Anti-platelet Aggregation Assay Research Articles

An integrated and rapid evaluation of Curcumae Radix from different botanical origins based on chemical components, antiplatelet aggregation effect and Fourier transform near-infrared spectroscopy

Curcumae Radix (CR) is a widely used traditional Chinese medicine with significant pharmaceutical importance, including enhancing blood circulation and addressing blood stasis. This study aims to establish an integrated and rapid quality assessment method for CR from various botanical origins, based on chemical components, antiplatelet aggregation effects, and Fourier transform near-infrared (FT-NIR) spectroscopy combined with multivariate algorithms. Firstly, ultra-performance liquid chromatography-photodiode array (UPLC-PDA) combined with chemometric analyses was used to examine variations in the chemical profiles of CR. Secondly, the activation effect on blood circulation of CR was assessed using an in vitro antiplatelet aggregation assay. The studies revealed significant variations in chemical profiles and antiplatelet aggregation effects among CR samples from different botanical origins, with constituents such as germacrone, β-elemene, bisdemethoxycurcumin, demethoxycurcumin, and curcumin showing a positive correlation with antiplatelet aggregation biopotency.Thirdly, FT-NIR spectroscopy was integrated with various machine learning algorithms, including Artificial Neural Network (ANN), K-Nearest Neighbors (KNN), Logistic Regression (LR), Support Vector Machine (SVM), and Subspace K-Nearest Neighbors (Subspace KNN), to classify CR samples from four distinct sources. The result showed that FT-NIR combined with KNN and SVM classification algorithms after SNV and MSC preprocessing successfully distinguished CR samples from four plant sources with an accuracy of 100%.Finally, Quantitative models for active constituents and antiplatelet aggregation bioactivity were developed by optimizing the partial least squares (PLS) model with interval combination optimization (ICO) and competitive adaptive reweighted sampling (CARS) techniques. The CARS-PLS model achieved the best predictive performance across all five components. The coefficient of determination (R2p) and root mean square error (RMSEP) in the independent test sets were 0.9708 and 0.2098, 0.8744 and 0.2065, 0.9511 and 0.0034, 0.9803 and 0.0066, 0.9567 and 0.0172 for germacrone, β-elemene, bisdemethoxycurcumin, demethoxycurcumin and curcumin, respectively. The ICO-PLS model demonstrated superior predictive capabilities for antiplatelet aggregation biotency, achieving an R2p of 0.9010, and an RMSEP of 0.5370.This study provides a valuable reference for the quality evaluation of CR in a more rapid and comprehensive manner.

Establishment of an antiplatelet aggregation efficacy-oriented effect-constituent index for quality evaluation of Curcumae Rhizoma from different species (Curcuma phaeocaulis Val, Curcuma kwangsiensis S. G. Lee et C. F. Liang and Curcuma wenyujin Y. H. Chen et C. Ling)

Curcumae rhizoma (CR) is the dried rhizoma of Curcuma phaeocaulis Val (CP), Curcuma kwangsiensis S. G. Lee et C. F. Liang (CK) and Curcuma wenyujin Y. H. Chen et C. Ling (CW), used widely to treat blood stagnation in China. Currently, quality control indicators for CR are limited to chemical composition analysis. It is unclear whether the current quality standard of the multicomponent content of CR can reflect clinical effects, due to the lack of the evaluation of biological effects. A method of evaluating quality was developed called the effect-constituent index (ECI). By meticulously measuring and calibrating the key active components, the ECI offers a comprehensive assessment of the CR's biological effects, establishing a crucial link to clinical efficacy and safety. An analytical protocol employing high-performance liquid chromatography (HPLC) was devised to ascertain the presence and measure ten principal constituents within CR sourced from various species and the content of total volatile oil was also measured. An In vitro antiplatelet aggregation assay was developed to measure the antiplatelet aggregation biopotencies of thirty batches of CR and ten main components. Then, the calibration weights for each constituent in the ECI were determined based on the antiplatelet aggregation biopotency values of eight components with notable efficacy. The ECI calculation involved summing the products obtained by multiplying the content (Ci) of each component by its corresponding biopotency weight (Wi). Correlation analysis unveiled a the most robust correlation (R = 0.8579, p < 0.001) between ECI and antiplatelet aggregation biopotency of CR, when compared to individual components or volatile oil content. The devised ECI, synthesizing chemical and biological data pertinent to clinical effectiveness, facilitates a nuanced assessment of CR quality across various species in its efficacy in treating blood stagnation. This method addresses the challenge of guaranteeing effectiveness through chemical analysis alone. This study offers substantiation for the applicability of the ECI as a tool for assessing the quality of traditional Chinese medicine (TCM).

