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

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.

Assessment of renal and hepatic dysfunction by co-exposure to toxic metals (Cd, Pb) and fluoride in people living nearby an industrial zone.

Togo's phosphate processing plant at Kpeme discharges waste, containing Cd, Pb, and fluoride, into the sea and on the soil. Heavy metals toxicity on kidneys and the liver has been studied. However, fluoride toxicity on these organs remains to be investigated. The present study deals with the variation in renal and hepatic functioning parameters due to fluoride, Cd and Pb. Totally, 350 volunteers were recruited from five different localities around this phosphate processing plant for sample collection. Cd and Pb contents in blood samples were determined by spectrophotometry and fluoride by the titanium chloride method. Biochemical parameters were measured using Biolab kits. The pollutant contents were elevated in polluted areas where ASAT, ALAT, creatinine, and urea increased, and total protein decreased. Correlation and multivariate tests showed that fluoride is related to the various pathologies mentioned. PCA revealed that phosphate processing in Togo is a source of renal and hepatic toxicity.

How do Spondias mombin L (Anacardiaceae) leaves extract increase uterine smooth muscle contractions to facilitate child birth in parturient women?

BACKGROUND: Spondias mombin L. (Anacardiaceae) leaves were used in Togolese folk to treat dystocia, expel placenta and manage post-partum hemorrhage during child birth. OBJECTIVES: This study aimed to establish how the extract of S. mombin leaves increase uterine smooth muscle contractions relevant to its traditional use to facilitate child birth. METHODS: Tests were performed on uterus muscle strips from Sprague-Dawley rats. Central portion of uterine horns were dissected, cleaned of surrounding fat and loose connective tissue, and cut longitudinally into strips which were placed in the organ bath for isometric tension record in presence of different substances. RESULTS: S. mombin leaves extract increased uterine spontaneous contractions. This effect was reduced by indomethacin (2 × 10-6 M), yohimbine (2 × 10-6 M) and 2-aminoethoxydiphenyl borate (2-APB) (5 × 10-5 M), but not by atropine (3.45 × 10-8 M) and cholesterol (2.5 mg/ml). CONCLUSION: The pharmacological justification for the traditional use of S. mombin leaves to treat dystocia and expel placenta was that its hydro-ethanolic extract induced prostaglandins release, α2-adrenoceptors stimulation, calcium release from internal stores and lifted inhibitory effect of cholesterol on uterine contractions in order to increase uterine smooth muscle contractions.