Decreased thrombin activity by a Congolese herbal medicine used in sickle cell anemia.

ETHNOPHARMACOLOGICAL RELEVANCE: Aqueous extracts from Ceiba pentandra (Malvaceae/Bombacoideae) and Quassia africana (Simaroubaceae) are used as crude medicines for the management of sickle cell anemia (SCA) in the Democratic Republic of Congo (DR Congo). Since it is postulated that the pathogenesis of SCA is associated with an increased blood coagulation activity, the present study is conducted to determine the effect of the two extracts on the coagulation by assessing the thrombin activity and the plasma clotting time. MATERIALS AND METHODS: Thrombin activity was measured by chromogenic assay in the presence of the aqueous extracts (10, 100 or 200 µg/ml); and plasma clotting times were measured by activated partial thromboplastin time (APTT) and prothrombin time (PT) in the presence of C. pentandra (10, 100 or 200 µg/ml) and Q. africana (5, 20 or 50 µg/ml). RESULTS: Reduced thrombin activity and prolonged plasma clotting time measured by APTT were observed in the presence of C. pentandra extract only. However, plasma clotting time measured by PT was not modified by the use of the two extracts. CONCLUSIONS: This study suggests that the aqueous extract of C. pentandra may contain active components that reduce the thrombin activity and prolong the plasma clotting time by affecting the coagulation intrinsic pathway.

Effect of a Congolese herbal medicine used in sickle cell anemia on the expression of plasminogen activators in human coronary aortic endothelial cells culture.

ETHNOPHARMACOLOGICAL RELEVANCE: Aqueous extract of Ceiba pentandra, which is used for the management of sickle cell anemia (SCA) in DR Congo, exhibits antithrombin response by activation of Heparin cofactor II in vitro. This study examines the effect of the plant on the fibrinolytic activity to understand whether it can influence the coagulation-fibrinolysis system, since fibrinolysis disorder is one of the contributing causes of thrombotic crises in SCA. MATERIALS AND METHODS: Fibrinolysis proteins were determined by enzyme-immunoassay in the conditioned medium of cultured endothelial cells after treatment with the extract. Electrophoresis-zymography and RT-PCR tests were conducted to examine the activity and the RNA synthesis of these proteins, respectively. RESULTS: It was found that the extract decreased the activity of both tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor type-1 (PAI-1). However, it was revealed that this effect was not the result of an inhibition of their biosynthesis by endothelial cells. CONCLUSION: From the foregoing, it was revealed that the extract inhibited the secretion of the fibrinolytic proteins without affecting their synthesis by endothelial cells. Thus, the extract may not accelerate the digestion of fibrin clot resulting from thrombotic disorders in SCA.

Bis(L-cysteinato)zincate(lI) as a coordination compound that induces metallothionein gene transcription without inducing cell-stress-related gene transcription.

Zinc is an essential micronutrient, deficiency of which results in growth retardation, immunodeficiency, and neurological diseases such as dysgeusia. Several zinc coordination compounds are used for zinc supplementation; however, supplemented zinc ions have no specificity and interact with various groups of molecules. Here, we found that, from a library of 30 zinc coordination compounds, bis(L-cysteinato)zincate(II), designated Z01, functioned as a metallothionein (MT) inducer. Z01 induced MT expression mediated by the transcription factor MTF-1, without inducing cell-stress-related heme oxygenase-1 gene expression at specific concentration. The zinc ion was necessary for the MT induction. (65)Zn incorporation following treatment with (65)Zn-labeled Z01 suggested that Z01 did not act as zinc ionophore despite its hydrophilicity. Electrophoretic mobility shift assays revealed that Z01 facilitates MTF-1-MRE complex formation, and, by inference, transfer of zinc from Z01 to MTF-1. Phosphorylated ERK levels were increased by ZnSO(4) treatment but not by Z01. Although our data do not definitely prove that Z01 is an MTF-1-specific activator, our observations suggest that zinc coordination compounds can regulate zinc distribution and act as zinc donors for specific molecules.

Inhibition of cultured bovine aortic endothelial cell proliferation by sodium spirulan, a new sulfated polysaccharide isolated from Spirulina platensis.

Sodium spirulan (Na-SP) is a sulfated polysaccharide isolated from the blue-green alga Spirulina platensis, which consists of two types of disaccharide repeating units, O-hexuronosyl-rhamnose (aldobiuronic acid) and O-rhamnosyl-3-O-methylrhamnose (acofriose) with sulfate groups, other minor saccharides and sodium ion. Vascular endothelial cells are present on the inner surface of blood vessels in a monolayer and have anticoagulant properties. To address the question whether Na-SP influences the maintenance of endothelial cell monolayers, we investigated the proliferation of cultured bovine aortic endothelial cells treated with Na-SP. It was found that Na-SP has an inhibitory activity on endothelial cell proliferation accompanied with suppression of whole protein synthesis but without non-specific cell damage. The inhibitory activity of Na-SP was the strongest when compared to that of heparan sulfate, heparin, dextran sulfate, dermatan sulfate, chondroitin sulfate A/C and hyaluronan. Furthermore, it was shown that the inhibitory activity of Na-SP disappeared by either desulfation or depolymerization. The present data suggest that Na-SP is a unique sulfated polysaccharide that strongly inhibits vascular endothelial cell proliferation, and the inhibitory activity requires polymerization of sulfated O-rhamnosyl-acofriose repeating units.