Stilbenoids from Gnetum macrostachyum Attenuate Human Platelet Aggregation and Adhesion

Platelets play a critical role in pathogenesis of cardiovascular disorders and strokes. The inhibition of platelet function is beneficial for the treatment and prevention of these diseases. The phytochemical investigation of stilbenoids from Gnetum macrostachyum Hook. f. led to the isolation of trans‐resveratrol (1), isorhapotigenin (2), gnetol (3), bisisorhapontigenin B (4), gnetin C (5), parvifolol A (6), latifolol (7) and gnetuhainin C (8). The isolated stilbenoids were evaluated for in vitro antiplatelet activities via agonist‐induced platelet aggregation and static platelet‐collagen adhesion assays using washed human platelets. Compounds 1, 2 and 3 were active in the inhibition of arachidonic acid (AA)‐induced platelet aggregation. Compound 2 and its dimer, compound 4, were the most active stilbenoids in thrombin‐induced platelet aggregation. Moreover, compounds 4, 5 and 6, tended to be more potent than monomeric and trimeric stilbenoids in a human platelet‐collagen adhesion assay under static conditions. This is the first report of the antiplatelet activity of stilbenoids isolated from G. macrostachyum. Copyright © 2012 John Wiley & Sons, Ltd.     

Antiplatelet activities of newly synthesized derivatives of piperlongumine

Piperlongumine, a pyridone alkaloid isolated from Piper longum L., exhibited a potential inhibitory effect on washed rabbit platelet aggregation induced by collagen, arachidonic acid (AA) and platelet activating factor (PAF), without any inhibitory effect on that induced by thrombin. Piperlongumine was used as a lead compound for the synthesis of new antiplatelet agents. Seven synthetic compounds were newly synthesized from 3,4,5-trimethoxycinnamic acid (TMCA). They were 1-piperidin-1-yl-3-(3,4,5-trimethoxy-phenyl)prop-2-en-1-one (1'), 1-morpholin-4-yl-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (2'), 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3'), 1-(2-methylpiperidin-1-yl)-3-(3,4,5-tri-methoxyphenyl)prop-2-en-1-one (4'), 1-(3-hydroxypiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)- prop-2-en-1-one (5'), 1-[3-(3,4,5-tri-methoxyphenyl) acryloyl]-piperidin-2-one (6') and ethyl 1-[3-(3,4,5-trimethoxyphenyl)-acryloyl]piperidine-4-carboxylate (7'). Among those seven synthetic derivatives, 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3') had the most inhibitory effect on platelet aggregation induced by collagen, AA and PAF.     

The Operculina macrocarpa (l.) urb. (jalapa) tincture modulates human blood platelet aggregation

Ethnopharmacological relevance

Operculina macrocarpa is an ornamental climbing plant of the Northeastern Brazil extensively used in traditional medicine as depurative of the blood and for the treatment of thrombosis. To investigate the antiplatelet and anticoagulant potential of Operculina macrocarpa and to determine the possible mechanisms of action.

Material and methods

The Operculina macrocarpa tincture (OMT) was characterized by the polyphenol content and chromatographic profile established by HPLC with detection and quantification of three phenol acids (caffeic, clorogenic and gallic acids). The human platelet aggregation was induced in vitro by the agonists ADP, collagen, thrombin, epinephrine or arachidonic acid, and the antiplatelet effect of OMT was evaluated in the presence or absence of aspirin (a nonselective inhibitor of cyclooxygenase), pentoxifylline (a phosphodiesterase inhibitor), ticlopidine (a P2Y₁₂ purinoceptor antagonist) or ODQ (a selective inhibitor of guanilate cyclase). The effect of OMT on the partial thromboplastin time, prothrombin time and bleeding time were investigated on human or rat plasma.

Results

The strongest antiplatelet effect of OMT (50–400 µg/mL) was observed on the ADP- induced aggregation with inhibitions up to 55%, while among others agonists (epinephrine, collagen, thrombin and arachidonic acid) maximal inhibitions reached by OMT (200 µg/mL) were on platelet aggregation induced by collagen (18%) or epinephrine (20%). The antiplatelet effect of OMT (400 µg/mL) was comparable to aspirin, a nonspecific inhibitor of cyclooxygenase. The ticlopidine and pentoxifylline increased 5.1 and 3.8 fold the inhibitory effect of OMT on ADP-induced platelet aggregation, respectively. On the other hand, l-arginine, ODQ and aspirin showed a slightly or no effect on antiplatelet effect of OMT. The bleeding time in rats was significantly increased by OMT, but the tincture did not interfere on the activated partial thromboplastin or prothrombin time in human plasma.

