RÉSUMÉ
Brazilein, a natural small molecule, shows a variety of pharmacological activities, especially on nervous system and immune system. As a potential multifunctional drug, we studied the distribution and the transport behavior and metabolic behavior of brazilein in vivo and in vitro. Brazilein was found to be able to distribute in the mouse brain and transport into neural cells. A metabolite was found in the brain and in the cells. Positive and negative mode-MS/MS and Q-TOF were used to identify the metabolite. MS/MS fragmentation mechanisms showed the methylation occurred at the 10-hydroxyl of brazilein (10-O-methylbrazilein). Further, catechol-O- methyltransferase (COMT) was confirmed as a crucial enzyme correlated with the methylated metabolite generation by molecular docking and pharmacological experiment.
Sujet(s)
Benzopyranes/métabolisme , Indènes/métabolisme , Neurones/métabolisme , Animaux , Benzopyranes/administration et posologie , Benzopyranes/composition chimique , Benzopyranes/pharmacologie , Transport biologique/effets des médicaments et des substances chimiques , Encéphale/métabolisme , Catechol O-methyltransferase/composition chimique , Catechol O-methyltransferase/métabolisme , Mort cellulaire/effets des médicaments et des substances chimiques , Chromatographie en phase liquide à haute performance , Complexe IV de la chaîne respiratoire/antagonistes et inhibiteurs , Complexe IV de la chaîne respiratoire/métabolisme , Indènes/administration et posologie , Indènes/composition chimique , Indènes/pharmacologie , Mâle , Méthylation/effets des médicaments et des substances chimiques , Souris de lignée ICR , Neurones/effets des médicaments et des substances chimiques , Cellules PC12 , Rats , Reproductibilité des résultats , Spectrométrie de masse en tandem , Température , Rayons ultravioletsRÉSUMÉ
Due to the comparative nature of a bioassay, the relative potency is usually used to describe the potency of a sample. Only when the two samples are similar can a valid and meaningful estimate of relative potency be obtained. Thus, assessing similarity is a crucial part in developing a bioanalytical method. The current commonly used approach for assessing similarity focuses on the response parameters, such as the slope in the linear case, using either a significance test or an equivalence test. The current direct evaluation of the response parameters ignores the information about the shape of the curve and the possible variance heterogeneity. To overcome this, we propose a method based on the idea of equivalence testing that compares the shapes of the curves directly. The new method first measures the difference of the response between the standard sample and the test sample at each of the concentration (dilution) levels and then determines whether the differences are consistent by comparing them to the equivalence limits. The benefits of the new method are investigated by a simulation study. LAY ABSTRACT: Due to the comparative nature of a bioassay, the relative potency is usually used to describe the potency of a sample. Only when the two samples are similar can a valid and meaningful estimate of relative potency be obtained. Thus, assessing similarity is a crucial part in developing a bioanalytical method. The current commonly used approach for assessing similarity focuses on the response parameters, such as the slope in the linear case, which have many drawbacks To overcome this, we propose a method based on the idea of equivalence test but comparing the shape of curve directly. The new method first measures the difference of the response between the standard sample and the test sample at each of the concentration (dilution) levels and then determines whether the differences are consistent by comparing them to the equivalence limit.