• Herbal Formula Science
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• v.21 no.2
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• pp.63-71
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• 2013

Objectives : Artemisia princeps is used as moxa in moxibustion and traditional herbal medicine. And its extracts or compounds is known to have an efficacy of antioxidant, anti-diabete, anti-cancer, anti-inflammation and neuroprotection. This study was performed to investigate the cytoprotective effect of Artemisia princeps extract (APE) against arachidonic acid (AA)+iron-induced oxidative stress on HepG2 cell. Methods : The effects of APE on cell viability has been assessed using MTT assay. And flow cytometric analysis was performed to estimate APE's effects on mitochondrial function. To investigate its underlying mechanism, related protein was analysed by using immunoblot analysis. Results : Treatment of APE increased relative cell viability, prevented a decline of B-cell lymphoma-extra large (Bcl-xL) and cleavage of poly(ADP-ribose) polymerase (PARP) and procaspase-3, and also protected mitochondrial membrane permeability (MMP) against oxidative stress induced by AA+iron. In addition, APE treatment increased phosphorylation of AMP-activated protein kinase (AMPK) exerts a cytoprotective effect. Conclusions : This results demonstrate that APE has an ability to activation of AMPK which protects cells from AA+iron-induced oxidative stress and restores MMP.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.223-230
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• 2007

We have previously reported that green tea catechins(GTC) displayed potent antithrombotic effect, which was due to the antiplatelet activity. In the present study, the antiplatelet activity of each green tea catechin components was compared in vitro. Galloylated catechins including (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), (-)-epicatechin gallate (ECG) and (-)-catechin gallate (CG), significantly inhibited collagen $(5{\mu}g/mL)-induced$ rabbit platelet aggregation with $IC_{50}$ values of 79.8, 63.0, 168.2 and $67.3{\mu}M$, respectively. EGCC GCG and CG also significantly inhibited arachidonic acid (AA, $100{\mu}M$)-induced rabbit platelet aggregation with $IC_{50}$ values of 98.9, 200.0 and $174.3{\mu}M$, respectively. However catechins without gallate moiety showed little inhibitory effects against rabbit platelet aggregation induced by collagen or AA compared with galloylated catechins. These observations suggest that the presence of gallate moiety at C-3 position may be essential to the antiplatelet activity of catechins and the presence of B ring galloyl structure may also contribute to the antiplatelet activity of GTC. In line with the inhibition of collagen-induced platelet aggregation, EGCG caused concentration-dependent decreases of cytosolic calcium mobilization, AA liberation and serotonin secretion. In contrast, epigallocatechin (EGC), a structural analogue of EGCG lacking a galloyl group in the 3' position, although slightly inhibited collagen-stimulated cytosolic calcium mobilization, failed to affect other signal transductions as EGCG in activated platelets. Taken together, these observations suggest that the antiplatelet activity of EGCG may be due to inhibition of arachidonic acid liberation and inhibition of $Ca^{2+}$ mobilization and that the antiplatelet of EGCG is enhanced by the presence of a gallate moiety esterified at carbon 3 on the C ring.

• Molecules and Cells
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• v.26 no.5
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• pp.481-485
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• 2008

As an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), D609 has been widely used to explain the role of PC-PLC in various signal transduction pathways. This study shows that D609 inhibits group IV cytosolic phospholipase $A_2$ ($cPLA_2$), but neither secretory $PLA_2$ nor a $Ca^{2+}$-dependent $PLA_2$. Dixon plot analysis shows a mixed pattern of noncompetitive and uncompetitive inhibition with $K_i=86.25{\mu}M$ for the $cPLA_2$ purified from bovine spleen. D609 also time- and dose-dependently reduces the release of arachidonic acid from a $Ca^{2+}$- ionophore A23187-stimulated MDCK cells. In the AA release experiment, $IC_{50}$ of D609 was ${\sim375}{\mu}M$, suggesting that this reagent may not enter the cells easily. The present study indicates that the inhibitory effects of D609 on various cellular responses may be partially attributable to the inhibition of $cPLA_2$.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.411-417
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• 1998

