Anticoagulant Properties of a Green Algal Rhamnan-type Sulfated Polysaccharide and Its Low-molecular-weight Fragments Prepared by Mild Acid Degradation.

The active sulfated polysaccharide from seaweed possesses important pharmaceutical and biomedical potential. In the study, Monostroma sulfated polysaccharide (MSP) was obtained from Monostroma angicava, and the low-molecular-weight fragments of MSP (MSP-Fs: MSP-F1⁻MSP-F6) were prepared by controlled acid degradation. The molecular weights of MSP and MSP-F1⁻MSP-F6 were 335 kDa, 240 kDa, 90 kDa, 40 kDa, 24 kDa, 12 kDa, and 6.8 kDa, respectively. The polysaccharides were sulfated rhamnans that consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ units with partial sulfation at C-2 of →3)-α-l-Rhap-(1→ and C-3 of →2)-α-l-Rhap-(1→. Anticoagulant properties in vitro of MSP and MSP-F1⁻MSP-F6 were evaluated by studying the activated partial thromboplastin time, thrombin time, and prothrombin time. Anticoagulant activities in vivo of MSP and MSP-F4 were further evaluated; their fibrin(ogen)olytic activities in vivo and thrombolytic properties in vitro were also assessed by D-dimer, fibrin degradation products, plasminogen activator inhibitior-1, and clot lytic rate assays. The results showed that MSP and MSP-F1⁻MSP-F4 with molecular weights of 24⁻240 kDa had strong anticoagulant activities. A decrease in the molecular weight of MSP-Fs was accompanied by a decrease in the anticoagulant activity, and higher anticoagulant activity requires a molecular weight of over 12 kDa. MSP and MSP-F4 possessed strong anticoagulant activities in vivo, as well as high fibrin(ogen)olytic and thrombolytic activities. MSP and MSP-F4 have potential as drug or helpful food supplements for human health.

New Fluvirucinins C1 and C2 Produced by a Marine Derived Actinomycete.

Two new fluvirucin aglycones, named fluvirucinins C, and C2 (1-2), have been isolated from the ethyl acetate mycelial cake extract of the fermentation broth of.a marine sponge-associated actinomycete. Fluvirucinins C, (1) and C2 (2) represent a new type of 14-membered macrolactam aglycon, structurally related with the common aglycon of the known fluvirucins. Their structures were elucidated on the basis of ID and 2D NMR analyses, as well as HRESIMS experiments. The antimicrobial and cytotoxic activities of compounds 1 and 2 have been evaluated, but no significant activities found for fluvirucinins C, and C2.

Antiviral activities against HSV-1, HCMV, and HIV-1 of rhamnan sulfate from Monostroma latissimum.

Rhamnan sulfate (RS), a natural sulfated polysaccharide isolated from Monostroma latissimum, showed potent inhibitory effects on the virus replication of herpes simplex virus type 1 (HSV-1), human cytomegalovirus (HCMV), and human immunodeficiency virus type 1 (HIV-1) in vitro. The antiviral action of RS was not only due to the inhibition of virus adsorption, but also might involve the later steps of viral replication in host cells on the basis of the results of time-of-addition experiments. Furthermore, RS and 3'-azido-3'-deoxythymidine (AZT) were synergistic in their anti-HIV-1 activities. These data indicate that RS is a potent antiviral substance against HSV-1, HCMV, and HIV-1.