Antiplatelet Aggregation Activity Research Articles

Role of Whole Plant Extract of Nelumbo nucifera Gaertn in the Treatment of Thrombolysis.

This study aims to find out the components responsible for the antithrombotic activity of Nelumbo nucifera. Petroleum ether, chloroform and hydroalcoholic extracts of whole plant of Nelumbo nucifera (Lotus) were prepared and assessed for its thrombolytic, anti-platelet aggregation activity and bleeding time. The extracts were further analyzed through HPTLC and GC-MS. Statistical analysis was conducted through ANOVA trailed by Tukey's multiple comparison test test. Hydroalcoholic extract showed the highest activity at the concentration of 400µg/ml in thrombolytic assay (42.03 ± 5.76), anti-platelet aggregation assay (57.93 ± 1.68) and bleeding time (70.17 ± 2.16) in comparison to clopodigrel (33.76 ± 3.43), aspirin (66.55 ± 1.86) and aspirin (93.85 ± 2.75) at the concentration of 100 µg/ml respectively. 25 peaks were identified through GC-MS, out of which, ferulic acid (14.2µ/g) and quercetin (5.4 µ/g) are active chemical compounds. HPTLC showed different chromatograms in hydroalcoholic extracts like (1) chlorogenic, (2) quercetin, (3) benzoic acid, (4) caffeic acid, (5) ferulic acid, (6) kaempferol, and (7) gallic acid. Based on these findings, flavonoids present in hydroalcoholic extract may be developed into a drug for clinical application for the treatment of thrombosis in patients.

(±)-6-3'a,7-6'-Isowallichilide: A pair of enantiomeric phthalide dimers from Ligusticum chuanxiong with new 6-3'a,7-6' dimerization sites

(+)-6-3'a,7-6'-Isowallichilide and (−)-6-3'a,7-6'-isowallichilide, a pair of enantiomeric phthalide dimers featuring new 6-3'a,7-6' dimerization sites, were isolated from Ligusticum chuanxiong. The structures were elucidated by NMR spectroscopy and X-ray diffraction analysis. Furthermore, the absolute configurations were assigned using experimental and theoretical electronic circular dichroism methods. Their nitric oxide inhibition, antiplatelet aggregation and antioxidant activities were investigated.

Synthesis, pharmacological evaluation and molecular docking of novel R-/S-2-(2-hydroxypropanamido)-5-trifluoromethyl benzoic acid as dual anti-inflammatory anti-platelet aggregation agents.

R-/S-2-(2-hydroxypropanamido) benzoic acid (R-/S-HPABA), marine-derived anti-inflammatory antiplatelet drugs, were initially synthesised in our group. However, preliminary research showed that R-/S-HPABA were eliminated rapidly because of extensive hydroxylation metabolism of phenyl ring in vivo. In order to reduce significant hydroxylation metabolism to improve pharmacological activity and bioavailability, trifluoromethyl group was incorporated into R-/S-HPABA to synthesise R-/S-2-(2-hydroxypropanamido)-5-trifluoromethyl benzoic acid (R-/S-HFBA), respectively. The purposes of this study were to report the synthesis of R-/S-HFBA and compare the anti-inflammatory antiplatelet effect and pharmacokinetic properties of R-/S-HFBA with those of R-/S-HPABA. Carrageenan-induced rat paw edema assay was used for the evaluation of the anti-inflammatory activity. R-/S-HFBA showed better results in inhibiting edema and were able to prolong the anti-inflammatory effect after carrageenan injection. The antiplatelet aggregation activity of R-/S-HFBA and R-/S-HPABA was studied on arachidonic acid-induced platelet aggregation of rabbit platelet-rich plasma. The aggregation inhibition rate of R-/S-HFBA was significantly (p < 0.05) higher than that of R-/S-HPABA, respectively. Molecular docking study revealed that R-/S-HFBA possess more potent binding affinity with COX-1/COX-2 than R-/S-HPABA, respectively, and that the presence of trifluoromethyl group leads to increase in activity of R-/S-HFBA. R-/S-HFBA also afford more favorable pharmacokinetic properties than R-/S-HPABA, respectively, such as higher Cmax, larger AUC0-∞, and longer t1/2, which, as expected, are more metabolically stable.