Discovering peptide inhibitors of thrombin as a strategy for anticoagulation.

Unusual blood clots can cause serious health problems, such as lung embolism, stroke, and heart attack. Inhibiting thrombin activity was adopted as an effective strategy for preventing blood clots. In this study, we explored computational-based method for designing peptide inhibitors of human thrombin therapeutic peptides to prevent platelet aggregation. The random peptides and their 3-dimentional structures were generated to build a virtual peptide library. The generated peptides were docked into the binding pocket of human thrombin. The designed strong binding peptides were aligned with the native binder by comparative study, and we showed the top 5 peptide binders display strong binding affinity against human thrombin. The 5 peptides were synthesized and validated their inhibitory activity. Our result showed the 5-mer peptide AEGYA, EVVNQ, and FASRW with inhibitory activity against thrombin, range from 0.53 to 4.35 μM. In vitro anti-platelet aggregation assay was carried out, suggesting the 3 peptides can inhibit the platelet aggregation induced by thrombin. This study showed computer-aided peptide inhibitor design can be a robust method for finding potential binders for thrombin, which provided solutions for anticoagulation.

(1R,3S)-THCCA-Asn: To show the discovery of selective inhibitor of thrombin by successfully combining virtual screening and biological assay

Thrombin is the most potent platelet aggregator. To discover the selective inhibitor of thrombin that is important to curing platelet aggregation-related diseases, docking experiments were performed to dock (1R,3S)-2,3,4,9-tetrahydro-β-carboline-3- carboxylic acid, [(1R,3S)-THCCA], and (1S,3S)-2,3,4,9-tetrahydro-β-carboline-3- carboxylic acid, [(1S,3S)-THCCA], into the p pocket of bovine thrombin. The ideal match supported that (1R,3S)-THCCA could be used as a potential lead compound. In this case 20 natural amino acids were theoretically introduced into the 3-carboxyl of (1R,3S)-THCCA and 20 derivatives, (1R,3S)-THCCA-amino acids, were docked into p pocket of bovine thrombin to perform virtual screening. The screening revealed that comparing to (1R,3S)-THCCA itself the DockScores of 16 derivatives were higher, and (1R,3S)-THCCA-Asn (4j) got the highest DockScore. Thus, 16 derivatives were synthesized for experimental study. The in vitro anti-platelet aggregation assay showed that at 100 μM of concentration the 16 derivatives failed to inhibit the platelet aggregation induced by both adenosine diphosphate and arachidonic acid. On the other hand, however, the IC50 value of the 16 derivatives inhibiting the platelet aggregation induced by platelet activating factor and thrombin ranged from 9.44 μM to 194.64 μM and from 0.07 μM to 9.56 μM, respectively. The in vitro anti-platelet aggregation assay suggested that the 16 derivatives selectively inhibited the platelet aggregation induced by thrombin. In particular, the IC50 of (1R,3S)-THCCA-Asn (4j) had the lowest value. On rat model at 1 nmol/kg of dosage the 16 derivatives effectively prevented thrombus formation. It is worth pointing out that even at 0.01 nmol/kg of dosage, 4j still effectively prevented thrombus formation. 4j hardly has effects on the proliferation of mammalian cells and rat tail bleeding time. In conclusion, the combination of virtual screening and biological assays successfully lead to the discovery of 4j as a promising candidate of selective inhibitor of thrombin.

