RESUMO
We designed 1-alkyloxygenipins with the aim of improving the stability of genipins based on the structural and electronic properties of genipins, and prepared 1-alkyloxygenipins and examined their neuritogenic activities in PC12h cells. All genipin-derivatives exhibited electronic properties similar to those of genipin and induced significant neurite outgrowth. These compounds will be classified as nitric oxide synthase (NOS) activators (neuritogenic active compounds) since their lowest unoccupied molecular orbital (LUMO)-energies are similar to that of tetrahydrobiopterin (H4B). (1R)-isoPropyloxygenipin showed activity comparable to that of genipin, and unlike the parent compound genipin, it was found to be physiologically stable in rat liver homogenate.
Assuntos
Iridoides/química , Iridoides/farmacologia , Neuritos/metabolismo , Neurônios/efeitos dos fármacos , Animais , Linhagem Celular , Estabilidade de Medicamentos , Glicosídeos Iridoides , Iridoides/síntese química , Iridoides/metabolismo , Fígado/metabolismo , Modelos Moleculares , Estrutura Molecular , Neurônios/citologia , Óxido Nítrico Sintase/metabolismo , Ligação Proteica , Ratos , Ratos WistarRESUMO
The binding of amino acids to water-soluble zinc porphyrins in basic aqueous solution was spectrophotometrically analyzed. The amino acids were bound to the porphyrins through the coordination of the N atom with the central zinc ion. Additional attractions arise due to Coulomb interactions between the -COO(-) anion of the amino acids and the -N(CH(3))(3)(+) cation of the porphyrin substituents and due to hydrophobic interactions between the porphyrin plane and the hydrophobic substituents of the amino acids. These attractions could be explained based on the binding data. The compensatory relationships of DeltaS and DeltaH were also discussed.
Assuntos
Metaloporfirinas/química , Receptores de Aminoácido/química , Aminas/química , Cinética , Espectroscopia de Ressonância Magnética , TermodinâmicaRESUMO
The binding of amines to artificial zinc-porphyrin receptors 1-4 was examined in basic aqueous solutions. For nicotinic acid and 3,5-dicarboxypyridine, substantial binding enhancements were observed compared to other amines with no pi system or carboxyl group. This observation suggested that interligand attractions of Coulomb and CH-pi interactions in addition to N-atom coordination can act effectively as recognition factors. The differences in the Coulomb interaction between carboxylate and sulfonate anions were also discussed.
Assuntos
Metaloporfirinas/química , Niacina/químicaRESUMO
A chiral water-soluble zinc porphyrin was optically resolved on a chiral HPLC column, and the binding of chiral amino acids and peptides to each of the enantiomers was examined spectrophotometrically in basic aqueous solution. The binding data apparently indicated that the zinc porphyrin has chiral selectivity for amino acids and dipeptides. This was reasonably explained in terms of the triple cooperation of coordination, Coulomb, and steric interactions of the chiral amino carboxylates with the porphyrin. A compensatory relationship among the thermodynamic parameters for chiral recognition was also shown.
Assuntos
Aminoácidos/química , Dipeptídeos/química , Metaloporfirinas/química , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Conformação Molecular , Solubilidade , Soluções/química , Análise Espectral , Estereoisomerismo , Termodinâmica , Água/químicaRESUMO
Water-soluble porphyrins containing four platinum(II) complexes per molecule, [5alpha,10beta,15alpha,20beta-tetrakis(2-trans-(alpha,beta,alpha,beta-trans-Pt) and cis-(alpha,beta,alpha,beta-cis-Pt) [PtCl(NH(3))(2)]N-2-aminophenylporphyrin)], were synthesized and characterized. The binding of synthetic nucleotide polymers (poly(dG)-poly(dC), poly(dA)-poly(dT)) to the porphyrins was examined spectrophotometrically in aqueous solution. UV-vis spectral data suggested that these porphyrins bind to the nucleic acids by coordinative and Coulomb interactions.
