Antiplatelet Aggregation Activity Research Articles

Polycyclic N‐Heterocyclic Compounds. Part 86: Synthesis and Evaluation of Antiplatelet Aggregation Activity of 2,4‐Disubstituted 9‐Chloro‐5,6‐dihydropyrimido[5,4‐d]benzazepine and Related Compounds

Libraries of tricyclic 2‐substituted 4‐alkylamino‐9‐chloro‐5,6‐dihydropyrimido[5,4‐d]benzazepines and tetracyclic 12‐substituted 8‐chloro‐1,2,5,6‐tetrahydro‐4H‐imidazo[1′,2′:1,6]pyrimido[5,4‐d]benzazepines were synthesized as part of our research to develop new effective antiplatelet drugs. Several alkyl and aryl groups were used as substituents at the 2‐position. Evaluation of the effects of the newly synthesized compounds on collagen‐induced platelet aggregation revealed several promising antiplatelet candidates with potencies superior to aspirin.

눈개승마 지상부의 항혈전 활성

The oriental traditional medicine, Aruncus dioicus var kamtschaticus (ADK) is used for hemostasis (blood stopping) and the promotion of blood circulation. Recently, the demands of the aerial part of ADK as edible mountain herbs are rapidly increased due to its unique fragrance and bioactivity. In this study, to evaluate the anti-thrombosis activity of ADK, ethanol extract and organic solvent fractions were prepared from aerial parts of ADK, and their anticoagulation and anti-platelet aggregation activities were determined. In an anticoagulation activity assay, the ethanol extract of ADK increased the thrombin time, prothrombin time, and activated partial thromboplastin time (aPTT) 1.4–2.3 times at a concentration of 5 mg/ml. Among the fractions, the ethylacetate fraction showed strong inhibitory effects against blood clotting factors, as shown in an extension of the aPTT. In contrast, the butanol fraction strongly promoted blood clotting. In an anti-platelet aggregation assay, the activity of the ethanol extract was comparable to that of aspirin, a commercial anti-platelet aggregation agent, and the butanol fraction showed 2-fold higher aggregation inhibitory activity than aspirin. The aforementioned ethanol extract and active fractions have ignorable hemolytic activity against human red blood cells up to a concentration of 0.5 mg/ml. Considering the high content of total polyphenol, total flavonoid, and total sugar of the ethylacetate and butanol fractions, the purified active substances have potential as safe and novel anti-thrombosis agents. This report provides the first evidence of anti-thrombosis activity of ADK.

Alditols and monosaccharides from sorghum vinegar can attenuate platelet aggregation by inhibiting cyclooxygenase-1 and thromboxane-A2 synthase

Ethnopharmacological relevanceVinegar has been used as both a common seasoning and a traditional Chinese medicine. Sorghum vinegar is an excellent source of physiological substances with multiple health benefits. Aim of this studyTo evaluate the antiplatelet aggregation activity of alditols and monosaccharides extracted from sorghum vinegar and analysis its mechanism. Materials and methodsAlditol and monosaccharide extract (AME) from sorghum vinegar was first evaluated for antiplatelet activity using the turbidimetric method. Blood was collected from healthy volunteer donors. The platelet aggregation was induced by arachidonic acid (AA), collagen, adenosine diphosphate (ADP) and thrombin in vitro. AME was divided into three experimental groups with the concentration were 0.10, 0.25 and 0.50mg/mL. In order to determine the inhibitory activity of AME on COX1, TXS and TXA2 production experiments were conducted using the COX1, TXS and TXB2 EIA kit. Computational docking was used to find the docking pose of monosaccharides and alditols with COX1. ResultsAME showed significant induction of antiplatelet activity by arachidonic acid (AA), collagen, adenosine diphosphate (ADP) and thrombin in a concentration-dependent manner (p<0.05). AME (0.50mg/mL) reduced the AA-induced aggregation rate to 10.35%±0.46%, which was comparable to acetylsalicylic acid (aspirin, ASA) (0.50mg/mL, 6.35%±0.58%), a medical standard. Furthermore, AME strongly inhibited cyclooxygenase-1 (COX1) and thromboxane-A2 synthase (TXS), and subsequently attenuated thromboxane-A2 (TXA2) production. These findings indicated that AME attenuates platelet aggregation through the AA metabolism pathway. Computational docking showed that alditols (L-erythritol, L-arabitol, xylitol and D-sorbitol), monosaccharides (D-glucopyranose, D-fructofuranonse, D-xylopyranose, D-galactopyranose and D-ribose), ethyl glucoside and 3,4-(methylenedioxy) mandelic acid could dock directly into the active site of COX1. ConclusionAlditols and monosaccharides from sorghum vinegar inhibit multiple steps in the platelet aggregation pathway, and may be beneficial for the treatment of cardiovascular diseases.

