ETHNOPHARMACOLOGICAL RELEVANCEMedicinal plants are frequently used in Caribbean traditional medicine as low-cost, culturally relevant treatments for women's health concerns, such as gynecological infections. These plants are typically applied topically, potentially affecting both pathogenic bacteria (e.g., Gardnerella vaginalis) and beneficial vaginal microbes (Lactobacillus spp.). However, few studies have examined the impact of these plants on both beneficial and pathogenic vaginal bacteria.AIM OF THE STUDYArgemone mexicana, available in New York City and commonly used to treat gynecological infections by immigrants from the Dominican Republic, was investigated for its chemical variation and effects on the vaginal microbiota. We hypothesized that variations in the bioactivity of Argemone mexicana on Gardnerella vaginalis and Lactobacillus spp. are due to differences in antimicrobial compounds across different preparations.MATERIALS AND METHODSUntargeted and targeted metabolomic analysis using UPLC-qToF-MS and UPLC-TQD-MS were conducted on Argemone mexicana samples collected in New York City. Antimicrobial assays were used to assess the effects of Argemone mexicana samples on beneficial and pathogenic vaginal bacteria. ProGenesis QI and EZinfo were used for metabolomic analysis to link bioactivity with chemometric data.RESULTSUPLC-qToF-MS and statistical analyses showed that chemical variation correlated with plant tissue type and processing (dry or fresh samples). These differences were evident in antimicrobial screenings, where active plant samples were antimicrobial against pathogenic bacteria only, with no effect on beneficial Lactobacillus. Known antimicrobial benzoquinone alkaloids, such as berberine, were partly responsible for the observed microbiological activity. Berberine exhibited similar inhibition patterns, reduced biofilm formation, and trended towards higher concentration in active samples.CONCLUSIONSExtracts of Argemone mexicana, a plant used in Caribbean women's health, did not have an effect on beneficial vaginal microbes, but did inhibit pathogenic Gardnerella vaginalis. This antimicrobial activity correlated with the chemical variation of berberine and other related alkaloids across traditional preparations of Argemone mexicana. These results may be relevant for treating gynecological infections, not only with this plant, but other berberine-containing taxa.