Evaluating the inhibitory potential of Withania somnifera on platelet aggregation and inflammation enzymes: An in vitro and in silico study

Abstract

Context Withania somnifera (L.) Dunal is traditionally used for treating various ailments, but lacks scientific evaluation.

Objective This study evaluates Withania somnifera (WS) for its effect on platelet activity and inflammatory enzymes.

Materials and methods Aqueous and ethanolic (1:1) leaf extracts were subjected to in vitro indirect haemolytic activity using Naja naja venom, human platelet aggregation was quantified for lipid peroxidation using arachidonic acid (AA) as agonist and 5-lipoxygenase (5-LOX) levels were determined using standard spectrometric assays. Further, molecular docking was performed by the ligand fit method using molegro software package (Molegro ApS, Aarhus, Denmark).

Results The study found that aqueous and ethanol extracts have very negligible effect (15%) with an IC₅₀ value of 13.8 mg/mL on PLA₂ from Naja naja venom. Further, extracts of WS also had very little effect (18%) with an IC₅₀ value of 16.6 mg/mL on malondialdehyde (MDA) formation. However, a 65% inhibition of 5-LOX with an IC₅₀ value of 0.92 mg/mL was observed in 1:1 ethanol extracts. The same was evident from SAR model with the active ingredient withaferin A binding predominantly on Phe 77, Tyr 98, Arg 99, Asp 164, Leu 168, Ser 382, Arg 395, Tyr 396 and Tyr 614 with an atomic contact energy value of −128.96 compared to standard phenidone (−103.61). Thus, the current study validates the application of WS for inflammatory diseases.

Conclusion This study reveals the inhibitory potential of W. somnifera on inflammatory enzymes and platelet aggregation. Thus, WS can serve as a newer, safer and affordable medicine for inflammatory diseases.

Keywords:

• Cyclooxygenase
• 5-lipoxygenase
• Naja naja venom
• phospholipases
• Solanaceae
• structure–activity relationship
• withaferin-A

Acknowledgements

F. Z. and R. H. gratefully acknowledge Prof. Dr. K. V. Prabhakara, Principal, SBRR First Grade College, Mysore, and the management, Mahajana Education Society and Research Foundation, for their constant support and inspiration. All authors are grateful to Mr. Kamran Waseem, Department of Studies in Chemistry, University of Mysore, for the language corrections and suggestions. D. B. L. acknowledge the financial assistance of DST, Govt of India for the International Grant – Indo-Srilankan (DST/INT/SLP/P-007/2012, dated 5th May, 2014), and European Union for International Grant – Indo-European – Marie Curie IRSES - (PIRSES-GA-2013-612131, dated 15th Nov, 2014). DBL would like to place on record the deepest gratitude towards Dr. Chenraj Roychand, President Jain University trust and Dr. Krishna Venkatesh, CEO, Centre for Emerging Technologies (CET) for their constant motivation and support.

Declaration of interest

The authors report no conflicts of interest.