Genus Kadsura, a good source with considerable characteristic chemical constituents and potential bioactivities

In China, the plants of genus Kadsura had been used as the folk medicines for a long time and showed good effect of activating blood and dissolving stasis, promoting qi circulation to relieve pain, dispelling wind and eliminating dampness. The bioactivities of genus Kadsura were attributed to the existence of its characteristic chemical constituents. This review systematically summarized the traditional efficacy and medicinal application of genus Kadsura in China, chemical constituents and bioactivities of the plants of genus Kadsura. And, lignans and triterpenoids were the main bioactive constituents, which exhibited good anti-HIV, anti-tumor, anti-hepatitis, anti-oxidant, anti-platelet aggregation activities and neuroprotective effect etc. Moreover, some structure–activity relationships mining would greatly enrich the opportunity of finding new and promising lead compounds and promote the reasonable development and utilization of the plants of genus Kadsura.

Antioxidant and antiplatlet aggregation properties of bark extracts of Garcinia pedunculata and Garcinia cowa.

The bark extracts of Garcinia pedunculata and Garcinia cowa, which are abundant in the Northeastern regions of India, were screened for their antioxidant and in vitro antiplatelet aggregating activities. By β-carotene linoleate model for antioxidant assay, acetone extract of G. pedunculata and hexane extracts of G. cowa exhibited higher antioxidant activity (86.47 and 66.94% respectively, at 25ppm) than other extracts. Similar pattern was observed for superoxide radical scavenging method for antioxidant assay. The ethyl acetate extract of G. pedunculata and hexane extract of G. cowa exhibited higher antiplatelet aggregation capacity towards ADP induced platelet aggregation (IC50 0.16 and 0.43ug, respectively) than other extracts.

Monoterpenes from the fruits of Amomum kravanh

Two new monoterpenes, (7S)-p-cymene-2,7,8-triol (1) and (3R,4R,6S)-p-menth-1-ene-3,6,10-triol (2), were isolated from the fruits of Amomum kravanh. Their structures were established by spectroscopic data. The absolute configuration of the 7,8-diol moiety in 1 was assigned by CD data after addition of Mo2(OAc)4 in dimethyl sulfoxide (DMSO) solution. Compounds 1 and 2 exhibited weak activity of anti-platelet aggregation in vitro.

Synthesis of analogues of gingerol and shogaol, the active pungent principles from the rhizomes of Zingiber officinale and evaluation of their anti-platelet aggregation effects.

The present study was aimed at discovering novel biologically active compounds based on the skeletons of gingerol and shogaol, the pungent principles from the rhizomes of Zingiber officinale. Therefore, eight groups of analogues were synthesized and examined for their inhibitory activities of platelet aggregation induced by arachidonic acid, collagen, platelet activating factor, and thrombin. Among the tested compounds, [6]-paradol (5b) exhibited the most significant anti-platelet aggregation activity. It was the most potent candidate, which could be used in further investigation to explore new drug leads.

ACE and platelet aggregation inhibitors from Tamarix hohenackeri Bunge (host plant of Herba Cistanches) growing in Xinjiang.

