Hydrocleys nymphoides (water poppy): a cosmopolitan aquatic plant with a phytochemical-rich extract exhibiting antimicrobial and antibiofilm activity against multidrug-resistant Staphylococcus.

This article investigates the antimicrobial and antibiofilm potential of Hydrocleys nymphoides, a cosmopolitan aquatic plant, against multidrug-resistant Staphylococcus species, including Staphylococcus aureus, S. epidermidis, S. haemolyticus, S. pseudintermedius, and S. coagulans. Hexane extracts from the plant’s leaves exhibited notable antimicrobial activity with inhibition zones of 9–17 mm and minimum inhibitory concentrations (MICs) as low as 0.8 mg/ml for certain strains, while subinhibitory concentrations significantly reduced biofilm formation by up to 46.9%. Gas chromatography–mass spectrometry identified bioactive apolar compounds such as linoleic acid and n-hexadecanoic acid, which are known for antimicrobial and antibiofilm effects. Although cytotoxicity was observed at concentrations near the MIC, lower doses were non-toxic to human keratinocytes, suggesting potential for controlled therapeutic or surface-coating applications. The study highlights H. nymphoides as a sustainable source of bioactive compounds with promise for developing alternative strategies to combat antimicrobial resistance and biofilm-associated infections.