益母草碱、丁香酰胍醇及丁香酸氨基醇酯类化合物抗血小板聚集活性及其与结构的关系

 目的：观察和比较益母草碱、丁香酰胍醇及丁香酸氨基醇酯类化合物抗血小板聚集活性及其与结构的关系。方法：以血小板聚集为指标并计算IC₅₀以比较各样品的作用强度。结果：益母草碱(Ⅰ)，化合物Ⅱ，Ⅲ和Ⅳ1，2均能对抗ADP诱导大鼠和兔的血小板聚集作用，其IC₅₀分别为0.97，4.4，5.2，0.36和1.14 mg/ml。所有化合物在体外均有抑制ADP诱导大鼠和兔的血小板聚集的作用，以Ⅳ1，Ⅴ1和Ⅶ1，2的作用最强，IC₅₀在0.15～0.36 mg/ml,其次为Ⅳ3，5，7，8和Ⅵ1，2，IC₅₀在0.43～0.94 mg/ml。化合物Ⅰ，Ⅱ，Ⅲ，Ⅳ2，4，6和9虽有抑制作用，但无实际意义。结论：益母草碱具有明显的抗血小板聚集活性，完整的益母草碱分子是维持这种活性的基本结构，改变分子结构碱性胍基为氨基，引入双键或碳链加长以及丁香酸氨基醇酯乙烯化或乙氧羰基化，其活性均比母体化合物强。     

注射用血栓通体外对家兔血小板聚集的影响

目的研究注射用血栓通(冻干,主要成分为三七总皂苷,质量分数为95%)体外对二磷酸腺苷(ADP)、花生四烯酸(AA)、血小板活化因子(PAF)诱导家兔血小板聚集的影响。方法采用Born法,检测ADP、AA、PAF诱导的家兔血小板聚集率。结果与对照组比较,注射用血栓通7.2、14.4 mg/mL组能显著抑制ADP、AA、PAF诱导的兔血小板聚集率(P<0.01),注射用血栓通3.6 mg/mL组能显著抑制ADP诱导的兔血小板聚集率(P<0.01)。结论注射用血栓通具有体外抑制家兔血小板聚集的作用。     

基于活性筛选和靶标网络预测的蒲黄和赤芍选择性抑制血小板聚集作用

目的:探讨常用活血化瘀中药抗血小板活性的激动剂选择性及可能的作用通路。方法:通过体外高通量血小板聚集实验系统评价24种常用活血化瘀中药醇提取物抗二磷酸腺苷(ADP)和凝血酶诱导的血小板聚集活性;通过Ingenuity Pathway Analysis(IPA)预测代表性药物蒲黄与赤芍已知单体成分的作用靶点,并加以验证。结果:蒲黄抗ADP,凝血酶诱导血小板聚集的半数抑制浓度(IC50)分别为55.27,300.60 mg·L~(-1);赤芍抗ADP,凝血酶诱导血小板聚集的IC50分别为336.20,101.60 mg·L~(-1)。IPA预测提示,蒲黄与赤芍有可能通过调节Ca2+,环磷酸腺苷(c AMP)和一氧化氮(NO)水平抑制血小板聚集。实验发现,蒲黄可明显抑制ADP对血小板内Ca2+的升高(P0.05,P0.01);赤芍可显著提高凝血酶导致的血小板内NO浓度降低(P0.01);蒲黄、赤芍均不能逆转ADP,凝血酶引起的血小板内c AMP浓度降低。结论:蒲黄和赤芍醇提物分别具有选择性抗ADP和凝血酶诱导的大鼠血小板聚集活性。与IPA预测相符,蒲黄可降低血小板内钙离子水平,赤芍可提高血小板内NO浓度,可能分别激活嘌呤能P2Y1受体下游的Gq亚基/磷脂酶C(PLC)/三磷酸肌醇(IP3)和磷脂酰肌醇-3-激酶(PI3K)/蛋白激酶B(Akt)/内皮型一氧化氮合酶(e NOS)通路抑制血小板聚集。     

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.     