Background:Tamarix hohenackeri Bunge is a salt cedar that grows widespread in the desert mountains in Xinjiang. T. hohenackeri has not been investigated earlier, although there are many reports of phytochemical work on other Tamarix species.Materials and Methods:To find out natural angiotensin-converting enzyme (ACE) inhibitor and platelet aggregation inhibitors, the bioactive extract (ethyl acetate [EtOAc] fraction) from the dried aerial parts of T. hohenackeri were investigated. The active fraction was purified by repeated column chromatography, including silica gel, Sephadex LH-20 column, medium-pressure liquid chromatography (MPLC) (polyamide column) and high-performance liquid chromatography (HPLC). The isolated major constituents were tested for their anti-platelet aggregation activity.Results:Bioassay-directed separation of the EtOAc fraction of the 70% ethanol extract from the air-dried aerial parts of T. hohenackeri led to the isolation of a new triterpenoid lactone (1), together with 13 known compounds (2-14). It was the first time to focus on screening bioactive constituents for this plant. The chemical structures were established on the basis of spectral data (ESI-MS and NMR). The results showed that the flavonoid compounds (7 and 8) and phenolic compounds (9, 10, 11, and 14) were potential ACE inhibitors. And the flavonoid compounds (5 and 7) showed significant anti-platelet aggregation activities.Conclusion:On the basis of the chemical and biological data, the material basis of ACE inhibitory activity for the active part was the phenolic constituents. However, the flavonoid compounds were responsible for the anti-platelet aggregation. The primary structure and activity relationship were also discussed respectively.

Content Analysis of Shikimic Acid in the Masson Pine Needles and Antiplatelet-aggregating Activity

Shikimic acid content was measured by high-performance liquid chromatography (HPLC) in the Masson pine needles as one potential source of shikimic acid. The antiplateletaggregating activity of shikimic acid was characterized by turbidimetry with an animal model. The shikimic acid level was compared with Oriental arborvitae leafytwigs and Star anise. The results showed that the shikimic acid content in Masson pine needles, Oriental arborvitae leafytwigs and Star anise was 5.71%, 1.74% and 8.95%, respectively. The yield of shikimic acid was the highest when the powder of Masson pine needles was ultrasonically-treated for 60 min in 3.5 mmol/L phosphoric acid. Shikimic acid, when separated by HPLC, exhibited a dose-dependent inhibitory effect on platelet aggregation induced by adenosine diphosphate and collagen in rabbits. Because of the relative high content and good antiplatelet-aggregating activity of shikimic acid, the Masson pine needles can be used as a potential source of shikimic acid.

Effect of Toona microcarpa Harms leaf extract on the coagulation system.

Toona microcarpa Harms is a tonic, antiperiodic, antirheumatic, and antithrombotic agent in China and India and an astringent and tonic for treating diarrhea, dysentery, and other intestinal infections in Indonesia. In this study, we prepared ethyl-acetate extract from the air-dried leaves of Toona microcarpa Harms and investigated the anticoagulant activities in vitro by performing activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) assays. Antiplatelet aggregation activity of the extract was examined using adenosine diphosphate (ADP), collagen, and thrombin as agonists, and the inhibitions of factor Xa and thrombin were also investigated. Bleeding and clotting times in mice were used to determine its anticoagulant activities in vivo. It is found that Toona microcarpa Harms leaf extract (TMHE) prolonged APTT, PT, and TT clotting times in a dose-dependent manner and significantly inhibited platelet aggregation induced by thrombin, but not ADP or collagen. Clotting time and bleeding time assays showed that TMHE significantly prolonged clotting and bleeding times in vivo. In addition, at the concentration of 1 mg/mL, TMHE inhibited human thrombin activity by 73.98 ± 2.78%. This is the first report to demonstrate that THME exhibits potent anticoagulant effects, possibly via inhibition of thrombin activity.

Construction and Characterization of Novel Hirulog Variants with Antithrombin and Antiplatelet Activities

The RGD sequence was used to design potent hirudin isoform 3 mimetic peptides with both antithrombin activity and antiplatelet aggregation activity. The RGD and proline were inserted between the catalytic active binding domain (D-Phe-Pro-Arg-Pro) on the N-terminus and the anion-binding exosite binding domain (QGDFEPIPEDAYDE) on the Cterminus. Thrombin titration assay and ATP-induced platelet aggregation test revealed that the peptide with the linker RGDWP or RGDGP possessed potent antithrombin and antiplatelet activities, while other peptides without the Pro residue in the linker only showed antithrombin activity. Similar results were obtained in the RGD-containing hirulog-1 variants. Our study indicates that the inserted Pro residue facilitates the exposure of RGD and the binding of the peptide to glycoprotein IIb/IIIa (GPIIb/IIIa). The strategy of combining the RGD sequence and the Pro residue may be used for future designs of bifunctional antithrombotic agents.

