|
1
|
Faleschini T, Syafni N, Schulte HL, Garifulina A, Hering S, Espindola LS, Hamburger M. A neolignan from Connarus tuberosus as an allosteric GABA A receptor modulator at the neurosteroid binding site. Biomed Pharmacother 2023; 161:114498. [PMID: 36906973 DOI: 10.1016/j.biopha.2023.114498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/24/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
In a screening of a small library of extracts from plants of the Amazonian and Cerrado biomes, a hexane extract of Connarus tuberosus roots was found to significantly potentiate the GABA induced fluorescence in a fluorescence (FLIPR) assay in CHO cells stably expressing the α1β2γ2 subtype of human GABAA receptors. With the aid of HPLC-based activity profiling the activity was linked to the neolignan connarin. In CHO cells the activity of connarin was not abolished by increasing concentrations of flumazenil, while the effect of diazepam was increased by increasing concentrations of connarin. The effect of connarin was abolished by pregnenolone sulfate (PREGS) in a concentration-dependent manner, and the effect of allopregnanolone was further increased by increasing concentrations of connarin. In a two-microelectrode voltage clamp assay with Xenopus laevis oocytes transiently expressing GABAA receptors composed of human α1β2γ2S and α1β2 subunits connarin potentiated the GABA-induced currents, with EC50 values of 1.2 ± 0.3 μM (α1β2γ2S) and 1.3 ± 0.4 μM (α1β2), and with a maximum enhancement of currents Emax of 1959 ± 70% (α1β2γ2S) and 185 ± 48% (α1β2). The activation induced by connarin was abolished by increasing concentrations of PREGS.
Collapse
Affiliation(s)
- Teresa Faleschini
- Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland
| | - Nova Syafni
- Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland; Faculty of Pharmacy and Sumatran Biota Laboratory, Andalas University, 25163 Padang, West Sumatra, Indonesia
| | - Heidi Luise Schulte
- Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland; Universidade de Brasília, Laboratório de Farmacognosia, Campus Universitário Darcy Ribeiro, 70910-900 Brasília, DF, Brazil
| | - Aleksandra Garifulina
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, 1090 Vienna, Austria
| | - Steffen Hering
- Universidade de Brasília, Laboratório de Farmacognosia, Campus Universitário Darcy Ribeiro, 70910-900 Brasília, DF, Brazil
| | - Laila Salmen Espindola
- Universidade de Brasília, Laboratório de Farmacognosia, Campus Universitário Darcy Ribeiro, 70910-900 Brasília, DF, Brazil
| | - Matthias Hamburger
- Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland.
| |
Collapse
|
|
2
|
Fouche G, van Rooyen S, Faleschini T. Siphonochilus aethiopicus, a traditional remedy for the treatment of allergic asthma. ACTA ACUST UNITED AC 2013. [DOI: 10.5667/tang.2012.0040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|