Exploring the inhibitory activity of Withaferin-A against Pteridine reductase-1 of L. donovani

Abstract

Withaferin A is an abundant withanolide present in Withania somnifera leaves and to some extent in roots. It has been known for its profound anti-cancer properties, but its role in counteracting the Leishmania donovani infection has to be explored. Pteridine reductase 1 (PTR1) is involved in pteridine salvage and an important enzyme for the parasite growth, which could be targeted for the development of an efficient antileishmanial drug. We employed molecular docking studies to identify the binding mode of withaferin A with PTR1 in silico. We further cloned, expressed, and purified PTR1 of L. donovani and performed the enzyme kinetics using the Michaelis-Menten equation and enzyme inhibition studies with withaferin A by plotting the Lineweaver-Burk graph, which followed an uncompetitive mode of inhibition. We also showed the inhibition of the enzyme in the crude lysate of treated parasites. Thus, our study contributes towards understanding the mode of action of withaferin A against L. donovani parasite.

Homology modelling, molecular docking, and molecular dynamics simulations reveal the inhibition of Leishmania donovani dihydrofolate reductase-thymidylate synthase enzyme by Withaferin-A

“…Due to the lack of purified DHFR-TS enzyme, the current study could not include enzyme assay. However, enzyme assayed from parasite lysate with WA has shown the inhibition activity reported earlier [ 45 ].…”

“…Recently, we reported that WA inhibits Ld PTR1 enzyme activity and molecular docking studies of WA showed high binding affinity with PTR1. Enzyme assay with purified PTR-1 revealed that WA inhibits enzyme activity through uncompetitive mode [ 45 ]. The present molecular docking study reveals that the binding energy of WA with Ld DHFR-TS is higher than Hu DHFR, Hu TS enzymes and WA inhibits Ld DHFR-TS same as the PTR-1 enzyme.…”

Proteomic Analysis of Leishmania donovani Membrane Components Reveals the Role of Activated Protein C Kinase in Host-Parasite Interaction

“…Our current finding of Leishmania-activated C kinase protein interacting with the macrophage membrane protein, strongly backed by previous studies, indicated this as an important molecule to explore as a potential target for chemotherapeutic intervention. Withaferin A (WA), an inhibitor of activated C kinase and other enzymes of Leishmania, significantly reduced the proliferation of L. donovani to macrophages, highlighting its role in the host-parasite interaction [31,32]. Leishmania-activated C kinase (LACK) facilitates the cytochrome c oxidase subunit expression to promote the fitness of L. major.…”

Withaferin A – A natural multifaceted therapeutic compound

“…Another important enzyme that can be targeted for developing an effective anti-leishmanial drug is Pteridine reductase 1(PTR1). The molecular docking studies of WA against PTR 1 showed the binding efficacy with lowest binding energy of -6.73kJ/mol (Chandrasekaran et al, 2015). Due to structural similarity between the PTR1 and DHFR-TS, the inhibitor that targets PTR1 can also target DHFR-TS.…”