Chemical Profile, Antibacterial, Antibiofilm, and Antiviral Activities of Pulicaria crispa Most Potent Fraction: An In Vitro and In Silico Study

Infectious diseases caused by viruses and bacteria are amajor public health concernworldwide, with the emergence of antibiotic resistance, biofilm-forming bacteria, viral epidemics, and the lack of effective antibacterial and antiviral agents exacerbating the problem. In an effort to search for new antimicrobial agents, this study aimed to screen antibacterial and antiviral activity of the total methanol extract and its various fractions of Pulicaria crispa (P. crispa) aerial parts. The P. crispa hexane fraction (HF) was found to have the strongest antibacterial effect against both Gram-positive and Gram-negative bacteria, including biofilmproducers. TheHF fraction reduced the expression levels of penicillin binding protein (PBP2A) and DNA gyrase B enzymes in Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Additionally, the HF fraction displayed the most potent antiviral activity, especially against influenza A virus, affecting different stages of the virus lifecycle. Gas chromatography/mass spectrometry (GC/MS) analysis of the HF fraction identified 27 compounds, mainly belonging to the sterol class, with beta-sitosterol, phytol, stigmasterol, and lupeol as the most abundant compounds. The in silico study revealed that these compounds were active against influenza A nucleoprotein and polymerase, PBP2A, and DNA gyrase B. Overall, this study provides valuable insights into the chemical composition and mechanism of action of the P. crispa HF fraction, which may lead to the development of more effective treatments for bacterial and viral infections.