Two new components from the rhizome of Anemarrhena asphodeloides Bge. and their antiplatelet aggregative activity

Two new components, anemarrhena A (1) and anemarrhena B (2), together with five known ones (3–7), were isolated from the rhizome of Anemarrhena asphodeloides Bge. Their structures were established by detailed spectral studies, including 1D-NMR (1H NMR, 13C NMR and DEPT), 2D-NMR (HSQC, HMBC and NOESY), HR-ESI-MS and by the comparison with literature data. The absolute configuration of 2 was further determined by CD analysis. The isolated compounds were evaluated for their antiplatelet aggregative activity. Compounds 1, 2, 3, 5, 6 and 7 exhibited moderate activity of antiplatelet aggregation in vitro, compound 4 showed potential antiplatelet aggregation activity.

A simple high-performance liquid chromatographic method for the determination of brazilin and its application to a pharmacokinetic study in rats

Ethnopharmacological relevanceCaesalpinia sappan is a medicinal plant native to China popularly used to treat chronic pelvic inflammation, dysmenorrhea and hysteromyoma. Its main bioactive component is brazilin which had presented antibacterial, anti-inflammatory and anti-platelet aggregation activities. To establish a sensitive, selective, reproducible, and accurate high performance liquid chromatographic (HPLC) method for the quantitative determination of brazilin in plasma, and study the pharmacokinetics of brazilin in rats after intravenous administration of brazilin. Materials and methodsRats received intravenous injection of 25, 50 and 100mg/kg of brazilin. Concentrations of brazilin in plasma were determined by HPLC method at different time points and all pharmacokinetic parameters were estimated by non-compartmental analysis with WinNonLin 6.2 software. ResultsAfter single intravenous doses of 25, 50 and 100mg/kg brazilin in rats, the main PK parameters were as follows: Cmax were 18.1±4.1, 46.7±8.7 and 82.2±9.6µg/mL; AUC0–24 were 20.4±4.3, 48.7±6.8 and 90.4±10.3µgh/mL; and t1/2 were 5.4±1.5, 5.8±0.9 and 6.2±1.2h, respectively. ConclusionIt showed that the brazilin was eliminated moderately in rat by intravenous injection route with t1/2 of 6h and showed a dose-dependence profile of Cmax and AUC0–24 at the doses of 25~100mg/kg of brazilin for injection in rats.

Synthesis and activity of a cyclo-heptapeptide containing Lys-Gly-Asp-sequence as a novel anti-platelet agent

Linear hepta-peptide Cys-Lys-Gly-Asp-Trp-Asp-Cys was synthesized first and then disulfide bond was formed between the Cys1 and Cys7 to develop cyclo-heptapeptide containing Lys-Gly-Asp-sequence. Structural simulation showed that Lys-Gly-Asp-motif (KDG) displayed functional conformation. The cyclo-heptapeptide exhibited potent anti-platelet aggregation activity based on specific recognition and interaction with the GPIIb-IIIa receptor on platelet cell membrane. The specific and potent anti-platelet activity makes the KGD-containing cyclo-heptapeptide a possible therapeutic agent.

Bioactive constituents from the twigs of Zanthoxylum ailanthoides

Zanthoxylum ailanthoides Sieb. & Zucc. (Rutaceae) is a medium-to-large-sized tree, found at low altitude in forests of China, Japan, Korea, Philippines, and Taiwan. Various benzo[c]phenanthridines, coumarins, lignans, flavonoids, quinolines, benzenoids, and triterpenoids are widely distributed in this plant. Many of these compounds exhibit anti-platelet aggregation, anti-HIV, and anti-inflammatory activities. Investigation on EtOAc-soluble fraction of the twigs of Z. ailanthoides has led to the isolation of a new benzo[c]phenanthridine, oxynorchlerythrine (1), and a new benzenoid, methyl 4-(2-hydroxy-4-methoxy-3-methyl-4-oxobutoxy)benzoate (2), together with 5 known compounds, including, two benzo[c]phenanthridines, decarine and 6-acetonyldihydrochelerythrine, and three lignans, (-)-syringaresinol, 5′,5′′-didemethoxypinoresinol, and (+)-episesamin. The structure of new compound 1 and 2 were determined through spectral analyses including extensive 2D NMR data. Among the isolated compounds, decarine, (-)-syringaresinol, and xanthyletin exhibited potent inhibition (IC50 values ≤4.79 µg/ml) of superoxide generation by human nutrophils in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB).