Synthesis of phthalide derivatives and evaluation on their antiplatelet aggregation and antioxidant activities

As part of our continuing efforts to discover structurally interesting bioactive phthalide derivatives, 23 of them with a structure incorporating thiophen or halogens were designed and synthesized, 17 of which are previously unreported. In vitro antiplatelet aggregation activity screening showed that 14b could significantly inhibit platelet aggregation induced by arachidonic acid, compared with edaravone (p < 0.01). Meanwhile, oxidative damage models using SH-SY5Y and PC12 cells induced by H2O2 were built to evaluate the antioxidant activity of the phthalide derivatives. In SH-SY5Y cells, compared with aspirin, 1a significantly increased the relative cell survival rate (p < 0.05). Compared with edaravone, 1a (p < 0.01) and 15b (p < 0.05) significantly increased the relative cell survival rate. In PC12 cells, 1a (p < 0.01), 15b (p < 0.01), and 12a (p < 0.05) remarkably increased the cell survival rate compared with edaravone. The present study identified lead structures to develop potential anti-ischemic stroke agents.

New Copper Compounds with Antiplatelet Aggregation Activity.

Ischemic heart disease, cerebrovascular accident, and venous thromboembolism have the presence of a thrombotic event in common and represent the most common causes of death within the population. Since Schiff base copper(II) complexes are able to interact with polyphosphates (PolyP), a procoagulant and potentially prothrombotic platelet agent, we investigated the antiplatelet aggregating properties of two novel tridentate Schiff base ligands and their corresponding copper( II) complexes. The Schiff base ligands (L1) and (L2), as well as their corresponding copper(II) complexes (C1) and (C2), were synthesized and characterized by chemical analysis, X-ray diffraction, mass spectrometry, and UV-Visible, IR and far IR spectroscopy. In addition, EPR studies were carried out for (C1) and (C2), while (L1) and (L2) were further analyzed by 1H and 13C NMR. Tests for antiplatelet aggregation activities of all of the four compounds were conducted. X-ray diffraction studies show that (L1) and (L2) exist in the enol-imine tautomeric form with a strong intramolecular hydrogen bond. NMR studies show that both ligands are found as enol-imine tautomers in CDCl3 solution. In the solid state, the geometry around the copper(II) ion in both (C1) and (C2) is square planar. EPR spectra suggest that the geometry of the complexes is similar to that observed in the solid state by X-ray crystallography. Compound (C2) exhibited the strongest antiplatelet aggregation activity. Schiff base copper(II) complexes, which are attracting increasing interest, could represent a new approach to treat thrombosis by blocking the activity of PolyP with a potential anticoagulant activity and, most importantly, demonstrating no adverse bleeding events.

TO STUDY THE IN VITRO INHIBITION OF BLOOD PLATELET AGGREGATION BY ISOLATED COMPOUNDS FROM CLAUSENA DENTATA (WILLD.) ROEM.

Objectives: The objectives of the study were to study the antiplatelet aggregation activity of compounds isolated from extracts of Clausena dentata. Clausena (Rutaceae) is a genus of about 23 species of unarmed trees and shrubs. The stem bark of C. dentata is used in veterinary medicine for the treatment of wounds and sprains. Even though C. dentata has a lot of potential medical uses, the study of pharmacological properties is very scarce.&#x0D; Methods: The plant C. dentata was collected from Kadagaman, near Tiruvannamalai, Tamil Nadu, India, and authenticated by Centre for Advanced Study in Botany, University of Madras, Chennai. The dry powder of stem bark was extracted with hexane, chloroform, and methanol. The extracts were subjected to qualitative phytochemical screening and column chromatography. Four compounds were isolated. All the isolated compounds were subjected to adenosine diphosphate (ADP)-induced platelet aggregation and compared with aspirin.&#x0D; Results: The isolated compounds from C. dentata and standard aspirin showed significant antiplatelet activity against ADP-induced platelet aggregation.&#x0D; Conclusion: The compounds, 3-(1,1-dimethylallyl)xanthyletin, dentatin, nordentatin, and carbazole showed significant antiplatelet aggregation activity. Among the compounds, nordentatin showed more activity of antiplatelet aggregation.

