Molecular docking studies of Triphala with catalytic portion of HMG-CoA reductase enzyme

Triphala, consisting of three fruits, Phyllanthus emblica L. (Phyllanthaceae), Terminalia bellirica (Gaertn.) Roxb. (Combretaceae), and T. chebula Retz, is a well-recognized Ayurvedic herbal formulation, used for various therapeutic purposes, including the treatment of dyslipidemia. Inhibitory activity against 3‑hydroxy‑3‑methylglutaryl‑coenzyme A (HMG‑CoA) reductase, a rate-limiting enzyme in the endogenous cholesterol synthesis pathway, is an essential target for the management of hypercholesterolemia. This in silico study aimed to investigate the HMG-CoA reductase inhibitory activity of the phytochemical compounds derived from Triphala formulation by employing molecular docking analysis.

Ten phytochemical constituents of Triphala formulation were selectively used for docking study by using the HMG-CoA reductase template (PDB: 1HWK). Docking analysis was performed using AutoDock 4.2. The candidates were ranked by the binding energy parameters.

From the docking studies, the phytochemical compounds with HMG-CoA reductase inhibition could be classified into 4 groups, including phytosterols, polyphenols, tannins, and flavonoids. Beta-sitosterol exhibited the highest binding affinity to HMG-CoA reductase with a binding energy of -7.75 kcal/mol.

These 10 phytochemical compounds in Triphala potentially exert their cholesterol-lowering effects via inhibition against HMG-CoA reductase. Nonetheless, further in vitro and in vivo experiments should be conducted subsequently to confirm this finding.