Ankita Misra

Anti-platelet effects of Curcuma oil in experimental models of myocardial ischemia-reperfusion and thrombosis

Extensive research on the mechanism of action and medicinal importance of curcumin obtained from turmeric (Curcuma longa) has unfolded its potential therapeutic value against many chronic ailments. Curcuma oil (C.oil), the highly lipophilic component from Curcuma longa has been documented for its neuroprotective efficacy against rat cerebral ischemia-reperfusion injury; however its effect on myocardial reperfusion injury remains unexplored. In the present study, effect of C.oil (500 mg/kg, po) was evaluated against myocardial ischemia-reperfusion induced injury in the rat model. C.oil failed to confer protection against cardiac injury, however significant reversal of ADP induced platelet aggregation (p<0.05) was evident in the same animals. Moreover, collagen and thrombin induced platelet aggregation (p<0.001) as well as tyrosine phosphorylation of various proteins in activated platelets was also suppressed. C.oil also offered significant protection against collagen-epinephrine induced thromboembolism in mice as well as augmented total time to occlusion against FeCl(3) induced arterial thrombosis in rats. C.oil however had no effect on coagulation parameters (TT, PT and aPTT) and exerted a mild effect on the bleeding time. Bioavailability of C.oil, as assessed by monitoring ar-turmerone, α,β-turmerone and curlone, was 13%, 11% and 7% respectively, indicating high systemic exposure. Moreover, longer mean residence time (MRT) of ar-turmerone (13.2h), α,β-turmerone (11.6h) and Curlone (14.0 h) and plasma elimination half lives in the range of 5.5 to 7.2h correlated with single 500 mg/kg dose regimen of C.oil. In the present study, C.oil thus seems to be an efficacious and safe anti-platelet agent which was protective against intravascular thrombosis.

Curcuma oil ameliorates hyperlipidaemia and associated deleterious effects in golden Syrian hamsters

Essential oil components from turmeric (Curcuma longa L.) are documented for neuroprotective, anti-cancer, anti-thrombotic and antioxidant effects. The present study aimed to investigate the disease-modifying potential of curcuma oil (C. oil), a lipophilic component from C. longa L., in hyperlipidaemic hamsters. Male golden Syrian hamsters were fed a chow or high-cholesterol (HC) and fat-rich diet with or without C. oil (30, 100 and 300 mg/kg) for 28 d. In HC diet-fed hamsters, C. oil significantly reduced plasma total cholesterol, LDL-cholesterol and TAG, and increased HDL-cholesterol when compared with the HC group. Similar group comparisons showed that C. oil treatment reduced hepatic cholesterol and oxidative stress, and improved liver function. Hyperlipidaemia-induced platelet activation, vascular dysfunction and repressed eNOS mRNA expression were restored by the C. oil treatment. Furthermore, aortic cholesterol accumulation and CD68 expression were also reduced in the C. oil-treated group. The effect of C. oil at 300 mg/kg was comparable with the standard drug ezetimibe. Delving into the probable anti-hyperlipidaemic mechanism at the transcript level, the C. oil-treated groups fed the chow and HC diets were compared with the chow diet-fed group. The C. oil treatment significantly increased the hepatic expression of PPARa, LXRa, CYP7A1, ABCA1, ABCG5, ABCG8 and LPL accompanied by reduced SREBP-2 and HMGCR expression. C. oil also enhanced ABCA1, ABCG5 and ABCG8 expression and suppressed NPC1L1 expression in the jejunum. In the present study, C. oil demonstrated an anti-hyperlipidaemic effect and reduced lipid-induced oxidative stress, platelet activation and vascular dysfunction. The anti-hyperlipidaemic effect exhibited by C. oil seems to be mediated by the modulation of PPARa, LXRa and associated genes involved in lipid metabolism and transport.

A review on biological and chemical diversity in Berberis (Berberidaceae).

Berberis is an important genus and well known in the Indian as well as European systems of traditional medicine. It is used since ancient times for curing eye disease, fever, jaundice, rheumatism, vomiting during pregnancy, kidney and gall balder stones and various other ailments due to the presence of biologically active alkaloid berberine. Action of the root extracts of few species are believed to be as powerful as quinine in the treatment of malarial fever. A plethora of literature pertaining to the taxonomy, biology, chemistry, traditional and ethnic uses of Berberis in different countries and indigenous cultures was collected by both offline (library, journals, textbooks etc.) and online mode (electronic search of available databases). In addition to this, books on traditional medicine and ethno pharmacological knowledge were also referred to extract ancient uses of Berberis in different traditional medicine systems. Most of the folklore, traditional and ethno botanical claims about Berberis species were validated by broad spectrum in vitro and vivo pharmacological studies. The present article summarizes its usage in eye and liver disorder, fever, kidney and gall stones along with anticancer activity. This comprehensive review will not only help researchers for further evaluation but also provide substantial information for future exploitation of species to develop novel herbal formulations.

