• Korean Journal of Pharmacognosy
• /
• v.40 no.1
• /
• pp.13-17
• /
• 2009

It was previously reported that yeast elicitor transiently increased oleanolic acid and ursolic acid in Scutellaria baicalensis suspension cultures and also doubled phospholipase $A_2$ ($PLA_2$) activity. Thus, $PLA_2$ was purified from the soluble fractions of S. baicalensis suspension cultures and the characters of the purified $PLA_2$ were identified. The $PLA_2$ was purified about 160 times compared with the starting soluble-protein extract from S. baicalensis suspension culture cells. The purified protein showed a molecular mass of about 43 kDa by SDS-PAGE. The purified plant $PLA_2$ had a neutral pH optimum (pH 7.0) and required $Ca^{2+}$ for activity. The $PLA_2$ activity was inhibited by mammalian $PLA_2$ inhibitors such as 5,8,11,14-eicosatetraynoic acid(ETYA) and arachidonyl trifluoromethyl ketone ($AACOCF_3$).

• Microbiology and Biotechnology Letters
• /
• v.23 no.5
• /
• pp.526-530
• /
• 1995

Phospholipase A$_{2}$ (PLA$_{2}$) is lipolytic enzyme that has known to be involved in inflammation. In the course of our screening for antiinflammatory compounds from natural products, a compound having PLA$_{2}$ inhibitory activities was isolated from the methanol extract of Umbilicaria esculenta. The compound was identified as lecanoric acid based on various NMR studies including DEPT, HETERO-COSY and HMBC experiments. Lecanoric acid inhibited human rheumatoid synovial PLA$_{2}$ activity with IC$_{50}$ of 0.17 mM and also exhibited antitumor activity (ED$_{50}$=2.7 $\mu $g/ml) against skin tumor cell line (LOX-IMVI).

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.179-180
• /
• 2002

The phospholipase $A_2$($PLA_2$) family represents a diverse group of enzymes that hydrolyze sn-2 fatty acid from the cell membrane. Several mammalian cytosolic $PLA_2$ and secretory $PLA_2$(s$PLA_2$) have been characterized and classified into different families. At present, 12 distinct sPLA$_2$s have been identified in mammals and classified into different groups, depending on their primary structures as characterized by the number and position of cysteine residues. (omitted)

• The Korean Journal of Physiology and Pharmacology
• /
• v.14 no.3
• /
• pp.163-167
• /
• 2010

This study investigated the effects of the methanol extracts of Morinda citrifolia containing numerous anthraquinone and iridoid on phospholipase $A_2$ ($PLA_2$) isozyme. $PLA_2$ activity was measured using various $PLA_2$ substrates, including 10-pyrene phosphatidylcholine, 1-palmitoyl-2-[$^{14}C$]arachidonyl phosphatidylcholine ([$^{14}C$]AA-PC), and [$^3H$]arachidonic acid (AA). The methanol extracts suppressed melittin-induced [$_3H$]AA release in a concentration-dependent manner in RAW 264.7 cells, and inhibited $cPLA_2/sPLA_2$-induced hydrolysis of [$^{14}C$]AA-PC in a concentration- and time-dependent manner. A Dixon plot showed that the inhibition by methanol extracts on $cPLA_2$ and $sPLA_2$ appeared to be competitive with inhibition constants ($K_i$) of $3.7{\mu}g/ml$ and $12.6{\mu}g/ml$, respectively. These data suggest that methanol extracts of Morinda citrifolia inhibits both $Ca^{2+}$-dependent $PLA_2$ such as, $cPLA_2$ and $sPLA_2$. Therefore, Morinda citrifolia may possess anti-inflammatory activity secondary to $Ca^{2+}$-dependent $PLA_2$ inhibition.

• YAKHAK HOEJI
• /
• v.45 no.4
• /
• pp.407-412
• /
• 2001

A $Ca^{2+}$_dependent PLA$_2$activity termed rPLA$_2$, was detected in the cytosol of bovine red blood cells (RBCs). The rPLA$_2$was characterized as a similar form to Group IV cPLA$_2$, but different in several column chromatographic profiles including an anion exchange column. To examine whether this rPLA$_2$is different from the well characterized cPLA$_2$, a quinone derivative, BJ50, was developed and tested for the inhibitory effect on the two PLA$_2$enzymes. The rPLA$_2$activity was inhibited by a quinone derivative (BJ50) with ID$_{50}$ of 20 $\mu$M., but had no effect on the cPLA$_2$, suggesting that rPLA$_2$may be a novel type of cytosolic PLA$_2$in RBCs.s.s.

