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23 Congress of the International Union for Biochemistry and Molecular Biology
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44 Annual Meeting of the Brazilian Society for Biochemistry and Molecular Biology
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Foz do Iguaçu, PR, Brazil, August 24 to 28 , 2015
Evaluation of inhibitor potential of thrombin from white mangrove (Laguncularia
racemosa) plant.
Toyama, D.O.1, Rodrigues, C.F.B.1, Gaeta, H.H.1, Belchor, M.N.1, Otolam, B.1,
Betollucci, C.1, Ferreira, M.J.P. 2, de Pinho, M.V.T.1, and Toyama, M.H. 1*.
1Universidade Estadual Paulista Julio de Mesquita Filho, UNESP, Praça Infante Dom
Henrique, s/n, São Vicente, SP,11330-900, Brazil.
2Universidade de São Paulo, Instituto de Biociências, Departamento de Botânica, Rua
do Matão, 277, CEP 05508-090, São Paulo, SP, Brazil.
The aim of this work is to verify the action of methanol (MeOH) and
hydroalcoholic (HA) extracts and their respective partitions phases obtained from the
leaves of mangrove plant Laguncularia racemosa on the enzymatic activity of human
thrombin. From the incubation of thrombin (TH) aliquots with same concentration of
several partitions from HA and MeOH, only ethyl acetate and buthanolic partitions
showed the most significant inhibition of both enzymatic activity as well as the plasma
coagulation in presence of human thrombin. Chromatographic analysis from the
samples of thrombin incubated with these phases suggested that different compounds
were able to interact with thrombin and some of these probably induced significant
modifications in the thrombin structure. Our results showed that the most potent
inhibition was found in buthanolic phase from methanolic extract, which virtually
abolished the enzymatic and strongly reduced the ability of thrombin to induce plasma
coagulation. From this partition were found two glycosylated flavonoids as the most
potent inhibitors of the enzymatic activity of human thrombin which significantly
decrease the plasma coagulation. Both flavonoids were characterized as quercetin-3-Oarabinoside (QAra) and quercetin-3-O-rhamnoside (Qn). Despite the high molecular
similarities both either QAra and Qn have different capacity to interact to human
thrombin. On the other hand, our experiments also showed that aqueous phase also
strongly decreased and inhibited the blood coagulation. Chromatographic analysis of
the flavonoids from the previous incubation of enzyme showed the thrombin chemically
modified through the different retention times among them and the native human
thrombin. These results also suggest that methanolic extract has other compounds that
induced structural changes as well as induce a significant diminishing of the thrombin
activity.
Keywords: thrombin, Laguncularia racemosa, flavonoids, plasma coagulation.
Finantial supports: FAPESP, CNPq e CAPES.
Brazilian Society for Biochemistry and
Molecular Biology (SBBq)