|Life Sci. 2002 Aug 9;71(12):1449-63. |
|Anti-Helicobacter pylori flavonoids from licorice extract.[Pubmed: 12127165]|
|Licorice is the most used crude drug in Kampo medicines (traditional Chinese medicines modified in Japan).
METHODS AND RESULTS:
The extract of the medicinal plant is also used as the basis of anti-ulcer medicines for treatment of peptic ulcer. Among the chemical constituents of the plant, glabridin and glabrene (components of Glycyrrhiza glabra), licochalcone A (G. inflata), licoricidin and licoisoflavone B (G. uralensis) exhibited inhibitory activity against the growth of Helicobacter pylori in vitro. These flavonoids also showed anti-H. pylori activity against a clarithromycin (CLAR) and amoxicillin (AMOX)-resistant strain. We also investigated the methanol extract of G. uralensis. From the extract, three new isoflavonoids (3-arylcoumarin, pterocarpan, and isoflavan) with a pyran ring, gancaonols A[bond]C, were isolated together with 15 known flavonoids. Among these compounds, vestitol, licoricone, 1-Methoxyphaseollidin and gancaonol C exhibited anti-H. pylori activity against the CLAR and AMOX-resistant strain as well as four CLAR (AMOX)-sensitive strains. Glycyrin, formononetin, isolicoflavonol, glyasperin D, 6,8-diprenylorobol, gancaonin I, dihydrolicoisoflavone A, and gancaonol B possessed weaker anti-H. pylori activity.
These compounds may be useful chemopreventive agents for peptic ulcer or gastric cancer in H. pylori-infected individuals.
|Biol Pharm Bull. 1999 Oct;22(10):1144-6. |
|Inhibition of lysoPAF acetyltransferase activity by components of licorice root.[Pubmed: 10549875]|
METHODS AND RESULTS:
Licorice root traditionally used as an anti-inflammatory drug exhibited an inhibitory effect on lysoPAF (platelet-activating factor) acetyltransferase in vitro: the ether soluble fraction of the crude drug produced a 27.3% inhibition at a concentration 10 microg/ml. From this fraction, licoricidin (1), 1-methoxyphaseollin (2), 6,8-diprenylgenistein (3) and 1-Methoxyphaseollidin (4) were isolated as active components, whose IC50 values were 7.7, 57, 19 and 48 microM, respectively.
Licoricidin (1) seems to be one of the most potent compounds of plant origin isolated so far.