Estudios científicos

The dietary polyphenols trans-resveratrol and curcumin selectively bind human CB1 cannabinoid receptors with nanomolar affinities and function as antagonists/inverse agonists

Abstract:

The dietary polyphenols trans-resveratrol [5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1,3-benzenediol; found in red wine] and curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1E,6E-heptadiene-3,5-dione] (found in curry powders) exert anti-inflammatory and antioxidant effects via poorly defined mechanisms. It is interesting that cannabinoids, derived from the marijuana plant (Cannabis sativa), produce similar protective effects via CB1 and CB2 receptors. We examined whether trans-resveratrol, curcumin, and ASC-J9 [1,7-bis(3,4-dimethoxyphenyl)-5-hydroxy-1E,4E,6E-heptatriene-3-one] (a curcumin analog) act as ligands at cannabinoid receptors. All three bind to human (h) CB1 and mouse CB1 receptors with nanomolar affinities, displaying only micromolar affinities for hCB2 receptors. Characteristic of inverse agonists, the polyphenols inhibit basal G-protein activity in membranes prepared from Chinese hamster ovary (CHO)-hCB1 cells or mouse brain that is reversed by a neutral CB1 antagonist. Furthermore, they competitively antagonize G-protein activation produced by a CB1 agonist. In intact CHO-hCB1 cells, the polyphenols act as neutral antagonists, producing no effect when tested alone, whereas competitively antagonizing CB1 agonist mediated inhibition of adenylyl cyclase activity. Confirming their neutral antagonist profile in cells, the polyphenols similarly attenuate stimulation of adenylyl cyclase activity produced by a CB1 inverse agonist. In mice, the polyphenols dose-dependently reverse acute hypothermia produced by a CB1 agonist. Upon repeated administration, the polyphenols also reduce body weight in mice similar to that produced by a CB1 antagonist/inverse agonist. Finally, trans-resveratrol and curcumin share common structural motifs with other known cannabinoid receptor ligands. Collectively, we suggest that trans-resveratrol and curcumin act as antagonists/inverse agonists at CB1 receptors at dietary relevant concentrations. Therefore, these polyphenols and their derivatives might be developed as novel, nontoxic CB1 therapeutics for obesity and/or drug dependence.

Comentarios divulgativos:

Los polifenoles presentes el la dieta. Trans-resveratrol y curcumina muestran efectos antinflamatorios y antioxidantes pero sus mecanismos de acción no están bien definidos. Es interesante que además los canabinoides derivados de la planta de mariguana (Cannabis sativa) producen efectos similares por medio de los receptores CB1 y CB2. En este estudio se examina como el resveratrol y la curcumina así como un análogo de esta (ASC-J9) actuan como ligandos de los receptores de canabinoides.
Los polifenoles son capaces de reducer el peso en ratones de manera similar a los resultados encontrados para los antagonistas de Los resultados sugieren que el trans-rresveratrol y la curcumina actuan como antagonistas de los receptores CB1 a altas concentraciones. Por tanto estos compuestos y sus derivados pueden ser desarrollados como un nuevo tratamiento en obesidad o dependencia a la drogadicción