Search results for "porphine"
showing 10 items of 24 documents
Selective action of two aporphines at alpha 1-adrenoceptors and potential-operated Ca2+ channels.
1993
Abstract Contractions evoked by noradrenaline (1 μM) or a depolarizing solution of 60 mM KCI were concentration dependently depressed by the aporphine alkaloids (S)-boldine and (R)-apomorphine in rataorta. Both drugs had a greater inhibitory potency on the contraction elicited by noradrenaline. Dose-response curves for noradrenaline were shifted to the right in presence of (S)-boldine. (R)-Apomorphine acted by a complex mechanism at α 1 -adrenoceptors and its inhibitory effects was irreversible. The conformational features of these alkaloids may explain their different behaviour at α 1 -adrenoceptors. In Ca 2+ -free solution, the alkaloids inhibited the contraction evoked by noradrenaline b…
Multiple actions of glaucine on cyclic nucleotide phosphodiesterases, α1-adrenoceptor and benzothiazepine binding site at the calcium channel
1992
1. In the present study, the properties of glaucine (an aporphine structurally related to papaverine) were compared with those of papaverine, diltiazem, nifedipine and prazosin. The work includes functional studies on rat isolated aorta contracted with noradrenaline, caffeine or KCl, and a determination of the affinity of glaucine at calcium channel binding sites of alpha-adrenoceptors, by use of [3H]-(+)-cis-diltiazem, [3H]-nitrendipine and [3H]-prazosin binding to cerebral cortical membranes. The effects of glaucine on the different molecular forms of cyclic nucleotide phosphodiesterases (PDE) isolated from bovine aorta were also determined. 2. Contraction evoked by noradrenaline (1 micro…
The effect of S-(+)-boldine on the α1-adrenoceptor of the guinea-pig aorta
1996
1. The cardiovascular activity of S-(+)-boldine, an aporphine alkaloid structurally related to papaverine, was determined. The work includes functional studies on guinea-pig isolated aorta contracted with noradrenaline, caffeine, KCl or Ca2+, and on guinea-pig trachea contracted with acetylcholine or histamine. 2. S-(+)-boldine inhibited in a concentration-dependent manner the contractile response evoked by noradrenaline (10 microM) in guinea-pig aorta (IC50 = 1.4 +/- 0.2 microM) while the KCl depolarizing solution (60 mM)- or the Ca2+ (1 mM)-induced contractions were only partially affected by boldine up to 300 microM. In contrast, papaverine relaxed noradrenaline (NA), KCl or Ca2+ induced…
Electrochemical reactivity of magnesium porphine : functionalization, oligo-polymerization and application to the synthesis of porphyrins and multi-p…
2012
This work deals with the redox reactivity of magnesium porphine, the study of its electropolymerization and resulting materials, of its functionalization by nucleophiles as well as the mechanistic investigation of the C-C oxidative coupling on a tris-meso-substituted porphyrin model.The electrochemical oxidation of magnesium porphine to its cation radical leads to oligomers in solution and polymers on the electrode, which molecular structure depends on the imposed potential. The reactivity of the cation radical has also been exploited by adding sufficient amount of nucleophiles (pyridine and triphenylphosphine) in the reactional in order to inhibit the oligomerization/polymerization process…
New alkaloid antibiotics that target the DNA topoisomerase I of Streptococcus pneumoniae
2011
16 pags, 3 figs, 3 tabs
Synthesis of New 8-Arylisoquinoline Derivatives by Application of Palladium-Catalyzed Suzuki Cross-Coupling Reactions.
2005
Abstract New 8-(het)aryltetrahydroisoquinolines ( 10–14 ), 8-aryltetrahydroisoquinolin-4-ols ( 15 , 16 ), and 8-phenylisoquinolin-4-ol ( 17 ), flexible analogues of aporphine, were synthesized in good yields using palladium-catalyzed Suzuki cross-coupling reactions from 8-bromotetrahydroisoquinolin-4-one ( 6 ) as a common intermediate. We also describe the synthesis of this novel intermediate through an easy and efficient method, which involved intramolecular Friedel–Crafts cyclization.
Vasodilator Effects of Liriodenine and Norushinsunine, Two Aporphine Alkaloids Isolated from <i>Annona cherimolia,</i>in Rat Aorta
1995
The effect of two aporphines, liriodenine and norushinsunine, isolated from Annona cherimolia, were studied in the rat aorta in order to examine their mechanism of action. Both alkaloids (10–7–10–4 mol/l) showed relaxant effects on the contractions elicited by 10–6 mol/l noradrenaline (NA) or 80 mmol/l KC1, but, while liriodenine showed a nonspecific relaxant action on both spasmogens, norushinsunine was more potent on KC1-induced contraction. In Ca2+-free medium, both alkaloids (0.1 mmol/l) inhibited the responses elicited by NA, but not those elicited by caffeine. This inhibitory action occurred when the alkaloids were present during the release of the Ca2+ internal stores or during the r…
8-NH2-Boldine, an Antagonist of α1Aand α1BAdrenoceptors without Affinity for the α1DSubtype: Structural Requirements for Aporphines at α1-Adrenocepto…
2005
Structure-activity analysis of 21 aporphine derivatives was performed by examining their affinities for cloned human alpha (1A), alpha (1B) and alpha (1D) adrenoceptors (AR) using membranes prepared from rat-1 fibroblasts stably expressing each alpha (1)-AR subtype. All the compounds tested competed for [ (125)I]-HEAT binding with steep and monophasic curves. The most interesting compound was 8-NH (2)-boldine, which retains the selective affinity for alpha(1A)-AR (pKi = 6.37 +/- 0.21) vs. alpha(1B)-AR (pKi = 5.53 +/- 0.11) exhibited by 1,2,9,10-tetraoxygenated aporphines, but shows low affinity for alpha(1D)-AR (pKi < 2.5). Binding studies on native adrenoceptors present in rat cerebral cor…
Porphyrin tributyltin(IV) complexes for a novel approach in the tratment of human melanoma
2012
Melanoma is the most deadly form of skin cancer, largely refractory to existing therapies. The study of porphyrin derivatives as potential anti-tumor drugs has been an interesting field of investigation in the last years. Recently, a photo-independent cytotoxic effect of (Bu3Sn)4TPPS in the blocking melanoma cell proliferation an inducing a morphology cell change was investigated.[1] Amphiphilic CD (ACyD) provides more water soluble and adaptable nanovectors through modulation of the balance between hydrophobic and hydrophilic chains at both CD sides. ACyD can be conveniently tailored by covalently appending fluorescent label or receptor-targeting glycosyl- groups and can encapsulate conven…
"Dna binding of organotin(IV) complexes of meso-tetra (4 sulfonatophenyl) porphine showing cellular activity"
2016
Our research group has reported about the synthesis of alkynyl-substituted metallophthalocyanines of symmetric and unsymmetric nature. In this study, a novel phthalocyanine precursor bearing pyridin-3-ylethynyl groups and its tetrasubstituted metallo- phthalocyanines at peripheral positions were reported.