Conclusions

This study showed that the tincture of Operculina macrocarpa has antiplatelet effect that cannot be attributed to a single biochemical mechanism and at least part of it cannot be related to the OMT inhibition of P2Y₁₂ purinergic receptors.     

Human platelet aggregation inhibitors from thyme (Thymus vulgaris L.)

Two antiaggregant compounds, thymol (compound 1) and 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (compound 2) were isolated from the leaves of thyme (Thymus vulgaris L.). The structures were determined by (1)H-, (13)C-NMR and mass spectra (MS) studies. These compounds inhibited platelet aggregation induced by collagen, ADP, arachidonic acid (AA) and thrombin except that compound 2 did not inhibit platelet aggregation induced by thrombin.     

Inhibitory Activities of Compounds from the Twigs of Garcinia hombroniana Pierre on Human Low‐density Lipoprotein (LDL) Oxidation and Platelet Aggregation

The methanol extract of the twigs of Garcinia hombroniana, which showed strong LDL antioxidation and antiplatelet aggregation activities, was subjected to column chromatography to obtain 3,5,3′,5′‐tetrahydroxy‐4‐methoxybenzophenone, 1,7‐dihydroxyxanthone and eight triterpenoids, garcihombronane B, D, E and F, friedelin, glutin‐5‐en‐3β‐ol, stigmasterol and lupeol. The structures of the compounds were elucidated by spectroscopic methods. The compounds were evaluated for their ability to inhibit copper‐mediated LDL oxidation and arachidonic acid (AA)‐, adenosine diphosphate (ADP)‐, collagen‐induced platelet aggregation in vitro. Among the compounds tested, 3,5,3′,5′‐tetrahydroxy‐4‐methoxybenzophenone and 1,7‐dihydroxyxanthone showed strong inhibitory activity on LDL oxidation with half‐maximal inhibitory concentration (IC₅₀) values of 6.6 and 1.7 µm , respectively. 3,5,3′,5′‐Tetrahydroxy‐4‐methoxybenzophenone exhibited strong activity on AA‐, ADP‐ and collagen‐induced platelet aggregation with IC₅₀ values of 53.6, 125.7 and 178.6 µm , respectively, while 1,7 dihydroxyxanthone showed significant and selective inhibitory activity against ADP‐induced aggregation with IC₅₀ value of 5.7 µm . Of the triterpenoids tested, garcihombronane B showed moderate activity against LDL oxidation and garcihombronane D and F showed selective inhibition on ADP‐induced platelet aggregation. Copyright © 2012 John Wiley & Sons, Ltd.     

维心脉抗心肌缺血的实验研究

 目的研究维心脉对实验性急性心肌缺血的保护作用及可能的机制。方法阻断犬冠状动脉前降支造成急性心肌缺血模型,测量心外膜心电图(ECG)、Ⅱ导联心电图[ECG(Ⅱ)]、平均动脉压(MBP)、心肌耗氧指数及心肌梗死面积;以体内血栓形成仪刺激大鼠血栓形成,二磷酸腺苷(ADP),花生四烯酸及胶原诱导血小板聚集,测量血栓形成时间和血小板聚集抑制百分率。结果维心脉1.5和3.0g·kg^-1可明显降低心肌梗死犬的∑ST,NST及心肌氧耗指数,缩小心肌梗死范围,降低血压而对心率无明显影响。维心脉3个剂量组:2.0,4.0和8.0g·kg^-1能显著推迟大鼠实验性动脉血栓形成时间,抑制ADP,花生四烯酸及胶原诱导的血小板聚集。结论维心脉可通过降低心肌耗氧量,抑制血小板聚集和血栓形成从而较好的保护缺血心肌。     

Korean red ginseng attenuates hypercholesterolemia-enhanced platelet aggregation through suppression of diacylglycerol liberation in high-cholesterol-diet-fed rabbits