Synthesis and Evaluation of in vitro Antiplatelet Aggregation Activities of 2-Methoxy-5-Aminobenzamides

Objective: According to the principles of drug design, the structures of picotamide and betrixaban were combined to design novel series of 2-methoxy-5-aminobenzamides. A total of twenty new compounds 1a-1t have been synthesized and evaluated for their antiplatelet aggregation activities in vitro. Methods: In the structural design of target compounds 1a-1t, the betrixaban was retained group characteristics and the picotamide was retained its 1, 3, 4-substitution position. With 2-methoxybenzoic acid as starting material, compounds 1a-1t were synthesized after 5 steps of nitration, acylation, ammoniation, reduction and secondary ammoniation. And their antiplatelet aggregation activities in vitro were assessed by the Born test with ADP, arachidonic acid and collagen as inducing agents, respectively, and with aspirin and picotamide as two reference drugs. Results: The compound 1f (46.14%±0.07) had the highest activity for ADP and its IC50 value was 0.17 µM, far better than the two control drugs aspirin (0.44 µM) and picotamide (0.47 µM). The IC50 value of four compounds 1i (0.24 µM), 1j (0.22 µM), 1r (0.25 µM) and 1t (0.24 µM), displayed higher antiplatelet activities in vitro for AA than aspirin (0.43 µM) and picotamide (0.34 µM). Evaluation of cytotoxicity activity of the compounds against L929 cells line revealed that at lower concentration of 10 µmol·L-1, compound 1p had lower effect on L929 cells, and its cell survival rate (88.24%±4.16) was higher than that (82.35%±4.16) of picotamide. Conclusion: Novel series of 2-methoxy-5-aminobenzamides has shown higher in vitro antiplatelet activities and lower effect on L929 cells at lower concentration.

Chemical constituents from heartwoods of Caesalpinia sappan with antiplatelet aggregation activities

ObjectiveTo clarify the active constituents of the heartwoods of Caesalpinia sappan, a traditional Chinese medicine with the functions of promoting blood circulation (Huoxue in Chinese) and removing blood stasis (Quyu in Chinese). MethodsThe chemical constituents were isolated and purified by combination of silica gel and Sephadex LH-20 column chromatography, along with semipreparative HPLC. Their chemical structures were established by multiple spectroscopic methods and comparison with literature data. The in vitro antiplatelet aggregation activities were evaluated using mouse platelet induced by AYPGKF-NH2, a gold agonist of protease-activated receptor 4 (PAR4). ResultsTwo new phenols, methyl 2-(4,4′,5′-trihydroxy-2′-(methoxymethyl) biphenyl-2-yloxy) acetate (1) and 1′-methylcaesalpin J (2), together with 24 known compounds (3–26), were isolated from the heartwoods of C. sappan. Among them, sappanchalcone (16) and brazilin (20) showed inhibitory activities against mouse platelet aggregation with IC50 values of 114.8 µmol/L and 100.8 µmol/L, respectively. ConclusionAntiplatelet compounds from C. sappan targeting at PAR4 are reported for the first time.

A pH-sensitive nanotherapeutic system based on a marine sulfated polysaccharide for the treatment of metastatic breast cancer through combining chemotherapy and COX-2 inhibition

