Snake venom proteins,particularly from the viper and elapid families, have been known to contain a number of platelet active components including what cause platelet aggregation or inhibit platelet aggregation. Some of them have potential clinical usefulness for the treatment of human hemorrhagic or thrombotic disease. Agkistrodon halys pallas belonging to viper family is only growing in China. The aim of this study was to purify a human platelet aggregation inhibitor from venom of Agkistrodon halys pallas and determine its biochemical character. Whether a component could inhibit human platelet aggregation was act as a method to follow the tracks of the protein. Crude venom of Agkistrodon halys pallas was loaded onto a DEAE-Sepharose CL-6B chromatography column could gain 6 peaks. A platelet inhibitor with molecular mass of 65 kD on SDS-PAGE, was purified from peak 2 by Sephadex G-75 gel filtration and SP-Sepharose, Mono Q on FPLC. It could inhibit human platelet aggregation induced by ADP, collagen without activities of phospholipase A2, esterase, fibrinogenolytic. It is concluded that a platelet inhibitor can be isolated and purified from venom of Agkistrodon halys pallas and its inhibition of platelet aggregation is does-dependent.
Crotalid Venoms ; analysis ; Humans ; Oligopeptides ; chemistry ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; isolation & purification

Chemical constituents of Leonurus japonicus were isolated and purified by a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, MCI, and Rp C18. Structures of the isolates were determined by spectroscopic analysis as 10 coumarins: bergapten (1), xanthotoxin (2), isopimpinellin (3), isogosferal (4), imperatorin (5), meransin hydrate(6), isomeranzin(7), murrayone(8) , auraptenol(9), and osthol(10). In addition to compound 9, the others were isolated from the genus Leonurus for the first time. In the in vitro assay, compounds 4 and 8 significantly inhibited the abnormal increase of platelet aggregation induced by ADP.
Blood Platelets ; drug effects ; Coumarins ; chemistry ; pharmacology ; Leonurus ; chemistry ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; chemistry ; pharmacology

BACKGROUND: Resveratrol has been shown to inhibit platelet aggregation. However, the mechanism for this action of resveratrol remains to be clarified. The purpose of this study was to elucidate the Ca METHODS: Ca RESULTS: Thapsigargin-induced Ca CONCLUSIONS The results suggest that resveratrol inhibits thrombin-induced platelet aggregation through decreasing Ca
Antioxidants/administration & dosage* ; Calcium/physiology* ; Humans ; Platelet Aggregation/drug effects* ; Platelet Aggregation Inhibitors/pharmacology* ; Resveratrol/pharmacology* ; Signal Transduction/drug effects*

The purpose of study was to investigate the effects of L-arginine and cilostazol on platelet-activation and aggregation reserve in vitro, so as to provide proof for selecting reversible activation-inhibitors for platelets lyophilization. Activation and function of platelets were investigated by using flow cytometry with the CD62p and PAC-1 expression and re-expression after being activated by thrombin, and by means of platelet aggregation reaction to thrombin, ADP and propyl gallate, as well as coagulation activity of platelets. The results showed that expression of CD62p and PAC-1 increased after being pretreated. Both L-arginie and cilostazol could inhibit CD62p and PAC-1 expression and related with their concentrations. Cilostazol had an intensive inhibition effect on expressions of CD62p and PAC-1 induced by thrombin, and the inhibition increased when concentration augmented. L-arginine had the same effects on PAC-1, but had no effects on CD62p. L-arginine and cilostazol inhibited aggregation induced by thrombin, ADP and propyl gallate, and the inhibitions were related directly with dosage. When L-arginine concentration was higher or equal to 15 mmol/L, or cilostazol concentration was in range of 1 - 4 mmol/L, the aggregation time were prolonged so much or even no aggregation. It is concluded that when L-Arginine concentration is 5 mmol/L and 10 mmol/L, platelet activation can be inhibited, but aggregation ability and characters keep intact. Concentration at 5 mmol/L may be the best. 1 mmol/L of cilostazol can inhibit activation in vitro and retain part of platelet ability of aggregation and reexpression.
Arginine ; pharmacology ; Blood Platelets ; metabolism ; Humans ; P-Selectin ; drug effects ; metabolism ; Platelet Activation ; drug effects ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Tetrazoles ; pharmacology

