• Journal of Applied Biological Chemistry
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• v.65 no.1
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• pp.57-62
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• 2022

Excessive activation and aggregation of platelets is a major cause of cardiovascular disease. Therefore, inhibition of platelet activation and aggregation is considered an attractive therapeutic target in preventing and treating cardiovascular diseases. In particular, strong platelet activation and aggregation by collagen secreted from the vascular endothelium are characteristic of vascular diseases. Artesunate is a compound extracted from the plant roots of Artemisia or Scopolia species, and has been reported to be effective in anticancer and Alzheimer's disease fields. However, the effect and mechanism of artesunate on collagen-induced platelet activation and aggregation have not been elucidated. In this study, the effect of artesunate on collagen-induced human platelet aggregation was confirmed and the mechanism of action of artesunate was clarified. Artesunate inhibited the phosphorylation of PI3K/Akt and Mitogen-activated protein kinases, which are phosphoproteins that are known to act in the signal transduction process when platelets are activated. In addition, artesunate decreased TXA₂ production and decreased granule secretion in platelets such as ATP and serotonin release. As a result, artesunate strongly inhibited platelet aggregation induced by collagen, a strong aggregation inducer secreted from vascular endothelial cells, with an IC₅₀ of 106.41 µM. These results suggest that artesunate has value as an effective antithrombotic agent for inhibiting the activation and aggregation of human platelets through vascular injury.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.239-245
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• 2022

Although normal activation of platelets is important in the process of hemostasis, excessive or abnormal activation of platelets can lead to cardiovascular diseases. Therefore, the discovery of novel substances capable of regulating or inhibiting platelet activation may be helpful in the prevention and treatment of cardiovascular diseases. Artemether is a derivative of artemisinin, known as an active ingredient of Artemisia annua, which has been reported to be effective in treating malaria, and is known to function through antioxidant and metabolic enzyme inhibition. However, the role of artemether in platelet activation and aggregation and the mechanism of action of artemether in collagen-induced human platelets are not known until now. This study investigated the effects of artemether on platelet activation and thrombus formation induced by collagen. As a result, cAMP level was significantly increased by artemether, and VASP and IP3R, substrates of cAMP-dependent kinase, were phosphorylated. IP3R phosphorylation by Artemether inhibited Ca²⁺ recruitment into the cytoplasm, and phosphorylated VASP inhibited fibrinogen binding by inactivating αIIb/β3 located on the platelet membrane. Consequently, artemether inhibited thrombin-induced fibrin clot formation. Therefore, we propose that artemether can act as an effective prophylactic and therapeutic agent for cardiovascular diseases caused by excessive platelet activation and thrombus formation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.249-249
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• 1994

PAF (Platelet-activating factor: 혈소판 활성화인자)는 1972년 Benveniste등에 의해 토끼의 호중구 배양 상청액중에서 발견되어 1979년 그 구조가 1-alkyl-2-acethyl-sn glycero-3-phosphocholine의 구조를 갖는 에테르형 인 지질임이 밝혀졌다. 그후 혈소판 이외 과립구, 단구나 macrophage, 혈관내피세포등 조직의 염증담당세포가 다양한 자극에 응하여 PAF를 생성됨이 보고되었다. PAF가 나타내는 대표적 활성으로는 혈소판, 호중구, 단구들의 활성화, 호중구의 유주 활성, 혈관투과성 항진, 혈압강하작용. 기관지 수축 등이 알려졌으며. 또한 염증, 알러지, 천식 endotoxin shock 등 여러질병에 직·간접적으로 관여함이 알려졌다. 이와같은 여러 생리 현상은 PAF의 특이적수용체를 개재하여 일어난다는 것이 밝혀졌다. 따라서 PAF의 다양한 질병의 관여가 밝혀짐으로서, PAF길항제의 개발이 활발히 진행되어왔다. 지금까지 PAF길항제의 개발은 PAF 구조 유사체. benzodiazepam유도체, thiazole유도체 등과 같은 합성품과 ginkolide, kadsurenone과 같은 천연물 유리의 것이 알려져 in vivo model에서도 그 효능이 확인되었다. 본 연구는 이와 같은 배경에서 20여 종의 생약에서 PAF 길항제를 검색하던 중 5종류의 생약에서 PAF 길항작용을 갖는 분획을 찾았기에 이에 보고한다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.979-984
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• 2006

