In vitro and in silico assessment of antimicrobial properties of Piper nigrum L. collected from Gajapati district, Odisha against some pathogenic bacteria

Background: Black pepper (Piper nigrum), is a member of the family Piperaceae and is cultivated for its dried fruit, which is used as a spice and condiment. Aim: To examine the effectiveness of the bioactive components of Piper nigrum L. against two human pathogenic bacteria, namely Escherichia coli and Staphylococcus aureus following both in vitro and in silico methods. Methods: Piper nigrum L. extracts were prepared using ethanol and antibacterial activity was tested in vitro against two selected pathogenic bacteria Escherichia coli and Staphylococcus aureus using the agar disc diffusion method. Lipinski rule of five was followed to identify the secondary metabolite which was safe for oral medication. In silico analysis involved molecular docking of the phytocompound with bacterial target protein DNA gyrase to predict binding affinity and potential antimicrobial interactions. Results: Antibacterial activity against both the studied microorganisms was shown by the bioactive compounds present in the plant. The leaf extract of the plant showed the height zone of inhibition against Escherichia coli, measuring 6.8 mm, compared to S. aureus. It was confirmed that the secondary metabolite 6-hydroxypiperitol was safe to use in oral medications because of the characteristic of the compound adherence to the Lipinski rule of five. The results of the molecular docking of 6-hydroxypiperitol showed that it has a significant binding affinity (-7.8 kcal/mol) to the bacterial metabolic enzyme E. coli DNA gyrase (PDBID: 1kzn). Conclusion: Piper nigrum has a secondary metabolite called 6-hydroxypiperitol, which may have potential as an antibacterial agent.