title: The effect of Katsura-uri (Japanese pickling melon, Cucumis melo var. conomon) and its derived ingredient methylthioacetic acid on energy metabolism during aerobic exercise.
abstract: OBJECTIVE
  We investigated the effect of Katsura-uri (Japanese pickling melon; Cucumis melo var. conomon) on energy metabolism during exercise in human and animal studies.
  
  
  METHODS
  Eight healthy men (mean age, 21.4 ± 0.7 years) participated in a single-blind, crossover study. Thirty minutes after ingesting the Katsura-uri drink or placebo drink, they exercised on a cycle ergometer at 40% maximal heart rate for 30 min. Respiratory gas analysis was performed during exercise to examine oxygen consumption and substrate utilization. Blood biochemical parameters were evaluated during exercise. In the animal study, the effect of methylthioacetic acid (MTA), a Katsura-uri derived component was examined in mice. Immediately after running at 25 m/min for 30 min, biochemical parameters in the hind limb muscle and blood of mice were measured.
  
  
  RESULTS
  Oxygen consumption during exercise was higher in the Katsura-uri condition (19.8 ± 3.5 mL/kg/min) than the placebo condition (18.6 ± 3.0 mL/kg/min) (P < 0.05). The elevation of blood lactate was lower in the Katsura-uri condition (1.7 ± 0.4 mM) than the placebo condition (2.2 ± 0.6 mM) 15 min after beginning exercise (P < 0.05). There was a higher positive correlation between lactate concentration and carbohydrate oxidation during exercise in the Katsura-uri condition (R(2) = 0.86) compared to the placebo condition (R(2) = 0.47). The decrease in intermuscular pH and the increase in blood lactate following exercise were prevented by MTA supplementation (250 ppm) with significant differences in the MTA-supplemented group compared to the control group.
  
  
  CONCLUSIONS
  These results suggest that the ingestion of Katsura-uri and/or MTA improves glucose metabolism and acidification in skeletal muscles during exercise in human and animal studies.
authors.affiliation: Laboratory of Health Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Aoi
authors.affiliation: Laboratory of Food Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Takeda
authors.affiliation: Laboratory of Food Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Azusa
authors.initials: A
authors.lastname: Sasaki
authors.affiliation: Laboratory of Food Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: Laboratory of Food Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Laboratory of Food Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Park
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502 Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sato
authors.affiliation: Laboratory of Health Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Masayo
authors.initials: M
authors.lastname: Iwasa
authors.affiliation: Laboratory of Health Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Airi
authors.initials: A
authors.lastname: Nakayama
authors.affiliation: Laboratory of Nutrition Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Minamikawa
authors.affiliation: Laboratory of Nutrition Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Horticultural Division, Kyoto Prefectural Agriculture, Forestry and Fisheries Technology Center, Kameoka, 621-0806 Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Shirota
authors.affiliation: Horticultural Division, Kyoto Prefectural Agriculture, Forestry and Fisheries Technology Center, Kameoka, 621-0806 Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Suetome
keywords: Aerobic exercise; Fragrant ingredient; Skeletal muscle