Anti‐Thrombotic Effect of a Novel Formula from Corni Fructus with Malic Acid,Succinic Acid and Citric Acid

Our previous investigation had confirmed the inhibition of platelet aggregation of a novel Corni fructus‐derived formula composed of malic acid, succinic acid and citric acid with a ratio of 3:2:2. The present study was to further evaluate the anti‐thrombotic effect of the formula in vivo. Mice of acute pulmonary thromboembolism, and rats of arterial thrombosis were used to determine the anti‐thrombotic effect of the formula. Histology analysis of endothelium was conducted with hematoxylin and eosin stain. TXB₂, 6‐K‐PGF_1α, cAMP, cGMP and NO in rat plasma were determined. In vitro assay of αIIbβ3 and phosphorylation of ERK1/2 were performed in ADP‐treated platelet. The formula significantly reduced the recovery time and mortality rate of mice with acute pulmonary thromboembolism. Remarkably extended occlusion time, decreased thrombus weight and more integrated endothelium were observed in rat with the formula. Enhanced 6‐K‐PGF_1α, cGMP and NO, but not TXB₂ and cAMP, were demonstrated in rat plasma with treatment of the formula. Finally, the formula was shown to inhibit αIIbβ3 expression and activation of ERK1/2 in platelet. The formula shows positive anti‐thrombotic effect. The direct interference on ADP activated signaling in platelet and regulation of endothelium function are two primary pathways involved in the action on thrombosis. Copyright © 2013 John Wiley & Sons, Ltd.     

Antithrombotic activity of ternatin,a tetramethoxy flavone from Egletes viscosa less

Ternatin, a tetramethoxy flavone isolated from Egletes viscosa Less. was evaluated for a possible antithrombotic acitivity on in vitro platelet aggregation induced by ADP and in vivo mouse model of tail thrombosis induced by kappa-carrageenan (KC). ADP-induced platelet aggegation was inhibited by ternatin in a concentration-dependent manner with an IC₅₀ of 390 μM. It also provided marked protection of mice from thrombotic challenge with KC. Tail thrombosis was totally prevented in mice that received ternatin prophylactically (1 h prior to KC injection) whereas therapeutically (4 h after KC injection) administered ternatin effectively reduced the length of the thrombosed/infarcted part of the tail. The observations suggest an antithrombotic action of ternatin.     

丹心Ⅰ号、丹心Ⅱ号对人血小板聚集的影响

 本文观察了丹心Ⅰ号、Ⅱ号对凝血酶、ADP诱导的人血小板聚集的影响，结果表明丹心Ⅰ号、Ⅱ号对其均有不同程度的抑制作用，IC₅₀分别为838.5μg／ml、2.51mg／ml；583.2μg／ml、3.63mg／ml。     

Antiplatelet activity of Phellinus baummii methanol extract is mediated by cyclic AMP elevation and inhibition of collagen-activated integrin-α(IIb) β₃ and MAP kinase

Phellinus baumii is a mushroom that has been used as folk medicine against various diseases and is reported to have antidiabetic, anticancer, antioxidant, antiinflammatory and antihypertensive activities. However, information on the effects of P. baumii extract in platelet function is limited. Therefore, the aim of this study was to examine the impact of a P. baumii methanol extract (PBME) on platelet activation and to investigate the mechanism behind its antiplatelet activity. PBME effects on agonist‐induced platelet aggregation, granule secretion, [Ca²⁺]_i mobilization, α_IIbβ₃ activation, cyclic AMP release and mitogen‐activated protein kinase (MAPK) phosphorylations were studied using rat platelets. PBME dose‐dependently inhibited collagen, thrombin and ADP‐induced platelet aggregation with an IC₅₀ of 51.0 ± 2.4, 54.0 ± 2.1 and 53.0 ± 4.3 μg/mL, respectively. Likewise, thrombin‐induced [Ca²⁺]_i and collagen‐activated ATP secretions were suppressed in PBME treated platelets. Aggregation and ATP secretion were also markedly attenuated by PBME alone or in combination with PP2 (Src inhibitor) and U‐73122 (PLC inhibitor) in collagen‐stimulated platelets. Besides, PBME treatment elevated basal cyclic AMP levels and inhibited collagen‐induced integrin‐α_IIbβ₃ activation. Moreover, PBME attenuated extracellular‐signal‐regulated protein kinase 2 (ERK2) and c‐Jun N‐terminal kinase 1 (JNK1) phosphorylations. Further PD98059 (ERK inhibitor) and SP60025 (JNK inhibitor) reduced collagen‐induced platelet aggregation and ATP secretion. In conclusion, the observed PBME antiplatelet activity may be mediated by activation of cyclic AMP and inhibition of ERK2 and JNK1 phosphorylations. Finally, these data suggest that PBME may have therapeutic potential for the treatment of cardiovascular diseases that involve aberrant platelet function. Copyright © 2011 John Wiley & Sons, Ltd.     

