Pumpkin (Cucurbita moschata) fruit extract improves physical fatigue and exercise performance in mice

Abstract

Pumpkin (Cucurbita moschata) is a popular and nutritious vegetable consumed worldwide. The overall purpose of this study was to evaluate the effects of C. moschata fruit extract (CME) on anti-fatigue and ergogenic functions following physiological challenges. Male ICR mice from four groups designated vehicle, CME-50, CME-100 and CME-250, respectively (n = 8 per group in each test) were orally administered CME for 14 days at 0, 50, 100 and 250 mg/kg/day. The anti-fatigue activity and exercise performance were evaluated using exhaustive swimming time, forelimb grip strength, as well as levels of plasma lactate, ammonia, glucose, and creatine kinase after an acute swimming exercise. The resting muscular and hepatic glycogen was also analyzed after 14-day supplementation with CME. Trend analysis revealed that CME treatments increased grip strength. CME dose-dependently increased 5% body weight loaded swimming time, blood glucose, and muscular and hepatic glycogen levels. CME dose-dependently decreased plasma lactate and ammonia levels and creatine kinase activity after a 15-min swimming test. The mechanism was relevant to the increase in energy storage (as glycogen) and release (as blood glucose), and the decrease of plasma levels of lactate, ammonia, and creatine kinase. Therefore, CME may be potential for the pharmacological effect of anti-fatigue.

Figure 1

Effect of CME supplementation on plasma (a,e) lactate, (b,f) ammonia, (c,g) glucose levels and (d,h) creatine kinase (CK) levels before and after an acute exercise challenge. Mice were pretreated with vehicle, 50, 100, and 250 mg/kg of CME for 14 days, then 1 h later performed a 15-min swimming test without weight-loading. Data represent mean ± SEM of 8 mice in each group. * p < 0.05; ** p < 0.01; *** p < 0.001 compared to vehicle control.

Figure 2

Effect of C . moschata extract (CME) supplementation on forelimb grip strength. Male ICR mice were pre-treated with vehicle, 50, 100, and 250 mg/kg ethanol extract of C . moschata (CME-50, CME-100, and CME-250) for 14 days, and underwent a grip strength test after 1 h of last administration. Data are presented as mean ± SEM of 8 mice in each group. ** p < 0.01; *** p < 0.001 compared to vehicle control.

Figure 3

Effect of CME supplementation on swimming exercise performance. Mice were pretreated with vehicle, 50, 100, and 250 mg/kg of CME for 14 days and, then 1 h later performed an exhaustive swimming exercise with a 5% body-weight load attached to the mouse tail. Data represent mean ± SEM (n = 8 mice). * p < 0.05; ** p < 0.01 compared to vehicle control.

Figure 4

Effect of CME on (a) muscular and (b) hepatic glycogen levels at rest. Mice were pretreated with vehicle, 50, 100, and 250 mg/kg of CME for 14 days, all mice were sacrificed and examined for glycogen levels of muscle and liver tissues at 1 h after last treatment. Data represent mean ± SEM of 8 mice in each group. * p < 0.05; ** p < 0.01, *** p < 0.001 compared to vehicle control.

Figure 5

Effect of CME treatment on the morphology of liver (a) and skeletal muscle (b). Mice were pretreated with vehicle, 50, 100, and 250 mg/kg of CME for 14 days, all mice were sacrificed and examined for the morphology of liver and skeletal muscle at the end of experiment. Specimens were photographed with a light microscope (Olympus BX51; Olympus Co., Ltd., Tokyo, Japan). (H&E stain, magnification: ×200, Scale bar, 20 μm).