Tetrandrine, the active principle of Stephania tetrandra radix extracts, has broad pharmacological activity, including effects on the cardiovascular system: it has been shown to reduce the size of acute
myocardial infarction in rats undergoing coronary vessel
ligation and to improve heart lesions in the constriction/reperfusion model by means of mechanisms involving peroxidation,
calcium antagonism and coagulation. The aim of this study was to investigate whether
tetrandrine has anti-
infarction,
antioxidant and
anticoagulant effects in rabbits treated with
isoproterenol, a drug capable of causing
peroxide generation,
calcium overload and coagulation alterations, and inducing
myocardial infarction. The results showed that pretreatment with
tetrandrine protects against the myocardial
injuries caused by
isoproterenol. It counteracted the appearance of myocardial necrotic lesions and ischemic electrocardiographic modifications, such as ST segment alterations, prevented the appearance of the plasma cardiac
necrosis markers c-
troponin I and
myoglobin, lowered
malondialdehyde levels, and prolonged partial thromboplastin time. The protective effects of
tetrandrine can be attributed to its
antioxidant action in lowering
peroxide levels and its ability to counteract coagulating activity.
Tetrandrine seems to offer full protection against
myocardial infarction experimentally induced by the non-invasive treatment of rabbits with isoprotenerol.