Inhibition of the Generation of Thrombin and Factor Xa by a Fucoidan from the Brown Seaweed Ecklonia kurome

<b><i>In vitro</i> inactivation of thrombin generation by polysulfated fractions isolated from the tropical coenocytic green seaweed <i>Caulerpa racemosa</i> (Caulerpaceae, Bryopsidales)

“…This was in conformity to the PTh and TPeak parameters (Nishino et al, 1999;Rodrigues et al, 2016;Rodrigues et al, 2017a;Rodrigues et al, 2017b;Salles et al, 2017), based on the amidolytic activity of thrombin that decayed immediately until a plateau was reached at 28 and the negative control without activators min (Mourão et al, 2001;Salles et al, 2017). The anticoagulant dynamic of the fractions was monitored for 60 min at 37°C in parallel with the control curve of UHEP used (Figure 2) (Rodrigues et al, 2017a;Rodrigues et al, 2017b;Salles et al, 2017).…”

“…In these connections, decrease in TG by C. racemosa SPs reflected a different mode of action from the other classes of polysulfated that have diverse structures and mechanisms of thrombin inhibition (Nishino et al, 1999;Mourão et al, 2001;Glauser et al, 2009;Zhang et al, 2014;Rodrigues et al, 2016) distinct from that of UHEP, which abolished TG at 2 (intrinsic pathway) (Figure 2) (Rodrigues et al, 2016;Rodrigues et al, 2017b) or 4 (extrinsic pathway) (data not shown) μg well-plate -1 (Rodrigues et al, 2017a;Salles et al, 2017) because of its specific pentasaccharide sequence with high antithrombin affinity displaying thrombin inhibition (Mourão, 2015). These results allowed us to postulate that the modulation of TG by intrinsic pathway in the presence of UHEP were in concordance with the automated method (Jun et al, 2014), but occurred at concentration 5-fold lower than that of Glauser et al (2009), who reported no inhibition of TG by UHEP up to 10 μg.…”

“…The action of these compounds would be mediated by serpins (antithrombin and heparin II cofactor) (Rodrigues et al, 2013;Wang et al, 2014) because galactose-rich polysaccharides reveal as inhibitors of thrombin (Hayakawa et al, 2000;Ghosh et al, 2004), but the relationship between structure and anticoagulation still lacks in-depth details since the existence of complexity and heterogeneity of the algae glycans make comparison difficult with UHEP at molecular level and bioactivity (Athukorala et al, 2006;Pomin, 2012;Fidelis et al, 2014;Mourão, 2015;Rodrigues et al, 2016). TG assays may measure several feedback reactions to evaluate diverse classes of SPs regarding their anticoagulant dynamics (Nishino et al, 1999;Mourão et al, 2001;Glauser et al, 2009;Zhang et al, 2014;Rodrigues et al, 2017b;Salles et al, 2017).…”

“…This distinct inhibitory profile of the C. racemosa fractions on TG by the coagulation reaction of the intrinsic pathway stimulated by cephalin (contactactivation) could perhaps be revealed as serpinsdependent thrombin inhibitors (Rodrigues et al, 2013;Wang et al, 2014) at differential inactivation patterns to modulate thrombosis in vitro (Nishino et al, 1999;Mourão et al, 2001) because antithrombin-dependent anticoagulants do not enhance TG in plasma and have ability to attenuate thrombin activity (Furugohri, Sugiyama, Morishima & Shibano, 2011). On the contrary, the impact of sulfation on the extrinsic-pathway induced TG did not appear using both fractions F I and F II, showing that the sulfation level was not relevant in this process because the algal SPs had only a discrete inhibitory action from the positive control (thromboplastine); therefore, a significant response was not found in plasma treated with the polymers (data not shown).…”

Cytotoxic effect of magnetic iron oxide nanoparticles synthesized via seaweed aqueous extract

“…14 As mentioned in previous reports, 15 seaweed is a subgroup of macroalgae and an available food source in many countries, traditionally those in south-east Asia. 16 Seaweed contains a number of potentially biologically active ingredients, including polysaccharides, proteins, lipids, vitamins, soluble fiber, and minerals, with multiple medical applications in cancer, 17 inflammation, 18 allergy, 19 diabetes, 20 thrombosis, 21 and obesity (by bringing down the caloric value of the diet), 22 and may be useful in the reduction of lipid absorption and risk of cardiovascular disease, 23 hypertension, 24 and other degenerative diseases. 25 These biomedical applications of seaweed are mainly due to its functional groups, which act as capping agents in a green single-step process.…”