Anti-inflammation and anti-platelet aggregation activities of the ethanolic extract of Graptophyllum pictum leaves in Wistar rats

Graptophyllum pictum is a well-known folk medicine in Indonesia. The red leaves are widely used for their anti-inflammatory properties to relieve hemorrhoids. However, little is known about to what extent these properties can affect platelet aggregation. This study was aimed to determine the anti-inflammation and anti-platelet aggregation activities of the ethanolic extract of Graptophyllum pictum (EEGP). Apart from the ear and hind-paw edema assay, anti-platelet aggregation and bleeding time assay were also performed on male Wistar rats. The test animals were grouped into six groups: three treatment groups termed EEGP100, EEGP600, and EEGP3000 (received 100, 600, and 3000 mg/kg BW of EEGP, respectively), one control-solvent group (1% CMC-Na), and two positive control groups (aspirin and Na-diclofenac). Based on the percentage of edema inhibition, absorbance change, and bleeding time, EEGP600 and EEGP3000 produced a comparable percentage of edema inhibition to that of Na-diclofenac, which was not found in EEGP100. Also, EEGP600 and EEGP3000, but not EEGP100, inhibited platelet aggregation as effective as aspirin (positive control). In conclusion, if administered at 600 and 3000 mg/kg BW, the ethanolic extract of Graptophyllum pictum can function as an anti-inflammatory agent that inhibits platelet aggregation.

Cytotoxicity, anti-platelet aggregation assay and chemical components analysis of thirty-eight kinds of essential oils

Thirty-eight essential oils (EOs), including 4 products from Taiwan high-latitude trees, Chamaecyparis formosensis, Taiwania crypyomerioides, Cryptomeria japonica, and Chamaecyparis obtuse, as well as 34 commercial essential oils, were assayed on their cytotoxicity against 5 cancer cell lines and anti-platelet aggregation function.Two EOs from Juniperus virginiana and Santalum album showed significant cytotoxicity. Moreover, 2 EOs from Melissa officinalis and Piper nigrum exhibited moderate inhibitory effects on an anti-platelet aggregation assay. Some essential oils had been reported to contain cytotoxicity. However, the cytotoxicity of EOs from J. virginiana and S. album is revealed for the first time. To the best of our knowledge, this is the first report for anti-platelet aggregation effect of EOs.

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.

Development and activity evaluation of Arg-Gly-Asp-containing antithrombotic conjugate

Poly-α,β-D,L-aspartic acid (PD) is highly susceptible to the degradation of lysosomal enzyme and produce monomeric aspartic acid as the product. Exogenous RGD-containing sequences could inhibit platelet aggregation and formation of thrombosis by competitively binding to activated platelet membrane GPIIb/IIIa receptors. Poly-α,β-D,L-aspartyl-Arg-Gly-Asp-Ser (PD-RGDS) was synthesized by conjugating anti-thrombotic RGDS to the highly biodegradable poly-α,β-D,L-aspartic acid molecules (PD) and its structure was confirmed. PD-RGDS existed as the nanoparticles of 60–108 nm at 10−6 M by TEM and SEM. In vitro anti-platelet aggregation assay showed that PD-RGDS could preferentially inhibit platelet aggregation induced by PAF (IC50 33.5 nM). In vivo antithrombotic activity of PD-RGDS was evaluated with a rat model of carotid artery and venous bypass cannulation. PD-RGDS had increased antithrombotic activity (1 nmol/kg by ig.) compared with RGDS(5 μmol/kg). Furthermore, to measure blood concentration of PD-RGDS in rats, FITC-PD-RGDS was prepared and had an elimination half-life of 240.3 ± 49.6 min by intragastric administration of 50 mg/kg. Therefore PD-RGDS could be built as a novel oral antithrombotic agent.

In Vivo antiplatelet activity aggregation assay of bromelain fractionate by ethanol from extract pineapple core (Ananas comosus [l.] merr.)