Intake of Korean red ginseng (KRG, ginseng Radix rubra), rich in glycosylated saponins (ginsenosides), has been known to inhibit platelet aggregation in the normocholesterolemic condition. However, it is unclear whether KRG can attenuate hypercholesterolemia-enhanced platelet aggregation. This study examined whether the daily consumption of a KRG-water extract (WE) could prevent the hypercholesterolemia-enhanced platelet aggregation and progression of hypercholesterolemic atherosclerosis. KRG-WE administration (200 mg/kg/day) for 8 weeks potently inhibited the platelet aggregation induced by low doses of agonists (0.5 microg/mL collagen and 0.025 unit/mL thrombin), whereas it weakly reduced the blood-cholesterol levels and formation of atheromatous lesions. In further investigation, KRG-WE significantly suppressed collagen-induced 1,2-diacylglycerol liberation, but had no significant effect on arachidonic acid liberation. Taken together, it can be suggested that the antiplatelet effect of KRG-WE may, at least partly, be due to the inhibition of 1,2-diacylglycerol generation rather than regulation of blood lipid levels. In conclusion, daily consumption of KRG-WE could be a useful alternative measure for the prevention of thrombus and atheroma formation in hypercholesterolemia.     

Antiaggregant effects on human platelets of culinary herbs

The inhibitory effects of methanol extracts of 20 herb species on human platelet aggregation were investigated. Allspice, basil, marjoram, tarragon and thyme strongly inhibited the platelet aggregation induced by collagen. Basil, marjoram and tarragon strongly inhibited platelet aggregation induced by ADP. An active compound, arbutin, was isolated from sweet marjoram as an inhibitor of platelet aggregation induced by collagen; ADP, arachidonic acid (AA) and thrombin. Copyright © 1998 John Wiley & Sons, Ltd.     

六味地黄汤对家兔体外血小板聚集率的影响

目的：研究六味地黄汤及其配伍对血小板聚集率的影响。方法：本实验采用体外血小板聚集法，利用不同的诱导剂，观察了六味地黄汤及其拆方对血小板聚集率的抑制作用。结果：六味地黄汤全方和三补、三泻方均能抑制腺嘌呤核苷二磷酸（ADP）诱导的体外血小板聚集，对花生四烯酸（AA）诱导的血小板聚集也有抑制作用，但用药剂量较大，其中以全方药效最强，三补方次之，三泻方最弱，药物血清也呈现相似的结果。结论：六味地黄汤具有良好的抑制血小板聚集的作用，三味补药是其作用的主要成分，三补与三泻配伍具有协同和增效作用。     

Potential inhibitors of platelet aggregation from plant sources, III

3,4-Dihydroxybenzoic acid (DBA) was isolated from Acanthopanax senticosus as an antiplatelet aggregatory substance. This paper also reports the results of the investigations on the structural activity relationships among the various dihydroxybenzoic acid derivatives against rat platelet aggregations induced by ADP (adenosine 5'-diphosphate), AA (arachidonic acid), or collagen.     

Inhibitory effects of Tabebuia impetiginosa inner bark extract on platelet aggregation and vascular smooth muscle cell proliferation through suppressions of arachidonic acid liberation and ERK1/2 MAPK activation

The antiplatelet and antiproliferative activities of extract of Tabebuia impetiginosa inner bark (taheebo) were investigated using washed rabbit platelets and cultured rat aortic vascular smooth muscle cells (VSMCs) in vitro. n-Hexane, chloroform and ethyl acetate fractions showed marked and selective inhibition of platelet aggregation induced by collagen and arachidonic acid (AA) in a dose-dependent manner. These fractions, especially the chloroform fraction, also significantly suppressed AA liberation induced by collagen in [(3)H]AA-labeled rabbit platelets. The fractions, especially the chloroform fraction, potently inhibited cell proliferation and DNA synthesis induced by platelet derived growth factor (PDGF)-BB, and inhibited the levels of phosphorylated extracellular signal regulated kinase (ERK1/2) mitogen activated protein kinase (MAPK) stimulated by PDGF-BB, in the same concentration range that inhibits VSMC proliferation and DNA synthesis.     

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

Ethnopharmacological relevance

Vinegar 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 study

To evaluate the antiplatelet aggregation activity of alditols and monosaccharides extracted from sorghum vinegar and analysis its mechanism.

Materials and methods

Alditol 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 0.50 mg/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.

Results

AME 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 (0.50 mg/mL) reduced the AA-induced aggregation rate to 10.35%±0.46%, which was comparable to acetylsalicylic acid (aspirin, ASA) (0.50 mg/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.

Conclusion

Alditols and monosaccharides from sorghum vinegar inhibit multiple steps in the platelet aggregation pathway, and may be beneficial for the treatment of cardiovascular diseases.     