• Molecules and Cells
• /
• v.26 no.5
• /
• pp.481-485
• /
• 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
• /
• v.2 no.4
• /
• pp.411-417
• /
• 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.

• The Korean Journal of Pharmacology
• /
• v.27 no.2
• /
• pp.191-196
• /
• 1991

The present study was performed to determine whether estradiol, via cAMP mediation, induces prostaglandin synthesis by modulating phospholipase $A_2$ activity which hydrolyzes phospholipids into arachidonic acids, a precursor for prostaglandin synthesis, during the implantation process in rats. Uterine phospholipase $A_2$ activity was elevated on day 5 of pregnancy when implantation normally occurs in rats. Moreover, phospholipase $A_2$ activity was higher in the implant sites than in the non-implant sites of uterus on day 6. In delayed implantation model, phospholipase $A_2$ activity was increased at 12 hrs after estradiol administration and at 8 hrs after dbcAMP administration. In addition, higher activity of phospholipase $A_2$ was induced by the treatment of estradiol plus theophylline, compared with estradiol-only treated group. The simultaneous treatment of indomethacin with estradiol or dbcAMP did not alter phospholipase $A_2$ activity compared with estradiol or dbcAMP-only treated group although significant suppression was observed in uterine PGE and $PGF_{2{\alpha}}$ concentrations. These results suggest that estradiol or cAMP stimulates uterine phospholipase $A_2$ activity, thereby increasing prostaglandin synthesis during the implantation process in rats.

• Korean Journal of Acupuncture
• /
• v.21 no.3
• /
• pp.89-96
• /
• 2004

Objectives : In order to prove the effect of Phospholipase $A_2(PLA_2)$ Herbal-acupuncture, this experimental studies were performed by using rats that had neuronal damage due to the Middle Cerebral Artery Occulsion(MCAO). Methods : Microdialysis probes were implanted into the coordinate of striatum of anesthetized rats which consist of sham-operated 8 rats, MCAO-operated 8 rats and $PLA_2$ Herbal-acupuncture administrated 8 rats before MCAO operating. The $PLA_2$ Herbal-acupuncture(0.5mg/kg) was administrated to rats 30 minutes before having an operation causing the MCAO. The surgical excision lead the cross resected brain to the acute ischemic state. The brain was sliced in 2mm thickness and stained with cresyl violet buffer for the measurement of cerebral infarcted area and volume. Results : Based on the result of the tissue inspection for the cerebral ischemic cell, $PLA_2$ Herbal-acupuncture significantly protect neurocytes. Conclusions : We suggest $PLA_2$ Herbal-acupuncture produces protective effects against the neuronal damage induced by MCAO. Therefore, $PLA_2$ Herbal-acupuncture may prevent delayed neuronal death(DND) in selectively vulnerable focal areas of the brain effectively.

• YAKHAK HOEJI
• /
• v.41 no.2
• /
• pp.212-219
• /
• 1997

Multiple forms of extracellular phospholipase $A_2$ have been detected in human amniotic fluid (HAF). When HAF was subjected to heparin-Sepharose column chromatography, phospholipase $A_2$ activity was detected in both heparin-non binding and binding fraction. The activity of heparin-non binding fraction was further purified by sequential uses of column chromatographies on butyl-Toy-opearl 650M and DEAE-Sephacel. DEAE-Sephacel fraction contained three different phospholipase $A_2$ activities (Peak I, II, III). The molecular weight of DEAE-Sephacel fraction phospholipase $A_2$ determined by SDS-PAGE were about 52KDa (Peak I). Peak II, III required micromolar $Ca^{2+}$ ion for its maximum activity, but Peak I enzyme showed calcium independent phospholipase $A_2$ activity and showed broad range of pH (6.0~10.0) optimum. All these enzymes were not recognized by a monoclonal antibody raised against phospholipase $A_2$ from human synovial fluid. These results suggest that HAF might contain multiple forms of extracellular phospholipase $A_2$, which may neither belong to the 14KDa group II phospholipase $A_2$ family nor cytosolic phospholipase $A_2$.