Polysaccharides from Portulaca oleracea L Improve Exercise Endurance and Decrease Oxidative Stress in Forced Swimming Mice

Purpose: To explore the effects of polysaccharides from Portulaca oleracea L (POP) on exercise endurance and oxidative stress in forced-swimming mice. Methods: Forty-eight mice were divided into four groups of twelve animals each. All treatments were administered orally and daily for 28 days. Group A received isotonic saline solution (50 ml/kg bodyweight) as control group; B, C and D groups received 100, 200 and 400 mg/kg body wt. of POP as treatment groups, respectively. After the final treatment with POP, the mice were subjected to swimming to exhaustion and the exhaustive swimming time, blood lactic acid (BLA), blood glucose, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were measured. Results: The exhaustive swimming time of the POP-treated groups (967.3 ± 79.2, 1234.8 ± 97.6 and 1314.3 ± 107.3 s) was significantly longer than that of the control group (513.6 ± 41.2 s) (p < 0.05). After the exhaustive swimming exercise, BLA levels of the POP-treated groups (8.63 ± 0.91, 8.04 ± 0.86 and 7.51 ± 0.78 mmol/L) were significantly lower than that of the control group (11.39 ± 1.17 mmol/L) (p < 0.05). MDA levels of the POP-treated groups (2.69 ± 0.21, 2.41 ± 0.17 and 2.37 ± 0.23 U/mg.pro) were significantly lower than that of the control group (3.21 ± 0.29 U/mg.pro) (p < 0.05). On the other hand, blood glucose levels of the POP-treated groups (5.47 ± 0.48, 5.74 ± 0.57 and 6.04 ± 0.51 mmol/L) were significantly higher than that of the control group (4.89 ± 0.32 mmol/L) (p < 0.05). SOD levels of the POP-treated groups (124.36 ± 14.87, 136.39±13.48 and 145.87 ± 17.39 U/mg.pro) were significantly higher than that of the control group (108.41 ± 11.63 U/mg.pro) (p < 0.05). GPx levels of the POPtreated groups (68.24 ± 4.68, 71.33 ± 5.29 and 72.64 ± 5.99 U/mg.pro) were significantly higher than that of the control group (53.17 ± 5.24 U/mg.pro) (p < 0.05). CAT levels of the POP-treated groups (23.57 ± 1.71, 24.28 ± 2.14 and 26.72 ± 2.21 U/mg.pro) were significantly higher than that of the control group (19.48 ± 2.03 U/mg.pro) (p < 0.05). Conclusion: This study provides compelling evidence that POP can improve exercise endurance and decrease oxidative stress in forced swimming mice.