Although iron is essential for many physiological processes, excess iron can lead to tissue damage by promoting the generation of reactive oxygen species (ROS). There is increasing evidence that ROS might play an important role in the pathogenesis of cardiovascular disease. However, the effects of iron excess on platelet function and the thrombotic response to vascular injury are not well understood. We examined the effects of iron excess-induced oxidative stress and the antioxidants on platelet aggregation. Oxidative stress was accessed by either free iron $(Fe^{+2})$ or hydrogen peroxide $(H_2O_2)$, as well as their combination on washed rabbit platelets (WPs) in vitro. When WPs were stimulated with either $Fe^{+2}$ alone or a subthreshold concentration of collagen, which gave an aggregatory curve with a little effect, and a dose dependent increase in platelet aggregation was observed by increasing concentrations of $Fe^{+2}$ with $H_2O_2$. This aggregation was associated with the iron-catalyzed formation of hydroxyl radicals from $H_2O_2$, and were inhibited by NAD/NADP (proton acceptor), catalase $(H_2O_2\;scavenger)$, tiron (iron chelator), mannitol (hydroxyl radical scavenger), and indomethacin (cyclooxygenase inhibitor), but not by NADH/NADPH (proton donor), superoxide mutase, and aspirin. However, NADH/NADPH, an essential cofactor for the antioxidant capacity by the supply of reducing potentials, showed the effect of an enhanced radical formation, suggesting a role for NADH/NADPH-dependent oxidase. These results suggest that iron $(Fe^{+2})$ can directly interact with washed rabbit platelets and this aggregation be mediated by OH formation as in the Fenton reaction, inhibited by radical scavengers.

• Journal of Veterinary Clinics
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• v.31 no.3
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• pp.170-174
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• 2014

This study evaluated the efficacy of soluble canine small intestinal submucosa gel in comparison to bovine thrombin in activating rabbit platelet rich plasma (PRP) by detecting growth factors. PRP from rabbits was activated by using soluble canine SIS gel, bovine thrombin, or both. The surface morphology of each group of samples was examined by scanning electron microscopy. The release of transforming growth factor (TGF)-${\beta}1$ from each set of samples was measured over 7 days using enzyme-linked immunosorbent assay. The PRP-canine SIS gel group exhibited the highest total amount of released TGF-${\beta}1$. However, there were no significant differences between any groups. The use of soluble type of canine SIS gel could be an effective alternative to bovine thrombin.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.402-407
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• 2023

The regulation of platelet aggregation is crucial for maintaining normal hemostasis, but abnormal or excessive platelet aggregation can contribute to cardiovascular disorders such as stroke, atherosclerosis, and thrombosis. Therefore, identifying substances that can control or suppress platelet aggregation is a promising approach for the prevention and treatment of these conditions. Artemisinin, a compound derived from Artemisia or Scopolia plants, has shown potential in various areas such as anticancer and Alzheimer's disease research. However, the specific role and mechanisms by which artemisinin influences platelet activation and thrombus formation are not yet fully understood. This study investigated the effects of artemisinin on platelet activation and thrombus formation. As a result, cAMP production were increased significantly by artemisinin, as well as phosphorylated VASP and IP₃R which are substrates to cAMP-dependent kinase by artemisinin in a significant manner. The Ca²⁺ normally mobilized from the dense tubular system was inhibited due to IP₃R phosphorylation from artemisinin, and phosphorylated VASP by artemisinin aided in inhibiting platelet activity via αIIb/β3 platelet membrane inactivation and inhibiting fibrinogen binding. Finally, artemisinin inhibited thrombin-induced thrombus formation. Therefore, we suggest that artemisinin has importance with cardiovascular diseases stemming from the abnormal platelets activation and thrombus formation by acting as an effective prophylactic and therapeutic agent.

• Tuberculosis and Respiratory Diseases
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• v.40 no.2
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• pp.147-152
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• 1993

Background: There is evidence that platelet is activated in chronic obstructive pulmonary disease and activated platelet with injured endothelium contribute to the pathogenesis of pulmonary hypertension, prognostic factor of chronic obstructive pulmonary disease. So, we have investigated platelet function further in chronic obstructive pulmonary disease and effect of platelet activation on pulmonary hypertension. Method: We studied platelet aggregation ratio and alpha-granule products such as platelet factor 4(PF4) and beta-thromboglobulin (${\beta}$-TG) in control subjects and COPD without and with pulmonary hypertension subjects. Result: 1) The platelet aggregation ratio (PAR) was $0.99{\pm}0.04$ in control subjects, $0.98{\pm}0.05$ in COPD without pulmonary hypertension subjects and $0.89{\pm}0.08$ in COPD with pulmonary hypertension subjects. The platelet aggregation ratio of COPD subjects was tend to decrease than that of control subjects and the ratio of COPD with pulmonary hypertension subjects was significantly lower than that of control subjects. 2) The platelet factor 4 (PF4, IU/ml) was $4.7{\pm}1.2$ in control subjects, $18.6{\pm}4.9$ in COPD without pulmonary hypertension subjects and $57.2{\pm}12.7$ in COPD with pulmonary hypertension subjects. The level of COPD subjects was significantly higher than that of control subjects and the level of COPD with pulmonary hypertension subjects was significantly higher than that of COPD without pulmonary hypertension subjects. 3) The beta-thromboglobulin (${\beta}$-TG, IU/ml) was $34.4{\pm}5.8$ in control subjects, $80.4{\pm}18.1$ in COPD without pulmonary hypertension subjects and $93.0{\pm}14.0$ in COPD with pulmonary hypertension subjects. The level of COPD subjects was significantly higher than that of conrtrol subjects and the level of COPD with pulmonary hypertension subjects was tend to increase than that of COPD without pulmonary hypertension subjects. 4) There was no correlation between the clinical parameters and PAR, PF4 and ${\beta}$-TG but there was significant correlation among PAR, PF4 and ${\beta}$-TG. Conclusion: The platelet is activated in chronic obstructive pulmonary disease and the platelet of COPD with pulmonary hypertension is tend to be activated more than that of COPD without pulmonary hypertension. So, activated platelet may involve in the pathogenesis and maintenance of pulmonary hypertension in COPD subjects and modulation of platelet activity that might reduce pulmonary hypertension needs to be determined.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1992.05a
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• pp.20-20
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• 1992

