MAO inhibiting phytochemicals from the roots of Glycyrrhiza glabra L.

Abstract

Glycyrrhizin, a natural compound that is substantially present in Glycyrrhiza glabra L. (Gg) root. Monoamine oxidase B (MAOB) inhibitor is used for the treatment of several important neuropsychological diseases like Parkinson’s disease. Gg is known to possess psychoactive properties which relates to its MAO inhibitory potential. This study sought to determine the MAO inhibition property of glycyrrhizin from Gg root extract. The Aqueous extract containing glycyrrhizin was isolated from the root of Gg and characterized using TLC, HPLC, and LC-MS techniques. In silico docking was conducted using Extra precision Glide 2018, Schrödinger docking suite. In addition, the pharmacokinetic properties of the compounds were predicted using SwissADME. The binding energies of the glycyrrhizin correlated well with their in vitro MAO inhibitory potential. Glycyrrhizin exhibited potent inhibitory activity towards MAOB whereas, an aqueous extract of Gg root inhibits both A and B forms of MAO enzyme. Further, molecular docking and molecular dynamics simulation showed that liquiritigenin and methoxyglabridin showed higher stability than other inhibitor compounds from the Gg root extract. These observations suggest that the phytochemicals from the Gg root extract have potent MAO inhibition properties, which can be exploited for the treatment of neurodegenerative disorders.

Communicated by Ramaswamy H. Sarma

HIGHLIGHTS

1. Catecholamine content decrement in the brain may cause neurobehavioural disorders.

2. MAO may degrade catecholamines in the brain.

3. MAO inhibitors enhance the catecholamine levels.

4. Glycyrrhiza glabra L. extract and their phytoconstituents exhibit MAO inhibiting properties.

5. Glycyrrhizin can be used to treat Catecholamine mediated neurodegenerative disorders.

Keywords:

• Monoamine oxidase inhibitors
• phytomedicine
• neurodegenerative disorders
• Glycyrrhiza glabra
• in-silico approach

Author contributions

MB and SM conceived the research idea, conducted all in vitro assays, isolated the extract and drafted the manuscript. SM performed in silico work. SU assisted in phytochemical extractions, in vitro assays, and analysis. TA analyzed LC-MS data and provided inputs for chromatographic assignments. The overall research was supervised by PE.

Acknowledgements

We thank Dr. K. Kadirvelu, Joint Director and Co-ordinator DRDO-BU CLS, for his support. The authors would also like to thank Dr. A. Roonie, Dr. M. Kasi Pandi, Mr. Aman, Dr. N. Maroli and Ms. Shoufia, Bharathiar University for their valuable contributions over the course of work. Dr. M. Venkataramana is acknowledged for arranging the plant material and for his valuable input in framing the work. Dr. Hemamalini, Department of Bioinformatics, Bharathiar University for supporting the Molecular dynamics simulation works.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by DRDO-BU Centre for Life Sciences and funded by the Ministry of Defence, New Delhi, India for financial support (DLS/86/50011/DRDO-BU Centre/Phase-II/2014).