title: New organic nitrate-containing benzyloxy isonipecotanilide derivatives with vasodilatory and anti-platelet activity.
abstract: A number of new nitric oxide (NO)-precursors were synthesized by grafting nitrate-containing moieties on the structures of the benzyloxy isonipecotanilide derivatives 1 and 2 already reported as moderately potent antiplatelet agents. Various nitrooxy (ONO2)-alkyl side chains were covalently linked to the piperidine nitrogen of the parent compounds through carbamate and amide linkage, and the synthesis of a benzyl nitrate analog (15) of compound 1 was also achieved. The in vitro vasodilatory activities, as well as platelet anti-aggregatory effects, of the newly synthesized organic nitrates were assessed. The (ONO2)methyl carbamate-based derivative 5a and the benzyl nitrate analog 15, which on the other hand retain activity as inhibitors of ADP-induced platelet aggregation, exhibited strong NO-mediated vasodilatory effects on pre-contracted rat aorta strips, with EC50 values in the low nanomolar range (13 and 29 nM, respectively). Experiments carried out with the selectively inhibited soluble guanylate cyclase (sGC), which is the key enzyme of the NO-mediated pathway leading to vascular smooth muscle relaxation, confirmed the involvement of NO in the observed vasodilation. The nitrate derivatives proved to be stable in acidic aqueous solution and at pH 7.4. In human serum, unlike 5a, which showed not to undergo enzyme-catalyzed decomposition, the other tested (ONO2)-alkyl carbamate-based compounds (5b and 5e) and benzyl nitrate 15 underwent a faster degradation. However, their decomposition rates in serum were quite slow (t½>2.6 h), which suggests that nitrate moiety is poorly metabolized in blood plasma and that much of the in vitro anti-platelet activity has to be attributed to the intact (ONO2)-containing molecules.
authors.affiliation: Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", Via E. Orabona 4, 70125 Bari, Italy.
authors.forename: Modesto
authors.initials: M
authors.lastname: de Candia
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, Via P. Giuria 9, 10125 Torino, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Marini
authors.affiliation: Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", Via E. Orabona 4, 70125 Bari, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Zaetta
authors.affiliation: Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", Via E. Orabona 4, 70125 Bari, Italy.
authors.forename: Saverio
authors.initials: S
authors.lastname: Cellamare
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, Via P. Giuria 9, 10125 Torino, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Di Stilo
authors.affiliation: Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", Via E. Orabona 4, 70125 Bari, Italy. Electronic address: cosimodamiano.altomare@uniba.it.
authors.forename: Cosimo D
authors.initials: CD
authors.lastname: Altomare
mesh_terms: D000328:Adult; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000737:chemistry / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D017208:Rats, Wistar; D044967:Serum / Q000737:chemistry; D014665:Vasodilator Agents / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D009566:Nitrates; D010975:Platelet Aggregation Inhibitors; D014665:Vasodilator Agents
keywords: Antiplatelet activity; Isonipecotamides; Nitric oxide-donors; Nitrooxy alkyl carbamate derivatives; Vasodilation