The role of phospholipase ($A_2\;PLA_2$) in tumor cell growth was investigated using SK-N-MC human neuroblastoma cells. 4-Bromophenacyl bromide (BPB) and mepacrine (Mep), known $PLA_2$ inhibitors, suppressed growth of the tumor cells in a dose-dependent manner without a significant cytotoxicity. Melittin (Mel), a $PLA_2$ activator, enhanced the cell growth in a concentration-dependent fashion. The growth-enhancing effects of Mel were significantly reversed by the co-treatment with $PLA_2$ inhibitors. In addition, Mel induced intracellular $Ca^{2+}$ release from internal stores like as did serum, a known intracellular $Ca^{2+}$ agonist in the tumor cells. Intracellular $Ca^{2+}$ release induced by these agonists was significantly blocked by $PLA_2$ inhibitors at growth-inhibitory concentrations. Arachidonic acid (AA), a product of the $PLA_2-catalyzed$ reaction, induced cell growth enhancement and intracellular $Ca^{2+}$ release. These effects of AA were significantly blocked by BAPTA/AM, an intracellular $Ca^{2+}$ chelator. Taken together, these results suggest that the modulation of $PLA_2$ activity may be one of the regulatory mechanisms of cell growth in human neuroblastoma cells. Intracellular $Ca^{2+}$ may act as a key mediator in the $PLA_2-induced$ growth regulation.

• Natural Product Sciences
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• v.3 no.1
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• pp.19-28
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• 1997

Constitutive cyclooxygenase (COX-I) is present in cells under physiological conditions, whereas inducible cyclooxygenase (COX-II) is induced by some cytokines, mitogens, and endotoxin presumably in pathological conditions such as inflammation. We have evaluated the inhibitory effects of solvent fractionated extracts of natural products on the activities of COX-I and COX-II. Oxygen uptake COX assay was performed, as a primary screening from the tissue extracts of bovine seminal vesicles (BSV), by monitoring the initial rate of oxygen uptake using an oxygen electrode. Additionally, we evaluated plant extracts for the inhibitory effects of COX-I (in HEL cells) and COX-II (in lipopolysaccharide activated J774A.1 macrophages) using thin layer chromatography of prostanoids produced from $^{14}C-labelled$ arachidonic acid (AA). The use of such models of COX-I and COX-II assay will lead to the identification of specific inhibitors of cyclooxygenases with presumably less side effects than present therapies. Inhibitory effects of 50 kinds of plant extracts on the COX-I and COX-II activities were determined and the active fractions were found in the ethyl acetate fractions of Dryopteris crassirhizoma (roots), Amomum cardamomum (roots), Triticum aestivum (seeds), Perilla sikokiana (leaves), Anemarrhena asphodeloides (roots). Especially, the ethyl acetate fraction of Dryopteris crassirhizoma (roots), which exhibited the strong inhibition against BSV COX $(IC_{50},\;65.4\;{\mu}g/ml)$, COX-I $(IC_{50},\;8.5\;{\mu}g/ml)$, and COX-II $(IC_{50},\;17.2\;{\mu}g/ml)$, is under investigation to isolate active principles using activity-guided fractionation method.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.219-219
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• 1996

Mucin release from hamster tracheal surface epithelial(HTSE) cells can be stimulated by extracellular ATP via activation of P$_2$ purinoceptors located on the cell surface which appears to be coupled to phospholipase C via G proteins. However, our preliminary data indicate that the ATP-induced mucin release involves, in part, activation of PKC, but not an increase in the intracellular Ca++ level, suggesting the presence of another pathway which is separate from the PLC-PKC pathway, In this study, we intended to confirm the previous observation and subsequently identify an additional mechanism. Confluent HTSE cells were metabolically labeled with either $^3$H-glucosamine or $^3$H-arachidonic acid(AA), and release of either $^3$H-mucin or $^3$H-AA was quantified following various treatments. $^3$H-mucin was assayed using the sepharose CL-4B gel-filtration method, whereas $^3$H-AA liberation was measured by counting $^3$H-radioactivity in the chase medium. We found that: (1)Desensitization of PKC by pretreatment with PMA completely abolished the mucin releasing effect of PMA but partially inhibited the ATP-induced mucin release; (2) ATP increases release of $^3$H-AA in a dose-dependent fashion; (3) mepacrine, an inhibitor of PLA$_2$, attenuates ATP-induced mucin release in a dose-dependent fashion. These results confirm our previous notion that the PLC-PKC pathway is responsible, in part, for ATP-induced mucin release. Furthermore, activation of PLA$_2$ appears to be an additional pathway which is involved in ATP-induced mucin release.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.37-45
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• 2005

