title: Three-Step Test System for the Identification of Novel GABAAReceptor Modulating Food Plants.
abstract: Potentiation of γ-amino butyric acid (GABA)-induced GABAAreceptor (GABAAR) activation is a common pathway to achieve sedative, sleep-enhancing, anxiolytic, and antidepressant effects. Presently, a three-component test system was established for the identification of novel GABAAR modulating food plants. In the first step, potentiation of GABA-induced response of the GABAAR was analysed by two-electrode voltage clamp (TEVC) for activity on human α1β2-GABAAR expressed in Xenopus laevis oocytes. Positively tested food plants were then subjected to quantification of GABA content by high-performance liquid chromatography with fluorescence detection (HPLC-FLD) to exclude test foods, which evoke a TEVC-response by endogenous GABA. In the third step, specificity of GABAA-modulating activity was assessed by TEVC analysis of Xenopus laevis oocytes expressing the homologous glycine receptor (GlyR). The three-component test was then applied to screen 10 aqueous extracts of food plants for their GABAAR activity. Thus, hop cones (Humulus lupulus) and Sideritis sipylea were identified as the most potent specific GABAAR modulators eliciting significant potentiation of the current by 182 ± 27 and 172 ± 19 %, respectively, at the lowest concentration of 0.5 μg/mL. The extracts can now be further evaluated by in vivo studies and by structural evaluation of the active components.
authors.affiliation: Food Chemistry Unit, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schuhstr. 19, 91052, Erlangen, Germany.
authors.forename: Sümeyye
authors.initials: S
authors.lastname: Sahin
authors.affiliation: Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Fahrstr. 17, 91054, Erlangen, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Eulenburg
authors.affiliation: Department of Biology, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Staudtstr. 5, 91058, Erlangen, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kreis
authors.affiliation: Institute for Clinical Neurobiology, Universitätsklinikum Würzburg, Versbacherstr. 5, 97078, Würzburg, Germany.
authors.forename: Carmen
authors.initials: C
authors.lastname: Villmann
authors.affiliation: Food Chemistry Unit, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schuhstr. 19, 91052, Erlangen, Germany. monika.pischetsrieder@fau.de.
authors.forename: Monika
authors.initials: M
authors.lastname: Pischetsrieder
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D018757:GABA Modulators / Q000737:chemistry / Q000494:pharmacology*; D005786:Gene Expression Regulation; D006801:Humans; D027582:Humulus / Q000737:chemistry; D009865:Oocytes / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D010945:Plants, Edible / Q000737:chemistry*; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism*; D031365:Sideritis / Q000737:chemistry; D014982:Xenopus laevis; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
chemical_list: D018757:GABA Modulators; D010936:Plant Extracts; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid
keywords: GABA; GABAA receptor; Glycine receptor; Hop cones; Lemon balm leaves; Sideritis