Biochemical and pharmacological evaluation of 4-hydroxychromen-2-ones bearing polar C-3 substituents as anticoagulants

Regulatory Effects of Curcumin on Platelets: An Update and Future Directions

The rhizomatous plant turmeric, which is frequently used as a spice and coloring ingredient, yields curcumin, a bioactive compound. Curcumin inhibits platelet activation and aggregation and improves platelet count. Platelets dysfunction results in several disorders, including inflammation, atherothrombosis, and thromboembolism. Several studies have proved the beneficial role of curcumin on platelets and hence proved it is an important candidate for the treatment of the aforementioned diseases. Moreover, curcumin is also frequently employed as an anti-inflammatory agent in conventional medicine. In arthritic patients, it has been shown to reduce the generation of pro-inflammatory eicosanoids and to reduce edema, morning stiffness, and other symptoms. Curcumin taken orally also reduced rats' acute inflammation brought on by carrageenan. Curcumin has also been proven to prevent atherosclerosis and platelet aggregation, as well as to reduce angiogenesis in adipose tissue. In the cerebral microcirculation, curcumin significantly lowered platelet and leukocyte adhesion. It largely modulated the endothelium to reduce platelet adhesion. Additionally, P-selectin expression and mice survival after cecal ligation and puncture were improved by curcumin, which also altered platelet and leukocyte adhesion and blood-brain barrier dysfunction. Through regulating many processes involved in platelet aggregation, curcuminoids collectively demonstrated detectable antiplatelet activity. Curcuminoids may therefore be able to prevent disorders linked to platelet activation as possible therapeutic agents. This review article proposes to highlight and discuss the regulatory effects of curcumin on platelets.

Characterization of active anticoagulant fraction and a fibrin(ogen)olytic serine protease from leaves of Clerodendrum colebrookianum, a traditional ethno-medicinal plant used to reduce hypertension

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiovascular diseases are the major cause of mortality and morbidity, causing over 17.9 million deaths a year worldwide. Currently used therapy is often having side effects and expensive, dietary interventions and alternative medicines are required. Clerodendrum colebrookianum has been used to treat cardiac hypertension but anticoagulant potency was not evaluated.

AIM OF THE STUDY

To characterize an active anticoagulant fraction (AAFCC) and a 30 kDa fibrin(ogen)olytic serine protease (clerofibrase) isolated from aqueous leave extract of C. colebrookianum.

MATERIALS AND METHODS

AAFCC/clerofibrase was subjected to extensive biochemical and pharmacological characterization including LC-MS/MS, amino acid compositional and GC-MS analyses. Interaction between clerofibrase with fibrinogen was studied by spectrofluorometric analysis. In vitro thrombolytic, antiplatelet and cytotoxicity assay were performed. In vivo toxicity, anticoagulant, defibrinogen and antithrombotic activities were determined on Swiss albino mice.

RESULTS

The in vitro anticoagulant activity of AAFCC was found to be superior to heparin and clerofibrase and comparable to Nattokinase and warfarin. The proteomics and amino acid composition analyses suggest that clerofibrase is a previously uncharacterized novel plant protease capable of degrading the -αβ chains of fibrinogen/fibrin. AAFCC/clerofibrase exerts their anticoagulant action via fibrinogenolytic activity and partially by antiplatelet activity albeit they have no effect on thrombin and FXa inhibition. The spectrofluorometric analysis revealed the binding of clerofibrase to fibrinogen but not to thrombin and FXa. The phytochemical constituents and bioactive components of AAFCC were characterized by biochemical, and GC-MS analyses. The AAFCC and clerofibrase inhibited collagen/ADP-induced mammalian platelet aggregation, showed in vitro thrombolytic activity, and non-cytotoxic to mammalian cells. The AAFCC showed and dose-dependent in vivo plasma defibrinogenating and anticoagulant activities and inhibited k-carrageen-induced thrombus formation in the tails of mice.