Metastasis and chemotherapy resistance are the leading causes of breast cancer mortality. Celecoxib (CXB), a selective cyclooxygenase-2 (COX-2) inhibitor, has antiangiogenetic activity and inhibitory effect on tumor metastasis, and can also enhance the sensitivity of chemotherapeutic drug doxorubicin (DOX) in breast cancer. To combine anticancer effects of DOX and CXB more efficiently, we designed a pH-sensitive nanotherapeutic system based on propylene glycol alginate sodium sulfate (PSS), a marine sulfated polysaccharide that possesses anti-platelet aggregation activity and has been used as a heparinoid drug in China. A facile one-pot nanoprecipitation method was used to prepare this nanotherapeutic system named as PSS@DC nanoparticles, in which DOX and CXB were complexed to form hydrophobic nanocores and PPS coated these nanocores through conjugation with DOX via a highly acid-labile benzoic-imine linker. PSS@DC nanoparticles showed distinct pH-sensitivity and significantly accelerated the release of DOX at the acidic pH mimicking the tumor microenvironment and endocytic-related organelles. Compared to single- and mixed-drug treatments, PSS@DC nanoparticles notably inhibited the growth of mouse breast cancer 4T1 cells with an IC50 of about 0.82 μg/mL DOX, and meanwhile reduced cell migration, invasion and adhesion abilities more efficiently. In 4T1 tumor-bearing mice, PSS@DC nanoparticles exhibited good tumor-targeting ability and markedly inhibited tumor growth with an inhibition rate of approximately 73.3%, and furthermore suppressed tumor metastasis through anti-angiogenesis. In summary, this nanotherapeutic system shows a great potential for the treatment of metastatic breast cancer by combining chemotherapy and COX-2 inhibitor. Statement of SignificanceA pH-sensitive nanotherapeutic system (PSS@DC nanoparticles) containing both chemotherapeutic drug doxorubicin (DOX) and COX-2 specific inhibitor celecoxib was designed based on a marine sulfated polysaccharide that possesses anti-platelet aggregation activity and has been used as a heparinoid drug in China. PSS@DC nanoparticles had distinct pH-sensitivity and could accelerate the release of DOX at the acidic pH values of tumor microenvironment and endocytic-related organelles. Both in vitro and in vivo, PSS@DC nanoparticles showed synergistic effects on the suppression of breast tumor growth and metastasis by combining chemotherapy and COX-2 inhibition.

Isolation of a Novel Metalloproteinase from Agkistrodon Venom and Its Antithrombotic Activity Analysis.

Snake venom contains large amounts of active proteins and peptides. In this study, a novel snake protein, metalloproteinase SP, was successfully isolated from the venom of Agkistrodon acutus by multi-gel chromatography. The isolated protein exhibits anti-platelet aggregation activity. Animal experiments showed that it exhibited defibration, anticoagulation, and antithrombotic effects and contributes to improved blood rheology and antiplatelet aggregation. In vivo experiments demonstrated that it prolonged clotting time, partial thromboplastin time, prothrombin time, thrombin time, fibrinogen time and reduced fibrinogen content of mice. Also, metalloproteinase SP inhibited carrageenan-induced tail thrombosis, ADP-induced acute pulmonary embolism, and ADP, Arachidonic acid (AA), or collagen-induced platelet aggregation. In vitro experiments showed that the protein cleaved the α, β, and γ chains of fibrinogen. Metabolomic analysis upon metalloproteinase SP treatment revealed that 14 metabolites, which are mainly involved in phenylalanine, tyrosine, and tryptophan biosynthesis, responded to metalloproteinase SP treatment. In summary, the isolated snake venom protein inhibits formation of acute pulmonary embolism probably through regulating and restoring perturbed energy, lipid, and amino acid metabolism.

Terpenoid and phenolic constituents from the roots of Ilex pubescens

Five new metabolites, including two monoterpene glycosides Pubescenosides L–M (1–2) and three phenolic glycosides, Pubescenosides N-P (3–5), along with nineteen known ones, including liganoids, hemiterpenoids and caffeoylquinic acid derivates, were isolated from the roots of Ilex pubescens. Their structures were elucidated from extensive spectroscopic analysis, including 1D and 2D NMR experiments. This study is the first to report monoterpene glycosides with β-pinene aglycone in Aquifoliaceae. Nine of these compounds were evaluated in vitro for their anti-platelet aggregation activities. Among them, compounds 3 and 4 showed moderate inhibitory activities on ADP-induced blood platelet aggregation [inhibition (%): 32.3 and 33.6, respectively] as compared to aspirin.

Synthesis and in vitro activities on anti-platelet aggregation of 4-methoxy-1,3-phthalamidesamides and benzenedisulfonamides

