In vitro and in silico antioxidant and anti-inflammatory potential of essential oil of Cymbopogon citratus (DC.) Stapf. of North-Western Himalaya

Abstract

Cymbopogon citratus (DC.) Stapf is an aromatic perennial herb of Gramineae (Poaceae) family and is known for its application in food and healthcare industry. The present study aimed to evaluate anti-inflammatory and antioxidant potential of C. citratus essential oil (CEO) through in vitro and in silico studies. Chemical characterization of CEO was done using Gas chromatography-mass spectrophotometry (GC-MS) method. In vitro antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric ion reducing antioxidant power (FRAP) assays, while egg albumin denaturation method was used to evaluate in vitro anti-inflammatory activity of CEO. Molecular docking investigation of major phytocompounds of CEO was done using Autodock vina software against human peroxiredoxin 5 (PDB ID: 1HD2) and human cyclooxygenase 2 (PDB ID: 5IKQ) proteins, which were further analyzed through molecular dynamics (MD) simulation using YASARA. GC-MS analysis of CEO showed the presence of geranial (48%) neral (34.04%), β-myrcene (9.77%), geraniol (1.88%), linalool (0.84%), isogeranial (0.81%), β-caryophyllene (0.80%), D-limonene (0.51%) as major constituents. CEO showed significant antioxidant activity with DPPH (IC₅₀-47.53 ± 2.16 µg/ml), FRAP (IC₅₀-30.7 ± 0.31 µM), and ABTS assays (IC₅₀-27.87 ± 0.09 µg/ml). CEO also exhibited significant in-vitro anti-inflammatory activity with IC₅₀-29.71 ± 1.95 µg/ml as compared to that of Diclofenac sodium (IC₅₀-36.52 ± 1.95 µg/ml). Molecular docking revealed that β-caryophyllene showed considerable binding potential with human peroxiredoxin 5 receptor (-6.0 kcal/mol) and human cyclooxygenase 2 receptor (-10.1 kcal/mol). Further, MD simulations demonstrated considerable and stable interactions of β-caryophyllene with 1HD2 and 5IKQ proteins up to 100 ns. Drug-likeness and ADME/T features also showed that β-caryophyllene can be used as a potential candidate to replace the synthetic anti-inflammatory drugs with side effects and also act as natural antioxidants.

Communicated by Ramaswamy H. Sarma

Keywords:

• Cymbopogon citratus
• essential oil
• antioxidant
• anti-inflammatory
• molecular docking
• MD simulations
• ADME/T

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.

Declaration of competing interest

We do not have any conflict of interest to declare regarding this research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Author’s contribution

All the experiments were performed by Miss Deeksha Salaria, Er. Rajan Rolta, Dr. Arabinda Ghosh and Dr. Chirag N. Patel provides technical inputs, Dr. Nitin Sharma help in finalizing figures and final draft of the manuscript; Dr Kamal Dev; Dr Anuradha Sourirajan and Dr. Vikas Kumar conceived the idea and provided guidance to execute the research project.