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.     

The Traditional Medicine Spilanthes acmella,and the Alkylamides Spilanthol and Undeca‐2E‐ene‐8,10‐diynoic Acid Isobutylamide,Demonstrate In Vitro and In Vivo Antimalarial Activity

Spilanthes spp. are used as traditional herbal medicines in Africa and India to treat malaria. Yet, to date, there are no data on the active constituents or the most effective extraction methods for this indication. The isolated alkylamides, spilanthol and undeca‐2E‐ene‐8,10‐diynoic acid isobutylamide, found in S. acmella Murr., were shown to have IC₅₀s of 16.5 μg/mL and 41.4 μg/mL on Plasmodium falciparum strain PFB and IC₅₀s of 5.8 μg/mL and 16.3 μg/mL for the chloroquine resistant P. falciparum K1 strain, respectively. Further investigations revealed that at relatively low concentrations, spilanthol and the water extract of S. acmella reduced the parasitemia 59% and 53% in mice infected with P. yoelii yoelii 17XNL at 5 mg/kg and 50 mg/kg, respectively. Unexpectedly, the 95% ethanol extract of S. acmella was less effective (36% reduction in parasitemia) at 50 mg/kg. These results provide the first evidence supporting S. acmella against malaria and demonstrating active constituents in S. acmella against P. falciparum. Copyright © 2011 John Wiley & Sons, Ltd.     

Cytotoxic and antitumour activity of scopadulcic acid from Scoparia dulcis L.

Scopadulcic acid B is a diterpenoid recently isolated from Scoparia dulcis L. This compound showed greater cytotoxicity against cell lines derived from tumour tissues with a 50% inhibitory concentration (IC₅₀) of 0.068–0.076 μg/mL, compared with cell lines from normal tissues with an IC₅₀ of 0.097–0.245 μg/mL. The in vivo antitumour activity of scopadulcic acid B was determined using mice inoculated with Ehrlich ascites tumour cells. Oral administration of the compound at doses of 25 or 100 mg/kg/day prolonged the median survival time of the animals. However, when administered intraperitoneally to mice at doses of 25, 50 or 100 mg/kg/day, scopadulcic acid B increased the survival rate by 12.5%, 12.5% and 25%, respectively, without weight change over the treatment period.     

Anti‐platelet Activity of Erythro‐(7S,8R)‐7‐acetoxy‐3,4,3′,5′‐tetramethoxy‐8‐O‐4′‐neolignan from Myristica fragrans

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. In this study, we investigated the anti‐platelet activity of erythro‐(7S,8R)‐7‐acetoxy‐3,4,3′,5′‐tetramethoxy‐8‐O‐4′‐neolignan (EATN), a neolignan isolated from Myristica fragrans, using human platelets. EATN preferentially inhibited thrombin‐ and platelet‐activating factor (PAF)‐induced platelet aggregation without affecting platelet damage in a concentration‐dependent manner with IC₅₀ values of 3.2 ± 0.4 and 3.4 ± 0.3 μM, respectively. However, much higher concentrations of EATN were required to inhibit platelet aggregation induced by arachidonic acid. EATN also inhibited thrombin‐induced serotonin and ATP release, and thromboxane B₂ formation in human platelets. Moreover, EATN caused an increase in cyclic AMP (cAMP) levels and attenuated intracellular Ca²⁺ mobilization in thrombin‐activated human platelets. Therefore, we conclude that the inhibitory mechanism of EATN on platelet aggregation may increase cAMP levels and subsequently inhibit intracellular Ca²⁺ mobilization by interfering with a common signaling pathway rather than by directly inhibiting the binding of thrombin or PAF to their receptors. This is the first report of the anti‐platelet activity of EATN isolated from M. fragrans. Copyright © 2013 John Wiley & Sons, Ltd.     