CONCLUSION

The potent in vivo anticoagulant and antithrombotic effects of AAFCC suggests its pharmacological significance as herbal anticoagulant drug for the prevention and/or treatment of hyperfibrinogenemia- and thrombosis associated cardiovascular disorders.

Curcumin, hemostasis, thrombosis, and coagulation

Atherothrombotic cardiovascular disease is a major cause of mortality throughout the world. Platelet activation and aggregation play a central role in hemostasis and thrombosis. Herbal medicines have been traditionally used in the management of cardiovascular disease and can help in modifying its progression, particularly in hemostasis and the coagulation process, as well as altering platelet function tests and some coagulation parameters. Curcumin is a polyphenol derived from the Curcuma longa plant and has been used extensively in complementary and alternative medicine, as it is nontoxic and safe with various therapeutic properties. Modern scientific research has demonstrated its anti-inflammatory, antioxidant, anti-carcinogenic, antithrombotic, and cardiovascular protective effects. The present study reviewed previous studies in the literature, which support the positive activity of curcumin in hemostasis, anticoagulation, and fibrinolysis. We also presented molecular mechanisms associated with the antiplatelet and anticoagulant activities of curcumin and potential implications for the treatment of cardiovascular disease.

Synthesis and biological evaluation of C-3 aliphatic coumarins as vitamin K antagonists

Since the discovery of Warfarin in the 1940s, the design of new warfarin-derived anticoagulants for rodent management has been challenging, with mainly structural modifications performed on the C3 position of the coumarin skeleton. In order to better understand the pharmacomodulation of such derivatives, we have synthesized a family of C3 (linear and branched) alkyl-4-hydroxycoumarins, which led to the identification of compounds 5e and 5f as potential short-term active anticoagulants.

Natural Products for Antithrombosis

Thrombosis is considered to be closely related to several diseases such as atherosclerosis, ischemic heart disease and stroke, as well as rheumatoid arthritis, hyperuricemia, and various inflammatory conditions. More and more studies have been focused on understanding the mechanism of molecular and cellular basis of thrombus formation as well as preventing thrombosis for the treatment of thrombotic diseases. In reality, there is considerable interest in the role of natural products and their bioactive components in the prevention and treatment of thrombosis related disorders. This paper briefly describes the mechanisms of thrombus formation on three aspects, including coagulation system, platelet activation, and aggregation, and change of blood flow conditions. Furthermore, the natural products for antithrombosis by anticoagulation, antiplatelet aggregation, and fibrinolysis were summarized, respectively.

Synthesis and toxicological studies of in vivo anticoagulant activity of novel 3-(1-aminoethylidene)chroman-2,4-diones and 4-hydroxy-3-(1-iminoethyl)-2H-chromen-2-ones combined with a structure-based 3-D pharmacophore model

Eight synthesized 3-(1-aminoethylidene)chroman-2,4-diones and 4-hydroxy-3-(1-iminoethyl)-2H-chromen-2-ones were evaluated as in vivo anticoagulants by intraperitoneal application to adult male Wistar rats in order to examine their pharmacological potential, evaluate ther toxicity and propose the mechanism of action. Two of them, 2f and 2a, in concentration of 2mg/kg of body weight, presented remarkable activity (PT=130s; PT=90s) upon seven days of continuous application. The results of rat serum and liver biochemical screening, as well those of histopathological studies, proved the compounds to be non-toxic. Activity of the compounds was further examined on the molecular level. Here, molecular docking studies were performed to position the compounds in relation to the active site of VKORC1 and determine the bioactive conformations. Docking results suggested a non-covalent mode of action during which the proton transfer occurs from Cys135 SH towards 4-carbonyl group of anticoagulant. All crucial interactions for anticoagulant activity were confirmed in generated structure-based 3-D pharmacophore model, consisted of hydrogen bond acceptor and hydrophobic aromatic features, and quantified by a best correlation coefficient of 0.97.