倒卵叶五加总皂甙对家兔血小板聚集的抑制作用

用比浊法及电镜技术观察了倒卵叶五加总皂甙对家兔血小板聚集性的影响。结果表明:倒卵叶五加总皂甙本身对血小板聚集和超微结构无明显影响,但可抑制AA、Collagen及ADP诱导的血小板聚集、外形改变、伪足形成和颗粒的释放。     

异钩藤碱对血小板聚集和血栓形成的影响

 目的研究异钩藤碱(isorhynchophylline,Isorhy)对血小板聚集和血栓形成的影响,并初步探讨其机制。方法比浊法测定Isorhy体内给药对大鼠血小板聚集的影响;放免法测定血小板血栓烷B₂(TXB₂)及血浆6-keto-PGF_1α含量;利用小鼠尾静脉注射胶原-肾上腺素合剂诱导血栓形成模型,测定15min内小鼠死亡率。结果iv Isorhy 2.5,5和10mg·kg^-1呈剂量依赖性地抑制ADP、胶原、花生四烯酸(AA)和凝血酶诱导的大鼠血小板聚集;iv Isorhy 50和100mg·kg^-1明显降低实验性血栓模型小鼠死亡率。Isorhy 0.33,0.65和1·30mmol·L^-1对AA诱导的TXB₂生成及家兔血浆6-keto-PGF_1α生成无明显影响,但可抑制胶原诱导的TXB₂生成。结论Isorhy具有抗血小板聚集和抑制血栓形成的作用,其抗胶原所致血小板聚集的作用可能部分与抑制TXA的生成有关。     

当归总苯酞活血化瘀作用的实验研究

目的 观察当归总苯酞在活血化瘀方面的功效.方法 大鼠ig给予当归总苯酞(生药1、2、4g/kg),观察当归总苯酞对大鼠实验性动脉血栓形成及血小板聚集功能的影响;采用高分子右旋糖酐制备高黏血症大鼠模型,观察当归总苯酞对大鼠血液黏度的影响;观察当归总苯酞对大鼠凝血相关指标的影响.结果 当归总苯酞(生药1、2、4 g/kg)能延长大鼠实验性动脉血栓的形成时间(P＜0.05、0.01);降低高分子右旋糖苷所致的高黏血症大鼠全血、血浆、血清黏度(P＜0.05);抑制花生四烯酸(AA)、腺苷二磷酸钠(ADP)、胶原(CG)诱导的血小板聚集功能(P＜0.05、0.01、0.001);明显延长大鼠凝血酶时间(TT)、凝血酶原时间(PT)、活化部分凝血活酶时间(APTT) (P＜0.05、0.01、0.001).结论 当归总苯酞具有显著的活血化瘀作用,表现为延长实验性动脉血栓的形成时间;改善高黏血症模型大鼠的全血及血浆黏度;抑制血小板聚集功能:影响凝血系统,延长大鼠TT、PT、APTT等指标.     

通心络胶囊对脑梗死患者血小板聚集功能的影响

目的 观察通心络胶囊对脑梗死患者血小板聚集功能的影响,探讨其可能的作用机制。方法 74例恢复期脑梗死患者,根据入选时是否正在服用阿司匹林分为通心络胶囊单用组30例,在阿司匹林基础上加通心络胶囊的合用组44例。采用二磷酸腺苷、肾上腺素、胶原和花生四烯酸为诱导剂,观察所有患者在加用通心络胶囊后血小板聚集率的变化。结果 单用组对二磷酸腺苷、肾上腺素诱导的血小板聚集率（%）在治疗后（80.9±16.5、91.8±4.0）较治疗前（88.5±4.9、92.9±3.1）下降,差异有统计学意义（P<0.05）。合用组对二磷酸腺苷、花生四烯酸诱导的血小板聚集率在治疗后〔62.0±16.3、17.7(10.2～23.7)〕较治疗前〔66.9±13.5、22.7(13.5～32.6)〕下降,差异有统计学意义（分别P<0.05、P<0.01）。合用组阿司匹林抵抗的例数在治疗后（10例,23％）较治疗前（20例,45％）减少,差异有统计学意义（P<0.05）。通心络胶囊与阿司匹林合用后未见明显不良反应增加。结论 通心络胶囊具有抑制血小板聚集作用,机制可能与二磷酸腺苷和花生四烯酸途径的抑制有关,同时与阿司匹林合用相对安全。     

