Protective Mechanisms of EGCG in Mitigating Oxidative Stress and Liver Toxicity From Cigarette Smoke-Induced Damage

Exposure to cigarette smoke leads to an increase in oxidative stress within the body, resulting in both an elevated oxidant burden and a compromised antioxidant defense system. This imbalance creates a significant risk factor for various diseases by promoting cellular damage, inflammation, and toxicity. The oxidants present in cigarette smoke are considered the primary contributors to these pathological conditions. Supporting the antioxidant system with specific bioactive compounds may help mitigate the toxic effects caused by cigarette smoke. In this study, the effects of EGCG pre-administration on the antioxidant system were evaluated under both acute and chronic exposure conditions to cigarette smoke. Different doses of EGCG were administered to determine its potential role in oxidative stress regulation, and histopathological examinations and antioxidant enzyme levels were assessed. The findings demonstrated that while acute EGCG administration did not significantly improve antioxidant enzyme activity, chronic administration of EGCG at a dose of 50 mg/kg effectively increased antioxidant enzyme production, reduced oxidative stress, and liver injury. In the presence of cigarette smoke, EGCG contributed to the stabilization of oxidative stress markers. However, chronic EGCG administration in the absence of oxidative stressors requires further investigation to assess its impact on other organs. EGCG appears to be a promising candidate for alleviating the adverse effects of external oxidant exposure and mitigating oxidative stress. However, its long-term application and potential side effects in different physiological conditions should be explored further examinations. Although acute EGCG application did not enhance antioxidant enzyme levels, it unexpectedly elevated oxidative stress, emphasizing the need for more comprehensive studies to clarify its mechanisms and optimize its usage. We further identify the principal underlying mechanisms involved in this process.