Antithrombotic activity of a newly synthesized coumarin derivative 3-(5-hydroxy-2,2-dimethyl-chroman-6-yl)-N-{2-[3-(5-hydroxy-2,2-dimethyl-chroman-6-yl)-propionylamino]-ethyl}-propionamide.

Anti‐platelet therapy is a useful strategy to prevent acute thromboembolic artery occlusions. This study was designed to assess the efficacy of seselin derivatives against murine pulmonary thromboembolism, bleeding time, platelet activation and thrombosis. Administration of C3 (16 mg/kg) offered 70% protection against collagen‐ and epinephrine‐induced pulmonary thromboembolism and 30% protection against arachidonic acid‐induced death in mice, without adversely affecting bleeding time. No significant difference was observed by C3 in ferric chloride‐induced arterial thrombosis in rats. Significant reduction in thrombus weight was observed in arteriovenous shunt model. In rat PRP, C3 reduced ADP and collagen‐induced platelet aggregation. In chronic hamster model of dyslipidemia, administration of C3 (16 mg/kg p.o. for 90 days) had no effect on plasma lipids, vasoreactivity and platelet adhesion. C3 fed hamsters showed reduced whole‐blood aggregation response to ADP and collagen compared to HC‐fed hamsters. In addition, C3 augmented thrombin time; however, time to occlusion was not increased. These results convincingly demonstrated that C3 is a novel molecule that reduces the risk of thrombosis and alleviates prothrombotic state associated with hyperlipidemia without any adverse effect on bleeding time. The high benefit/risk ratio of this compound makes it a suitable candidate for future valid studies.

Curcuma oil ameliorates insulin resistance & associated thrombotic complications in hamster & rat.

Background & objectives: Curcuma oil (C. oil) isolated from turmeric (Curcuma longa L.) has been shown to have neuro-protective, anti-cancer, antioxidant and anti-hyperlipidaemic effects in experimental animal models. However, its effect in insulin resistant animals remains unclear. The present study was carried out to investigate the disease modifying potential and underlying mechanisms of the C. oil in animal models of diet induced insulin resistance and associated thrombotic complications. Methods: Male Golden Syrian hamsters on high fructose diet (HFr) for 12 wk were treated orally with vehicle, fenofibrate (30 mg/kg) or C. oil (300 mg/kg) in the last four weeks. Wistar rats fed HFr for 12 wk were treated orally with C. oil (300 mg/kg) in the last two weeks. To examine the protective effect of C. oil, blood glucose, serum insulin, platelet aggregation, thrombosis and inflammatory markers were assessed in these animals. Results: Animals fed with HFr diet for 12 wk demonstrated hyperlipidaemia, hyperglycaemia, hyperinsulinaemia, alteration in insulin sensitivity indices, increased lipid peroxidation, inflammation, endothelial dysfunction, platelet free radical generation, tyrosine phosphorylation, aggregation, adhesion and intravascular thrombosis. Curcuma oil treatment for the last four weeks in hamsters ameliorated HFr-induced hyperlipidaemia, hyperglycaemia, insulin resistance, oxidative stress, inflammation, endothelial dysfunction, platelet activation, and thrombosis. In HFr fed hamsters, the effect of C. oil at 300 mg/kg was comparable with the standard drug fenofibrate. Curcuma oil treatment in the last two weeks in rats ameliorated HFr-induced hyperglycaemia and hyperinsulinaemia by modulating hepatic expression of sterol regulatory element binding protein 1c (SREBP-1c), peroxisome proliferator-activated receptor-gamma co-activator 1 (PGC-1)α and PGC-1β genes known to be involved in lipid and glucose metabolism. Interpretation & conclusions: High fructose feeding to rats and hamsters led to the development of insulin resistance, hyperglycaemia, endothelial dysfunction and oxidative stress. C. oil prevented development of thrombotic complications associated with insulin resistance perhaps by modulating genes involved in lipid and glucose metabolism. Further studies are required to confirm these findings.