Anti-platelet effects of bioactive compounds isolated from the bark of Rhus verniciflua Stokes

It has previously been shown that EtOAc extracts of Rhus verniciflua Stokes (RVS) inhibit the platelet aggregation response. In this report, bioassay-guided fractionation using ADP-, arachidonic acid-, and collagen-induced human platelet aggregation by a whole blood aggregometer yielded the bioactive compounds isomaltol and pentagalloyl glucose from different highly effective fractions. In addition, column chromatography of fractions from RVS yielded another five compounds: butin, fisetin, sulfuretin, butein and 3,4',7,8-tetrahydroxyflavone. We investigated the effects of bioactive compounds from RVS fractions on several markers of platelet activation using receptor expression on platelet membranes, including glycoprotein IIb/IIIa (CD41), GPIIb/IIIa-like expression (PAC-1) and P-selectin (CD62), and intracelluar calcium mobilization responses by flow cytometry in healthy subjects. Dose-dependent inhibition of platelet aggregation and significantly decreased platelet activation were observed for the isomaltol- and pentagalloyl glucose-treated platelets, respectively. These results show that isomaltol and pentagalloyl glucose from the bark of Rhus verniciflua Stokes have potent anti-platelet activity and emphasize the need to further examine the mechanism of these active compounds for platelet modulation.     

从益气活血方拆方对健康人血小板聚集功能的影响探讨方剂组成

目的：观察益气活血方及其拆方对健康人血小板聚集功能的影响来探讨其配伍规律。方法：健康献血者静脉采血抗凝,制备富血小板血浆(platelet rich plasma,PRP)和贫血小板血浆(platelet poor plasma,PPP),然后在比浊管中加药孵育,用血小板聚集仪检测二磷酸腺苷(adenosine diphosphate,ADP)、血小板活化因子(platelet activating factor,PAF)、花生四烯酸(arachidonic acid,AA)诱导的最大聚集率。结果：益气活血方能显著提高ADP,PAF诱导的血小板聚集功能,其中黄芪、当归配伍为方中主药,益气药与活血药相须为用才能发挥促聚作用。结论：益气活血方体外实验能增强健康人血小板聚集功能,但确切作用机制有待进一步实验验证。     

Bioactive cembrane diterpenoids of Anisomeles indica

Five new cembrane-type diterpenoids with a trans-fused alpha-methylene-gamma-lactone (1-5), a new flavonoid glucoside (6), and 17 known compounds were isolated from a methanol extract of Anisomeles indica. The structures of 1-6 were elucidated by spectroscopic analysis, and the absolute configuration of compound 1 was determined using the modified Mosher's method. Compound 8 (4,5-epoxovatodiolide) exhibited cytotoxicity against a small panel of human cancer cell lines. Additionally, compounds 4 and 7 (ovatodiolide) exhibited selective antiplatelet aggregation activities toward collagen, while compounds 4, 5, and 8 showed inhibitory effects on antiplatelet aggregation induced by thrombin.     

Anti‐Platelet Activity of Water Dispersible Curcuminoids in Rat Platelets

Curcuminoids are active principle of turmeric with plethora of health beneficial properties. In this study, we have evaluated for the first time the effect of water dispersible curcuminoids on rat platelet aggregation. Curcuminoids (10–30 µg/mL) significantly inhibited platelet aggregation induced by agonists viz., collagen, ADP and arachidonic acid. Curcuminoids were found to be two‐fold more potent than curcumin in inhibiting platelet aggregation. Intracellular curcuminoid concentration was relatively higher than curcumin in rat platelets. Curcuminoids significantly attenuated thromboxane A₂, serotonin levels in rat platelets which play an important role in platelet aggregation. Curcuminoid treatment increased nitric oxide (NO) levels in platelets treated with agonists. Curcuminoids inhibited free radicals such as superoxide anion released from activated platelets, which ultimately inhibits platelet aggregation. Further, curcuminoids inhibited 12‐lipoxygenase activity and formation of 12‐hydroperoxyeicosatetraenoic acid (12‐HPETE) in activated rat platelets which regulates platelet aggregation. The results suggest that curcuminoids have remarkable anti‐platelet activity by modulating multiple mechanisms involved in platelet aggregation. Thus curcuminoids may have a therapeutic potential to prevent platelet activation related disorders. Copyright © 2015 John Wiley & Sons, Ltd.