This study was aimed to investigate the inhibiting effects of adenosine on platelet in vitro in order to select functional protectants for platelets before lyophilization. Platelet membrane surface CD62P expression was assayed by flow cytometer (FCM). Platelet aggregations induced by restocetin, thrombin, ADP and propyl gallate were detected by APACT-2. The results showed that platelets membrane surface CD62P expression increased significantly after pre-treating of freeze-drying. 0.75 mmol/L adenosine could inhibit CD62P expression in a dose-dependent manner. Adenosine could inhibit platelet aggregation induced by propyl gallate, but no action on restocetin. When adenosine concentration was 1.0 mmol/L or higher, the aggregation induced by thrombin was significantly restrained. When concentration of adenosine was 0.75 mmol/L, platelet activation resulted from retreating could be inhibited and platelet aggregation induced by restocetin and thrombin were not affected markedly. It is concluded that adenosine can be one of the functional protectants and activation inhibitors in vitro for platelet cryo-preservation.
Adenosine ; pharmacology ; Blood Platelets ; drug effects ; metabolism ; Blood Preservation ; Cryopreservation ; Flow Cytometry ; Humans ; P-Selectin ; analysis ; Platelet Activation ; drug effects ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology

Abstract: Fifteen novel ligustrazine-tetrahydroisoquinoline derivatives were designed and synthesized according to the association principle of pharmaceutical chemistry. The structures were identified by IR, NMR and ESI-MS. The inhibitory activities of platelet aggregation induced by ADP and AA have been measured by Bron method. Preliminary pharmacological results showed that compounds 7g, 7h and 7n had potent inhibitory activity against platelet aggregation induced by AA, and the compound 7o showed significant inhibitory activity against platelet aggregation induced by ADP.
Drug Design ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; chemical synthesis ; chemistry ; Pyrazines ; chemical synthesis ; chemistry ; Tetrahydroisoquinolines ; chemical synthesis ; chemistry

This study was aimed to explore the change of aggregation and activation of platelets loaded with epigallocatechin gallate (EGCG). The platelets were treated by loading buffer with different concentrations of EGCG (0, 2.5, 5, 7.5, 10, 12.5, 15, 20 and 30 mmol/L) and were divided into 2.5, 5, 10 mmol/L groups and control group. The physiological and biochemical functions of platelets were observed, including recovery rate, aggregation and activation of platelets. The platelet counts were determined by Counter Cell-DYN 1200. The aggregation activities were tested through turbidimetry, the platelet apoptosis was detected by flow cytometry. The results showed that the concentrations of EGCG loading in platelets of 2.5, 5 and 10 mmol/L groups were 0.4006 ± 0.12, 1.0527 ± 0.1503, 1.6902 ± 0.1112 mmol/L respectively. Along with the increasing of EGCG concentrations in loading-buffer, the EGCG absorbed by platelets increased too. When the concentration of EGCG in loading-buffer exceeded 15 mmol/L, the EGCG absorbed by platelets did not increase. The recovery rate in 2.5 mmol/L loading buffer group was 82.45 ± 0.360% which was lower than that in control group (90.33 ± 1.115%) (p < 0.05). As compared with control group, the recovery rate in 5 mmol/L loading buffer group (57.51 ± 2.468)% and 10 mmol/L loading buffer group (47.45 ± 2.030)% were even significantly lower (p < 0.01). When ADP was used as the inducer, the maximal aggregation rate (MAR) in control group was (63.6 ± 4.037)%, which was higher than that in other EGCG-loading groups (p < 0.01). And the aggregation activity of platelets negatively correlated with the concentration of EGCG in loading-buffer. When THR was used as the inducer, the MAR in control group was (89.3 ± 6.533)% and higher than that those in other groups (p < 0.05), especially in groups with loading-buffer higher than 10 mmol/L EGCG (70.1 ± 5.400%) (p < 0.01). In the experiment of cellular apoptosis, the early apoptosis easy appeared in platelets loaded with EGCG. It is concluded that the EGCG loading in platelets markedly influences the physiological and biochemical functions of platelets, the apoptosis easy occurs in platelets loaded with EGCG. The EGCG accelerates the course of platelet apoptosis.
Apoptosis ; drug effects ; Blood Platelets ; drug effects ; Catechin ; analogs & derivatives ; pharmacology ; Flow Cytometry ; Humans ; Platelet Aggregation ; drug effects ; Platelet Count

OBJECTIVETo explore the anti-platelet activation effect and partial mechanisms of Taohong Siwu decoction (TSD).

