Nicole Grimaud

Effects of tumour necrosis factor-α synthesis inhibitors on rat trinitrobenzene sulphonic acid-induced chronic colitis

The fact that tumour necrosis factor-alpha (TNF-alpha) is clearly involved in the pathogenesis of intestinal bowel disease, especially Crohns disease, suggests that TNF-alpha synthesis inhibitors could be beneficial for treatment. The present study assessed the effect of chronic oral gavage of two in vitro TNF-alpha synthesis inhibitors, JM 34 maleate or [N-(4,6-dimethylpyridin-2-yl)-furane-2-carboxamide)] maleate and XC 21 or (N-betapicolyl-tetrafluorophtalimide), on colonic inflammation in trinitrobenzene sulphonic acid-induced colitis in rats. Rats received JM 34 maleate (100 mg/kg) and XC 21 (50 mg/kg) 1 h before colitis induction and then daily for 8 days by oral gavage. The colon was removed on day 8 and processed for clinical score, myeloperoxidase activity, and soluble TNF-alpha release. Treatment with XC 21, as well as dexamethasone and sulphasalazine, reduced colonic damage and decreased (except with dexamethasone) the incidence of diarrhoea. JM 34 maleate failed to improve the clinical signs of chronic colitis. After trinitrobenzene sulphonic acid-induced colitis, myeloperoxidase activity and TNF-alpha colonic mucosal production were substantially increased compared to the control (saline instillation). Both of these inflammatory indicators were then significantly decreased (P< or =0.05) after the four chronic treatments (JM 34 maleate, XC 21, sulphasalazine, and dexamethasone). XC 21 appeared to be as efficient as sulphasalazine in improving colonic inflammation.

New anti-inflammatory N-pyridinyl(alkyl)phthalimides acting as tumour necrosis factor-α production inhibitors

This paper describes the synthesis of N-pyridinyl(alkyl)phthalimides related to N-phenyl-4,5,6,7-tetrafluorophthalimides known to be inhibitors of tumour necrosis factor-alpha (TNFalpha) production. Pharmacomodulation at the phthalimidic nitrogen led to the selection of two pharmacophoric fragments (2,4-lutidinyl and beta-picolyl), allowing significant inhibition of TNFalpha production (compounds 12 and 17). Variation of the substituents linked to the homocycle of their phthalimide scaffold indicated that high (TNFalpha production) inhibitory potency could be achieved, notably by 5-fluoro, 4- or 5-nitro, 5-amino and especially tetrafluoro substitution. The most active compound, N-(pyridin-3-ylmethyl)-4,5,6,7-tetrafluorophthalimide (32) (84% inhibition at 10 microM), also produced an anti-oedematous effect in the PMA-induced mouse-ear swelling test. Although less active than dexamethasone, it exerted a marked reduction in ear thickness after oral administration (63% vs. 85% for dexamethasone at 0.2 mMkg(-1)) and remained efficient after topical application (46% vs. 96% for the dexamethasone). It also induced potent inhibition in the rat carrageenan foot oedema test with an ID(50) (0.14 microMkg(-1)) comparable with that of N-(2,6-diisopropylphenyl)phthalimide (4) (0.15 microMkg(-1)).

N-pyridinyl-indole-3-(alkyl)carboxamides and derivatives as potential systemic and topical inflammation inhibitors

N-substituted-(indol-3-yl)carboxamides 10-15 and alkanamides 16-18 were prepared starting from the corresponding acids and submitted to screening for evaluation of their anti-inflammatory activity. None of the considered carboxamides exhibited significant inhibitory effect in the carrageenin-induced rat paw oedema after oral administration of 0.1 mM x kg(-1); nevertheless introduction of an alkyl chain, leading to alkanamides 16-18, induced moderate to high activity: 46-95% inhibition. The efficacy of these compounds in the inhibition of topical inflammation was confirmed by measuring reduction of ear thickness in the acute tetradecanoyl phorbol acetate (TPA)-induced mouse ear swelling assay. Preliminary pharmacomodulation brought to the fore that toxic effects induced, at 0.4 mM x kg(-1), by N-(pyridin-4-yl)(indol-3-yl)propanamide (17) could be attenuated or suppressed by 5-fluorination or introduction of a methoxycarbonylborane moiety, leading to 18 and 21.

