Functional and binding studies of gallic acid showing platelet aggregation inhibitory effect as a thrombin inhibitor

• Published in: Chinese herbal medicines Vol. 14; no. 2; pp. 303 - 309
• Main Authors: Zhang, Yuxin, Wang, Xing, Lu, Binan, Gao, Yanbin, Zhang, Yanling, Li, Yatong, Niu, Hongjuan, Fan, Lu, Pang, Zongran, Qiao, Yanjiang
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier B.V 01.04.2022; Elsevier
• Subjects: gallic acid; molecular dynamics; natural thrombin inhibitor; Original; platelet aggregation; surface plasmon resonance; natural thrombin inhibitor; molecular dynamics; surface plasmon resonance; gallic acid; platelet aggregation
• ISSN: 1674-6384; 2589-3610; 2589-3610
• DOI: 10.1016/j.chmed.2021.09.001

This study was devoted to identifying natural thrombin inhibitors from traditional Chinese medicine (TCM) and evaluating its biological activity in vitro and binding characteristics. A combination strategy containing molecular docking, thrombin inhibition assay, surface plasmon resonance (SPR) and molecular dynamics simulation were applied to verify the study result. Gallic acid was confirmed as a direct thrombin inhibitor with IC50 of 9.07 μmol/L and showed a significant inhibitory effect on thrombin induced platelet aggregation. SPR-based binding studies demonstrated that gallic acid interacted with thrombin with a KD value of 8.29 μmol/L. Molecular dynamics and binding free energy analysis revealed that thrombin-gallic acid system attained equilibrium rapidly with very low fluctuations, the calculated binding free energies was −14.61 kcal/mol. Ala230, Glu232, Ser235, Gly258 and Gly260 were the main amino acid residues responsible for thrombin inhibition by gallic acid, providing a mechanistic basis for further optimization. This study proved that gallic acid is a direct thrombin inhibitor with platelet aggregation inhibitory effect, which could provide a basis for the follow-up research and development for novel thrombin inhibitors.