Novel Glycoprotein VI Antagonists as Antithrombotics: Synthesis, Biological Evaluation, and Molecular Modeling Studies on 2,3-Disubstituted Tetrahydropyrido(3,4-b)indoles

The development of small molecule inhibitors targeting GPVI has promising therapeutic role, as they inhibit arterial thrombosis with limited risk of bleeding. Among the compounds showing in vivo antithrombotic activity, the most active compound 6b (ED50 = 28.36 μmol/kg po in mice) showed improved inhibition for collagen (IC50 = 6.7 μM), CRP-XL (IC50 = 53.5 μM), and convulxin (CVX) (IC50 = 5.7 μM) mediated platelet aggregation as compared to losartan (LOS) (collagen, IC50 = 10.4 μM; CRP-XL, IC50 = 158 μM; CVX, IC50 = 11 μM) than any of its enantiomers S (6c) (collagen, IC50 = 25.3 μM; CRP-XL, IC50 = 181.4 μM; CVX, IC50 = 9 μM) and R (6d) (collagen, IC50 = 126.3 μM; CRP-XL, IC50 > 500 μM; CVX, IC50 = 86.8 μM). Compound 6b also inhibited platelet P-selectin expression and thus may diminish atherosclerosis. The molecular interactions of both enantiomers 6c and 6d at the GPVI receptor have been explained through docking studies.

Phospholipase C-γ2 via p38 and ERK1/2 MAP kinase mediates diperoxovanadate-asparagine induced human platelet aggregation and sCD40L release

Abstract Objective Redox imbalance either inside platelets or in their immediate surroundings prove detrimental to their physiologic functions during haemostasis. This study was therefore aimed to assess the effect of peroxide radicals on platelet functions and underlying signalling mechanisms using asparagine-conjugated diperoxovanadate (DPV-Asn). Methods Platelet aggregation, ATP secretion, TxB2 release, intra-platelet calcium mobilization, protein tyrosine phosphorylation, GPIIbIIIa activation by PAC1 labelling and sCD40L release (enzyme-linked immunosorbent assay) was monitored using various concentrations of DPV-Asn. Cell viability was assessed by Annexin V labelling, MTT assay, LDH leakage and mitochondrial membrane potential by JC-1. Results Platelet aggregation induced by DPV-Asn was chiefly regulated by dense granule secretion, thromboxane A2 (TxA2) generation, intra-platelet [Ca2+] influx, GPIIbIIIa activation and sCD40L release, which were significantly reduced in presence of U73122 (PLC inhibitor), aspirin (COX), SB203580 (p38 inhibitor), and PD98059 (ERK inhibitor). This was further corroborated by enhanced tyrosine phosphorylation of numerous platelet proteins including PLC-γ2, which apparently played a central role in transducing peroxide signals to regulate [Ca2+] influx and phosphorylation of p38 and ERK1/2 MAP kinase. Discussion Peroxide radicals critically regulate the thrombo-inflammatory functions of platelets via the PLCγ2-p38-ERK1/2-TxA2 pathway, which closely resembles the clinical scenario of various pathologies like hyperglycemia and atherosclerosis during which oxidative stress disrupts platelet functions.

Progression and characterization of the accelerated atherosclerosis in iliac artery of New Zealand White rabbits: effect of Simvastatin.

