81-85The study was conducted to determine the effects
of boiled extract of Cleistanthus collinus on rats by observing ECG changes
and electrolyte levels in serum and urine. Influence of minoxidil and
glibenclamide on Cleistanthus collinus induced toxicity was determined. ED50
for arrhythmia, changes in contractility and heart rate were recorded using the
isolated frog heart. Cleistanthus 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 Cleistanthus extract hindered comparison of its levels. There
was excretion of sodium even in the presence of hyponatraemia. Cleistanthus 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 Cleistanthus. 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