新疆鼠尾草总酚酸的体外抗氧化活性

目的：研究新疆鼠尾草总酚酸提取物和纯化物的体外抗氧化活性。方法：以40%乙醇提取和大孔吸附树脂纯化分别制备得到新疆鼠尾草总酚酸的提取物和纯化物,以维生素C（VC）为对照,通过体外化学模拟方法测定新疆鼠尾草总酚酸提取物和纯化物的还原能力、对·DPPH自由基、羟基自由基（·OH）和超氧自由基（O₂^-·）的清除能力,研究新疆鼠尾草总酚酸的抗氧化活性。结果：新疆鼠尾草总酚酸提取物和纯化物清除·DPPH自由基的作用50%清除浓度（IC₅₀,分别为0.029,0.039 g·L^-1）弱于VC（IC₅₀0.018 g·L^-1）;对羟基自由基（·OH）的清除作用（IC₅₀分别为0.212,0.165 g·L^-1）强于VC（IC₅₀0.356 g·L^-1）;对超氧自由基（O₂^-·）的清除能力（IC₅₀分别为3.735,1.913 g·L^-1）弱于VC（IC₅₀0.390 g·L^-1）,其纯化物还具有一定的还原能力。结论：新疆鼠尾草总酚酸具有较强的抗氧化作用。     

Antioxidant activity of yellow dock (Rumex crispus L., Polygonaceae) fruit extract

The methanol extract of ripe Rumex crispus L. fruits was evaluated for its antioxidant potential by assays for ferric‐reducing antioxidant power (FRAP), DPPH‐free radical scavenging activity (DPPH) and the influence on lipid peroxidation in liposomes (LP). Considerable activity was observed in all test systems (FRAP: 9.9 mmol Fe²⁺/g; DPPH IC₅₀: 3.7 μg/mL; LP IC₅₀: 4.9 μg/mL), comparable to that of BHT (FRAP: 8.0 μg/mL; DPPH IC₅₀: 19.4 μg/mL; LP IC₅₀: 3.5 μg/mL), but lower than the activity of ascorbic acid, rutin and quercetin, used as positive control substances. The in vivo effects were evaluated in several hepatic antioxidant systems (activities of LPx, GSH‐Px, Px, CAT and XOD, as well as GSH content), after treatment with the studied yellow dock extract in different doses, or in combination with carbon tetrachloride (CCl₄). Pretreatment with the R. crispus extract inhibited CCl₄‐induced oxidative stress by decreasing LPx and increasing GSH content in a dose dependent manner, bringing the levels of antioxidant enzymes to near control values. Copyright © 2010 John Wiley & Sons, Ltd.     

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。     

Antithrombotic Effect of a Polysaccharide Fraction from Laminaria japonica from the South China Sea