혈관내에서의 비정상적인 혈소판의 활성화는 혈소판 응괴 또는 혈전 형성을 초래함으로서 동맥경화증, 심근 경색증, 혈전중등의 허혈성 질환의 발현에 직접 또는 간접적인 원인으로서 주목되고 있다. 본 연구자 등은 천연물로부터 혈소판 응집억제작용 물질의 개발을 목표로 하여 한약 또는 민간약의 형태로서 관련질환에 사용되어온 식물생약 약 40종을 검색하였으며 이들중 혈소판 응집억제작용을 갖는 식물로부터 작용 물질의 분리를 계속하여 오고있다. 본 실험에서는 작약을 메타놀로 추출하고 작용을 추적하면서 용매로 분획하였으며, 작용분획인 Et0Ac fr.으로부터 methyl gallate를 분리하였다. Methyl gallate는 오가피로부터 작용성분으로서 이미 분리 보고된 protocatechuic acid 및 artifact인 ethyl protocatechuate와 구조적으로 매우 유사하여 이들 analogs 수종에 대하여 작용을 비교 검색하였다.

• Journal of Acupuncture Research
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• v.24 no.2
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• pp.31-38
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• 2007

목적 : 백자인에서 추출된 Carvacrol이 혈소판 활성화와 혈액 응고에 미치는 영향에 대해 알아보고자 하였다. 방법 : Carvacrol의 항혈소판 효과의 기제를 밝히기 위해 토끼 혈소판으로 Arachidonic Acid 유리，TXB2, PGD2, 12-HETE의생성을 방사선 크로마토그래피 분석을 사용하여 측정하였다. 결과 : 1. U46619를 제외하고 Collagen과 AA에 의해 유발된 응고는 Carvacrol 농도에 따라 억제되었다. 2. Collagen으로 인하여 자극된 AA 유리에 대한 Carvacrol의 유의한 억제 효과는 나타나지 않았다. 3. AA로 유발된 TXB2, PGD2와 12-HETE의 생성억제에 대한 실험에서 Carvacrol은 유의한 억제가 있는 것으로 나타났으며，농도의존적으로 억제되었다. 결론 : Carvacrol은 항혈소판 작용이 있는 것으로 볼 수 있다. 이는 한의학에서 활혈거어 작용으로 해석될수 있으며，타박상，윌경곤란증，탈모증 등 어혈질환의 예방 및 치료와 관련된 약침개발에 기초가 될수 있을 것으로 사료된다.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.236-243
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• 2023

Platelets act a fundamental role in primary- and secondary-hemostasis, however, platelet activation may cause thrombosis simultaneously. Therefore, control of platelet aggregation is crucial in preventing thrombosis-mediated diseases. Recently, the development of insect materials is attracting attention. Among the highly nutritious functional food sources, insects such as two-spotted cricket (Gryllus bimaculatus). Gryllus bimaculatus (G. bimaculatus) contains high protein and unsaturated fatty acids and has been registered as a food material September 2015 by the Ministry of Food and Drug Safety of Korea. In this study, we examined whether G. bimaculatus extract (GBE) inhibits platelet aggregation, intracellular calcium mobilization, thromboxane A₂ production and glycoprotein IIb/IIIa (integrin αIIb/β3) activation. We investigated whether GBE can regulate signaling molecules, such as 1, 4, 5-triphosphate receptor type I, extracellular signal-regulated kinase, cytosolic phospholipase A₂, mitogen-activated protein kinases p38, vasodilator-stimulated phosphoprotein, phosphatidylinositol-3 kinase, Akt, glycogen synthase kinase-3α/β, and SYK. Taken together, GBE is a potential therapeutic drug candidate to prevent platelet-related thrombosis and cardiovascular disease.