Eucalyptol Promotes Heart Restoration in Rats Following Myocardial Infarction Through TLR/NF-κB

Background: Eucalyptol, a terpenoid oxide isolated from the essential oil of several Eucalyptus species, exhibits numerous pharmacological actions. Myocardial infarction is a major reason for death worldwide, although major advancements have occurred in its treatment. Objectives: Existing study aims to reveal the cardioprotective action of Eucalyptol in myocardial infarction rat models and examines the toll-like receptor 4 (TLR4)/myeloid differentiation protein 88 (MyD88)/nuclear factor-kappa B (NF-κB) pathway as a possible mechanism of action. Materials and Methods: Animals were distributed into five groups, which were treated by saline or Eucalyptol (100 or 200 mg/kg) for 3 weeks. Myocardial infarction was induced with isoproterenol on 20th and 21st days. Results: Pretreatment with Eucalyptol revealed infarcted area-restricting effect, cardiac indicator enzymes diminishing, and electrocardiogram (ECG) adjustment, as all those parameters were challenged by isoproterenol-induced myocardial infarction insult. Furthermore, Eucalyptol reduced inflammatory mediator levels and apoptotic markers. Additionally, it suppressed messenger ribonucleic acid (mRNA) expression of TLR2, TLR4, MyD88, and TRIF, suggesting downregulation of the TLR pathway. The docking study of Eucalyptol with TLR4 demonstrates a binding affinity of –4.193 kcal/mol, indicating favorable interaction affinity. Conclusion: Eucalyptol could act as a probable defending agent in myocardial infarction via diminishing inflammatory mediators and attenuating the apoptosis of myocardial cells through inhibition of TLR/NF-κB. These results might widen the clinical application of such a natural compound.