In the present study, we examined the effect of crude methanolic extract (CME) from Euonymus alatus (Thunb.) Sieb on arachidonic acid (AA) cascade in SKBR3 human breast cancer cell line. CME had a potent inhibitory activity of prostaglandin E2 (PGE2) release induced by A23187, a $Ca^{2+}$ ionophore. The inhibition was concentration-dependent, with the 50 value of about 5 M. CME had no inhibitory effect on A23187-induced phosphorylation of p42/p44 extracellular signal regulated kinase/mitogen-activated protein kinase or on the liberation of [14C]-AA from the cells labeled with [14C]-AA. However, CME concentration-dependently inhibited the conversion of AA to $PGE_2$ in microsomal preparations, showing its possible inhibition of cyclooxygenase (COX). In enzyme assay in vitro, CME inhibited the activities of both constitutive COX (COX­I) and inducible COX (COX-2) in a concentration-dependent manner, with the 50 values of about 0.8 and 2M, respectively. Lineweaver-Burk plot analysis indicated that CME competitively inhibited the activities of both COX-l and -2. This study is a first demonstration that CME directly inhibits COX activity.

• Journal of Korean Biological Nursing Science
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• v.3 no.1
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• pp.41-52
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• 2001

This study was undertaken to investigate the effects of n-6(corn oil) & n-3(fish oil) fatty acids on infarction size and the cerebral activities of antioxidant enzyme in rat focal brain ischemia model. Weaning Sprague-Dawley rats were fed with either corn oil supplemented diet(COD, 14% corn oil) or fish oil supplemented diet(FOD, 14% menhaden oil) for 6 weeks. The right middle cerebral artery was occluded for 2 hours with a silicon rubber coated nylon surgical thread. After 24 hours of recirculation, the rats were sacrificed and brain sections were photographed using CCD camera after staining with 2, 3, 5-triphenyltetrazolium chloride for 60 minutes in room temperature. The infarcted area was measured and the volume of infarction was calculated. Catalase(CAT), superoxide dismutase(SOD) activities, and fatty acid composition in the brain were also measured. The total and corrected infarction volumes were not significantly different between FOD and COD group. The docosagexaenoic acid(DHA) and DHA content/arachidonic acid(AA) ratio of the cerebral cortex, an index of defense against lipid oxidation, were significantly increased in FOD group compared to those of COD group(p<0.05). In the left cortex(non-infarction side) as well as the right cortex(infarction side) of FOD group, CAT and Cu/Zn SOD activities were higher than those of the COD group(p<0.05). However, CAT and Cu/Zn SOD activities were not significantly different between the left cortex(non-infarction side) and the right cortex(infarction side) of both FOD and COD group. GPx activities were also not significantly different between two groups. Our results demonstrate that the brain infarction size in FOD and COD were not significantly different. However, cerebral lipid composition and antioxidant enzyme activities in FOD and COD group were different. Fish oil, a source of n-3 polyunsaturated fatty acid(PUFA) and corn oil, that of n-6(PUFA) may have a protective effect against oxidative stress induced via different mechanisms.

• Journal of Nutrition and Health
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• v.42 no.3
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• pp.213-220
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• 2009

Studies on the relationship between blood fatty acids and the risk of breast cancer have not yielded definite conclusions. The role of fatty acids in the development and progression of breast cancer is unclear. We conducted a case-control study to determine serum phospholipid fatty acid composition in benign breast tumor and breast cancer. Subjects consisted of 27 benign breast tumor and 68 breast cancer patients, and 28 matched controls. The levels of fatty acids were measured by gas chromatography. Higher arachidonic and palmitic acids were observed in breast cancer patients as compared with control and benign breast tumor patients. The percentage of total saturated fatty acids in breast cancer was higher than in control and benign breast tumor patients. The level of stearic acid was lower in benign breast tumor and breast cancer patients. Saturation index, the ratio of stearic to oleic acid, was lower in benign breast tumor and breast cancer patients compared to the control. Moreover, stearic acid was negatively and arachidonic acid was positively correlated with the cancer stage. In conclusion, our results support that serum phospholipid compositions of specific fatty acids are associated with the risk of benign breast tumor as well as breast cancer. Further studies are necessary to investigate mechanisms linked to the breast cancer etiology.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.102.1-102.1
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• 2003

Phospholipase A$_2$(PLA$_2$) catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid(AA), a precursor of eicosanoids including prostaglandins(PGs) and leukotrienes (LTs). The same reaction also produces lyso-phospholipids. So far, at least 19 enzymes that possess PLA2 activity have been identified, consists of low-molecular-weight, Ca$\^$2+/-requiring, secretory enzymes that have been implicated in a number of biological processes, such as modification of eicosanoid generation, inflammation, host defense, and atherosclerosis. (omitted)