• Korean Journal of Psychosomatic Medicine
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• v.28 no.1
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• pp.36-41
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• 2020

Objectives : Clozapine has been known to increase the possibility of developing cardio/cerebrovascular diseases, and the platelet activation has been deemed to be related to the occurrence of them. In author's previous study, we observed the increase of platelet activity with short-term clozapine administration. This study was conducted, as a follow-up study, to investigate the effect of clozapine on the platelet activity when administered continuously for long-term period of time of 1 year. Methods : The medical records of the patients with schizophrenia or schizoaffective disorder who were treated with clozapine for 1 year were retrospectively reviewed. The degree of platelet activation was assessed by measuring the mean platelet component. Results : Total of 24 patients were enrolled. 9 of them (37.5%) were male and 15 of them (62.5%) were female. In the Wilcoxon sign-ranks test, no significant change was observed between the mean platelet factor values at the beginning and at the end of one year. Conclusions : No significant changes of mean platelet activity were observed after continued administration of clozapine for 1 year. Considering the author's previous findings that observed a prominent decrease of mean platelet component after short-term clozapine administration, the result of this study suggests the possibility that the activity of the platelet may change depending on the duration of the clozapine administration.

• Journal of Ginseng Research
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• v.35 no.4
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• pp.442-448
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• 2011

We previously reported that in vitro anti-platelet activity of tissue-cultured mountain ginseng (TCMG) ethanol extracts show improved efficacy when compared with commercial ginseng products such as Korean red ginseng and Panax ginseng. However, information on the anti-platelet activity of the ethyl acetate fraction from TCMG adventitious roots is limited. Therefore, in this study, we further investigated the effects of an ethyl acetate extract of TCMG (EA-TCMG) adventitious roots on in vitro antiplatelet activity in whole human blood and its effect on peripheral blood flow in mice. We found that EA-TCMG inhibited platelet aggregation with $IC_{50}$ values of 271, 180, and 147 ${\mu}g$/mL induced by collagen, adenosine-5'-diphosphate, and arachidonic acid, respectively. Among the three agonists used, thromboxane $A_2$ formation induced by arachidonic acid was markedly suppressed. Furthermore, EA-TCMG improved the peripheral circulatory disturbance by improving vascular blood flow. In conclusion, these results suggest that ethyl acetate extracts from TCMG adventitious roots might inhibit vascular platelet aggregation and thrombus formation.

• Biomedical Science Letters
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• v.20 no.2
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• pp.70-76
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• 2014

In this study, we investigated the effect of DMSO, a highly dipolar organic liquid, in collagen ($5{\mu}g/ml$)-stimulated platelet aggregation. DMSO inhibited platelet aggregation at 0.5% by inhibiting production of thromboxane $A_2$ ($TXA_2$) which was associated with blocking cyclooxygenase (COX)-1 activity and $TXA_2$ synthase. In addition, DMSO significantly increased the formation of cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP) and cyclic guanosine monophosphate (cGMP) from guanosine triphosphate (GTP). On the other hand, DMSO (0.1~0.5% concentration) did not affect the LDH release which indicates the cytotoxicity. Based on these results, DMSO has anti-platelet effect by regulation of several platelet signaling pathways, therefore we suggest that DMSO could be a novel strategy on many thrombotic disorders.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.80-84
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• 1997

Substituted cinnamoyl-tyramine derivatives were synthesized by DCC-coupling of substituted cinnamic acid with tyramine or tyramine methyl-1-ether to evaluate PAF-receptor binding antagonistic activities and inhibitory activities on PAF-induced platelet aggregation with interest on structure-activity relations. The results show that 3,4-dimethoxy-cinnamoyl tyramine-amide or its methyl ether have significant PAF-receptor binding antagonistic activity and platelet anti-aggregatory activities.

• Korean Journal of Oriental Medicine
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• v.9 no.2
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• pp.55-67
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• 2003

To evaluate anti-aggregatory activity of traditional prescriptions and medicines for treatment of Ohyul symptom, 70% methanol extracts were examined using collagen stimulated in vitro platelet aggregation by impedance method in rat whole blood. The crude extracts from DoHaekSeungKiTang, BoYangHwanOhTang, Caesalpinia sappan, Rhus verniciflua, Rheum palmatum, Polygonum cuspidatum, Salvia miltiorrhiza were found to inhibit platelet aggregation. The effective crude extracts of traditional medicine were fractionated to dichloromethane, ethyl acetate, butanol and aqueous layer. Polygonum cuspidatum, Caesalpinia sappan aud Rhus verniciflua ethyl acetate fractions concentration-dependently $(250-50{\mu}m/ml)$ inhibited the aggregation of platelet in whole blood induced by collagen. These results suggested that ethyl acetate fractions of Polygonum cuspidatum, Caesalpinia sappan and Rhus verniciflua have potent anti-aggregatory activity.