METHODThe effect to venous thrombosis model and pulmonary thromboembolism model induced by vein injecting ADP and Adr was observed. The platelet adhesion rate was analyzed by using spinning glass bottle, and the platelet aggregation rate induced by ADP, Adr was analyzed by using turbidimetry. The acute blood stasis rat model was established to analyze the content of plasm TXB2 and PGI2 by RIA, and the content of VWF, GMP-14 by ELISA.

RESULTTSD could effectively reduce platelet the adhesion rate of normal rat, inhibit the platelet aggregation of normal rat induced by ADP, Adr. It significantly reduced the plasma TXB2 VWF, and GMP-140 level of blood stasis rats. It also had significant tendency to increase 6-keto-PGF1alpha level.

CONCLUSIONTSD possessed obvious activity of inhibiting platelet activation. The mechanism related with the restraining of platelet adhesion, platelet aggregation and platelet releasion.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Female ; Male ; Medicine, Chinese Traditional ; Platelet Activation ; drug effects ; Platelet Aggregation ; drug effects ; Rats

The aim of study was to evaluate the function of modified platelet additive solution (PAS-IIIM) with trehalose as a substitute of plasma for the storage of platelet concentrates at low temperature (10 degrees C). Apheresis platelets from 6 donors were divided and added with different media (group A: 100% plasma; group B: 70% PAS-IIIM/30% plasma; group C: 100% plasma/trehalose). Groups A, B, C were stored at 10 degrees C, 22 degrees C and -85 degrees C separately. In addition, group D (platelet concentrates stored with 100% plasma at 4 degrees C) was set up as control group for scan electronmicroscopy. The samples of each platelets were collected on day 0, 1, 5, 7 and 9 after storage respectively, while samples of platelets stored at -85 degrees C (group C) were collected on day 20 after storage. CD62p, hypotonic shock response (HSR), platelet aggregation, lactic dehydrogenase (LDH) and morphology of platelets were evaluated. The results showed that the expressions of CD62p in groups A and B increased in a time-dependent manner, but HSR and platelet aggregations decreased. The expression of CD62p, LDH release, and platelet aggregation in group A were significant higher than that in group B (p < 0.05). HSR in group A was significant lower than that in group B (p < 0.05). LDH release was significant high in samples of group C and the expression of CD62p was lower than that in other two groups (p < 0.05). It is concluded that the protective effects of 70% PAS-IIIM/30% plasma (10 degrees C) and plasma platelets (22 degrees C) on morphology of platelets are similar, but better than those of plasma platelets (4 degrees C) and plasma/trehalose (-85 degrees C). In short, PAS-IIIM serves as a good substitute of plasma for platelet storage, and protects the chilled platelets.
Blood Platelets ; drug effects ; Blood Preservation ; methods ; Cold Temperature ; Humans ; Pharmaceutical Solutions ; pharmacology ; Platelet Aggregation ; Platelet Count ; Platelet Transfusion

Berbamine (molecular formular C37H40N2O6) is a bi-benzle-isoquinolyl alkaloid extracted from Berberis poiretil Schneid (genus of Berberis, family of Beridaceae), a kind of Chinese plants. In aspect of cardiovascular pharmacology, berbamine shows actions of anti-arrhythmia, anti-myocardial ischemia, vasodilatating to lower blood pressure, and antithrombosis, it could lower heart function and heart rate. Study on its anti-arrhythmia was the deepest one. The significant anti-arrhythmia action can be achieved by inhibiting ionic channels of sodium, potassium, calcium, etc., negative frequency and negative transduction, improving the diastolic excitation threshold of myocardium, prolonging effective refractory period of myocardium. As a direction of researches on new type of antiarrhythmic herbs and herbal drugs, the study on berbamine is worthy of further research and development.
Alkaloids ; pharmacology ; Anti-Arrhythmia Agents ; pharmacology ; Antihypertensive Agents ; pharmacology ; Benzylisoquinolines ; pharmacology ; Heart Rate ; drug effects ; Ion Channel Gating ; drug effects ; Platelet Aggregation ; Platelet Aggregation Inhibitors ; pharmacology