Interaction of zincite, alpha-terpineol, geranyl acetate, linalool, myrcenol, terpinolene, and thymol with virulence factors of Escherichia coli, Mycobacterium tuberculosis, Pseudomonas aeruginosa, and Staphylococcus aureus.

BACKGROUND: Based on gas chromatography - mass spectrometry (GC-MS) results of a previous study, six metabolites including alpha-terpineol, geranyl acetate, linalool, myrcenol, terpinolene, and thymol showed significantly higher amounts relative to other metabolites.

METHODS: A continuation of the previous study, the interaction of these metabolites with the main virulence factors of P. aeruginosa (pseudomonas elastase and exotoxin A), Staphylococcus aureus (alpha-hemolysin and protein 2a), Mycobacterium tuberculosis (ESX-secreted protein B and the serine/threonine protein kinase), and Escherichia coli (heat-labile enterotoxin and Shiga toxin) were evaluated by molecular docking study and molecular simulation.

RESULTS: In the case of Shiga toxin, higher and lower binding affinities were related to alpha-terpinolene and zincite with values of -5.8 and -2.6 kcal/mol, respectively. For alpha-hemolysin, terpinolene and alpha-terpinolene demonstrated higher binding affinities with similar energies of -5.9 kcal/mol. Thymol and geranyl acetate showed lower binding energy of -5.7 kcal/mol toward protein 2a. Furthermore, thymol had a higher binding affinity toward heat-labile enterotoxin and ESX-secreted protein B with values of -5.9 and -6.1 kcal/mol, respectively.

CONCLUSIONS: It is concluded that the availability of secondary metabolites of A. haussknechtii surrounding zinc oxide (ZnO) NPs can hinder P. aeruginosa by inactivating Pseudomonas elastase and exotoxin.