Zebrafish bioassay-guided isolation of antiseizure compounds from the Cameroonian medicinal plant Cyperus articulatus L

Théo Brillatz; Maxime Jacmin; Emerson Ferreira Queiroz; Laurence Marcourt; Ivan Slacanin; Charlotte Petit; Pierre-Alain Carrupt; Elisabeth Ngo Bum; Paul Herrling; Alexander D Crawford; Jean-Luc Wolfender

doi:10.1016/j.phymed.2020.153175

Zebrafish bioassay-guided isolation of antiseizure compounds from the Cameroonian medicinal plant Cyperus articulatus L

Phytomedicine. 2020 Jan 23:70:153175. doi: 10.1016/j.phymed.2020.153175. Online ahead of print.

Affiliations

¹ Institute of Pharmaceutical Sciences of Western Switzerland, CMU - Rue Michel-Servet 1, Geneva 4 CH-1211, Switzerland.
² Luxembourg Centre for Systems Biomedicine, Université du Luxembourg, 6, avenue du Swing, Belvaux 4367, Luxembourg; Theracule S.á r.l., 9, avenue des Hauts-Fourneaux, Belval 4362, Luxembourg.
³ ILIS Institut & Laboratory, Chemin de la Passerelle 17, Bienne CH-2503, Switzerland.
⁴ Department of Biological Sciences, Faculty of Sciences, University of Ngaoundéré, P.O. Box 454, Ngaoundéré, Cameroon.
⁵ Novartis Pharma Ltd., Research, Basel CH-4002, Switzerland.
⁶ Luxembourg Centre for Systems Biomedicine, Université du Luxembourg, 6, avenue du Swing, Belvaux 4367, Luxembourg; Theracule S.á r.l., 9, avenue des Hauts-Fourneaux, Belval 4362, Luxembourg; Department of Preclinical Sciences & Pathology, Norwegian University of Life Sciences, Ullevålsveien 72, Oslo 0454, Norway.
⁷ Institute of Pharmaceutical Sciences of Western Switzerland, CMU - Rue Michel-Servet 1, Geneva 4 CH-1211, Switzerland. Electronic address: jean-luc.wolfender@unige.ch.

PMID: 32302934
DOI: 10.1016/j.phymed.2020.153175

Abstract

Background: Epilepsy is a chronic neurological disorder affecting more than 50 million people worldwide, of whom 80% live in low- and middle-income countries. Due to the limited availability of antiseizure drugs (ASDs) in these countries, medicinal plants are the first-line treatment for most epilepsy patients. In Cameroon, a decoction of Cyperus articulatus L. rhizomes is traditionally used to treat epilepsy.

Purpose: The aim of this study was to identify and isolate the active compounds responsible for the antiseizure activity of C. articulatus in order to confirm both its traditional medicinal usage and previous in vivo studies on extracts of this plant in mouse epilepsy models.

Methods: The dried rhizomes of C. articulatus were extracted with solvents of increasing polaritie (hexane, dichloromethane, methanol and water). A traditional decoction and an essential oil were also prepared. These extracts were evaluated for antiseizure activity using a larval zebrafish seizure model with seizures induced by the GABA_A antagonist pentylenetetrazole (PTZ). The hexane extract demonstrated the highest antiseizure activity and was therefore selected for bioassay-guided fractionation. The isolated bioactive compounds were characterized by classical spectroscopic methods. Since they were found to be volatile, they were quantified by GC-FID. In addition, the absorption of the active compounds through the gastrointestinal tract and the blood-brain barrier was evaluated using a hexadecane and a blood-brain barrier parallel artificial membrane permeability assays (HDM-PAMPA and PAMPA-BBB).

Results: The hexane extract of C. articulatus exhibited the highest antiseizure activity with a reduction of 93% of PTZ-induced seizures, and was therefore subjected to bioassay-guided fractionation in order to isolate the active principles. Four sesquiterpenoids were identified as cyperotundone (1), mustakone (2), 1,2-dehydro-α-cyperone (3) and sesquichamaenol (4) and exhibited significant antiseizure activity. These volatile compounds were quantified by GC in the hexane extract, the essential oil and the simulated traditional decoction. In addition, the constituents of the hexane extract including compounds 1 and 2 were found to cross the gastrointestinal barrier and the major compound 2 crossed the blood-brain barrier as well.

Conclusion: These results highlight the antiseizure activity of various sesquiterpene compounds from a hexane extract of C. articulatus dried rhizomes and support its use as a traditional treatment for epilepsy.

Keywords: Bioassay-guided isolation; Cyperus articulatus L.; Epilepsy; Traditional medicine; Zebrafish.