Cardiovascular effects of lepadiformine, an alkaloid isolated from the ascidians Clavelina lepadiformis (Müller) and C. moluccensis (Sluiter)

The effects of lepadiformine, a natural marine alkaloid isolated from the ascidians Clavelina lepadiformis (Müller) and C. moluccensis (Sluiter), were studied in vivo by arterial blood pressure (aBP) recordings and electrocardiograms (ECG) in anaesthetised rats and in situ by peripheral vascular pressure recordings on perfused rabbit ear. Transmembrane resting (RP) and action (AP) potentials were also recorded by intracellular microelectrodes on electrically stimulated left ventricular papillary muscle and spontaneously beating atrium isolated from rat and frog hearts, respectively. Intravenous injection of lepadiformine (6mg/kg) produced marked bradycardia and a lengthening of ECG intervals as well as a transient decrease of aBP, which rapidly returned to normal. The decrease of aBP may have been related to a vasoconstrictor effect observed in the perfused ear experiment. Lepadiformine did not alter RP, but significantly lengthened the repolarising phase of AP in rat papillary muscle and frog atrium. Lepadiformine also mimicked the effect of Ba(2+) (0.2mM) on the rat AP repolarising phase. Moreover, the lengthening of the AP in frog atrium induced by lepadiformine still developed after the delayed outward K(+) current (I(K)) was blocked by tetraethylammonium (10mM). These observations suggest that lepadiformine-induced lengthening of AP duration was not due to a decrease of I(K), but may reasonably be attributed to a reduction of the inward rectifying K(+) current (I(K1)). This blockade of I(K1) could account for the cardiovascular effects of lepadiformine in vivo and in vitro and suggests that lepadiformine has antiarrhythmic properties.

Synthesis of N-Pyridinyl(methyl)-1,2-dihydro-4-hydroxy-2-oxoquinoline-3-carboxamides and analogues and their anti-inflammatory activity in mice and rats

The topical anti‐inflammatory activity of a series of N‐pyridinyl(methyl)1,2‐dihydro‐4‐hydroxy‐2‐oxoquinoline‐3‐carboxamides, analogues of roquinimex, has been evaluated by measuring their inhibitory effect in the phorbol myristate acetate (PMA)‐induced mouse ear swelling test, used as a screening test.

Non-carboxylic antiinflammatory compounds. III: N-(4,6-dimethylpyridin-2-yl)arylcarboxamides and arylthiocarboxamides acting as brain edema inhibitors

Summary Pharmacomodulation of the non-carboxylic NSAID N -(4,6-dimethylpyridin-2-yl)benzamide 1 led to the synthesis of structurally related furan, thiophene and pyrrole carboxamides 3–14 . The derivatives benzenethiocarboxamides 15–18 and heteroaryl-thiocarboxamides 19–22 were also prepared by oxygen/sulfur exchange; this reaction was more efficiently carried out by P 4 S 10 than by Lawessons reagent. The 20 synthesized compounds were evaluated against peripheral edema by a foot-pad carrageenin-induced edema test. Amides 3–5, 8, 9, 11, 12 and 14 were most active, exhibiting > 90% inhibition after oral administration of 0.8 mmol·kg −1 . Two amides, 3 and 5 , were selected for evaluation of their inhibitory activity in PLA 2 -induced brain edema and were found to be more potent than dexamethasone after IP administration.

