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AbstractThe interest in naturally occurring essential oils from medicinal plants has increased extremely over the last decade markedly because they possess antimicrobial and antioxidant protective properties against different chronic diseases. Extensive survival of drug-resistant infectious bacteria depends on quorum sensing (QS) signaling network which raises the need for alternative antibacterial compounds. The aim of this study was to examine the phytochemical compounds of patchouli essential oil (PEO) and to assess its antioxidant activity. Antioxidant studies estimated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method showed that the PEO has effective antioxidant activity (IC5019.53 µg/mL). QS inhibitory activity of PEO was examined by employing the biosensor strain, Chromobacterium violaceumCV12472. At sub-lethal concentrations, PEO potentially reduced the QS regulated violacein synthesis in CV12472 without inhibiting its cell proliferation. Moreover, it also effectively reduced the production of some QS regulated virulence factors and biofilm development in P. aeruginosaPAO1 without hindering its growth. Phytochemical analysis of PEO was done by GC/MS technique. Molecular docking of PEO major compounds with QS (LasR and FabI) and biofilm regulator proteins (MvfR and Sialidase) of PAO1 was evaluated. These phytocompounds showed potential hydrogen binding interactions with these proteins. The overall results, in vitroand in silico, suggest that PEO could be applied as biocontrol agent against antibiotic resistance pathogens. Communicated by Ramaswamy H. Sarma

In this study we aim to investigate the computational docking approach of biofabricated silver nanoparticles against P. aeruginosavirulent exoenzymes, such as ExoS and ExoY. Therefore, the synthesis and characterization of biofabricated silver nanoparticles using Piper betleleaves (Pb-AgNPs) were carried out. The surface topology and functional group attachment on the surface of Pb-AgNPs were analyzed using UV–visible spectroscopy, Scanning Electron Microscopy, Fourier Transformed Infrared Spectroscopy (FTIR), and X-Ray Diffraction. The FTIR analysis revealed that the synthesized silver nanoparticles were capped with P. betlephytochemicals importantly Eugenol and Hydroxychavicol. These are the major bioactive compounds present in P. betleleaves; therefore, computational docking of Eugenol-conjugated AgNPs (PbEu-AgNPs) and Hydroxychavicol-conjugated AgNPs (PbHy-AgNPs) against ExoS and ExoY was performed. The active residues of PbEu-AgNPs and PbHy-AgNPs interacted with the active site of ExoS and ExoY exoenzymes. Biofabricated AgNP-mediated inhibition of these virulent exoenzymes blocked the adverse effect of P. aeruginosaon the host cell. The computational analysis provides new approach into the design of biofabricated AgNPs as promising anti-infective nanomedicine agents.