Antibacterial properties of Buddleja globosa: a review of extracts and bioactive compounds

Buddleja globosa (Buddlejaceae) is a South American medicinal plant traditionally used for wound healing and other inflammatory conditions. In recent years, increasing attention has been given to its antibacterial potential and to the bioactive compounds that may contribute to this activity. This review summarizes the available evidence on the antibacterial-related activity of B. globosa extracts and selected metabolites reported in the species, including direct antibacterial effects, antibiofilm activity, antivirulence mechanisms, host-protective effects, and antibiotic-adjuvant properties. The available evidence indicates that polar extracts of B. globosa, particularly aqueous, hydroalcoholic, and ethanolic preparations, can inhibit clinically relevant bacteria such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, although reported activity varies according to extract type, plant material, and assay methodology. Among the identified metabolites, phenylethanoid glycosides, especially verbascoside and forsythoside B, are the most relevant compounds due to their abundance in B. globosa extracts and their reported antibacterial-related mechanisms. Verbascoside shows variable direct antibacterial activity but stronger evidence as an antibiofilm, antivirulence, antitoxin, and host-protective compound. Forsythoside B displays direct activity against selected Gram-negative pathogens and potentiates conventional antibiotics against multidrug-resistant bacteria. Flavonoids such as luteolin, apigenin, quercetin, and their glycosides also contribute relevant antibacterial, antibiofilm, or antivirulence evidence, although many studies have used commercial standards or compounds isolated from other plant species. Overall, B. globosa represents a promising source of antibacterial-related bioactive compounds, but future studies should prioritize standardized extract characterization, quantitative susceptibility testing, cytotoxicity assessment, mechanistic validation, and in vivo models that connect phytochemical composition with antibacterial efficacy.