Processed fruit from pineapple is one of largest commodities tropical fruit production in Indonesia and will bring the waste from the skin and core. This study aims to isolate bromelain from the pineapple core (Ananas comusus) are purified by fractionation using ethanol and continued by activity test as an antiplatelets agent by in vivo method using white mice male ddy type with acetosal as positive control. Fractionation of crude enzyme bromelain with ethanol produces highest specific activity on ethanol 30-60% fraction (fraction 2) 3.107 Unit/mg and the protein content 61.25 mg with the degree of purity of 155 times compared to crude enzyme. Antiplatelet aggregation tests from in vivo method shows that faction of bromelain with doses 70 μg/KgBW, 140 μg/KgBW, and 210 μg/KgBW can increase a meaningful bleeding time. The highest percentage of increase shown by the isolate at a dose of 210 μg/KgBW in the amount of 515.10 ± 182.23%, when compared to aspirin (231.20 ± 140.66), the value is relatively higher.

Localisation of Two Bioactive Labdane Diterpenoids in the Peltate Glandular Trichomes of Leonurus japonicus by Laser Microdissection Coupled with UPLC-MS/MS.

Glandular trichomes of plants are biochemical factories that could produce, store and secrete copious pharmaceutically important natural products. The Labiatae plant Leonurus japonicus is an important traditional Chinese medicine used to treat gynecological diseases, and has abundant peltate glandular trichomes (PGTs), in which the secondary metabolites accumulated are still unknown. To study the secondary metabolites specifically accumulated in the PGTs of L. japonicus and their biological activities, and provide a new way to pinpoint bioactive natural products from plants. Morphology of the trichomes on L. japonicus were observed under a scanning electron microscope. The PGTs of L. japonicus were precisely collected using laser microdissection (LMD) and analysed for their secondary metabolites with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Targeted compounds were isolated with classical phytochemical methods, and their structures were elucidated by spectroscopic analysis. Biological activities were evaluated by in vitro assays. Two labdane diterpenoids, leoheterin (1) and galeopsin (2), were localised in the PGTs of L. japonicus. Antithrombotic activity of 1 in anti-platelet aggregation assay induced by arachidonic acid was observed. Both compounds showed potential anti-inflammatory activity by inhibiting proinflammatory cytokine TNF-α. In addition, anti-proliferative effect of both compounds on several cancer cell lines was also detected. Two bioactive labdane diterpenoids were localised in the PGTs of L. japonicus. The findings suggested that it might be an efficient approach to explore bioactive natural products from the glandular trichomes of medicinal plants with LMD-UPLC/MS/MS. Copyright © 2017 John Wiley & Sons, Ltd.

A Standardized Composition Comprised of Extracts from Rosmarinus officinalis, Annona squamosa and Zanthoxylum clava-herculis for Cellulite.