Cardiovascular diseases are the most frequent cause of morbidity and mortality worldwide. In order to discover novel compounds with anti-platelet aggregation activities, a series of novel 4-methoxy-1,3-phthalamidesamides (1a–1i) and a series of novel 4-methoxy-1,3-benzenedisulfon-amides (2a–2i) were synthesized and their anti-platelet aggregation activities were evaluated by the turbidimetric method in response to the following agonists: adenosine diphosphate (ADP), arachidonic acid (AA), and Collagen. Those compounds that have better in vitro activities were subjected to cell toxicity tests via cell counting kit-8 (CCK-8) assay. The inhibition rates of anti-platelet in vitro of five compounds 1g (39.45%), 2d (38.87%), 2g (38.55%), 2h (44.56%), and 2i (43.93%) were higher than that of two reference drugs picotamide (36.12%) and aspirin (38.45%) when ADP was selected as an inducer. The inhibition rates of seven compounds 1c (43.63%), 1d (40.02%), 1g (47.42%), 1i (40.45%), 2c (40.11%), 2d (40.45%), and 2i (49.05%) were higher than that of picotamide (34.89%) and aspirin (39.43%) when AA was selected as inducer. And the inhibition rates of five compounds 1d (47.22%), 1i (45.01%), 2d (38.74%), 2e (42.21%), and 2f (39.94%) were higher than picotamide (38.45%) and aspirin (37.08%) when collagen was selected as inducer. Moreover, the effect of cell toxicity exhibited that none of the compounds had obvious cell toxicity against L-929 cells. Therefore, 4-methoxy-1,3-phthalamidesamides (1a–1i) and 4-methoxy-1,3-benzenedisulfon-amides (2a–2i) have the potential to become a novel kind of anti-platelet drugs and deserve further study.

Design, Synthesis and Anti-Platelet Aggregation Activity Study of Ginkgolide-1,2,3-triazole Derivatives.

Ginkgolides are the major active component of Ginkgo biloba for inhibition of platelet activating factor receptor. An azide-alkyne Huisgen cycloaddition reaction was used to introduce a triazole nucleus into the target ginkgolide molecules. A series of ginkgolide-1,2,3-triazole conjugates with varied functional groups including benzyl, phenyl and heterocycle moieties was thus synthesized. Many of the designed derivatives showed potent antiplatelet aggregation activities with IC50 values of 5~21 nM.

N, N’-disubstitutedphenyl-4-ethoxyl benzene-1, 3-disulfonamides: design, synthesis, and evaluation of anti-platelet aggregation activity

According to the bio-isosterism theory, a series of N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides (5a-p) were designed and synthesized by two steps of reactions including chlorosulfonation and ammonolysis. The structures of all compounds have been confirmed by IR, 1H-NMR, 13C-NMR, and ESI-MS spectra. The in vitro anti-platelet aggregation activities were evaluated by Born’s test induced by adenosine diphosphate (ADP) and arachidonic acid (AA), respectively. The biological evaluation results revealed that compound 5h had the lowest IC50 value (0.32 μM) and the highest inhibition rate (40.9 %) that of three positive control agents clopidogrel (0.41 μM, 23.5 %), aspirin (0.53 μM, 28.9 %), and picotamide (0.76 μM, 32.7 %). Afterwards, compounds with higher activities were selected to further study in vitro cytotoxicity via cell counting kit-8 (CCK-8) assay. The cytotoxicity results indicated that compound 5h had simultaneously the lowest cytotoxicity, while other compounds had no significant relationship between the anti-platelet activities and cytotoxicities. Based on above in vitro anti-platelet activity data, the SAR (Structure Activity Relationship) of the target compounds was preliminarily summarized. In general, N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides have the potential of further study and very likely become safer and more effective anti-platelet agents.

Design, synthesis and evaluation of phenylfuroxan nitric oxide-donor phenols as potential anti-diabetic agents

Both nitric oxide (NO) dysfunction and oxidative stress have been regarded as the important factors in the development and progression of diabetes and its complications. Multifunctional compounds with hypoglycemic, NO supplementation and anti-oxidation will be the promising agents for treatment of diabetes. In this study, six phenylfuroxan nitric oxide (NO) donor phenols were synthesized, which were designed via a combination approach with phenylfuroxan NO-donor and natural phenols. These novel synthetic compounds were screened in vitro for α-glucosidase inhibition, NO releasing, anti-oxidation, anti-glycation and anti-platelet aggregation activity as well as vasodilatation effects. The results exhibited that compound T5 displayed more excellent activity than other compounds. Moreover, T5 demonstrated significant hypoglycemic activity in diabetic mice and oral glucose tolerance test (OGTT) mice. T5 also showed NO releasing and anti-oxidation in diabetic mice. Based on these results, compound T5 deserves further study as potential new multifunctional anti-diabetic agent with antioxidant, NO releasing, anti-platelet aggregation and vasodilatation properties.

