|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). The extract of the medicinal plant is also used as the basis of anti-ulcer medicines for treatment of peptic ulcer.
METHODS AND RESULTS:
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.
|Future Microbiol. 2015;10(12):1953-68. |
|Attenuation of quorum sensing-mediated virulence of Acinetobacter baumannii by Glycyrrhiza glabra flavonoids.[Pubmed: 26582430 ]|
|To develop an alternative quorum quenching therapy against multidrug-resistant Acinetobacter baumannii.
METHODS AND RESULTS:
Activity-guided partially purified fraction (F1) from Glycyrrhiza glabra significantly (p < 0.05) reduced quorum sensing regulated virulence factors of A. baumannii viz. motility, biofilm formation and production of antioxidant enzymes. Mechanistically, F1 downregulated the expression of autoinducer synthase gene, abaI, and consequently reduced (92%) the production of 3-OH-C12-HSL as determined by ESI-MS. Q-TOF and Q-TRAP analyses suggested the presence of flavonoids viz. Licoricone, glycyrin and glyzarin as the active ingredients.
This is the first report on quorum quenching activity of G. glabra linked to its flavonoids that downregulated the expression of abaI and attenuated quorum sensing regulated virulence of A. baumannii.