Antibacterial, antibiofilm, and wound healing activities of Piper longum root in multidrug-resistant Staphylococcus aureus infected mice

Objective: To explore the effect of a hydrogel of Piper longum (P. longum ) root against biofilm-forming multidrug-resistant (MDR) Staphylococcus aureus (S. aureus ) through in vitro, in silico , and in vivo studies. Methods: We isolated the P. longum root ethanolic extract and the compounds using p-HPLC. In vitro antibacterial and antibiofilm activities of P. longum root extract and isolated alkamide compounds against biofilm-forming MDR S. aureus (ATCC 33591) were assessed using agar diffusion and broth microdilution methods, respectively. In silico investigations were conducted to investigate the interaction of alkamide compounds with three target proteins glycogen synthase kinase 3β (GSK3β), matrix metahoproteinases-8 (MMP-8), and inducible nitric oxide synthase (iNOS). In addition, the wound healing effect of P. longum root extract 2% and 5% ( w/v)- containing hydrogels was determined in mice. Results: The ethanolic root extract of P. longum and its compounds exhibited in vitro antibacterial activity with minimum inhibitory concentrations between 50 μg/mL and 700 μg/mL, as well as significantly reduced biofilm formation. Piperdardine isolated from P. longum root extract had the best molecular docking score (−9.7, −9.8, and −9.2 kcal/mol) with target proteins GSK3β, MMP-8, and iNOS. In vivo studies showed that P. longum hydrogels significantly lowered the number of colony-forming units ( P < 0.05). The P. longum 5% ( w/v ) hydrogel-treated group showed enhanced wound healing activity, achieving a wound contraction rate of 99.34% on day 14. Furthermore, histopathological analysis confirmed increased re-epithelialization and reduced inflammation in mice treated with P. longum 5% ( w/v ) hydrogel. Conclusions: P. longum root extract has pharmacological potential as an antibacterial and wound-healing agent, and further research is required to confirm its efficacy and clinical application.