Effect of hydroalcoholic extract of Aegle marmelos fruit on radical scavenging activity and exercise-endurance capacity in mice

Context: Aegle marmelos L. Corr (Rutaceae) is an important Indian Ayurvedic medicinal plant used for the treatment of various ailments. However, little information is available on the anti-fatigue properties of its fruit. Objective: Evaluation of the physical endurance and exercise-induced oxidative stress modulating properties of A. marmelos fruit in mice. Material and methods: Radical scavenging activity of the fruit hydroalcoholic extract was evaluated using in vitro systems. The extract was further evaluated for its endurance-enhancing properties at three oral doses (100, 200 and 400 mg/kg b.wt) in BALB/c mice for 21 d using a swimming test. Results and discussion: The extract exhibited significant scavenging activity against DPPH (IC50, 351 +/- 37 mu g/ml) and ABTS radicals (IC50, 228 +/- 25 mu g/ml), respectively, with the polyphenol content of 95 mu g/mg extract. It also inhibited AAPH radical-induced oxidation of biomolecules such as BSA protein (63%), plasmid DNA (81%) and lipids (80.5%). Administration of extract resulted in an increase in the duration of swimming time to exhaustion by 23.4 and 47.5% for medium and higher doses, respectively. The extract significantly normalized the fatigue-related biochemical parameters and also down-regulated the swim stress-induced over-expression of heat shock protein-70 and up-regulated the skeletal muscle metabolic regulators (GLUT-4 and AMPK1-alpha) by 2- and 3-fold, respectively, at the higher dose in muscle tissues. Conclusion: Our study demonstrates the anti-fatigue properties of A. marmelos fruit, most probably manifested by delaying the accumulation of serum lactic acid, increasing the fat utilization and up-regulating the skeletal muscle metabolic regulators.