New N -pyridinyl(methyl)-indole-2- and 3-(Alkyl)carboxamides and Derivatives Acting as Systemic and Topical Inflammation Inhibitors

A series of novel N -substituted-(indol-2-yl)carboxamides (12 - 18) and (indol-3-alkyl)carboxamides (25 - 31) were synthesized and evaluated as inhibitors of the inflammation process. Pharmacomodulation at the level of the amidic nitrogen by incorporation of the previously described pharmacophoric moieties 6-aminolutidine, β -picolylamine, 4-aminopyridine and piperazine was investigated; only two compounds (12) and (31) exhibited significant (~40%) inhibitory effect in the carrageenan-induced rat paw edema after oral administration of a dose of 0.1 mM kg −1. Replacement of the indole core by indazole failed to increase activity. Incorporation of an alkyl chain spacer led to more efficient compounds (46 - 52) especially in the indolepropanamide sub-series. Determination of the efficiency of the most active compounds on topical inflammation, by measuring reduction of ear thickness in the acute tetradecanoyl phorbol acetate (TPA)-induced mouse ear swelling assay, confirmed the high potency of propanamides (49) and (51) after oral administration: ID50 =0.041 ± 0.013 and 0.042 ± 0.016 mM kg −1 respectively. The less toxic propanamide (51) exerted a high level of inhibitory activity after topical application of 2 × 100 μg/ear: 78 ± 2%.

Non-acidic anti-inflammatory compounds: activity of N-(4,6-dimethyl-2-pyridinyl) benzamides and derivatives

The inhibition of the carragenin-induced rat-paw edema by previously synthesized N-(4,6-dimethyl)-2-pyridinyl) benzamides was evaluated. Among the 29 tested compounds, secondary benzamides 1, 12 and tertiary benzamide 60 exhibited a significant anti-inflammatory activity. It prompted us to envision a pharmacomodulation in this series by structural modifications on the homocycle, the amide function and the heterocycle. Although benzamide 38, acetamide 50 and benzylamine 56 elicited marked inhibitory activity, none was more active than N-(4,6-dimethyl-2-pyridinyl) benzamide 1. The mechanism of the anti-inflammatory action of 1 was investigated. The results showed that this molecule reduced eicosanoid biosynthesis but was unable to reduce cyclooxygenase or lipoxygenase activities. Although it did not directly block phospholipase activity, however, an inhibitory process at this level is likely.

Non-acidic antiinflammatory compounds II. Synthesis and activity of 6-amino-2,4-lutidine derivatives

Benzamides I, phenylalkanamides II and cinnamamides III are structurally related to the antiinflammatory N-(4,6-dimethylpyridin-2-yl)benzamide I. These were synthesized and the transformation of the 2-aminopyridine nucleus of benzamides I into a 2-imino-1,2-dihydropyridine structure (compounds IV) was also carried out. Of the 49 new derivatives, the 3-fluorobenzamide 9 was the most potent in the oral treatment of carrageenen-induced peripheral edema; IC50 = 12.2 mg·kg−1. It was 3 times as active as benzamide 1, but the latter nevertheless had a better therapeutic index (LD50/IC50) of 52 against 23. Benzamide 1, a non-acidic antiinflammatory compound devoid of any blocking activity on cyclooxygenase, markedly reduces the production of reactive oxygen species in rat peritoneal macrophages. This compound probably acts at the membrane, perhaps by interference with transmembrane events.

Effect of clonidine on experimental brain edema in the rat

Several experimental brain edema models are currently available for drug evaluation. Brain edemas are essentially vasogenic and/or cytotoxic, and eicosanoids are involved in the development of these edemas. Thus, a new model developed in our laboratory, which was obtained by phospholipase A2 intracerebral injection was used to study the antiinflammatory effect of clonidine. The copper wire edema model was chosen as reference.Edemas wer evaluated by determining the swelling and Na+ and K+ tissue concentrations of each hemisphere. Drugs were administered intraperitoneally.Dexamethasone was the only drug to inhibit copper wire-induced edema, whereas indomethacin and clonidine as well as dexamethasone exhibited marked antiedematous activity in our model. The effect of clonidine, which could be inhibited by prior administration of yohimbine, suggests that central α2 stimulation is involved in reducing experimental brain edema.