Background:Cellulite, characterized by changes in the skin morphology presented as dimpled or puckered skin appearance, is highly prevalent among postadolescent women. Cellulite management ranges from topical cream applications to invasive procedures. While some interventions showed improvements in physical appearances of affected areas, so far, none have reversed the condition to a full recovery. These unsuccessful measures signify the intricate nature of cellulite etiology highlighting its complexity leading to the possibility for a combination treatment approach to target multiple mechanisms.Materials and Methods:We screened our plant library for extracts that reduce cellular lipid accumulation, improve microcirculation, possess high total antioxidant capacity, significant anti-platelet aggregation, and anti-inflammatory activities using lipid accumulation assay in 3T3-L1 cells, Croton oil-induced hemorrhoid test in rats as a model for microcirculation, anti-platelet aggregation assay, nitric oxide (NO) inhibition assay, and 1,1-diphenyl-2-picrylhydrazyl assay.Results:Three known botanicals such as Rosemary officinalis, Annona squamosa and Zanthoxylum clava-herculis were identified as lead extracts in these tests. Treatment of 3T3 cell with A. squamosa at 1 μg/ml resulted in 68.8% reduction in lipid accumulation. In croton oil-induced hemorrhoid study, Z. clava-herculis reduced the recto-anus coefficient by 79.6% at 6 mg/kg indicating improvement in microcirculations. Similarly, R. officinalis caused inhibition of 82%, 71.8%, and 91.8% in platelet aggregation, NO production and free radical generation at 31.25 μg/ml, 6.2 μg/ml, and 40 μg/ml concentrations suggesting its anti-oxidant, and anti-inflammatory activities.Conclusions:Data depicted here suggest that formulation of these well-known botanicals at a specific ratio perhaps may yield a composition with a much wider spectrum of mechanisms of actions to impact the multiple pathways involved in cellulite onset, continuation, or exacerbations.SUMMARY Cellulite represents one of the main esthetic concerns of women with a likely cause of psychological insecurities. Its pathophysiology involves multiple pathways that include vascular, adipose tissues, inflammation, structural and physiological.Treatment strategies for cellulite comprises increasing microcirculation flow, reducing lipogenesis, promoting lipolysis, free radicals scavenging or formation reduction, anti-inflammation and other invasive procedures.We screened our plant library for extracts that reduces cellular lipid accumulation, improves microcirculation, possesses high total antioxidant capacity, inhibits platelet aggregation, and moderates inflammation.Botanical extracts from Rosmarinus officinalis, Annona squamosa and Zanthoxylum clava-herculis were identified as leads and formulated to yield a standardized composition designated as UP1307 and suggested its usage for cellulite. Abbreviations Used: GMP: Good Manufacturing Practice; CA: Carnosic acid; NF-kB: nuclear factor-kB; HPLC: high-performance liquid chromatography; EtOH: Ethanol; DMEM: Dulbecco's modified Eagle's medium; FBS: fetal bovine serum; SD: Sprague Dawley; RAC: recto-anus coefficient; LPS: Lipopolysaccharide; DPPH: 1,1-diphenyl-2-picryl-hydrazyl; TNF-α: tumor necrosis factor; NO: Nitric oxide

우엉 뿌리의 항혈전 및 항산화 활성

To investigate anti-thrombosis and anti-oxidation activities of the root of Arctium lappa L (RALL), which has been used as foodstuff and oriental medicine in Korea, the ethanol extract and its subsequent organic solvent fractions of the RALL were prepared. The yield of ethanol extraction was 10.94%, and the content of total polyphenol and total sugar of ethanol extract were 5.01 and 694.53 mg/g, respectively. The fraction yields of n-hexane, ethylacetate (EA), butanol and water residue were 1.62, 0.42, 5.98 and 85.38%, respectively. In anticoagulation activity assay, the ethanol extract of RALL did not show significant changes in thrombin time (TT), prothrombin time (PT) and activated partial thromboplastin time (aPTT), whereas the EA fractions showed 13 folds extended TT, PT, and aPTT respectively. Interestingly, the water residue showed strong activation effect against blood clotting factors with shortened aPTT, which might provide the evidence of coagulation agent of RALL in folk remedy. In anti-platelet aggregation assay, the activity of the ethanol extract and its fractions were comparable to that of aspirin. Especially the EA fraction showed 2-folds higher inhibitory activity than aspirin. In anti-oxidation activity assay, the EA fraction also showed strong in DPPH, ABTS and nitrite scavenging activity, and reducing power activity. The extract and fractions of RALL have ignorable hemolytic activity against human RBC up to 0.5 mg/mL concentration. Our results suggest that the EA fraction of RALL have potentials as safe and novel anti-thrombosis agent.

