RESUMO
Polysaccharides in boletes (Boletales) are economically significant to both function food and medicinal industries. The polysaccharides were extracted from the fruit bodies of eight boletes, namely, Aureoboletus longicollis, Butyriboletus hainanensis, Crocinoboletus rufoaureus, Hemioporus japonicus, Neoboletus infuscatus, Neoboletus obscureumbrinus, Tylopilus otsuensis, Xanthoconium fusciceps, which were collected from tropical China; their physicochemical properties and antioxidant activities were characterised and evaluated, respectively. The results revealed that the polysaccharides among the eight boletes were mainly composed of glucose, mannose, and galactose, with a broad molecular weight range, and contained a pyranose ring revealed by FT-IR and NMR spectral analyses. Many factors such as different species of boletes, geographic conditions, molecular weight, configuration, and monosaccharide content may affect the antioxidant power of polysaccharides, simultaneously, instead of one single factor. The antioxidant activities of the polysaccharides were measured according to in vitro assays of DPPH scavenging, superoxide anion scavenging, and ferrous ion reducing tests. The polysaccharide of C. rufoaureus has greatly superior antioxidant activity and it could serve as potential functional food or medicine.
RESUMO
BACKGROUND: Sodium pyruvate (PYR) has been reported to improve aerobic metabolism and attenuate metabolic acidosis. Aerobic capacity and the ability to remove hydrogen ions affect the recovery from repeated high intensity activities. However, the effects of PYR supplementation on repeated sprint exercise (RSE) performance have not been elucidated. This study explored the effects of PYR ingestion on RSE ability and recovery. METHODS: A total of 14 male soccer athletes (aged 20±2 years) participated in this double-blinded crossover study. The subjects completed two experimental sessions after randomized ingestion of either PYR or the maltodextrin placebo (PLA) for 1 week. At each session, participants completed high-intensity interval exercise (HIIE) and RSE 60 minutes after supplementation. Additionally, acid-base parameters in venous blood, energy system contributions, and power output were assessed. RESULTS: Compared to PLA, PYR supplementation significantly increased the relative peak power output (PPO) of the first (P=0.034) and fifth (P=0.043) sprints, and the relative mean power output (MPO) of the fifth sprint (P=0.026). In addition, the mean PPO (P=0.031) and MPO (P=0.033) of sprints 1-6 were significantly elevated after PYR supplementation. After PYR administration, the phosphagen energy system [adenosine triphosphate (ATP)-phosphocreatine (PCr)] resynthesis of the fourth (P=0.034) and the overall recovery periods during HIIE (P=0.029) were higher than PLA administration. Additionally, the ATP-PCr resynthesis of the first (P=0.033) and fifth (P=0.019) recovery periods, and the mean of the six recovery periods during RSE (P=0.041) were increased in the PYR group compared to the PLA group. Furthermore, participants on the PYR regimen had higher blood pH, HCO3-, and base excess at pre-HIIE, post-HIIE, and pre-RSE (all P<0.05) compared to participants receiving PLA. CONCLUSIONS: PYR supplementation enhanced RSE performance, and the improvement may be attributed to accelerated restoration of the acid-base balance and ATP-PCr regeneration. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100053936.
