Protective Effect of Bombyx mori L Cocoon (Abresham) and its Formulations against Isoproterenol-Induced Cardiac Damage

Purpose: To investigate the potential activity of Bombyx mori and its formulations against isoproterenol (ISO) induced cardiotoxicity. Methods: Wistar rats were orally pretreated with the ethanol extract of Bombyx mori cocoons in two doses (250 and 500 mg/kg) for 30 days; rats were similarly pretreated with its polyherbal formulations incorporating Khamira Abresham sada (KAS) and Khamira Abresham Hakim Arshadwala (KAHAW) (800 mg/kg), standard drug metoprolol (10 mg/kg) and normal saline for 30 days. Cardiotoxicity was induced by administration of isoproterenol (ISO, 85 mg/kg, subcutaneous) given twice on days 29 and 30 in all six pre-treated groups (n = 6) except the normal control. Cardiotoxicity was assessed by morphological and biochemical evaluation and further confirmed by histopathological studies. Results: Pretreatment with Bombyx mori (500 mg/kg), KAHAW and KAS significantly decreased (p < 0.01) the heart weight:body weight (HW:BW) ratio; significantly decreases the elevated activities of the cardiac marker enzymes, namely, asparate transaminase (AST) (p < 0.01), alanine transaminase (ALT) (p < 0.01), lactate dehydrogenase (LDH) (p < 0.01) ,creatinine kinase (CK-MB) (p < 0.01) and thiobarbituric acid reactive substances (TBARS) (p < 0.01) similar to the standard drug metoprolol (p < 0.01) in ISO-injected rats. Pre-treatment of rats with Bombyx mori (500 mg/kg), KAS, KAHAW and metoprolol challenged with ISO also showed absence of troponin. Pretreatment with B. mori (500 mg/kg), KAHAW and KAS significantly increased the activities of Superoxide dismutase (SOD) (p < 0.01), Tissue glutathione (GSH) (p < 0.01) and catalase (p < 0.01) similar to the standard drug metoprolol (p < 0.01). Conclusion: The findings of this study indicate that Bombyx mori as well as its polyherbal formulations exerts potent cardioprotection against isoproterenol-induced cardiotoxicity. This effect is comparable with that of metoprolol.