194 research outputs found
Anti-inflammatory and analgesic activities with gastroprotective effect of semi-purified fractions and isolation of pure compounds from Mediterranean gorgonian Eunicella singularis.
Abstract Objective To explore anti-inflammatory activities of organic extract and its semi-purified fractions (ethanol, acetone, methanol/dichloromethane) from the Mediterranean gorgonian Eunicella singularis. Methods The anti-inflammatory and analgesic activities were evaluated, using the carrageenan-induced rat paw edema model and the acetic acid writhing test in mice. The gastroprotective activity was determined using HCl/EtOH induced gastric ulcers in rats. The purification and structure elucidation of compound(s) from the more effective fraction were determined by chromatographic and spectroscopic methods and in comparison with data reported in the literature. Results The fraction F–EtOH showed an important anti-inflammatory activity associated with significant analgesic and gastroprotective properties. The purification and structure elucidation of compound(s) from this fraction lead to the identification of one diterpenoid and four sterols. Conclusions These results suggested that components from the active fraction can be used to treat various anti-inflammatory diseases
Plakilactones G and H from a marine sponge. Stereochemical determination of highly flexible systems by quantitative NMR-derived interproton distances combined with quantum mechanical calculations of C-13 chemical shifts
In this paper the stereostructural investigation of two new oxygenated polyketides, plakilactones G and H, isolated from the marine sponge Plakinastrella mamillaris collected at Fiji Islands, is reported. The stereostructural studies began on plakilactone H by applying an integrated approach of the NOE-based protocol and quantum mechanical calculations of (13)C chemical shifts. In particular, plakilactone H was used as a template to extend the application of NMR-derived interproton distances to a highly flexible molecular system with simultaneous assignment of four non-contiguous stereocenters. Chemical derivatization and quantum mechanical calculations of (13)C on plakilactone G along with a plausible biogenetic interconversion between plakilactone G and plakilactone H allowed us to determine the absolute configuration in this two new oxygenated polyketides
Bioactive cembrane derivatives from the Indian Ocean soft coral, Sinularia kavarattiensis
Marine organisms and their metabolites represent a unique source of potential pharmaceutical substances. In this study, we examined marine-derived substances for their bioactive properties in a cell-based Chikungunya virus (CHIKV) replicon model and for in vitro anti-inflammatory activity. In the screening of a marine sample library, crude extracts from the Indian soft coral, Sinularia kavarattiensis, showed promising activity against the CHIKV replicon. Bioassay-guided chemical fractionation of S. kavarattiensis resulted in the isolation of six known norcembranoids (1–6) and one new compound, named kavaranolide (7). The structures were elucidated on the basis of NMR and MS spectroscopic data. Compounds 1–3 and 5–7 were evaluated for their replicon-inhibiting potential in the CHIKV model by using a luminescence-based detection technique and live cell imaging. Compounds 1 and 2 showed moderate inhibition of the CHIKV replicon, but imaging studies also revealed cytotoxic properties. Moreover, the effects of the isolated compounds on primary microglial cells, an experimental model for neuroinflammation, were evaluated. Compound 2 was shown to modulate the immune response in microglial cells and to possess potential anti-inflammatory properties by dose-dependently reducing the release of pro- and anti-inflammatory cytokines.Peer reviewe
Discovery That Theonellasterol a Marine Sponge Sterol Is a Highly Selective FXR Antagonist That Protects against Liver Injury in Cholestasis
Background: The farnesoid-x-receptor (FXR) is a bile acid sensor expressed in the liver and gastrointestinal tract. Despite
FXR ligands are under investigation for treatment of cholestasis, a biochemical condition occurring in a number of liver
diseases for which available therapies are poorly effective, mice harboring a disrupted FXR are protected against liver injury
caused by bile acid overload in rodent models of cholestasis. Theonellasterol is a 4-methylene-24-ethylsteroid isolated from
the marine sponge Theonella swinhoei. Here, we have characterized the activity of this theonellasterol on FXR-regulated
genes and biological functions.
Principal Findings: Interrogation of HepG2 cells, a human hepatocyte cell line, by microarray analysis and transactivation
assay shows that theonellasterol is a selective FXR antagonist, devoid of any agonistic or antagonistic activity on a number of
human nuclear receptors including the vitamin D receptor, PPARs, PXR, LXRs, progesterone, estrogen, glucorticoid and
thyroid receptors, among others. Exposure of HepG2 cells to theonellasterol antagonizes the effect of natural and synthetic
FXR agonists on FXR-regulated genes, including SHP, OSTa, BSEP and MRP4. A proof-of-concept study carried out to
investigate whether FXR antagonism rescues mice from liver injury caused by the ligation of the common bile duct, a model
of obstructive cholestasis, demonstrated that theonellasterol attenuates injury caused by bile duct ligation as measured by
assessing serum alanine aminostrasferase levels and extent of liver necrosis at histopathology. Analysis of genes involved in
bile acid uptake and excretion by hepatocytes revealed that theonellasterol increases the liver expression of MRP4, a
basolateral transporter that is negatively regulated by FXR. Administering bile duct ligated mice with an FXR agonist failed
to rescue from liver injury and downregulated the expression of MRP4.
Conclusions: FXR antagonism in vivo results in a positive modulation of MRP4 expression in the liver and is a feasible
strategy to target obstructive cholestasis
Natural Products Target Discovery. Marine Cyclopeptides and Steroids as New Pharmacological Leads
Meeting congiunto fra chimici organici italiani e chimici organici israelian
Macrolidi e peptidinaturali ad azione antitumorale:Una storia di interazioni chimiche e di vita
Alkene metathesis: a “magic” tool in the synthesis of natural products
La Scuola delle Sostanze Naturali e di Chimica Biorganica “Luigi Minale”, giunta alla quarta edizione, si rivolge a giovani laureati, dottorandi di ricerca e ricercatori attivi in istituzioni accademiche, in industrie o in centri di ricerca pubblici e privati, che sono interessati allo studio delle Sostanze Naturali nel loro contesto multidisciplinare applicativo e biologico e che intendono approfondire specifiche tematiche chimiche. Essa rientra nell’ambito delle iniziative culturali di grande tradizione promosse dalla Divisione di Chimica Organica della Societa' Chimica Italiana, e si svolge con cadenza biennale. La prima edizione della Scuola si è tenuta a Salerno nel 2003 ed è stata abbinata al convegno NAT6, la seconda edizione a Napoli nel 2005, la terza edizione a Forte dei Marmi nel 2009 abbinata al convegno NAT8
MAREX: Exploring Marine Resources for Bioactive Compounds: From Discovery to Sustainable Production and Industrial Applications 2010-2014
Studies towards the synthesis of superstolide A. Synthesis and stereochemical assignment of the C(21)-C(26) fragment of superstolide A
An asymmetric synthesis of the C(21) C(26) fragment of superstolide A is described. A fragment, corresponding to a reductive ozonolysis product of superstolide, as also prepared. Comparison of spectroscopic and optical properties of the corresponding fragment obtained by degraduation of natural superstolide A allowed the confirmation of the stereochemistry of the natural product
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