Mapping antimicrobials in plant lineages

Plant species with antimicrobial activity occur across many angiosperm families, yet the factors driving the diversity of bioactive compounds remain unclear. This study investigates the antimicrobial activity of 285 flowering plants representing 65 families and 131 genera across lineages reputed to exhibit antimicrobial potential. Over 462 plant extracts were screened against Staphylococcus aureus, Escherichia coli and Aspergillus brasiliensis. Active extracts were fractionated and metabolomically profiled using LC-MS and NMR to identify chemical drivers and their phylogenetic distribution. About 37% of extracts, including preliminary and serial extracts, inhibited S. aureus and 4% inhibited E. coli (MIC ≤ 1000 µg/mL). Hexane and EtOAc extracts showed the highest activity against S. aureus while 60%MeOH extracts showed limited activity against E. coli. The lowest MIC values were <1.95 and 125 µg/mL, respectively, and no antifungal activity was detected. Active extracts mainly contained phenols or diterpenes with characteristic pharmacophores. Phylogenetic comparison revealed antimicrobial hotspots, highlighting plants as promising sources of anti-S. aureus compounds but limited leads against E. coli or A. brasiliensis.