RESUMO
Struthanthus venetus (Sv) from family Loranthaceae is employed in traditional medicine to treat coughs. In previous studies, a methanol extract of Sv shows hypotensive effects and changes in heart rate in rats. The purpose of this study was to determine the effect of a methanol extract of Sv on the electrocardiogram (EKG), and histological changes in the guinea pig heart. Male Hartley guinea pigs anesthetized with sodium pentobarbital received 50 mg/kg ip of Sv extract. An EKG was taken before and after the ip application of Sv extract. The EKG showed changes in QRS morphology, ST segment and T wave, Q wave in DI and AVL, data of ischemia, and myocardial injury. Guinea pigs were sacrificed after 1-93 days; the hearts were prepared for histopathological study with HE, PAS, Masson and Gallegos staining. The methanol extract of Sv causes apoptosis of myocardial fibers, degeneration of muscle fibers, staying only the fibro vascular skeleton, necrosis areas, hyperplasia of endothelial cells and mitotic figures in vascular endothelial cells and myocardial fibers. Changes in the EKG of the guinea pig could explain the hypotensive effects of Sv in rats. Sv extract causes cardio toxicity, apoptosis, autophagic and mitogenic activity in guinea pig heart, suggesting regeneration of the heart.