Anti-platelet aggregation assay and chemical composition of essential oil from Allium atroviolaceum Boiss growing in Iran

Plants belonging to genera Allium have widely been acquired as food and medicine. Their wide use was mainly due to the medicinal properties attributed to these plants over the centuries, lately supported by epidemiological and research studies. In this study, essential oil constituents of Allium atroviolaceum growing in Shahr-e-kord, Iran, were investigated through gas chromatography/mass spectrometry (GC-MS) technique. In this essential oil two major constituents were trisulfide, di-2-propenyl (26.85%) and diallyl disulphide (10.98%) while trans-2-(2- pentenyl) furan (0.02%) and Limonene (0.06%) have been identified in lower amounts. The in-vitro antiplatelet activity of essential oil was evaluated, using arachidonic acid (AA) and adenosine diphosphate (ADP) as the platelet aggregation inducers. The results showed that essential oil of Allium atroviolaceum with IC50; 0.25 mg/ml and 0.47 mg/ml inhibited in-vitro platelet aggregation induced by AA and ADP respectively.

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.

Antiplatelet Aggregation Effects of Phenanthrenes from Calanthe arisanensis

Three phenanthrenes (1-3), four indole alkaloids (4-7) and one steroid (8) were isolated from the leaves of Calanthe arisanensis for the first time. In the antiplatelet aggregation assay, phenanthrenes 1 and 2 showed potential antiplatelet activity. We have reported and discussed here the antiplatelet aggregation properties of the eleven naturally-occurring phenanthrenes (1-2 and 9-17) isolated from the underground part of the plant and eighteen chemically synthesized phenanthrenes (18-35). Overall, our data demonstrated that 1,4-phenanthrenequinones 20, 21 and 22 (collagen, IC50 0.2, 0.2, 0.1 microg/mL; thrombin, IC50 0.8, 1.0, 1.1 microg/mL, respectively) could be promising lead candidates for further cardiovascular disease studies.

Nanosized Aspirin-Arg-Gly-Asp-Val: Delivery of Aspirin to Thrombus by the Target Carrier Arg-Gly-Asp-Val Tetrapeptide

Resistance and nonresponse to aspirin dramatically decreases its therapeutic efficacy. To overcome this issue, a small-molecule thrombus-targeting drug delivery system, aspirin-Arg-Gly-Asp-Val (A-RGDV), is developed by covalently linking Arg-Gly-Asp-Val tetrapeptide with aspirin. The 2D ROESY NMR and ESI-MS spectra support a molecular model of an A-RGDV tetramer. Transmission electron microscopy images suggest that the tetramer spontaneously assembles to nanoparticles (ranging from 5 to 50 nm in diameter) in water. Scanning electron microscopy images and atomic force microscopy images indicate that the smaller nanoparticles of A-RGDV further assemble to bigger particles that are stable in rat blood. The delivery investigation implies that in rat blood A-RGDV is able to keep its molecular integrity, while in a thrombus it releases aspirin. The in vitro antiplatelet aggregation assay suggests that A-RGDV selectively inhibits arachidonic acid induced platelet aggregation. The mechanisms of action probably include releasing aspirin, modifying cyclic oxidase, and decreasing the expression of GPIIb/IIIa. The in vivo assay demonstrates that the effective antithrombotic dose of A-RGDV is 16700-fold lower than the nonresponsive dose of aspirin.

The oestrogenic and anti-platelet activities of dihydrobenzofuroisocoumarins and homoisoflavonoids from Liriope platyphylla roots

The ethanolic extract of Liriope platyphylla (Liliaceae) roots showed potential oestrogenic and anti-platelet activities. Twenty-six compounds were isolated and classified as 10 skeletons, including two unusual new dihydrobenzofuroisocoumarins, (+)-platyphyllarin A (1) and B (2), one new butanoate, ethyltributanoate (3), and two new homoisoflavanones, (−)-liriopein A (4) and B (5), along with 21 known compounds, including six homoisoflavonoids, one chalcone, six amides, one lignan, one fatty acid derivative, one alkaloid, three benzenoids, and two steroids. The biosynthetic pathway of compounds 1 and 2 was proposed in the current investigation. The oestrogenic activity of the isolates was evaluated utilising the pER8:GUS reporter assay system in transgenic Arabidopsis plant as well as the SEAP reporter assay system in MCF-7 breast cancer cell-line; the anti-platelet activity was evaluated using the anti-platelet aggregation assay. Several components exhibited significant oestrogenic and anti-platelet activities; demonstrating for the first time the potential use of L. platyphylla as a nutritional supplement for cardiovascular and endocrine diseases.

