Hydrocotyle bonariensis Comm ex Lamm (Araliaceae) leaves extract inhibits IKs not IKr potassium currents: Potential implications for anti-arrhythmic therapy

Komla Kaboua; Aklesso Mouzou; Tcha Pakoussi; Mindede Assih; Aurelien Chatelier; Aboudoulatifou Diallo; Patrick Bois; Jocelyn Bescond

doi:10.1016/j.jtcme.2021.09.004

Hydrocotyle bonariensis Comm ex Lamm (Araliaceae) leaves extract inhibits IKs not IKr potassium currents: Potential implications for anti-arrhythmic therapy

J Tradit Complement Med. 2021 Sep 16;12(4):330-334. doi: 10.1016/j.jtcme.2021.09.004. eCollection 2022 Jul.

Authors

Komla Kaboua¹, Aklesso Mouzou¹, Tcha Pakoussi¹, Mindede Assih¹, Aurelien Chatelier², Aboudoulatifou Diallo³, Patrick Bois², Jocelyn Bescond²

Affiliations

¹ Laboratoire de Physiologie-Pharmacologie, FDS, Université de Lomé, BP 1515, Lomé, Togo.
² Laboratoire de Signalisation et Transport Ionique Membranaire, Pole Biosanté, Université de Poitiers, BP 86000, Poitiers, France.
³ Laboratoire de Pharmacologie-toxicologie, FSS, Université de Lomé, BP 1515, Lomé, Togo.

Abstract

Background and aim: Hydrocotyle bonariensis Comm ex Lamm (Araliaceae) is one of these plants sufficiently exploited in traditional African medicine for its hypotensive effect. However, the pharmacological effects of those plants on cardiac functions are not well known. The potassium currents IKs and IKr, responsible for the repolarization of cardiac cell action potential, strongly influence the human cardiac rhythm. Therefore, modulators of these currents have a beneficial or undesirable medical importance in relation to cardiac arrhythmias. In order to optimize the therapeutic use of this medicinal plant, we studied the effects of hydro-ethanolic leaf extract of Hydrocotyle bonariensis on both potassium currents.

Experimental procedure: The patch clamp experiments for IK currents recording were performed on the HEK 293 (Human Embryonic Kidney 293) cell line, stably transfected with either KCNQ1 and KCNE1 genes encoding the channel responsible for the "IKs" current (HEK293 IKs), or with hERG (human ether-a-go-go related gene) gene encoding "IKr" current (HEK293 IKr).

Results and conclusion: This study revealed that the hydro-ethanolic leaf extract of H. bonariensis significantly inhibits the slow potassium component (IKs) without altering the fast potassium component (IKr). The extract at 0.5 mg/ml decreases IKs conductance by 24 ± 4.1% (n = 6) without modifying its activation threshold suggesting a direct blockade of the slow potassium channel. This selective action of the extract on the IKs current reflects a class III anti-arrhythmic effect.

Keywords: Anti-arrhymics; Electrophysiology; HB, Hydrocotyle bonariensis; HEK, Human Embryonic Kidney; HERG, human ether-a-gogo related gene product; Hydrocotyle bonariensis; IKs and IKr currents.