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Biomedical subjects

C Cena

Publications and source records attributed to C Cena.

14 recordsLinked to original sources
PubMed2001

A new class of ibuprofen derivatives with reduced gastrotoxicity.

A new series of nonsteroidal antiinflammatory drugs (NSAIDs) obtained by linking ibuprofen to selected furoxan moieties and to related furazans were synthesized and tested for their antiinflammatory, antiaggregatory, and ulcerogenic properties. All the derivatives are endowed with antiinflammatory activity comparable to that of ibuprofen, but, unlike this drug, they display reduced acute gastrotoxicity. The masking of the ibuprofen-free carboxylic group seems to be principally at the basis of this reduced topical irritant action. The two furoxan derivatives 8 and 9 also trigger potent antiaggregatory effects, principally as a consequence of their NO-donor ability.

Animals↗
PubMed2001

Studies on agents with mixed NO-dependent and calcium channel antagonistic vasodilating activities.

PURPOSE: To obtain new cardiovascular agents with mixed Ca2+-channel antagonistic and NO-donor properties, a series of "hybrid" 1,4-dihydropyridines (1,4-DHPs), bearing NO-donating furoxan moieties on the 3-positioned lateral ester chain were synthesized and pharmacologically characterized. Furazan analogues were also prepared and investigated for control purposes, because they are unable to release NO. METHODS: Synthesis of the models was achieved by a modified Hantzsch approach. All of the final furoxan 1,4-DHPs were assessed for their ability to produce nitrite in the presence of a large excess of cysteine by the Griess reaction. Vasodilating activity was evaluated on rat aorta and expressed as EC50 and EC50MB values, obtained in the absence and in the presence of methylene blue (MB) respectively, a well-known guanylate cyclase inhibitor. Affinities to 1,4-DHP receptor on Ca2+-channels, expressed as IC50 values, were determined through displacement experiments of [3H]-nitrendipine on rat cortex homogenates. RESULTS: Some hybrid compounds (derivatives 15a, 15b, 16a, and 16b) displayed vasodilating activity depending predominantly on their Ca2+-channel blocker properties. By contrast, some others (derivatives 17a, 17b, and 21) behaved as well-balanced hybrids with mixed Ca2+-channel blocking and NO-dependent vasodilating activities. CONCLUSION: This work demonstrates the possibility of obtaining well-balanced hybrids endowed with mixed NO-donor and Ca2+-channel blocker properties using appropriate 1,4-DHP and furoxan moieties. A procedure for the individual evaluation of the NO-dependent vasodilator component and that due to Ca2+-channel blocking is proposed.

Animals↗
PubMed2000

Nicorandil analogues containing NO-donor furoxans and related furazans.

The synthesis and in vitro vasodilating properties of hybrid compounds in which furoxan (1,2,5-oxadiazole 2-oxide) moieties, endowed with different NO-donor properties, were substituted for the nitroxy function of Nicorandil are reported. The corresponding cyanoguanidine analogues are also considered. This approach has led to a series of vasorelaxing compounds devoid of affinity for K(ATP) channels, whose activity is prevalently due to their ability to activate sGC, at the concentrations of the experiments. Related furazan (1,2,5-oxadiazole) derivatives, unable to release nitric oxide were also prepared and studied for control. The amide analogues of Nicorandil display feeble vasorelaxing action not involving the activation of K+ channels, while in the guanidine analogues, this mechanism seems to underlie this action.

Animals↗
PubMed1998

New 1,4-dihydropyridines conjugated to furoxanyl moieties, endowed with both nitric oxide-like and calcium channel antagonist vasodilator activities.

A series of 4-phenyl-1,4-dihydropyridines substituted at the ortho and meta positions of the phenyl ring with NO-donating furoxan moieties and their non-NO-releasing furazan analogues were synthesized and pharmacologically characterized. The vasodilator activities of these compounds were evaluated on rat aorta and expressed as EC50 values or as EC50iGC values when obtained in the presence of inhibitors of guanylate cyclase methylene blue (MB) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Affinities to 1, 4-DHP receptors on Ca2+ channels, expressed as IC50 values, were determined through displacement experiments of [3H]nitrendipine on rat cortex homogenates. A linear correlation between IC50 and EC50 values was found for compounds unable to release NO. EC50calcd values for derivatives containing NO-donor moieties, expression of the Ca2+-blocking component of their vasodilator activity, were interpolated on this linear regression. They showed a good correspondence with EC50iGC values determined in the presence of soluble guanylate cyclase inhibitors. Analysis of EC50iGC/EC50 ratios provided a useful tool to distinguish well-balanced hybrids from derivatives biased toward Ca2+-blocking or NO-dependent vasodilator activity. A detrimental effect on affinity to the 1, 4-DHP receptor, due to substitution at the ortho and meta positions of the 4-phenyl ring, was observed. SAR to explain this effect is proposed.

Animals↗
PubMed1997

Water soluble furoxan derivatives as NO prodrugs.