Novel Cu(II)-RGD-octapeptides: Synthesis, coordination mode, in vitro anti-platelet aggregation/in vivo anti-thrombotic evaluation and correlation of sequence with nano-structure

The synthesis, bioassays and nano-structure characterization of Cu(II)-RGD-octapeptide complexes Cu(II)-Arg-Gly-Asp-Ser-Arg-Gly-Asp-Ser [Cu(II)-4a], Cu(II)-Arg-Gly-Asp-Val-Arg-Gly-Asp-Val [Cu(II)-4b] and Cu(II)-Arg-Gly-Asp-Phe-Arg-Gly-Asp-Phe [Cu(II)-4c] were investigated. UV-vis, CD and CD/ESI-MS spectra suggested that the coordination of Cu(II)-4a-c met a 3 N mode. In the in vitro anti-platelet aggregation assay the IC50 values of Cu(II)-RGD-octapeptide complexes were 10 − 110 folds lower than that of RGD-octapeptides. In the in vivo anti-thrombotic assay the effective dose of Cu(II)-RGD-octapeptide complexes was 5000 folds lower than that of RGD-octapeptides. In transmission electron microscopy measurement Cu(II)-4a-c offered distinct nano-images. The effect of the sequence on the in vitro anti-platelet aggregation/in vivo anti-thrombotic activity and the nano-structure of Cu(II)-4a-c was discussed. From the Clinical EditorThis basic science paper discusses the synthesis, coordination mode, in vitro anti-platelet aggregation and in vivo anti-thrombotic evaluation of novel Cu(II)-RGD-octapeptides.

2-Substituted (S)-2-(3,3-dimethyl-1-oxo-10,10a-dihydroimidazo[1,5-b]isoquinolin-2(1H,3H,5H)-yl)acetic acids: Conformational prediction, synthesis, anti-thrombotic and vasodilative evaluation

(S)-1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid (TIC) can inhibit thrombosis by inhibiting platelet aggregation. The investigation of amino acids modified TIC reveals that a stretching conformation is critical for high anti-thrombotic activity. The conformational modeling shows that introducing a ring into amino acid modified TIC results in a desirable stretching conformation. According to this hypothesis, we synthesized seventeen novel 2-substituted (S)-2-(3,3-dimethyl-1-oxo-10,10a-dihydroimidazo[1,5-b]isoquinolin-2(1H,3H,5H)-yl)acetic acids (5a-q). In the in vitro anti-platelet aggregation assay, for ADP-induced platelet aggregation the IC(50) values of 5a-q are 1.8-3.4-folds lower than that of TIC. In the in vivo anti-thrombotic assay, the effective dose of 5a-q was 167-folds lower than that of TIC. The vessel strip assay showed that 5a-q had mild vasorelaxation activity.

The synthesis and biologic evaluation of anti-platelet and cytotoxic β-nitrostyrenes

Our previous studies demonstrated that two cytotoxic β-nitrostyrene derivatives, 3,4-methylenedioxy-β-nitrostyrene (MNS) and 4- O-benzoyl-3-methoxy-β-nitrostyrene (BMNS) exhibit potent anti-platelet activities. In this study, a series of β-nitrostyrenes were synthesized and subjected to anti-platelet aggregation assay and cytotoxicity assay. The mono- and di-substitutions on the B ring of BMNS tended to increase the anti-platelet activity and decrease the cytotoxic activity. Of these, compounds 19 and 24 exhibited the most potent inhibitory effects on thrombin- and collagen-induced platelet aggregation (IC 50 ⩽ 0.7 μM) without significant cytotoxicity on a human cancer cell line (up to 20 μM). Further studies indicated that compounds 19 and 24 inhibited platelet aggregation via prevention of glycoprotein IIb/IIIa activation. The potent and novel effects of BMNS derivatives make them attractive candidates for the development of new anti-platelet agents.