• The Journal of Korean Medicine
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• v.29 no.5
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• pp.52-66
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• 2008

Objectives :Ginkgo-Chunghyul-dan (GCHD) is newly developed herbal medicine to prevent and treat stroke. In this study, we investigated whether the GCHD had antioxidant activity and anti-platelet aggregation effect in vitro and hypolipidemic activities in vivo. Methods :Anti-oxidant activity of GCHD was measured using the Blois method, anti-platelet effect of GCHD was assessed by the Born method, and hypolipidemic activities of GCHD were evaluated in corn oil- or Triton WR-1339-induced and cholesterol-fed rats. Results :GCHD showed anti-oxidant activity in the study inhibiting the formation of 1-diphenyl-2-picrylhydrazyl radicals and xanthine oxidase activity. GCHD had anti-platelet aggregation activity. GCHD significantly lowered total cholesterol (TC), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) in high cholesterol diet and Triton WR-1339 induced model TG in corn oil-induced model. GCHD had no acute toxicity at a single dosage. Conclusion : These results suggest that GCHD has the potential to treat hyperlipidemia and stroke.

• YAKHAK HOEJI
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• v.43 no.2
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• pp.233-236
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• 1999

In order to clarify the anti-Ohyul activity of rhubarb, we investigated the effects of water extract from rhizomes of four different rhubarb on blood platelet aggregation induced by arachidonic acid, ADP, collagen and PAF in vitro. The cultivated Korean rhubarb rhizomes (Rheum undulatum) exhibited the most potent inhibitory action on the aggregation induced by arachidonic acid and also among the four fractions, stilbene components containing part showed strong inhibitory action. These inhibitory effect may partially contributed to anti-Ohyul activity of rhubarb.

• Archives of Pharmacal Research
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• v.14 no.4
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• pp.352-356
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• 1991

The anti-platelet activity of ilexoside D isolated from the roots of Ilex pubescens Hook. et Arn. was investigated in in vitro and ex vivo models of platelet aggregation induced by ADP, thrombin or collagen in rats. In vitro ilexoside D inhibited more effectively platelet aggregation induced by ADP and thrombin than by collagen as compared with aspirin. Ex vivo ilexoside D also inhibited platelet aggregation induced by ADP and collagen, but not by thrombin, and the inhibitory action of ilexoside D was more effective than that of aspirin. However, in vitro ilexoside D inhibited very poorly the generation of malonyldialdehyde, which is known to be concomitantly released with thromboxane $A_2$ during platelet aggregation. These results suggest that the anti-platelet activity of ilexoside D may not be responsible for prostaglandin synthesis in platelets.

• Natural Product Sciences
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• v.2 no.2
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• pp.86-89
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• 1996

Methanolic extracts of 25 species of Malaysian medicinal plants were screened for platelet-activating factor (PAF) receptor binding activity using rabbit platelet. Extracts of Cinnamomum sintoc, Ixonanthes iconsandra, Paederia foetida, Piper aduncum, Premna integrifolia, Ardisia crispa, and Ardisia elliptica showed significant inhibitory effect on the platelet-activating factor (PAF) receptor binding.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.201-205
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• 2011

Although various biological activities of resveratrol have been extensively studied, most reports have focused on trans-resveratrol and little attention has been paid to the cis-isomer. In this study, the effect of cis-resveratrol on platelet activity was examined and compared with that of the trans-isomer. Treatment with cis-resveratrol resulted in inhibition of platelet aggregation induced by thrombin, collagen or ADP, which are representative aggregation-inducing agents, and the trans-isomer elicited the same effects. These effects were concentration-dependent in the range of 1-100 ${\mu}M$. However, the potency of the cis-isomer was much lower than that of the trans-isomer; the $IC_{50}$ values for the cis-isomer versus the trans-isomer were $31{\pm}12$ vs $151{\pm}3$, $161{\pm}3$ vs $91{\pm}4$, and $601{\pm}15$ vs $251{\pm}6\;{\mu}M$ for thrombin-, collagen- and ADP-induced aggregation, respectively. These results indicate that cis-resveratrol has a less potent anti-platelet activity, compared with the trans-isomer, and raise the possibility that the biological activities of the cis-isomer may be different from those of the trans-isomer. It will be necessary to evaluate the activity of cis-resveratrol independently of the trans-isomer.