In vitro and in silico analysis of Thymus serpyllum essential oil as bioactivity enhancer of antibacterial and antifungal agents

Abstract

Wild thyme (Thymus serpyllum L.) of family Laminaceae is an unexplored perennial medicinal shrub. Aerial part of this plant is traditionally used for the treatment of respiratory and gastrointestinal problems. The current study was designed to evaluate the GC-MS, antimicrobial and synergistic potential of T. serpyllum essential oil (TEO). Chemical characterization of TEO showed the presence of thymol (15.79%), Phenol, 2-(1,1-dimethylethyl) (11.55%), o-Cymene (10.96%) as major phytocompounds. Antimicrobial activity of TEO in terms zone of inhibition (ZOI) varied from 13.66 ± 0.58 mm to 33.66 ± 1.52 mm, while, thymol (10%, v/v) showed ZOI ranged from 15.5 ± 0.5 mm to 26.33 ± 2.08 mm against tested bacterial and fungal species. MIC of TEO was 0.039% to 0.078% against tested bacterial and fungal species, whereas, thymol showed 1.25% to 2.5% MIC against tested bacterial and fungal species. Different combinations of TEO (2MIC to ½MIC) and thymol (2MIC to ½MIC) with antibacterial and antifungal antibiotics (2MIC to ½MIC) were found to increase the efficacy of antibiotics by 4-130 folds against bacterial and fungal pathogens. Molecular docking showed the good binding of thymol with both bacterial and fungal targets. Whereas MD simulation showed the stability of thymol complexed with target proteins over 100 ns time scale. Thymol also fulfills the Lipinski rule and showed characteristics similar to that of drugs. Therefore, it can be concluded from the present study that TEO and its major phytocompound, thymol can act as a bioactivity enhancer of antibacterial and antifungal antibiotics and could be used as a potential candidate to fight against antimicrobial drug resistance.

Communicated by Ramaswamy H. Sarma

Keywords:

• Thymus serpyllum
• Antimicrobial
• Synergistic
• Molecular docking
• MD simulations

Acknowledgements

The authors are thankful to Shoolini University of Biotechnology and Management Sciences, Solan (HP) for providing the infrastructural support for this study. The authors also gratefully acknowledge the Department of Botany, Bioinformatics and Climate Change Impacts Management, Gujarat University for providing an opportunity to access the bioinformatics research facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.

Author’s contribution

All the experiments were performed by Miss Deeksha Salaria. Er. Rajan Rolta provides technical inputs; Dr. Kamal Dev, Dr. Anuradha Sourirajan and Dr. Vikas Kumar conceived the idea and provided guidance to execute the research project.