Swimming capacity of mice is increased by oral administration of a nonpungent capsaicin analog, stearoyl vanillylamide

Effects of Capsiate Supplementation on Maximal Voluntary Contraction in Healthy Men

This study aimed to investigate the effects of acute capsaicin analog (Capsiate - CAP) supplementation on maximal voluntary isometric contraction (MVIC) performance in healthy young men. Thirteen subjects (25.2±3.2 yrs) participated in the present study. In two different days separated by one week, the subjects ingested capsiate (12 mg) or placebo (starch: 12 mg) 45 minutes before a MVIC test. The MVIC test consisted of five 10-second knee extension maximal isometric contractions with 45 seconds of recovery between efforts. The peak force, mean force, minimum force, fatigue index, and area under the curve of each contraction were calculated. Main condition effect was found, with higher values of peak force (+4.83%, F=6.867, p=0.02), fatigue index (+8.96%, F=5.228, p=0.041), and area under the curve (+4.19%, F=4.774, p=0.04) for CAP compared to placebo, however, no interaction effect was found for any variable (F=0.090 to 1.356, p≥0.276). In summary, healthy young men produced higher maximal isometric force and delayed fatigue in the CAP condition compared to placebo condition (condition effect) but without significant difference between each effort.

Capsaicinoid and Capsinoids as an Ergogenic Aid: A Systematic Review and the Potential Mechanisms Involved

CONTEXT

Capsaicinoids and capsinoids (CAP) are natural substances found primarily in chili peppers and other spicy foods that agonize the transient receptor potential vanilloid-1 in the mouth, stomach, and small intestine. Several studies have shown CAP to be a potential antiobesity agent and to exhibit an analgesic effect in both rodents and humans. However, there is no scientific consensus about the effects of CAP on physical exercise performance and its physiological mechanisms of action.

PURPOSE

This systematic review aimed to better elucidate the effects of CAP compounds as ergogenic aids and to discuss underlying mechanisms of action by which this supplement may potentially enhance endurance performance and muscular strength.

CONCLUSIONS

Among 22 studies included in the review, 14 examined the effects of capsaicinoid or capsinoid compounds on endurance and resistance exercise performance in animals, with 9 studies showing benefits on performance. In humans, 8 studies were included: 3 demonstrated significant acute endurance benefits and 2 showed acute resistance exercise performance benefits compared with a placebo condition. Therefore, while more mechanistic studies are necessary to confirm these outcomes in humans, the available scientific literature appears to suggest that these compounds could be considered an effective nutritional strategy to improve exercise performance.

Can taste be ergogenic?

Taste is a homeostatic function that conveys valuable information, such as energy density, readiness to eat, or toxicity of foodstuffs. Taste is not limited to the oral cavity but affects multiple physiological systems. In this review, we outline the ergogenic potential of substances that impart bitter, sweet, hot and cold tastes administered prior to and during exercise performance and whether the ergogenic benefits of taste are attributable to the placebo effect. Carbohydrate mouth rinsing seemingly improves endurance performance, along with a potentially ergogenic effect of oral exposure to both bitter tastants and caffeine although subsequent ingestion of bitter mouth rinses is likely required to enhance performance. Hot and cold tastes may prove beneficial in circumstances where athletes' thermal state may be challenged. Efficacy is not limited to taste, but extends to the stimulation of targeted receptors in the oral cavity and throughout the digestive tract, relaying signals pertaining to energy availability and temperature to appropriate neural centres. Dose, frequency and timing of tastant application likely require personalisation to be most effective, and can be enhanced or confounded by factors that relate to the placebo effect, highlighting taste as a critical factor in designing and administering applied sports science interventions.

Relationship between the acyl chain length of paradol analogues and their antiobesity activity following oral ingestion

6-Paradol is known to activate thermogenesis in brown adipose tissue (BAT), and paradol analogues with different acyl chain lengths possess different pungency thresholds. In this study, the influence of the acyl chain length on the antiobesity activity of the paradol analogues was investigated. The antiobesity activity of 6-paradol in mice fed a high-fat diet for 8 weeks was greater than that of dihydrocapsiate. A comparison of the antiobesity activities of zingerone and 6-paradol showed that the length of the acyl chain in the paradol analogue was important for strong activity. Furthermore, the antiobesity activities of 6-, 8-, and 12-paradol appeared to decrease in an acyl chain length-dependent manner. The mechanism of the antiobesity activity of 6-paradol was enhanced by increasing levels of energy metabolism in the BAT, as well as an increase in the expression of uncoupling proteins 1 via the activation of sympathetic nerve activity.

Stimulatory Effects ofPseudosasa japonicaLeaves on Exercise Performance

The performance-enhancing effects of Pseudosasa japonica were investigated in mice using an adjustable-current water pool. Compared to the control group, a 1.5-fold increase in swimming time was observed in the mouse group administered an 80% ethanol extract (PJE) of the leaves of P. japonica. The blood lactate level, an important indicator of fatigue, was significantly lower (28%, P<0.05) in PJE group than in the control group. These results suggest that PJE possesses stimulatory effects that can enhance exercise endurance and reduce fatigue.

