• Biomolecules & Therapeutics
• /
• v.19 no.4
• /
• pp.460-465
• /
• 2011

The present study was undertaken to investigate the influence of quercetin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Quercetin at a low concentration (0.01-0.03 mM) directly and more significantly relaxed fluoride or thromboxane $A_2$-induced vascular contraction than phorbol ester-induced contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, quercetin more significantly inhibited thromboxane $A_2$-induced increases in pMYPT1 levels than phorbol ester-induced increases. It also more significantly inhibited thromboxane $A_2$-induced increases in pMYPT1 levels than pERK1/2 levels suggesting the mechanism involving the primarily inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1. This study provides evidence regarding the mechanism underlying the relaxation effect of quercetin on agonist-induced vascular contraction regardless of endothelial function.

• The Korea Journal of Herbology
• /
• v.26 no.4
• /
• pp.125-132
• /
• 2011

Objectives : An aim of study is to investigate effects of curculiginis rhizoma in vitro (factor Xa (FXa) inhibitor assay, prothrombinase assay, prothrombin time (PT) assay, activated partial thromboplastin time (aPTT) assay) and in vivo experiment (blood clotting time, thromboxane B2 content assay in serum and weight of thrombus by AV-shunt rat model). Methods : We gained a human serum and used serum in vitro study such as factor X activity (FXa) inhibition, prothrombinase inhibition, prothrombin time (PT) and activated partial thromboplastin time. Fifteen SD rats were divided into three groups (intact control group and two experimental group treated with extract of Curculiginis Rhizoma(ECR)). Rats were orally administrated DW (intact control group), 600 mg/kg concertration of ECR and 200 mg/kg concertration of ECR. After one hour, we anesthetized rats and made arteriovenous (AV) shunt rat models to study weights of thrombus, took a hole blood to study content of thromboxane B2 and blood clotting time. Results : In vitro, ECR increased a inhibitory activity of FXa, prothrombinase and aPTT compared than intact control group. Especially ECR made significant increase of FXa and prothrombinase inhibitory activity (p<0.05, p<0.01). And PT were increased in ECR control group compared with intact control group. In vivo, a blood clotting time of experiment group treated with ECR 600 mg/kg were significantly increased compared with that of intact control group (p<0.05) and content of thromboxane B2 was significantly decreased in group treated with ECR 600 mg/kg in seum. The weight of thrombus were significantly reduced in group treated with ECR 600 mg/kg compared with intact control group (p<0.05). But in vivo experiment study, those of group treated with ECR 200 mg/kg were reduced compared with those of intact control group without statistical significance. Conclusions : ECR has a antithromboic activity in internal course with inhibitory activity of FXa and prothrombinase in vitro, it required to research more study for effective compounds.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.110.3-111
• /
• 2003

In the previous studies, we have reported that NQ30l, a synthetic l,4-naphthoquinone derivative, displayed a potent antithrombotic activity, and that this might be due to antiplatelet effect, which was mediated by inhibition of cytosolic $Ca^{2+}$ mobilization in activated platelets. In the present study, the effect of NQ301 on arachidonic acid cascade in activated platlets was examined. NQ301 concentration-dependently inhibited washed rabbit platelet aggregation induced by collagen (10 $\mu$g/ml), arachidonic acid (100 $\mu$M) and U46619 (1 $\mu$M), a thromboxane $A_2$receptor agonist, with $IC_50$ values of 0.60$\pm$0.02, 0.79$\pm$0.04 and 0.58$\pm$0.04 $\mu$M, respectively. (omitted)

• Korean Journal of Oriental Medicine
• /
• v.13 no.2 s.20
• /
• pp.143-148
• /
• 2007

The present study examined inhibitory effects of 20 efficient experience prescriptions on platelet aggregation induced by collagen in human whole blood using the impedance method of aggregometry. Among them, a hot water extract of KIOM 2003-080 was selected to be the most effective candidate. In an in vivo study using a mouse acute thrombosis model, the anti-thrombotic effects of the KIOM2003-080 crude extract were also observed. In addition, we accessed bio-marker of platelet activation using thromboxane B2 by ELISA assay. A significantly decrease in thromboxane B2 production was seen in the presence of KIOM2003-080. Consequently, the results from this experiment provide pharmacological evidence for the traditional use of KIOM2003-080 prescription, suggesting that its hot water extracts could be used to prevent platelet aggregation and thrombosis disease.