Objective: Although atherosclerosis is described in New Zealand White rabbits iliac artery, yet details of time-dependent atherosclerosis progression are not well known. Further, a well characterized accelerated model of atherosclerosis is also required for the screening of candidate drugs to target specific steps of atherosclerosis development. The present study extensively characterizes the time-dependent plaque composition and functional responses of the atherosclerosis in rabbit iliac artery and its modification by simvastatin. Methods: Atherosclerosis was induced with a combination of balloon injury and atherogenic diet (AD) (1% cholesterol, 6% peanut oil) in rabbits iliac artery. Atherosclerosis progression was evaluated on days 8, 10, 15, 21, 35, and 56 after AD feeding. The plaque characterization was done using histology, real-time reverse transcription–polymerase chain reaction, and vasoreactivity experiments. The standard anti-hyperlipidemic drug, simvastatin (5 mg·kg−1·d−1), was used to investigate its effect on atherosclerotic changes. Results: Plasma lipids were elevated in a progressive manner after AD feeding from days 8 to 56. Similarly, arterial lipids, Monocyte Chemoattractant Protein-1 (MCP-1) level along with infiltration of macrophages in the lesion area were also increased from day 15 onward. This resulted in a significant increase in the plaque area and intimal–medial thickness ratio in contrast to normal animals. Inflammatory milieu was observed with a significant increase in expression of pro-inflammatory regulators like MCP-1, Tumor Necrosis Factor-&agr; (TNF-&agr;) and Vascular Cell Adhesion Molecule-1 (VCAM-1), whereas anti-inflammatory cytokine interleukin 10 decreased as disease progressed. Endothelial dysfunction was also observed, specifically Acetylcholine (ACh)-induced vasorelaxation was reduced from day 8 onward, whereas the phenylephrine-induced vasoconstriction response was progressively reduced from day 15 in the iliac artery. Ground substances including proteoglycans, &agr;-actin, and collagen content along with metalloproteinase-9 and Tissue inhibitor of metalloproteinases-1 (TIMP-1) inhibitors were significantly augmented at later time points, day 21 onward. Simvastatin treatment for 35 days, at a dose having no significant effect on plasma lipid levels, significantly reduced atherosclerotic progression as evident by reduced macrophage content, inflammatory burden, and extracellular matrix component like proteoglycans and metalloproteinase-9. Conclusions: The authors observed that AD feeding with balloon injury in the rabbit iliac artery accelerated the progression of atherosclerosis and exhibited predominant features of type III human lesion within 8 weeks (56 days). Simvastatin treatment for 35 days exhibited anti-atherosclerotic efficacy without significantly lowering the circulating lipids. The current study thus provides an insight into the time-dependent atherosclerotic progression in rabbit iliac artery and highlights its utility for anti-atherosclerotic evaluation of the candidate drugs.

Intersex effect of lamotrigine on the pharmacokinetic parameters of CDRI-97/78, a novel trioxane antimalarial compound, in rats.

Reports regarding drug toxicity and adverse events resulting from coadministration of multiple drugs are increasing at an alarming rate. CDRI-97/78 is an 1,2,4-trioxane antimalarial agent under development which gets metabolized to the in vivo active metabolite 97/63. In order to assess its drug interaction potential, CDRI-97/78 was administered alone and in combination with lamotrigine to male and female rats via the oral route. Quantification of the active metabolite 97/63 in rat plasma was achieved with an LC-MS/MS assay. After oral administration of 97/78, the Tmax and Cmax values of 97/63 in male rats were 1.75±0.77 h and 862±306 ng/mL while female rats showed values for Cmax of 622.75±95.09 ng/mL and for Tmax of 7.5±0.5 h. Coadministration of 97/78 and lamotrigine resulted in decreased Tmax and Cmax values in both male and female rats (Tmax and Cmax of 0.77±0.16 h and 58.58±6.43 ng/mL in male rats; 1.13±0.22 h and 62.95±12.00 ng/mL in female rats, respectively). A statistically significant difference (P<0.05) was observed for the pharmacokinetic parameters of 97/63 after oral administration of 97/78 alone and upon its coadministration with lamotrigine except for the Cmax and Tmax values in male and for the T1/2 value in female rats. Statistically, no significant difference for the pharmacokinetic parameters of 97/63 between male and female rats after oral administration of 97/78 alone or in combination with lamotrigine was determined except for Tmax. The study indicates that coadministration of 97/78, an antimalarial agent, and the antiepileptic lamotrigine may require dose adjustments. Additional clinical drug interaction trials may be required to confirm these findings.

Liquid chromatography tandem mass spectrometry method for determination of antidiabetic chalcones derivative S001-469 in rat plasma, urine and feces: application to pharmacokinetic study.

A sensitive and selective liquid chromatography tandem mass spectrometry assay was developed for quantitation of a novel antidiabetic chalcones derivative S001-469 in rat matrices. Plasma and urine samples were prepared by double liquid-liquid extraction with diethyl ether and feces by protein precipitation using acetonitrile. Chromatographic elution was carried on cyano guard column (30 mm × 4.6 mm i.d., 5 µm) in isocratic mode at a flow rate of 0.75 mL/min using mobile phase comprising of methanol: ammonium acetate buffer (pH 4.6, 10 mM) (90:10, v/v). Run time was 6 min. Detection was achieved by employing positive ionization mode on a triple-quadrupole LC-MS/MS system with an electrospray ionization (ESI) source. The calibration curves were linear over the range of 0.78-400 ng/mL for all 3 matrices. The method was validated and proved reliable through high and consistent intra- and inter- day accuracy and precision (<15%) values. Recoveries was >85% from spiked plasma, urine and feces samples. S001-469 was stable in plasma at room temperature till 8 h and at -60 °C for 30 d and 3 freeze-thaw cycles.