RESUMEN
Regioselective synthesis of methylated epigallocatechin gallate from epigallocatechin was accomplished using a 2-nitrobenzenesulfonyl (Ns) group as a protecting group for phenols. This methodology provided several methylated catechins, which are naturally scarce catechin derivatives.
Asunto(s)
Catequina/análogos & derivados , Animales , Catequina/síntesis química , Catequina/química , Catequina/farmacología , Química Orgánica/métodos , Química Farmacéutica/métodos , Diseño de Fármacos , Humanos , Concentración 50 Inhibidora , Metaloproteinasa 1 de la Matriz/metabolismo , Metaloproteinasa 7 de la Matriz/metabolismo , Metilación , Ratones , Modelos Químicos , Proteínas Recombinantes/química , Estereoisomerismo , TéRESUMEN
We synthesized several prodrugs of glycine and gamma-aminobutyric acid. In order to establish a screening system from the prodrugs of selective activity to MAO-A or MAO-B, we examined purification conditions such as solubilization with Triton X-100, precipitation with ammonium sulfate, gel filtration and anion exchange chromatography. MAO-B was purified from various tissues such as guinea pig brain, kidney and spleen. MAO-A from human placenta without MAO-B was unstable in above purifications and used as crude. At each purification step, we checked sensitivity of the enzyme to specific inhibitors by developing a convenient fluorescence assay, in which hydrogen peroxide produced by the enzyme was reacted with p-hydroxyphenylpropionic acid. A fluorescence microplate reader measured a fluorescence of the fluorescent product from p-hydroxyphenylpropionic acid with horseradish peroxidase. In comparison with milacemide, N,N-bis(carbamoylmethyl)-N-pentylamine was the best and exclusive substrate for MAO-B. 2-N-(phenylethylamino)-acetoamide was the good substrate for MAO-A and MAO-B same as milacemide. 4-N-(n-pentylamino)-butyric acid and 4-(N-phenylethylamino)-butyric acid were the moderate substrates for both enzymes, which should release gamma-aminobutyric acid. These drugs will be new leading compounds.
Asunto(s)
Inhibidores de la Monoaminooxidasa/farmacología , Monoaminooxidasa/metabolismo , Profármacos/farmacología , Animales , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos/métodos , Femenino , Cobayas , Humanos , Mitocondrias Hepáticas/efectos de los fármacos , Mitocondrias Hepáticas/enzimología , Inhibidores de la Monoaminooxidasa/análisis , Inhibidores de la Monoaminooxidasa/química , Profármacos/análisis , Profármacos/químicaRESUMEN
Matrix metalloproteinases (MMPs), especially membrane-type 1 matrix metalloproteinase (MT1-MMP), which generates an active form of MMP-2 from proMMP-2, are deeply involved in angiogenesis as well as in tumor cell migration and metastasis. To obtain a specific inhibitor for MT1-MMP, we screened a number of natural and synthetic compounds using recombinant human MMP-2, MMP-7, and soluble MT1-MMP in a fluorogenic peptide cleavage assay. (-)-Epigallocatechin 3-O-gallate (EGCG) followed by (-)-epigallocatechin 3,5-di-O-gallate and epitheaflagallin 3-O-gallate, was found to have potent and distinct inhibitory activity against MT1-MMP. Therefore, we investigated the effect of EGCG on the suppression of MMP-2 activation as determined by gelatin zymography, and observed that the active form of MMP-2 in the conditioned medium of human umbilical vein endothelial cells was decreased in the presence of EGCG. The results suggest the possibility that tea polyphenols suppress tumor growth through the suppression of angiogenesis.