Some in vitro studies have identified an antithrombotic effect of polysaccharides from Laminaria japonica, but this activity remains to be confirmed in vivo. In this study a polysaccharide fraction termed PLG was extracted from L. japonica in the Beibu Gulf in Guangxi, China, and its antithrombotic effects explored in rat models of carotid and venous thrombosis. Its anticoagulation and antiplatelet properties were assessed by measuring the prothrombin time (PT), activated partial thromboplastin time (APTT) and ADP‐induced platelet aggregation rate (Agg_max). Its effects on bleeding time were measured using the tail transection method. It was found that pretreatment with an intraperitoneal injection of PLG at 2.5 or 5.0 mg/kg significantly prolonged the occlusion time in the carotid thrombosis model, and a dose of 5.0 mg/kg reduced the thrombus weight in the venous thrombosis model. Pretreatment with PLG (5.0 mg/kg) increased the APTT and decreased the ADP‐induced platelet Agg_max. Neither dose of PLG significantly prolonged the bleeding time compared with the control group. In an in vitro anticoagulation assay using human plasma, PLG at 57.14, 28.57 and 28.57 μg/mL inhibited APTT and PT in a concentration‐dependent manner. The results show that PLG possesses antithrombotic activity in a rat model, and that it may prove to be clinically useful in humans. Copyright © 2011 John Wiley & Sons, Ltd.     

Protective effects of neohesperidin and poncirin isolated from the fruits of Poncirus trifoliata on potential gastric disease

The effects of Poncirus trifoliata (P. trifoliata) (Ponciri Fructus, PF) extract and its constituents such as neohesperidin and poncirin on gastritis in rats and human gastric cancer cells were investigated. The PF 70% ethanol extracts (1 g) showed approximately 11.38% of acid‐neutralizing capacities and cytotoxicity (IC₅₀ = 85.39 µg/mL) against human AGS gastric cancer cells. In addition, neohesperidin exhibited antioxidant activity (IC₅₀ = 22.31 µg/mL) in the 1,1‐diphenyl‐2‐picryldydrazyl (DPPH) radical‐scavenging assay. Neohesperidin (50 mg/kg) and poncirin (100 mg/kg) significantly inhibited 55.0% and 60.0% of HCl/ethanol‐induced gastric lesions, respectively, and increased the mucus content. In pylorus ligated rats, neohesperidin (50 mg/kg) significantly decreased the volume of gastric secretion and gastric acid output, and increased the pH. From these results, it could be suggested that neohesperidin and poncirin isolated from PF may be useful for the treatment and/or protection of gastritis. Copyright © 2009 John Wiley & Sons, Ltd.     

复方椟木口服液的药理和毒性研究

药理实验证实:复方■木口服液(以下作样品液)含■木[Loropetalum chinense(R.Brown)Oliv.],紫珠草(Callicarpa sp.),蒲公英(Taraxacum mongolicum Hand-Mazz.),有明显缩短凝血时间,增加血小板数,促进血小板聚集,镇痛,消炎和加强子宫平滑肌收缩作用;小鼠口服半数致死量为339.6 g/kg 生药;大鼠(wistar)口服127g/kg/d×28d,结果脏器重量、血象(除血小板外),肝肾功能均无明显改变。     

Inhibition of rat platelet aggregation by Urtica dioica leaves extracts

Platelet hyperactivity plays an important role in arterial thrombosis and atherosclerosis. The present study was undertaken to investigate the effects of different extracts of Urtica dioica leaves on platelet aggregation. Rat platelets were prepared and incubated in vitro with different concentrations of the tested extracts and aggregation was induced by different agonists including thrombin (0.5 U/mL), ADP (10 microm), epinephrine (100 microm) and collagen (5 mg/mL). The crude aqueous extract inhibited thrombin-induced platelet aggregation in a dose-dependent manner. At 1 mg/mL, the percent inhibition was 17.1 +/- 4.2%. Soxhlet extraction of the plant leaves with different successive solvents showed that the ethyl acetate extract exhibited the most antiaggregant effect with an inhibition of 76.8 +/- 6.1% at 1 mg/mL. Flavonoids isolated from the plant leaves, produced a strong inhibitory effect on thrombin-induced platelet aggregation with an IC(50) of 0.25 +/- 0.05 and 0.40 +/- 0.04 mg/mL for genins and heterosidic flavonoids, respectively. Flavonoids also markedly inhibited platelet aggregation induced by ADP, collagen and epinephrine. It is concluded that Urtica dioica has an antiplatelet action in which flavonoids are mainly implicated. These results support the traditional use of Urtica dioica in the treatment and/or prevention of cardiovascular disease.     

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.