• YAKHAK HOEJI
• /
• v.50 no.4
• /
• pp.293-299
• /
• 2006

The aim of present study was to investigate the possible influence of Rho-kinase inhibition on the plant-derived estrogen-like compounds-induced arterial relaxation. Agonist- or depolarization-induced vascular smooth muscle contractions involve the activation of Rho-kinase pathway. However there are no reports addressing the question whether this pathway is involved in genistein-or daidzein-induced vascular relaxation in rat aortae precontracted with phenylephrine or thromboxane $A_2$ mimetic U-46619. We hypothesized that Rho-kinase inhibition plays a role in vascular relaxation evoked by genistein or daidzein in rat aortae. Endothelium-intact and denuded arterial rings from male Sprague-Dawley rats were used and isometric contractions were recorded using a computerized data acquisition system. Genistein concentration-dependently inhibited phenylephrine or thromboxane $A_2-induced$ contraction regardless of endothelial function. Surprisingly, in the agonists-induced contraction, similar results were also observed in aortae treated with daidzein, the inactive congener for protein tyrosine kinase inhibition, suggesting that Rho-kinase might act upstream of tyrosine kinases in phenylephrine-induced contraction. In conclusion, in the agonists-precontracted rat aortae, genistein and daidzein showed similar relaxant response regardless of tyrosine kinase inhibition or endothelial function.

• The Korea Journal of Herbology
• /
• v.26 no.4
• /
• pp.139-147
• /
• 2011

Objectives : The aim of this study is to research an anti-thrombus effect by Diospyros Kaki Calyx. Methods : The healthy human plasma were gained and used in vitro study such as factor X activity (FXa) inhibition, prothrombinase inhibition, prothrombin time (PT) and activated partial thromboplastin time. Fifteen SD rats were divided into three groups ; intact control group (orally administrated with distilled water 5ml/kg) and two experimental group treated with extract of diospyros kaki calyx (EKC). Experimental rats were orally 600 mg/kg concentration of EKC and 200 mg/kg concentration of EKC. After an hour from administration, we anesthetized rats and made arteriovenous (AV) shunt rat models to study weight of thrombus, took whole blood to study content of thromboxane B2 and blood clotting time. Results : In vitro, EKC significantly increased inhibitory activity of FXa, prothrombinase compared with intact control group ($^*P$ <0.05). PT and aPTT were increased in EKC treated (600 mg/kg) group compared with intact control group ($^*P$ <0.05). In vivo, blood clotting time of experiment group treated with EKC 600 mg/kg were significantly increased compare with that of intact control group (p<0.05) and content of thromboxane B2 was significantly decreased in group treated with EKC 600 mg/kg in serum. The weight of thrombus were significantly reduced in group treated with EKC 600 mg/kg compared with intact control group (p<0.05). But in vivo experiment study, those parameters of group treated with EKC 200 mg/kg were relatively decreased compared with those of intact control group without statistical significance. Conclusions : EKC has an antithrombic activity because of inhibition internal course such as FXa and prothrombin. And EKC inhibited a hole blood clotting in vivo experiment by low content of thromboxane B2.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.11 no.1
• /
• pp.187-202
• /
• 1989

This study was undertaken to investigate the effect of indomethacin on prostaglandins in 4-Nitroquinoline-N-Oxide (4-NQO) induced palatal carcinoma of albino rats. 128 Sprague-Dawley strain albino rats-about 100g in body weight-were used in this study, divided into as belows; 1. Normal group (16-albino rats) with no treatment, 2. Control group (16-albino rats) treated with prophylene application onto palatal mucosa 3 times a week. 3. Experimental group I (48-albino rats) treated with 0.5% 4-NQO in prophylene application onto palatal mucosa 3 times a week. 4. Experimental group II (48-albino rats) treated with 0.5% 4-NQO in prophylene application with administered $20{\mu}g/ml$ of indomethacin in drinking water ad. lib. Four animals were sacrificed 7th, 13th, 19th, and 25th week respectively in normal and control group, and 7th, 9th, 11th, 13th, 15th, 17th, 19th, 21st, 23rd, 25th, 27th and 29th week respectively in experimental group I and II at each time. The palatal and lingual tissues were excised and kept frozen at $-70^{\circ}C$. Densitometer scan and Beta-counting counter were used for the thin layer chromatography of the arachidonic acid metabolites. The obtained results were as belows; 1. In normal and control group, there was little change of the arachidonic acid metabolites during experiment period, and the tissue homogenates included prostaglandin $D_2$, 6-keto-prostaglandin $F_{1{\alpha}}$, prostaglandin $E_2$, thromboxane $B_2$, prostaglandin $F_{2{\alpha}}$ in that order of relative abundances. 2. In experimental group I, prostaglandin $D_2$, and prostaglandin $E_2$ were increased, while 6-keto-prostaglandin $F_{1{\alpha}}$ and thromboxane $B_2$ were decreased in relative abundances of arachidonic acid metabolites. And there was little change in prostaglandin $F_{1{\alpha}}$ 3. In experimental group II, prostaglandin $D_2$, and prostaglandin $E_2$ were increased, while 6-keto-prostaglandin $F_{1{\alpha}}$ and thromboxane $B_2$ were decreased in relative abundances of arachidonic acid metabolites. And there was little change in prostaglandin $F_{2{\alpha}}$ also. 4. In the range of increase in prostaglandin $D_2$, and prostaglandin $E_2$, and that of decrease in 6-keto-prostaglandin $F_{1{\alpha}}$ and thromboxane $B_2$, in relative abundances, there was wider in experimental group I than in group II. 5. In the range of increase in prostaglandin $D_2$, and prostaglandin $E_2$, and that of decrease in 6-keto-prostaglandin $F_{1{\alpha}}$ and thromboxane $B_2$, in relative abundances, there was wider in palatal mucosa than in lingual mucosa in experimental group I and II.

