Evaluation of Potential Thrombin Inhibitors from the White Mangrove (Laguncularia racemosa (L.) C.F. Gaertn.).

Caroline Fabri Bittencourt Rodrigues,Henrique Hessel Gaeta,Marcos Hikari Toyama,Mariana Novo Belchor,Marcelo José Pena Ferreira,Daniela De Oliveira Toyama,Marcus Vinícius Terashima Pinho

doi:10.3390/md13074505

Caroline Fabri Bittencourt Rodrigues, Henrique Hessel Gaeta + Show 5 more

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https://doi.org/10.3390/md13074505

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Abstract

The aim of this work was to verify the effects of methanol (MeOH) and hydroalcoholic (HA) extracts and their respective partition phases obtained from white mangrove (Laguncularia racemosa (L.) C.F. Gaertn.) leaves on human thrombin activity. Among the extracts and phases tested, only the ethyl acetate and butanolic partitions significantly inhibited human thrombin activity and the coagulation of plasma in the presence of this enzyme. Chromatographic analyses of the thrombin samples incubated with these phases revealed that different compounds were able to interact with thrombin. The butanolic phase of the MeOH extract had the most potent inhibitory effects, reducing enzymatic activity and thrombin-induced plasma coagulation. Two glycosylated flavonoids in this partition were identified as the most potent inhibitors of human thrombin activity, namely quercetin-3-O-arabinoside (QAra) and quercetin-3-O-rhamnoside (Qn). Chromatographic analyses of thrombin samples incubated with these flavonoids demonstrated the chemical modification of this enzyme, suggesting that the MeOH extract contained other compounds that both induced structural changes in thrombin and diminished its activity. In this article, we show that despite the near absence of the medical use of mangrove compounds, this plant contains natural compounds with potential therapeutic applications.

Highlights

The enzyme thrombin is involved in the final coagulation cascade, in which it is responsible for the formation of fibrin clots and the conversion of fibrinogen into fibrin
0.1% trifluoroacetic acid (TFA)) at a flow rate of 2 mL/min and the following gradient: 5 min, 100% buffer A; 30 min, 100% buffer B; and 36 min, 100% buffer A; (B) The high-performance liquid chromatography (HPLC) profile of purified thrombin measured at 288 nm; (C) UV-Vis spectra of purified thrombin analyzed by performing UV scanning from 190 nm to 500 nm
The results obtained with the EtOAc-MeOH partition indicated the possible presence of both a thrombin inhibitor and activator

Summary

Introduction

The enzyme thrombin is involved in the final coagulation cascade, in which it is responsible for the formation of fibrin clots and the conversion of fibrinogen into fibrin. Thrombin activates other substrates, such as factors V, VIII, XI, and XIII [1]. This enzyme can mediate additional clotting events and enhance the efficiency of coagulation and peeling. Thrombin is the primary physiological mediator of platelet accumulation and fibrin thrombus formation at sites of vascular injury [3]. It is regarded as the central mediator of thrombogenesis, and its inhibition may disrupt thrombus formation and minimize lesion formation [4]. Thrombin has chemotactic activity toward monocytes [5], acts as an effective mitogen for lymphocytes and mesenchymal cells [6], and causes the production of platelet growth factors in the endothelium [7]

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