Green Tea Extract Reduces Oxidative Stress in Smoke-Exposed Mice: Antioxidant Potential of Camellia sinensis

Aim: This study aimed to investigate the effects of green tea extract (GTE) on serum malondialdehyde (MDA) and superoxide dismutase (SOD) levels in mice exposed to cigarette smoke, elucidating its potential as an antioxidant intervention to mitigate smoking-related oxidative stress. Methods: Twenty-five male mice were randomly assigned to five groups (n=5): negative control (C−, no smoke exposure), positive control (C+, smoke-exposed), and three treatment groups receiving GTE at 20 mg/kg (T1), 40 mg/kg (T2), and 60 mg/kg (T3) body weight alongside smoke exposure. Over 36 days, GTE was administered via oral gavage, and cigarette smoke exposure occurred in a specialized chamber for 20 minutes daily. On day 37, serum MDA and SOD levels were measured using ELISA colorimetric assays. Data were analyzed using one-way ANOVA with Duncan’s post hoc test.. Results: Cigarette smoke significantly increased MDA levels in C+ (30.51 ± 3.76 µmol/L) compared to C− (11.45 ± 2.93 µmol/L; p < 0.05), while reducing SOD activity (C+: 129.72 ± 22.63 U/mL; C−: 181.39 ± 18.24 U/mL; p < 0.05). GTE treatment dose-dependently reduced MDA levels, with T3 showing the greatest effect (15.27 ± 2.41 µmol/L; p < 0.05). However, SOD levels in T1 (118.08 ± 21.82 U/mL), T2 (135.34 ± 22.09 U/mL), and T3 (115.50 ± 19.19 U/mL) remained lower than C+ and C−. Conclusion: GTE effectively reduces cigarette smoke-induced oxidative stress by lowering MDA levels, with the 60 mg/kg dose being most effective. The lack of SOD restoration suggests complex interactions with endogenous antioxidant systems, warranting further mechanistic studies.