Search results for "Phospholipases A2"
showing 10 items of 52 documents
Inhibition of human sPLA2 and 5-lipoxygenase activities by two neo-clerodane diterpenoids
1999
Abstract The inhibitory effect of two neo -clerodane diterpenoids, E -isolinaridial (EI) and its methylketone derivative (EIM), isolated from Linaria saxatilis var. glutinosa , on PLA2 and other enzyme activities involved in the inflammatory process was studied. Both compounds inhibited human synovial sPLA 2 in a concentration-dependent manner with IC 50 values of 0.20 and 0.49 μM, respectively, similar to scalaradial. Besides, these compounds decreased the cell-free 5-lipoxygenase activity and A23187-induced neutrophil LTB 4 biosynthesis. Another function of human neutrophils, such as receptor-mediated degranulation, was also significantly reduced. In contrast, none of the compounds affect…
Phospholipase A2 and arachidonic acid: a common link in the generation of the eosinophil chemotactic factor (ECF) from human PMN by various stimuli.
1980
An eosinophil chemotactic factor (ECF) of low molecular weight can be generated and released from human polymorphonuclear neutrophils by the calcium ionophore, phagocytosis of zymosan particles, arachidonic acid, and phospholipase A2. Since the activation of cells by the ionophore and during the phagocytic event leads to phospholipid turnover, with the subsequent generation of arachidonic acid, it is reasonable that phospholipase A2 represents the common link for ECF production. The kinetics of ECF release by phospholipase A2 is similar to the pattern observed with the various stimuli. After a rapid rise in activity a decline occurred at later times of secretion, suggesting a mechanism of i…
Hydrolytic action of phospholipase A2 in monolayers in the phase transition region: direct observation of enzyme domain formation using fluorescence …
1990
Phospholipase A2, a ubiquitous lipolytic enzyme highly active in the hydrolysis of organized phospholipid substrates, has been characterized optically in its action against a variety of phospholipid monolayers using fluorescence microscopy. By labeling the enzyme with a fluorescent marker and introducing it into the subphase of a Langmuir film balance, the hydrolysis of lipid monolayers in their liquid-solid phase transition region could be directly observed with the assistance of an epifluorescence microscope. Visual observation of hydrolysis of different phospholipid monolayers in the phase transition region in real-time could differentiate various mechanisms of hydrolytic action against …
Development of a second generation of inhibitors of microsomal prostaglandin E synthase 1 expression bearing the γ-hydroxybutenolide scaffold
2008
Petrosaspongiolide M (PM), a marine sesterterpene metabolite bearing the gamma-hydroxybutenolide scaffold and displaying a potent inhibitory activity toward PLA(2) enzyme, was selected by us as an attractive target in order to explore its mechanism of action at molecular level. In the course of our investigations we decided to synthetically modify the parent compound to clarify the structural determinants responsible for the activity; in fact, very recently, our research group reported the synthesis and the pharmacological properties of a first collection of PM analogues generated by Ludi approach. The synthesized compounds showed a poor or moderate activity toward PLA(2) enzymes, neverthel…
PLA2-mediated catalytic activation of its inhibitor 25-acetyl-petrosaspongiolide M: serendipitous identification of a new PLA2 suicide inhibitor.
2004
Abstract25-Acetyl-petrosaspongiolide M (PMAc) (1), a mild non-covalent PLA2 inhibitor, unexpectedly recovers, after incubation with bvPLA2, the ability to covalently modify the enzyme target. This study demonstrates the catalytic effect of bvPLA2 in converting 1 in its deacetylated congener petrosaspongiolide M (PM) (2), a strong covalent PLA2 inhibitor whose molecular mechanism of inhibition has already been clarified. Moreover, our findings outline the potential role of PMAc as anti-inflammatory pro-drug, by virtue of its ability of delivering the active PM agent at the site of inflammation, functioning as a suicide inhibitor.
Sialotranscriptomics of the argasid tick ornithodoros moubata along the trophogonic cycle
2021
32 páginas, 8 tablas, 6 figuras
Two fungal lanostane derivatives as phospholipase A2 inhibitors.
1996
The hydroalcoholic extract of Poria cocos and two lanostane derivatives isolated from it, pachymic acid (1) and dehydrotumulosic acid (2), were active as inhibitors of phospholipase A2 from snake venom when a polarographic method was used. Dehydrotumulosic acid exhibited an IC50 of 0.845 mM. These two compounds are structurally related to certain triterpenoids from Ganoderma and Schinus that have previously been described as competitive inhibitors of phospholipase A2. These comprise a new group of natural potential antiinflammatory agents due to their interaction with that enzyme.
Morelloflavone, a novel biflavonoid inhibitor of human secretory phospholipase A2 with anti-inflammatory activity
1997
Abstract The flavanonylflavone morelloflavone inhibited secretory phospholipase A 2 (PLA 2 ) in vitro , with a high potency on the human recombinant synovial and bee venom enzymes ( IC 50 = 0.9 and 0.6 μM, respectively). The inhibition was apparently irreversible. In contrast, the compound was inactive on cytosolic PLA 2 activity from human monocytes. Morelloflavone scavenged reactive oxygen species generated by human neutrophils ( IC 50 = 2.7 and 1.8 μM for luminol and lucigenin, respectively) but did not modify cellular responses such as degranulation or eicosanoid release. This biflavonoid exerted anti-inflammatory effects in animal models, with a potent inhibition of 12-O-tetradecanoylp…
Anti-phospholipase A2 and anti-inflammatory activity of Santolina chamaecyparissus
2000
The activity of the Santolina chamaecyparissus methanol extract was tested against the phospholipase A2 (PLA2)-induced mouse paw edema and in vitro inhibition of PLA2 activity. After fractionation, only the dichloromethane extract was active against the PLA2 in vitro test. In addition, it reduced the edema induced by arachidonic acid, and by 12-O-tetradecanoylphorbol-13-acetate in a multidose test. After chromatography on silicagel and gel filtration on Sephadex, and using an in vitro anti-PLA2 assay-guided process, we have isolated and identified from the dichloromethane extract the flavone nepetin and four sesquiterpenes.
Anti-inflammatory activity of two cucurbitacins isolated from Cayaponia tayuya roots.
2004
Fractionation of an anti-inflammatory extract from Cayaponia tayuya roots yielded two active compounds, identified as 23,24-dihydrocucurbitacin B (1) and cucurbitacin R (2). Both were evaluated for their anti-inflammatory activity on several experimental models of pain and inflammation. In addition, their cytotoxicity and effects on leukotriene B 4 (LTB 4 ) formation were evaluated in rat polymorphonuclear leukocytes. Both compounds showed activity in the following models: carrageenan-induced mouse paw oedema (1, 4 mg/kg p.o., 46% inhibition at 3 h), phospholipase A 2 -induced mouse paw oedema (2, 3 mg/kg i.p., 61% inhibition at 60 min), serotonin-induced mouse paw oedema (1 and 2, 0.5 mg/k…