title: In vitro chronotropic effects of Erythrina senegalensis DC (Fabaceae) aqueous extract on mouse heart slice and pluripotent stem cell-derived cardiomyocytes.
abstract: BACKGROUND
  Erythrina senegalensis DC (Fabaceae) bark is commonly used in sub-Saharan traditional medicine for the treatment of many diseases including gastrointestinal disorders and cardiovascular diseases. In this study, we investigated the effect of the aqueous extract of the stem bark of Erythrina senegalensis on the contractile properties of mouse ventricular slices and human induced pluripotent stem (hiPS) cell-derived cardiomyocytes. We also investigated the cytotoxic effect of the extract on mouse embryonic stem (ES) cells differentiating into cardiomyocytes (CMs).
  
  
  METHODS
  We used well-established electrophysiological technologies to assess the effect of Erythrina senegalensis aqueous extract (ESAE) on the beating activity of mouse ventricular slices, mouse ES and hiPS cell-derived CMs. To study the cytotoxic effect of our extract, differentiating mouse ES cells were exposed to different concentrations of ESAE. EB morphology was assessed by microscopy at different stages of differentiation whereas cell viability was measured by flow cytometry, fluorometry and immunocytochemistry. The electrical activity of CMs and heart slices were respectively captured by the patch clamp technique and microelectrode array (MEA) method following ESAE acute exposure.
  
  
  RESULTS
  Our findings revealed that ESAE exhibits a biphasic chronotropic activity on mouse ventricular slices with an initial low dose (0.001 and 0.01 µg/mL) decrease in beating activity followed by a corresponding significant increase in chronotropic activity at higher doses above 10 µg/mL. The muscarinic receptor blocker, atropine abolished the negative chronotropic activity of ESAE, while propranolol successfully blocked its positive chronotropic activity. ESAE showed a significant dose-dependent positive chronotropic activity on hiPS cell-derived CMs. Also, though not significantly, ESAE decreased cell viability and increased total caspase-3/7 activity of mouse ES cells in a concentration-dependent manner.
  
  
  CONCLUSIONS
  Erythrina senegalensis aqueous extract exhibits a biphasic chronotropic effect on mouse heart and a positive chronotropic activity on hiPS cell-derived CMs, suggesting a possible mechanism through muscarinic and β-adrenergic receptor pathways. Also, ESAE is not cytotoxic on mouse ES cells at concentrations up to 100 µg/mL.
authors: Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany.
authors: Erastus Nembu
authors: EN
authors: Nembo
authors: Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors: Albert Donatien
authors: AD
authors: Atsamo
authors: Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors: Télesphore Benoît
authors: TB
authors: Nguelefack
authors: Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors: Albert
authors: A
authors: Kamanyi
authors: Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany.
authors: Jürgen
authors: J
authors: Hescheler
authors: Institute of Neurophysiology, University of Cologne, 50931 Cologne, Germany. Electronic address: filo.nguemo@uni-koeln.de.
authors: Filomain
authors: F
authors: Nguemo
mesh_terms: D000818:Animals; D022062:Electrophysiologic Techniques, Cardiac; D004895:Erythrina / Q000737:chemistry*; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008839:Microelectrodes; D009200:Myocardial Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000187:drug effects*; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D039904:Pluripotent Stem Cells / Q000187:drug effects*
chemical_list: D010936:Plant Extracts
keywords: Cardiomyocytes; Chronotropy; Erythrina senegalensis; Heart slice; Microelectrode arrays; Patch-clamp technique; Stem cells