Inhibition of G protein-activated inwardly rectifying K+ channels by extracts of Polygonum persicaria and isolation of new flavonoids from the chloroform extract of the herb.
Planta Med
; 79(18): 1736-41, 2013 Dec.
Article
en En
| MEDLINE
| ID: mdl-24218371
ABSTRACT
The G protein-activated inwardly rectifying K+ channel-modulatory activities of Polygonum persicaria extracts were investigated by using an automated patch-clamp method, with the aim of identifying natural sources of promising ion channel-blocking compounds. The chloroform extract of the whole plant at 0.1 mg/mL exhibited high G protein-activated inwardly rectifying K+ channel-inhibitory activity. Fractionation of this extract by vacuum liquid chromatography on RP-silica gel resulted in 6 fractions, which were evaluated for G protein-activated inwardly rectifying K+ channel-modulatory activity. RP-HPLC of the most active fractions afforded the main compounds 1-4 in pure form and a mixture containing the minor constituents. The structures were identified by means of UV, HRMS, and advanced NMR methods as 3-O-senecioyl-isorhamnetin (1), 3-O-angeloyl-isorhamnetin (2), 5,3',4',5'-tetramethoxy-6,7-methylenedioxyflavone (3), and 3,5,3',4',5'-pentamethoxy-6,7-methylenedioxyflavone (4). Compounds 1-4 are new natural products, though 4 was reported earlier as a synthetic compound. Neither the individual, nor the combined application of compounds 1-4 modified the G protein-activated inwardly rectifying K+ channel activity. However, a marked G protein-activated inwardly rectifying K+ current-inhibitory effect was detected on use of the HPLC eluates containing the minor compounds. These results indicate the presence of electrophysiologically active agents among the minor compounds.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Flavonoides
/
Extractos Vegetales
/
Polygonum
/
Canales de Potasio Rectificados Internamente Asociados a la Proteína G
Idioma:
En
Revista:
Planta Med
Año:
2013
Tipo del documento:
Article
País de afiliación:
Hungria