elucidated through a comprehensive analysis of their physical, HR-MS/MS and NMR spectroscopic data. Several additional compounds were putatively identified by comparing their MS 2 features with analogous structures in established databases. Moreover, the antibacterial activity of extracts, fractions and isolated compounds were evaluated against a range of Gram-positive and -negative bacteria. Some fractions and isolated compounds displayed promising antibacterial activity against Gram-negative bacteria such as K. pneumoniae , S. enterica and P. aeruginosa with MIC values ranging from 3.9-62.5 μg/mL. The molecular networking-guided applied methodology speeds up the dereplication, targeting and isolation of natural products from plant extracts. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany