Effects of hibiscus sabdariffa linn on hippocampus glutathione level and spatial memory of overtraining rats

Introduction: Excessive physical exercises (overtraining; OT) can increase the production of reactive oxygen species (ROS) and can affect the brain, especially the hippocampus that plays an important role in spatial memory formation. Administration methanolic extract of Hibiscus sabdariffa Linn. (H. sabdariffa), a potent antioxidant, is expected to increase glutathione (GSH) level, the important endogenous antioxidant in hippocampus and to prevent the hippocampus-dependent spatial memory impairment on OT. Methods: This experimental study was conducted on 25 male rats (Rattus norvegicus 250–350 grams), randomly allocated into 5 groups: (1) control (C); (2) control with H. sabdariffa (C-Hib); (3) mild aerobic exercise (A-Ex); (4) overtraining exercise (OT); (5) overtraining exercise with H. sabdariffa (OT-Hib). Methanolic extract of H. sabdariffa (500 mg/kg/d, 11 weeks) were administered orally via syringe cannula. Overtraining exercise correspondent to Hohl et al overtraining protocol. Hippocampus-dependent spatial memorywas measured by using consolidation Y-Maze test in the end week 11. Hippocampal GSH level will be measured by Ellman method. Result: GSH level in OT group was lower significantly than A-Ex group (p = 0.002), OT-Hib group (p = 0.04), but lower not significant compared to C group (p = 0.05) (ANOVA followed by Tamhane Post Hoc Tests). GSH level in OT-Hib was higher significantly than C group (p = 0.016) and C-Hib group (p = 0.048). Memory test in OT-Hib was significantly higher than C group (p = 0.008) and C-Hib group (p = 0.017). Statistical analysis revealed that there is a strong positive correlation between GSH level and memory test result (Pearson test, r = 0.746; p = 0.000). Conclusion: It was concluded that 500 mg/kgBW H. sabdariffa methanolic extract can maintain the GSH levels and is expected to prevent impairment memory in excessive physical exercise.