In vitro inhibition of thrombin generation by sulfated polysaccharides from the marine alga Solieria filiformis (Kützing) Gabrielson (Solieriaceae, Rhodophyta) / Inibição in vitro de geração de trombina por polissacarídeos sulfatados da alga marinha Solieria filiformis (Kützing) Gabrielson (Solieria

Abstract Solieria filiformis is a rich source in carrageenans-type sulfated polysaccharides (SPs) containing two fractions (F I and F II), of which F I presented in vivo antinociceptive and inflammatory actions. However, the effects of its SPs on thrombin generation (TG) assays have not been investigated. This study characterized the physicochemical properties of SPs isolated from Solieria filiformis cultured in the coast of Ceara, Brazil and analyzed in vitro inhibitory effects on a TG system using a chromogenic method by continuous detection. Crude extract obtained with papain and fractionated by anion-exchange chromatography on a DEAE-cellulose column contained two fractions (F I and F II). Electrophoresis in agarose gel revealed an difference in terms of charge density between extract and fractions obtained from the DEAE-cellulose chromatography, suggesting the presence of both kappa- and iota-carrageenans, confirming a previous study using the respective S. filiformis fractions. Anticoagulant assays using normal human plasma and unfractionated heparin (UHEP) (193 IU mg-1) by activated partial thromboplastin time test showed virtual effects in order of 1.34 (extract), 0.86 (F I) and 0.98 (F II) IU mg-1 less potents than UHEP; additionally, extract and fractions had no actions on the prothrombin time. 60-fold diluted human plasma treated with extract and fractions inhibited dependently of concentration TG stimulated by cephalin (intrinsic pathway) and thromboplastin (extrinsic pathway), with charge density-related TG inhibition pattern of the algal SPs. UHEP totally abolished TG at 4.15-fold lower concentration. Therefore, SPs from S. filiformis prevent thrombosis, in vitro, by interfering with the TG system, as a promising plasma alternative to modulate blood coagulation.Resumo Solieria filiformis e uma fonte rica em polissacarideos sulfatados (PSs) tipo carragenanas contendo duas fracoes (F I e F II), das quais F I apresentou acoes antinociceptiva e inflamatoria in vivo. Entretanto, nao tem sido investigados os efeitos de seus PSs sobre ensaios de geracao de trombina (GT). Este estudo caracterizou as propriedades fisico-quimicas de PSs isolados de Solieria filiformis cultivada na costa do Ceara, Brasil e analisada efeitos inibitorios in vitro sobre um sistema de GT usando um metodo cromogenico por deteccao continua. O extrato bruto obtido com papaina e fracionado por cromatografia de troca-ionica em uma coluna de DEAE-celulose conteve duas fracoes (F I e F II). Eletrophorese em gel de agarose revelou diferenca de densidade de cargas entre extrato e fracoes obtidas da cromatografia em DEAE-celulose, sugerindo a presenca de ambas carragenanas-kappa e -iota, respectivamente, e confirmando, ainda, um estudo previo usando as fracoes de S. filiformis. Ensaios anticoagulantes usando plasma humano e heparina nao-fracionada (HEPNF) (193 UI mg-1) pelo teste do tempo de tromboplastina parcial ativada mostraram efeitos virtuais na ordem de 1,34 (extrato), 0,86 (F I) e 0,98 (F II) UI mg-1 potentes menos que HEPNF. Ademais, extrato e fracoes nao possuiram acoes sobre o time de protrombina. Plasma humano diluido 60 vezes tratado com extrato e fracoes inibiu GT estimulada por cefalina (via intrinsica) e tromboplastina (via extrinsica), com grau de inibicao relacionada a densidade de carga dos PSs da alga. HEPNF aboliu totalmente GT em concentracao 4,15 vezes menor. Os PSs de S. filiformis previnem trombose in vitro por interferir com o sistema de GT, alternativa promissora no plasma para modular a coagulacao sanguinea.