• Clinical and Experimental Reproductive Medicine
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• v.19 no.1
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• pp.9-14
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• 1992

Platelet activating factor(PAF) has been reported to play a significant role in ovulation, establishment and maintnance of early pregnancy. The object of this study was to investigate the influence of PAF on progesterone secretion in rabbit by measurement of pheripheral blood concentration of progesterone. PAF had no effect on progesterone secretion and did not induce decidual reaction in nonovulatory rabbit. But 8th day of hCG induced pesudopregnant rabbit, PAF significantly increase progesterone secretion. Progesterone level was significantly increased at 0.5 and 4 hours after treatment with $10^{-8}$ M PAF on days 2, 4, 6, 8 of gestation as compared than those treated with normal saline. When PAF was injected 2 days after coitus, progesterone levels on days 4, 6, 10, 14 of gestation was significantly increased than those with saline injected group. These results suggest that PAF increase progesterone secretion from the hCG-primed ovary and during pregnancy in rabbit.

• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.100-108
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• 2003

The regulation of plasma lipid level, particularly LDL cholesterol, represents the focus of current therapy for atherosclerosis. And $Lp-PLA_2$ is able to hydrolyse oxidized phosphatidylcholine within LDL into lyso-PC and oxidized fatty acids. $Lp-PLA_2$ is a potential biomarker of coronary heart disease and plays an important proinflammatory role in the progression of atherosclerosis. We investigated the inhibitory effects of methanol extracts of 224 natural plants on $Lp-PLA_2$ activity. Seven kinds of methanol extracts of tested plants showed above 50% inhibitory effect with the concentration of $100\;{\mu}g/ml$. The concentrated aqueous suspensions of each methanol extract were partitioned with n-hexane, $CHCl_3$, and EtOAc. Among them, EtOAc extracts of Astilbe chinensis var. davidii (root) and Pourthiaea villosa var. brunnea (leaf) significantly inhibited $Lp-PLA_2$ activity at the same concentration.

• Journal of Life Science
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• v.22 no.10
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• pp.1352-1358
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• 2012

In acute lung injury (ALI) by lipopolysaccharide (LPS), the underlying cause of infiltration and migration of neutrophils into the alveoli is considered to be from increased production of platelet-activating factor (PAF) in the pulmonary surfactant lining the alveolar lumen. In this study I partially confirmed this concept. LPS increased lung leak and the infiltration of neutrophils in the lung of rats given LPS intratracheally. The migration of neutrophils into the lung, which had caused oxidative stress, was also morphologically identified. I verified that the metabolism of the pulmonary surfactant was affected and that there was increased production of PAF in the pulmonary surfactant, both of which are considered to contribute to ALI by LPS in rats.

• Natural Product Sciences
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• v.8 no.4
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• pp.152-154
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• 2002

The methanol extract of Viscum album var. coloratum, Korean mistletoe, showed potent prolongation effects on the bleeding time in rats in vivo, and whole blood clotting time and plasma recalcification time in rats ex vivo. The prolongation effect on the bleeding time of Korean mistletoe is comparable to that of Viscum album L., European mistletoe, 185.6% and 176.5%, respectively. However, the water extracts of the both plants did not show any prolongation effects. Platelet activating factor (PAF) receptor binding assay was carried out to elucidate the action mechanisms of the extracts, and both of the methanol extracts did not show any inhibitory activity. The $LD_{50}$ of the methanol extracts of both mistletoes are more than 2 g/kg. These results suggest that the mehtanol extract of Korean mistletoe might be a potential candidate to develop new drug to improve microcirculation.

• Korean Journal of Pharmacognosy
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• v.24 no.4
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• pp.304-308
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• 1993

A platelet activating factor(PAF) antagonist ginkgolides produced from Ginkgo biloba are well known for their potential usage in septic shock and other PAF related diseases. Even though they are extracted from the leaves and on occasion the root bark, the exact biosynthetic site and pathway have not proved yet. In order to locate the enzymes involved and elucidate the biosynthetic site of the compounds, embryo-derived aseptic intact plantlet and plantlet without root have been cultured on 0.3% active carbon-containing solid Murashige and Skoog's medium. The leaves from the six-week-old normal plantlet contained similar amount of ginkgolide B to that of outdoor plant leaves, while the plantlets without root had less than 30% of the ginkgolide B compared to the in vitro intact plantlets. The results suggest that the ginkgolides may be synthesized in the root and transported to the aerial part.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.177-177
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• 1998

In the previous report, tetrandrine (TET) and fangchinoline (FAN) showed antithrombotic and antiplatelet aggregation activities. The present study was undertaken to investigate the effects of tetrandrine and fangchinoline on human platelet aggregation, formation of thromboxane B$_2$ and coagulation of platelet poor plasma. TET and FAN inhibited platelet activating factor (PAF) induced human platelet aggregation, but didn't inhibit the specific binding of PAF to its receptor. Meanwhile, TET and FAN also inhibited PAF, thrombin and arachidonic acid induced thromboxane B$_2$ formation in human washed platelets. In addition, neither TET nor FAN showed any anticoagulation activities in the measurement of the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) using human platelet poor plasma. These results suggest that antithrombotic effects of TET and FAN in mice may be mainly related to the antiplatelet aggregation activities, and the antiplatelet aggregation effects may be related to the intracellular messenger system such as TXA$_2$ formation etc., but not to the binding of PAF to PAF-receptor on the platelet membrane directly.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.218-222
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• 2007

