Search results for "Sesterterpenes"
showing 6 items of 6 documents
Sesterterpenes and macrolide derivatives from the endophytic fungus Aplosporella javeedii.
2020
Abstract Five sesterterpenes (1–5) including two new compounds (1 and 2), as well as a new (6) and a known macrolide (7) were isolated from the endophytic fungus Aplosporella javeedii. The structures of the new compounds were elucidated by analysis of their 1D and 2D NMR and HRMS data as well as by comparison with the literature. Compound 4 and its acetyl derivatives 4a, 4b, 4c which were prepared by acetylation of 4 exhibited moderate cytotoxicity against the mouse lymphoma cell line L5178Y with IC50 values ranging from 6.2 to 12.8 μM, respectively. Moreover, 4a and 4c exhibited also cytotoxicity against human leukemia (Jurkat J16) and lymphoma (Ramos) cell lines. Compound 7 showed strong …
Coscinolactams A and B: new nitrogen-containing sesterterpenoids from the marine sponge Coscinoderma mathewsi exerting anti-inflammatory properties
2009
Abstract Investigation of the marine sponge Coscinoderma mathewsi led to the isolation of two novel nitrogen-containing cheilanthane sesterterpenoids, coscinolactams A and B, together with known suvanine. The structures were elucidated by extensive spectroscopic measurements including NOE experiments to deduce the stereochemistry. The natural compounds, as well as a semisynthetic derivative, showed moderate anti-inflammatory activity measured as their capability to inhibit PGE2 and NO production. The suvanine aldehyde derivative 4 inhibited inducible nitric oxide protein expression with an IC50 value of 7.3 μM.
Characterization of γ-aminobutyrate type A receptors with atypical coupling between agonist and convulsant binding sites in discrete brain regions
2001
Abstract γ-Aminobutyric acid type A (GABA A ) receptor ionophore ligand t -[ 35 S]butylbicyclophosphorothionate ([ 35 S]TBPS) was used in an autoradiographic assay on brain cryostat sections to visualize and characterize atypical GABA-insensitive [ 35 S]TBPS binding previously described in certain recombinant GABA A receptors and the cerebellar granule cell layer. Picrotoxinin-sensitive but 1-mM GABA-insensitive [ 35 S]TBPS binding was present in the rat cerebellar granule cell layer, many thalamic nuclei, subiculum and the internal rim of the cerebral cortex, amounting in these regions up to 6% of the basal binding determined in the absence of exogenous GABA. Similar binding properties wer…
Inhibition of phospholipase A2 activities and some inflammatory responses by the marine product ircinin
1996
The marine product ircinin has been tested for its effects on secretory and cytosolic phospholipase A2 (PLA2) activities in vitro as well as for inhibition of cellular functions in human neutrophils and inflammatory responses in mice. Ircinin inhibited Naja naja venom, human synovial recombinant, bee venom and zymosan-injected rat air pouch PLA2 with IC50 values in the microM range, similar to those of the known inhibitor scalaradial. On the other hand, ircinin was less active on cytosolic PLA2 from human monocytes and decreased potently the release of LTB4 in human neutrophils. This marine product affected weakly human neutrophil functions like superoxide generation and degranulation. In t…
Involvement of secretory phospholipase A2 activity in the zymosan rat air pouch model of inflammation.
1996
1. In the zymosan rat air pouch model of inflammation we have assessed the time dependence of phospholipase A2 (PLA2) accumulation in the inflammatory exudates as well as cell migration, myeloperoxidase activity, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. 2. A significant increase in PLA2 activity was detected in 1,200 g supernatants of exudates 8 h after injection of zymosan into rat air pouch. This event coincided with peaks in cell accumulation (mainly neutrophils) and myeloperoxidase activity in exudates and was preceded by a rise in eicosanoid levels. 3. This enzyme (without further purification) behaved as a secretory type II PLA2 with an optimum pH at 7-8 units, lack o…
Two New Retigerane-Type Sesterterpenoids from the Lichen Leprocaulon microscopicum
2016
International audience; Two new sesterterpenes, 1 and 2, have been isolated from the lichen Leprocaulon microscopicum. In addition to classic chromatographic methods, a liquid-liquid chromatography technique, namely centrifugal partition chromatography (CPC) was applied for the purification of compound 2. The structures were determined by analyses of mass spectrometry and 1D- and 2D-NMR data. The relative configuration of the isolated compounds was assigned on the basis of 2D-NOESY experiments. The two compounds possess a rare pentacyclic carbon skeleton typical for lichen metabolism, and quite unusual in the vegetal kingdom.