Anticoagulant and antithrombotic activity of a sulfate obtained from a glucan component of the lichen Parmotrema mantiqueirense Hale

A β-(1→6)-linked glucan (β-G) was isolated from the lichen Parmotrema mantiqueirense Hale and was sulfated, to give a product (β-G-SO4) with 76.8% sulfate, corresponding to a degree of substitution of 1.95. Both β-G and β-G-SO4 were evaluated by its activated partial thromboplastin (APTT) and thrombin time (TT), using pooled normal human plasma, and compared with that having 140 USP units/mg (porcine intestinal mucosa heparin). Anticoagulant activity was detected for β-G-SO4, but not β-G. The in vivo antithrombotic properties of β-G-SO4 were determined using a stasis thrombosis model in Wistar rats, with an intravenous administration of 0.5 mg/kg body weight totally inhibiting thrombus formation. It caused dose-dependent increases in tail transection bleeding time. The results obtained show that this sulfated polysaccharide is a promising anticoagulant and antithrombotic agent.