The anticoagulant properties of Cinnamomum cassia bark-derived materials were evaluated against platelet aggregation induced by arachidonic acid (AA), collagen, platelet activating factor (PAF), or thrombin, and these effects were then compared to those of three commercially available compounds (cinnamic acid, cinnamyl alcohol, and aspirin). The active constituent obtained from C. cassia barks was isolated by silica gel column chromatography and high pressure liquid chromatography (HPLC), and was characterized as trans-cinnamaldehyde by MS, $^1H-NMR$, $^{13}C-NMR$, and IR spectroscopy. With regard to 50% inhibitory concentration ($IC_{50}$) values, cinnamaldehyde was found to effectively inhibit platelet aggregation induced by AA ($IC_{50},\;43.2\;{\mu}M$) and collagen ($IC_{50},\;3.1\;{\mu}M$). By way of comparison, cinnamaldehyde proved to be a significantly more potent platelet inhibitor against platelet aggregation induced by collagen than aspirin. The effect exerted by cinnamaldehyde against platelet aggregation induced by AA was 1.2 times less than that of aspirin. These results indicate that cinnamaldehyde may prove useful as a lead compound for the inhibition of platelet aggregation induced by AA and collagen.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.425-427
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• 2005

The steam distillate obtained from Thujopsis dolabrata var. hondai sawdust was fractionated by centrifugal thin-film evaporation, and the fractions were then investigated for antiplatelet activity using washed rabbit platelets. The biologically active constituent of T. dolabrata var. hondai sawdust was isolated by silica gel column and HPLC chromatographies and characterized as carvacrol by various spectral analyses. Carvacrol inhibited platelet aggregation induced by collagen, arachidonic acid, and platelet activating factor with IC$_{50}$ values of 12.6, 2.5, and 385.3 $\mu$M, respectively. However, carvacrol had no effect on thrombin, calcium ionophore A23l87, or phorbol l2-myristate l3-acetate induced platelet aggregation. Carvacrol was a much more potent inhibitor, as antiplatelet agents, compared with aspirin. These results suggest that carvacrol isolated from T. dolabrata var. hondai sawdust may be useful as a lead compound for inhibiting arachidonic acid-induced platelet aggregation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.4
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• pp.823-829
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• 2002

The thrombosis importantly came to the front as the risk factor of these circulation system's disease. SilsoSanGami(SSG) was used for investigating the inhibitory effect on platelet-activating factor-induced platelet aggregation about drugs that used to improvement various symptoms created by the thrombosis in oriental medicine. In this study, the water-extracted SSG was investigated for its possible antithrombotic action on platelets. The antithrombotic activity of water-extracted SSG was deduced from its ability to suppress platelet aggregation, ATP-exocytosis, and the generation of prostaglandin E₂ and thromboxane A₂ by human platelets, stimulated with arachidonic acid. Water-extracted SSG dose-dependently suppressed the aggregation of human platelets, the release of endogenous ATP, and the formation of PGE₂ and TXB₂, both the latter usually detected to estimate the activity of COX and TXS, respectively. Since the IC/sub 50/ values necessary to inhibit COX (115 ㎍/㎖ SSG) and TXS(74 ㎍/㎖ SSG) were in the same range, inhibition of COX is suggested to be the primary target of water-extracted SSG, thus suppressing the formation of PGE₂ which is metabolized by TXS to TXA₂. We considerated that SSG has practical applicational value of clinical trial in the thrombosis caused by platelet aggregation.

• The Korean Journal of Physiology
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• v.30 no.1
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• pp.77-83
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• 1996

Platelet-activating factor(PAF) is a phospholipid mediator of pulmonary inflammation, and immunologic reaction. In this study, the role of PAF on tumor necrosis factor$(TNF_{-{\alpha}})$ production by rat alveolar macrophages(AM) was examined. When PAF $(10^{-12}{\sim}10{-16}\;M)$ alone was added to AM culture, $(TNF_{-{\alpha}})$ production was not significantly increased above the resting level. In contrast, the combined addition of PAF $(10^{-6}\;M)$ and muramyl dipeptide(MDP) $(1.0\;{\mu}g\ml)$ to AM cultures markedly enhanced $(TNF_{-{\alpha}})$ production with 8.2 fold increase compared with AM culture in resting state. This potentiative effect was 313% above the sum of the separate effects of PAF and MDP. To characterize MDP effects on $(TNF_{-{\alpha}})$ production, the dose-response of AM cultured with various concentrations of MDP was tested. High level of MDP $(10\;{\mu}g\ml)$ could not significantly enhance the potentiation effect on $(TNF_{-{\alpha}})$ production compared with AM cultures with low level of MDP $(0.1\;{\mu}g\ml)$, i.e. 112.5% vs 107.8%, respectively when $10^{-10}$ M of PAF was simultaneously added to the cell culture. These data support that the potentiation of TNF. g production in AM culture is mediated by PAF rather than MDf It was also evaluated whether the similar result was obtained in silica, respirable toxic particle-treated AM culture. $(TNF_{-{\alpha}})$ production was also significantly enhanced in the PAF $(10^{-6}\;M)$ and silica $(50\;{\mu}g\ml)$-added cell cultures with 4.7 fold above the value of silica alone-stimulated cells. These results indicate that PAF can potentiate $(TNF_{-{\alpha}})$ production by MDP-or silica- stimulated AM and suggest that PAF may play a potent role in lung inflammation and disease associated with microbe and occupational dust exposures.