The synthesis, characterization, NO donor properties, and in vitro vasodilating activity of a series of water soluble furoxans (5-14a,b) are described. All of the compounds released NO when treated with a large excess of cysteine under physiological conditions (pH 7.4; 37 degrees C). The amount of NO produced after 1 h of incubation was evaluated by detecting nitrites, via the Griess reaction. Derivatives 5b, 7b, and 14b were able to release nitric oxide also in the absence of the thiol cofactor. The initial rates of NO release were determined at different concentrations, using a spectrophotometric technique based on the NO-induced oxidation of oxyhemoglobin (HbO2) to methemoglobin (MetHb). The initial rates of NO release were linearly dependent on the concentrations of the single compounds. The vasodilating potency (EC50) of all the derivatives was assessed on rat aortic strips precontracted with noradrenaline. Correlation between potency and initial NO release rate is discussed.

Animals↗
PubMed1997

Studies on agents with mixed NO-dependent vasodilating and beta-blocking activities.

PURPOSE: A series of derivatives having a propranolol-like moiety linked to NO-donor furoxan substructures were synthesized. The main objective of this investigation was to obtain agents with mixed NO-dependent vasodilating and beta-blocking activities. METHODS: Most of the target compounds were synthesized from the appropriate furoxans bearing XCH2CH2NH2 (X = O, S, SO2) chains at the 4 position of the ring, using Al(C2H5)3 in methylene chloride solution and (+/-)2,3-epoxypropyl 1-naphtyl ether. Two of the final products (X = CONH) were obtained by coupling the appropriate furoxancarboxylic acids with N-[2-hydroxy-3-(1-naphthoxy)propyl]-ethylenediamine. beta 1- and beta 2-blocking activities were examined on isolated guinea pig right atria and on guinea pig trachea respectively. Vasodilating properties were assessed on endothelium denuded strips of rat aorta. RESULTS: Some derivatives behave as well balanced "hybrids" displaying NO-dependent vasodilating and beta-blocking properties in the same concentration range. Some others display either prevalent beta-blocking or vasodilating activity. Generally speaking hybrid formation lowers the affinity for beta-receptors, in particular for beta 2-type, to give an increase in beta 1/beta 2 selectivity. CONCLUSIONS: The furoxan system is a flexible tool in designing analogues of propranolol whose NO-donating and beta-blocking properties are modulated over a wide range.

Adrenergic beta-Antagonists↗
PubMed1995

The cyano-NNO-azoxy function in the design of an irreversible label for alpha 1 adrenoreceptors.

A potential alpha 1-adrenergic irreversible antagonist 6, containing the cyano-NNO-azoxy function was synthesized and tested. The effects of norepinephrine on rat thoracic aorta were irreversibly blocked by this compound at the concentration of 1 x 10(-5) M after 60 minutes. Binding studies showed that 6, at 1 x 10(-6) M, did not modify the KD of Prazosin and caused a 30% decrease of the Bmax. Substitution in 6 of the bis (2-chloroethyl)amino moiety for the cyano-NNO-azoxy function afforded 7 which behaves as an irreversible antagonist able to change KD of Prazosin without influencing Bmax.

Adrenergic alpha-1 Receptor Antagonists↗
PubMedDate not supplied

SAR studies on H2 antagonists containing alkylamino substituted 1,2, 5-thiadiazole 1-oxide moieties.

A number of ranitidine analogues in which the diamino-1,2,5-thiadiazole 1-oxide substructure bearing alkyl chains of different length is present as the urea equivalent group, were synthesised and studied for their lipophilic and H2 antagonist properties. Derivatives which displayed a logP < or = 3 behaved as competitive antagonists of histamine at H2 receptors present on guinea pig right atrium. The remaining more lipophilic members of the series showed an insurmountable antagonism not completely reversible after prolonged washing. A binding study suggested that an increase in the length of alkyl chain gave rise to hydrophobic interactions with the receptor which were responsible for the apparent irreversible H2 antagonism shown by the higher homologues of the series.

Animals↗
PubMedDate not supplied

Antisecretory and gastroprotective activities of compounds endowed with H2 antagonistic and nitric oxide (NO) donor properties.

In spite of the well recognized gastric antisecretory activity, the gastroprotective potential of histamine H2 receptor antagonists is controversial. Most clinical studies in fact indicate that these drugs do not substantially protect the gastric mucosa from aggressive factors. Nitric oxide (NO) has been recently recognized as a fundamental mediator in gastric defence mechanisms, due to its ability to increase gastric mucosal blood flow and mucus production and to inhibit neutrophils adherence to endothelial cells. The aim of this study was to investigate the gastroprotective and H2 receptor antagonistic activity of a series of lamtidine analogues which contain different NO-releasing moieties (furoxan, nitroxy and nitrosothiol). These compounds were tested, in comparison with related H2 antagonists devoid of NO-donor structures, in different H2 receptor assays and in the conscious rat against 0.6 N HCl-induced gastric lesions. All the compounds tested were able to antagonize histamine-mediated responses at cardiac and gastric H2 receptors; however, furoxan and nitroxy derivatives were 10-fold less potent than the analogues devoid of NO-donor properties. By contrast, NO-donor compounds were more active than reference H2 antagonists as gastroprotective agents against mucosal injury induced by 0.6 N HCl. Among the different NO-donor moieties, the furoxan group conferred to the H2 antagonist molecule the highest gastroprotective potential; this finding closely correlates with the characteristics of NO release. In conclusions, lamtidine-analogue H2 antagonists combined with NO-donor moieties are endowed with gastric antisecretory and protective activity and could be the prototypes of a new class of anti-ulcer drugs. Finally, the furoxan NO donor group seems to be the most favourable among the different moieties tested.

Animals↗