Degraded limonoids and quinoline alkaloids from Dictamnus angustifolius G. Don ex Sweet. and their anti-platelet aggregation activity

A new degraded limonoid, named isodictamdiol A (1), two known degraded limonoids (2, 3) and a new nature product of quinoline alkaloid (4) along with five known quinoline alkaloids (5–9) were isolated from the root bark of Dictamnus angustifolius G. Don ex Sweet.. Certain useful NMR data were generalized to determine the structures of compounds 1 and 4. The structural elucidation of Compound 4 was first reported herein. Compounds 1–9 showed significant inhibitory effects on platelet aggregation induced by ADP at 250μM, while Compound 4 showed potent anti-platelet aggregation activity.

Synthesis of thioether derivatives of quinazoline-4-one-2-thione and evaluation of their antiplatelet aggregation activity

A series of 2-(arylmethylthio)-3-phenylquinazolin-4-one derivatives have been synthesized and their antiplatelet aggregation activities were assessed against ADP and arachidonic acid-induced platelet aggregation in human plasma. Among the tested thioethers, derivative 2, 3, 5 and 16 were the most potent compounds with satisfactory IC50 for inhibition of platelet aggregation induced by ADP. Analysis of global physicochemical parameters shows some correlations between activities and molecular volume and also surface area of the studied derivatives.

ChemInform Abstract: Polycyclic N‐Heterocyclic Compounds. Part 77. Synthesis of [1]Benzothieno[3′,2′:2,3]oxepino[4,5‐d]pyrimidines and Evaluation of Their Antiplatelet Aggregation Activity.

AbstractA series of title compounds is prepared and tested for their antiplatelet aggregation activity.

Protective Mechanisms of Guanosine from Solanum lycopersicum on Agonist-Induced Platelet Activation: Role of sCD40L

In the past 30 years, only three natural products have been sources of new drugs with antiplatelet activity. In this study, we have demonstrated for the first time that guanosine from Solanum lycopersicum possesses antiplatelet (secretion, spreading, adhesion and aggregation) activity in vitro and inhibition of platelet inflammatory mediator of atherosclerosis (sCD40L). According to ADP-induced platelet aggregation inhibiting, the total extract residue was fractionated by liquid chromatography/phase separation, affording an aqueous fraction. This fraction was subjected to repeated permeation over Sephadex LH-20 and semi-preparative TLC. The isolated compound finally obtained was identified as guanosine on the basis of its UV-spectra, HPLC and 1H-NMR data. Guanosine concentration dose-dependently (1 to 4 mmol/L) inhibited platelet secretion and aggregation induced by ADP and collagen. Spread of human platelets on collagen in the presence of guanosine was fully inhibited. After incubation of whole blood with guanosine, the platelet adhesion and aggregation under flow conditions was inhibited concentration dependently (0.2 to 2 mmol/L). At the same concentrations that guanosine inhibits platelet aggregation, levels of sCD40L were significantly decreased. Guanosine is thus likely to exert significant protective effects in thromboembolic-related disorders by inhibiting platelet aggregation.

Extract of Ulmus macrocarpa Hance prevents thrombus formation through antiplatelet activity

Ulmus macrocarpa Hance (Ulmaceae) has been used as a traditional oriental medicine for the treatment of edema, mastitis, gastric cancer and inflammation. The aim of this study was to investigate the effects of Ulmus macrocarpa extract (UME) on thrombus formation in vivo, platelet activation ex vivo and fibrinolytic activity in vitro. To identify the antithrombotic activity of UME in vivo, we used an arterial thrombosis model. UME delayed the occlusion time by 13.4 and 13.9 min at doses of 300 and 600 mg/kg, respectively. UME significantly inhibited ex vivo platelet aggregation induced by collagen and adenosine 5'-diphosphate (ADP), respectively, but did not affect the coagulation times following activated partial thromboplastin and prothrombin activation. Therefore, to investigate the antiplatelet effect of UME, the effect of UME on collagen and ADP-induced platelet aggregation in vitro was examined. UME exhibited antiplatelet aggregation activity, induced by ADP and collagen. Furthermore, the fibrinolytic activity of UME was investigated. The results showed that UME significantly increased fibrinolysis at 1,000 mg/ml. In conclusion, the results suggested that UME may significantly inhibit artery thrombus formation in vivo, potentially due to antiplatelet activity, and also exhibits potential as a clot‑dissolving agent for thrombolytic therapy.