Assessment of chemical composition and antibacterial activity of Verbesina encelioides (Cav.) Benth. & Hook. f. ex A. Gray (Wild Sunflower)

The rapid emergence of antimicrobial resistance has created an urgent need for new antibacterial agents from natural sources. Verbesina encelioides, a medicinal plant rich in bioactive phytochemicals, remains insufficiently explored for its antibacterial potential. The present study aimed to evaluate the antibacterial activity of leaf, stem, and root extracts of V. encelioides prepared using methanol, petroleum ether, and water, and to identify the major phytochemical constituents responsible for the observed activity. Extracts were screened against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa using the disc diffusion assay. The most active extracts were subsequently characterized by GC–MS analysis. Methanolic extracts exhibited the strongest antibacterial activity, with the leaf extract producing the highest inhibition zones of 13.67 ± 0.33 mm against B. subtilis, 12.33 ± 0.33 mm against E. coli, 12.00 ± 0.58 mm against S. aureus, and 11.56 ± 0.29 mm against P. aeruginosa. GC–MS profiling identified several bioactive compounds, including isoeugenol, carvacrol, β-amyrin, methyl petroselinate, β-sitosterol, stigmasterol, palmitic acid methyl ester, and linoleic acid methyl ester, which are known for their antimicrobial properties. This study demonstrates the superior antibacterial potential of methanolic extracts, particularly from leaves, and provides a comparative phytochemical profile of different plant parts of V. encelioides. The findings support its potential as a natural source of antibacterial compounds and provide a foundation for future isolation of active constituents and development of plant-based antimicrobial agents.