Antiarrhythmic Effects of Supercritical Extract of Acmella oleracea in Rats: Electrophysiological Evidence and Cardioprotective Potential

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, with cardiac arrhythmias being one of the main factors contributing to morbidity. Currently, several established antiarrhythmic medications with proven efficacy are available. However, frequent use of these medications causes adverse effects with medium- and long-term use. This necessitates the development of new medications, preferably of natural origin and with ethnopharmacological relevance. In this sense, <i>Acmella oleracea</i> presents itself as an alternative for the treatment of arrhythmia, considering studies suggesting its cardioprotective effect. Therefore, the objective of this study was to evaluate the electrophysiological and antiarrhythmic effects of a supercritical extract of <i>Acmella oleracea</i> (SEAO) in rats. The extract was obtained by supercritical CO₂ extraction at 70 °C and 320 bar, with an extract yield of 9.72 ± 0.26% (db) and a spilanthol yield of 25.91%. The extract was administered intraperitoneally at doses of 10, 15, and 20 mg/kg in two experimental models: (1) assessment of cardiac electrophysiology and (2) epinephrine-induced arrhythmia. Electrocardiogram (ECG) parameters were measured and compared with controls treated with epinephrine and lidocaine. The SEAO group maintained sinus rhythm and preserved cardiac intervals, with a significant reduction in heart rate and R-R interval compared to the epinephrine group. These findings demonstrate that SEAO exerts dose-dependent antiarrhythmic effects comparable to those of lidocaine. The results corroborate the potential use of SEAO as a natural alternative for arrhythmia management, encouraging further pharmacological and clinical studies.