title: Anti-inflammatory phloroglucinol derivatives from Hypericum empetrifolium.
abstract: Phytochemical investigation of Hypericum empetrifolium Willd. (Clusiaceae), a species native to Greece and Turkey has led to the bioassay-guided identification of two acylphloroglucinol derivatives with potent in vitro anti-inflammatory activity. Using NMR spectroscopy and mass spectrometry, the acylphloroglucinol derivatives were characterized as 3-geranyl-1-(2'-methylpropanoyl)phloroglucinol (1) and 3-geranyl-1-(2'-methylbutanoyl)phloroglucinol (2). Hypotheses are proposed regarding the biosynthetic origin of these and similar acylphloroglucinols from related Hypericum species. Compounds 1 and 2 were evaluated for in vitro inhibitory activity against COX-1, COX-2 and 5-LOX catalyzed LTB(4) formation. Compound 1 displayed good activity (IC(50) values: 6.0, 29.9, and 2.2 μM, respectively) in all three assays. Compound 2 showed good activity (IC(50) value: 5.8 μM) against LTB(4) formation and moderate activity (IC(50) value: 26.2 μM) against COX-1.
authors.affiliation: Institute for Pharmaceutical Sciences, Department of Pharmacognosy, Karl-Franzens-University-Graz, 8010 Graz, Austria.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Crockett
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Wenzig
authors.forename: Olaf
authors.initials: O
authors.lastname: Kunert
authors.forename: Rudolf
authors.initials: R
authors.lastname: Bauer