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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.

Authors :
Lajter, Ildikó
Vasas, Andrea
Orvos, Péter
Bánsághi, Száva
Tálosi, László
Jakab, Gusztáv
Béni, Zoltán
Háda, Viktor
Forgo, Peter
Hohmann, Judit
Source :
Planta Medica; Dec2013, Vol. 79 Issue 18, p1736-1741, 6p
Publication Year :
2013

Abstract

The G protein-activated inwardly rectifying K<superscript>+</superscript> 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<superscript>+</superscript> channel-inhibitory activity. Fractionation of this extract by vacuum liquid chromatography on RPsilica gel resulted in 6 fractions, which were evaluated for G protein-activated inwardly rectifying K<superscript>+</superscript> 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<superscript>+</superscript> channel activity. However, a marked G protein- activated inwardly rectifying K<superscript>+</superscript> 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. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00320943
Volume :
79
Issue :
18
Database :
Complementary Index
Journal :
Planta Medica
Publication Type :
Periodical
Accession number :
93312959
Full Text :
https://doi.org/10.1055/s-0033-1351016