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

Abstract Antimicrobial resistance among Staphylococcus species, including multidrug-resistant and biofilm-forming strains, poses a critical threat to global health, demanding innovative therapeutic solutions. In this context, this study explores the antimicrobial and antibiofilm potential of the aquatic plant Hydrocleys nymphoides as a promising alternative. Extracts from the plant's leaves and roots were obtained using solvents of increasing polarity and tested against five key pathogenic Staphylococcus species: S. aureus, S. epidermidis, S. haemolyticus, S. pseudintermedius, and S. coagulans. The hexane extract of H. nymphoides leaves showed the most notable activity, with inhibition zones of 9–17 mm and minimum inhibitory concentrations (MICs) as low as 0.8 mg/mL for certain strains. Subinhibitory concentrations of the extract significantly reduced biofilm formation in most strains, with reductions up to 46.9%. Gas chromatography-mass spectrometry revealed bioactive compounds such as linoleic acid, n-hexadecanoic acid, 9-octadecenal, eicosane, and tetratriacontane, known for their antimicrobial and antibiofilm properties. Although cytotoxicity was observed at concentrations near the MIC, lower concentrations were non-toxic, indicating potential for controlled therapeutic applications. These findings underscore the biotechnological value of H. nymphoides as a sustainable source of antimicrobial agents against multidrug-resistant Staphylococcus. This work emphasizes the critical role of phytotherapy in combating the escalating antimicrobial resistance crisis.