Effect of potassium channel modulators on toxicity of <i>Cleistanthus collinus</i>

Abstract

The study was conducted to determine the effects of boiled extract of <i>Cleistanthus collinus</i> on rats by observing ECG changes and electrolyte levels in serum and urine. Influence of minoxidil and glibenclamide on <i>Cleistanthus collinus</i> induced toxicity was determined. ED₅₀ for arrhythmia, changes in contractility and heart rate were recorded using the isolated frog heart. <i>Cleistanthus </i>at low doses caused transient tachycardia and increase in contractility and at high dose caused arrhythmia and cardiac arrest in rat. LD₅₀ was found to be 1690 mg/kg. Minoxidil potentiated cardiac toxicity, whereas glibenclamide did not produce any significant change. High concentration of potassium in <i>Cleistanthus </i>extract hindered comparison of its levels. There was excretion of sodium even in the presence of hyponatraemia. <i>Cleistanthus </i>at low dose caused transient tachycardia and increase in contractility and at high dose caused arrhythmia and cardiac arrest in isolated frog heart. ED₅₀ for arrhythmia was found to be 1406 mg/kg. Acute toxicity was mainly due to depressive cardiac activity of <i>Cleistanthus. </i>It also caused renal failure. Potassium channel modulators did not have important role in acute cardiac toxicity treatment. Probably in chronic toxicity, electrolyte level changes are involved and potassium channel modulators might have a role.