Construction of Hemocompatible and Histocompatible Surface by Grafting Antithrombotic Peptide ACH11 and Hydrophilic PEG.

Blood-contacting materials with antiplatelet aggregation and anticoagulant properties are in great demand in biomedical field. Herein, hydrophilic poly(ethylene glycol) (PEG) and antithrombotic peptide ACH11 were coimmobilized onto Au to develop a multifunctional surface with remarkable hemocompatibility, antiprotein adsorption, antiplatelet aggregation, anticoagulant properties, and good histocompatibility. PEG can not only help the surface resist nonspecific protein adsorption and improve its hemocompatibility but also be a benefit for the immobilized ACH11 to maintain its bioactivity in plasma. The anticoagulant peptide ACH11 can endow the surface with the ability of activated coagulation factor Xa (FXa) inhibition and antiplatelet aggregation activities. Au was first aminated with 2-aminoethanethiol through strong Au-S bond, and then it was reacted with PEG-ACH11 through active ester chemistry to prepare the multifunctional surface Au-PEG-ACH11, among which the heterobifunctional PEG served as a linker to immobilize antithrombotic ACH11. The surface chemical structure and composition quantified by attenuated total reflection Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy convinced us of the successful preparation of the PEG-ACH11 modified Au surface. The surface micromorphology and topography of the modified surfaces were observed by field emission scanning electron microscopy and atomic force microscopy. The good hydrophilicity of the modified Au surface was confirmed by water contact analysis. Enzyme immunoassay analysis demonstrated that the activation level of FXa in plasma after incubation with Au-PEG-ACH11 was obviously lower than that in control groups. In vitro hemocompatibility evaluation, including hemolysis rate, denaturation of adsorbed fibrinogen, and platelet adhesion and activation, indicated that Au-PEG-ACH11 possessed good hemocompatibility. In vivo subcutaneous implantation assay also confirmed the milder tissue response of Au-PEG-ACH11. These results indicated that the multifunctional surface has great potential for biomedical application.

Synthesis of Phenyl m-coumarylamide Analogs and Their Anti-platelet Aggregation Activity

Phenyl m-coumarylamide analogs were designed based on phenylpropanoid analogs such as coumaric acid, ferulic acid, and caffeic amide having anti-platelet aggregation activity. They prepared through concise synthetic method. Their anti-platelet aggregation was confirmed using ADP-induced rat platelet by aggregrometer. Compound 1b and 1d having dimethylamine and methoxy group on para-position of phenylamide ring, respectively, exhibit potent inhibitory activity (92.3 and 89.3% at 80 μg/mL). The results suggest that phenyl m-coumrylamide analogs could be used to develop potent anti-platelet aggregation agents.

Endothelial protection and anti-platelet aggregation activities of Ficus tsiangii extracts

Endothelial protection and anti-platelet aggregation activities of Ficus tsiangii extracts

Bioactive peptides and proteins as alternative antiplatelet drugs.

Antiplatelet drugs reduce the risks associated with atherothrombotic events and show various applications in diverse cardiovascular diseases including myocardial infarctions. Efficacy of the current antiplatelet medicines including aspirin, clopidogrel, prasugrel and ticagrelor, and the glycoprotein IIb/IIIa antagonists, are limited due to their increased risks of bleeding, and antiplatelet drug resistance. Hence, it is important to develop new effective antiplatelet drugs, with fewer side-effects. The vast repertoire of natural peptides can be explored towards this goal. Proteins and peptides derived from snake venoms and plants represent exciting candidates for the development of novel and potent antiplatelet agents. Consequently, this review discusses multiple peptides that have displayed antiplatelet aggregation activity in preclinical drug development stages. This review also describes the antiplatelet mechanisms of the peptides, emphasizing the signaling pathways intervened by them. Also, the hurdles encountered during the development of peptides into antiplatelet drugs have been listed. Finally, hitherto unexplored peptides with the potential to prevent platelet aggregation are explored.

Synthesis and antitumor, antityrosinase, and antiplatelet aggregation activities of xanthone Hot!

Synthesis and antitumor, antityrosinase, and antiplatelet aggregation activities of xanthone Hot!