• Journal of Ginseng Research
• /
• v.43 no.2
• /
• pp.236-241
• /
• 2019

Background: Thromboxane A2 ($TXA_2$) induces platelet aggregation and promotes thrombus formation. Although ginsenoside Ro (G-Ro) from Panax ginseng is known to exhibit a $Ca^{2+}-antagonistic$ antiplatelet effect, whether it inhibits $Ca^{2+}-dependent$ cytosolic phospholipase $A_2$ ($cPLA_{2{\alpha}}$) activity to prevent the release of arachidonic acid (AA), a $TXA_2$ precursor, is unknown. In this study, we attempted to identify the mechanism underlying G-Ro-mediated $TXA_2$ inhibition. Methods: We investigated whether G-Ro attenuates $TXA_2$ production and its associated molecules, such as cyclooxygenase-1 (COX-1), $TXA_2$ synthase (TXAS), $cPLA_{2{\alpha}}$, mitogen-activated protein kinases, and AA. To assay COX-1 and TXAS, we used microsomal fraction of platelets. Results: G-Ro reduced $TXA_2$ production by inhibiting AA release. It acted by decreasing the phosphorylation of $cPLA_{2{\alpha}}$, p38-mitogen-activated protein kinase, and c-Jun N-terminal kinase1, rather than by inhibiting COX-1 and TXAS in thrombin-activated human platelets. Conclusion: G-Ro inhibits AA release to attenuate $TXA_2$ production, which may counteract $TXA_2-associated$ thrombosis.

• Biomolecules & Therapeutics
• /
• v.7 no.3
• /
• pp.227-233
• /
• 1999

The effects of 2-bromo-3-(3,5-tert-butyl-4-hydroxylphenyl)-1,4-naphthalenedione(TPN2), a synthetic vitamin K derivative, on platelet aggregation and its action mechanisms were investigated in rat platelet. TPN2 inhibited the platelet aggregation induced by collagen($10\mu\textrm{g}$/ml), thrombin(0.1 U/ml), A23187($10\mu\textrm{M}$) and arachidonic acid($100\mu\textrm{M}$) in concentration-dependent manner with $IC_{50}$ values of 6.5$\pm$1.3, 59.3$\pm$4.5, 13.0$\pm$2.37 and 2.9$\pm$$1.0\mu\textrm{M}$, respectively. Collagen-induced serotonin release was significantly reduced by TPN2. The elevation of intracellular free $Ca^{2+}$ concentration ([$Ca^{2+}$]i) by collagen stimulation was greatly decreased by the pretreatment of TPN2, which was due to the inhibition of calcium release from intracellular store and influx from outside of the cell. TPN2 also significantly reduced the thromboxane $A_2$($TXA_2$) formation in a concentration-dependent manner. The collagen-induced arachidonic acid (AA) release in [$^3H$]-AA incorporated platelet, an indicative of the phospholipase $A_2$ activity, was decreased by TPN2 pretreatment. TPN2 significantly inhibited the activity of thromboxane synthase, but did not affect the cyclooxygenase activity. From these results. it is suggested that TPN2 exert its antiplatelet activity through the inhibition of the intra-cellular $Ca^{2+}$ mobilization and the decrease of the $TXA_2$ synthesis.

• YAKHAK HOEJI
• /
• v.58 no.5
• /
• pp.337-342
• /
• 2014

The present study was undertaken to investigate the influence of diosgenin on vascular smooth muscle contractility and to determine the mechanism involved. We hypothesized that diosgenin, the primary ingredient of Dioscorea villosa, plays a role in vascular relaxation through inhibition of Rho-kinase in rat aortae. Denuded arterial rings from male Sprague-Dawley rats were used and isometric tensions were recorded using a computerized data acquisition system. Interestingly, diosgenin inhibited fluoride-induced contraction but didn't inhibit phorbol ester-induced contraction suggesting that additional pathways different from endothelial nitric oxide synthesis such as inhibition of Rho-kinase might be involved in the vasorelaxation. Furthermore, diosgenin didn't inhibit thromboxane $A_2$-induced increases in pERK1/2 levels suggesting the mechanism excluding inhibition of thromboxane $A_2$-induced increases in ERK1/2 phosphorylation. This study provides evidence that diosgenin induces vascular relaxation through inhibition of Rho-kinase in rat aortae.