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

PurposeWe investigated the effect of Katsura-uri (Japanese pickling melon; Cucumis melo var. conomon) on energy metabolism during exercise in human and animal studies.MethodsEight 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.ResultsOxygen 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 (R2 = 0.86) compared to the placebo condition (R2 = 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.ConclusionsThese 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.

Methylthioacetic acid, a derivative of aroma compounds from <i>Cucumis melo</i> var. <i>conomon</i> dose-dependently triggers differentiation and apoptosis of RCM-1 human colorectal cancer cells

“…We used the number of domes formed in the RCM-1 cell culture as a guide for screening to isolate the above-mentioned MTPE and MTAE from Katsura-uri and piperitenone oxide (PO) from spearmint (Mentha spicata) as well (Nakamura et al, 2008(Nakamura et al, , 2010(Nakamura et al, , 2014. Furthermore, we identified methylthioacetic acid (MTA), an acid-hydrolyzed derivative of MTAE (Aoi et al, 2015) to have the most potent dome-inducing activity among the 37 MTPE and MTAE analogs and it is involved in the cell cycle arrest of RCM-1 (Kamimura et al, 2020). On the other hand, the physiological and molecular properties of MTA remain unknown.…”

Contribution of <i>Katsura-uri</i> (Japan’s Heirloom Pickling Melon, <i>Cucumis melo</i> var. <i>conomon</i>) at the Completely Ripe Stage to Diabetes Control

“…Certain compounds responsible for the aroma of the completely ripe Katsura-uri are also involved in other physiological functions (1)(2)(3)(4). Six aroma substances (methylthioacetic acid ethyl ester: MTAE; acetic acid 2-methylthio ethyl ester: AMTE; 3-methylthiopropionic acid ethyl ester: MTPE; acetic acid 3-methylthio propyl ester: AMTP; benzyl acetate: BA; eugenol) were identified in completely ripe Katsura-uri fruits, and five of them (except BA) possessed at least one or more anticarcinogenic effects as determined by differentiationinducing, antimutagenic, and antioxidative activities (2).…”

“…Six aroma substances (methylthioacetic acid ethyl ester: MTAE; acetic acid 2-methylthio ethyl ester: AMTE; 3-methylthiopropionic acid ethyl ester: MTPE; acetic acid 3-methylthio propyl ester: AMTP; benzyl acetate: BA; eugenol) were identified in completely ripe Katsura-uri fruits, and five of them (except BA) possessed at least one or more anticarcinogenic effects as determined by differentiationinducing, antimutagenic, and antioxidative activities (2). MTAE-derived methylthioacetic acid, which MTAE is acid-hydrolyzed to in stomach, improves glucose aerobic metabolism in skeletal muscle during exercise (3). We previously identified Katsura-uri fruit as a low-carbohydrate-content food material which was unique in the character of fruits kingdom, and had therefore potential benefit for obese people and diabetic subjects.…”