No Performance Benefits of Combined Mangiferin and Quercetin Supplementation in Cycling Athletes

The flavonoids mangiferin and quercetin are known for their antioxidant properties. The purpose of this study was to investigate the effects of combined mangiferin and quercetin (MQ) supplementation during prolonged intermittent cycling on sprint performance and 15-min time trial performance (15-min TT). Fourteen trained male endurance athletes (age 26 ± 5 years; body mass 80.7 ± 4.8 kg; stature 184 ± 7 cm; V̇O₂peak, 63.0 ± 8.9 mL min^-1 kg^-1), initially completed a 15-min TT in a fresh state to determine their maximal mean power output (MPO₁₅). On two separate days, participants then completed a 4-h intermittent cycling protocol at 60% of MPO₁₅, interspersed by 6- and 15-s maximal sprints every hour, as well as 30-s intervals at 120% of MPO₁₅ twice per hour. Upon completion of each protocol, participants immediately performed another 15-min TT. During the 4-h protocol, participants consumed 100 g CHO·h^-1. In addition, participants consumed 14.6 mg h^-1 of mangiferin and 23.9 mg h^-1 of quercetin in one of the trials, mixed into the CHO solution. Both trials showed similar reductions in 6-s peak power (MQ: -59 ± 82 W; Control: -42 ± 75 W, time effect: p = 0.007) and 15-s average power (MQ: -37 ± 50 W; Control: -19 ± 35 W, time effect: p = 0.02) during the 4-h protocol (trial × time: p = 0.35 and 0.34, respectively). Additionally, no difference was observed between the two conditions in 15-min TT performance following the 4-h protocols (MQ: 339 ± 56 W; Control: 341 ± 54 W, p = 0.61). In conclusion, combined mangiferin and quercetin supplementation during prolonged intermittent cycling did not affect sprint or time trial performance in trained endurance athletes.