A Mango Leaf Extract (Zynamite(®)) Combined with Quercetin Has Exercise-Mimetic Properties in Human Skeletal Muscle

Zynamite PX(®), a mango leaf extract combined with quercetin, enhances exercise performance by unknown molecular mechanisms. Twenty-five volunteers were assigned to a control (17 males) or supplementation group (8 males, receiving 140 mg of Zynamite(®) + 140 mg quercetin/8 h for 2 days). Then, they performed incremental exercise to exhaustion (IE) followed by occlusion of the circulation in one leg for 60 s. Afterwards, the cuff was released, and a 30 s sprint was performed, followed by 90 s circulatory occlusion (same leg). Vastus lateralis muscle biopsies were obtained at baseline, 20 s after IE (occluded leg) and 10 s after Wingate (occluded leg), and bilaterally at 90 s and 30 min post exercise. Compared to the controls, the Zynamite PX(®) group showed increased basal protein expression of Thr(287)-CaMKIIδ(D) (2-fold, p = 0.007) and Ser(9)-GSK3β (1.3-fold, p = 0.005) and a non-significant increase of total NRF2 (1.7-fold, p = 0.099) and Ser(40)-NRF2 (1.2-fold, p = 0.061). In the controls, there was upregulation with exercise and recovery of total NRF2, catalase, glutathione reductase, and Thr(287)-CaMKIIδ(D) (1.2–2.9-fold, all p < 0.05), which was not observed in the Zynamite PX(®) group. In conclusion, Zynamite PX(®) elicits muscle signaling changes in resting skeletal muscle resembling those described for exercise training and partly abrogates the stress kinases responses to exercise as observed in trained muscles.