The present study examined the effects of licorice on
antioxidant defense, functional impairment, histopathology, and ultrastructural alterations in
isoproterenol (ISP)-induced myocardial injury in rats. Myocardial
necrosis was induced by two
subcutaneous injection of ISP (85 mg/kg) at an interval of 24 h. Licorice was administered orally for 30 days in the doses of 100, 200, 400, or 800 mg/kg. ISP-treated rats showed impaired hemodynamics,
left ventricular dysfunction, and caused depletion of
antioxidants and marker
enzymes along with lipid peroxidation from myocardium. ISP also induced histopathological and ultrastructural alterations in myocardium. Pretreatment with licorice prevented the depletion of
endogenous antioxidants and myocyte injury marker
enzymes, inhibited lipid peroxidation, and showed recovery of hemodynamic and ventricular functions. Licorice treatment also reduced myonecrosis,
edema, and infiltration of inflammatory cells and showed preservation of subcellular and ultrastructural components. Our results demonstrate that licorice exerts cardioprotection by reducing oxidative stress, augmenting
endogenous antioxidants, and restoring functional parameters as well as maintaining structural integrity.