Intragastric administration of allyl isothiocyanate increases carbohydrate oxidation via TRPV1 but not TRPA1 in mice

The transient receptor potential (TRP) channel family is composed of a wide variety of cation-permeable channels activated polymodally by various stimuli and is implicated in a variety of cellular functions. Recent investigations have revealed that activation of TRP channels is involved not only in nociception and thermosensation but also in thermoregulation and energy metabolism. We investigated the effect of intragastric administration of TRP channel agonists on changes in energy substrate utilization of mice. Intragastric administration of allyl isothiocyanate (AITC; a typical TRPA1 agonist) markedly increased carbohydrate oxidation but did not affect oxygen consumption. To examine whether TRP channels mediate this increase in carbohydrate oxidation, we used TRPA1 and TRPV1 knockout (KO) mice. Intragastric administration of AITC increased carbohydrate oxidation in TRPA1 KO mice but not in TRPV1 KO mice. Furthermore, AITC dose-dependently increased intracellular calcium ion concentration in cells expressing TRPV1. These findings suggest that AITC might activate TRPV1 and that AITC increased carbohydrate oxidation via TRPV1.

Long-chain N-vanillyl-acylamides from Capsicum oleoresin

N-Vanillyl-acylamides (NVAs) naturally occur as capsaicinoids in Capsicum plants. NVAs with a longer chain acyl moiety (LCNVAs) have been developed as attractive tools for medicinal usage because of their capsaicin-like bioactive and physiological properties, without harmful irritancy. In this study, we isolated four LCNVAs from Capsicum oleoresin. Their structures were determined to be N-vanillyl-hexadecanamide (palvanil, 2), N-vanillyl-octadecanamide (stevanil, 3), N-vanillyl-9E-octadecenamide (olvanil, 4), and N-vanillyl-9E,12E-octadecadienamide (livanil, 5) by spectroscopic analysis and gas chromatography-mass spectrometry analysis of their methanolysis products. Furthermore, the existence of two LCNVAs in oleoresin, N-vanillyl-tetradecanamide (myrvanil, 1) and N-vanillyl-9E,12E,15E-octadecatrienamide (linvanil, 6), was suggested. The contents of these LCNVAs and the major capsaicinoids-capsaicin and dihydrocapsaicin-in three Capsicum oleoresins and the fresh fruits of two hot peppers were measured by a liquid chromatography-tandem mass spectrometry system. The content ratios of the total LCNVAs, except for myrvanil, versus the capsaicin in the oleoresins (0.1-41%) was significantly larger than that in fresh fruits (<0.01%). The composition of these LCNVAs in each oleoresin was similar to that of fatty acids in the oil fraction of each oleoresin. We observed no relationship between the composition of these LCNVAs in the fresh fruits.

Improved swimming pool achieves higher reproducibility and sensitivity to effect of food components as ergogenic AIDS

A previously developed current swimming pool for mice has been used to evaluate many food components that enhance endurance exercise performance. In this article, to improve reproducibility, reliability and sensitivity of this assay system, we improved the spout part to generate a uniform current and divided the pool into six lanes to avoid physical interference between swimming mice. The stability of the current flow was assessed by measuring the surface current speed and water volume from the spout part. Maximum swimming times of ddY and BALB/c mice were measured to assess the reproducibility of the maximum swimming time. The improvement in sensitivity compared to the original equipment was estimated under three physiological conditions: low carbohydrate diet feeding, low blood hemoglobin level, and carbohydrate supplementation during exercise. The new spout part improved uniformity and quick adjustment of surface current, yielding an increase of workload in a stepwise manner during swimming. Exercise workload was increased in proportion to surface current speed, as evidenced by cadence of kicks and serum lactic acid levels. The improved swimming pool showed higher reproducibility of swimming time until fatigue (p<0.0001). Correspondence between blood hemoglobin concentration and swimming time was improved in the swimming pool. The improved swimming pool yielded higher sensitivity for low carbohydrate diet feeding (p<0.0001) and carbohydrate supplementation during exercise (p<0.01) compared to the original swimming pool. The improvement of the swimming pool achieved higher sensitivity and reproducibility in assessing various diet and food components compared to the original swimming pool.

Effect of Erabu Sea Snake (Laticauda semifasciata) Lipids on the Swimming Endurance of Mice

BACKGROUND/AIM

This study was designed to investigate the effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance of mice.

METHOD

Twelve-week-old male Crlj: CD-1 (ICR) mice were fed one of three experimental diets containing 6% lard, fish oil or sea snake lipids for 16 weeks. Swimming exercise was conducted in an acrylic plastic tank filled with 25 cm of water maintained at 23 degrees C. Every 4 weeks, the mice were made to perform swimming exercises with loads attached to their tails, corresponding to approximately 1 or 2% of their body weights.

RESULTS

The group fed the sea snake lipid diet exhibited significantly improved swimming endurance compared with the lard diet group (p < 0.05); however, this result was not observed in the fish oil diet group. In the sea snake lipid diet group, plasma and muscle lactates were significantly lower, and plasma glucose and muscle glycogen were significantly higher than in the lard diet group (p < 0.05).

CONCLUSION

These results suggest that the intake of sea snake lipids enhanced the swimming endurance of the mice by delaying the accumulation of lactate during swimming exercise.

Transforming growth factor-beta in the brain regulates fat metabolism during endurance exercise

We have previously reported that the concentration of transforming growth factor-beta (TGF-beta) increases in the cerebrospinal fluid of rats during exercise and that there is an increase in whole body fat oxidation following the intracisternal administration of TGF-beta. These results led us to postulate that TGF-beta in the brain regulates the enhancement of fatty acid oxidation during exercise. To test this hypothesis, we carried out respiratory gas analysis during treadmill running following the inhibition of TGF-beta activity in rat brain by intracisternal administration of anti-TGF-beta antibody or SB-431542, an inhibitor of the type 1 TGF-beta receptor. We found that each reagent partially blocked the increase in the fatty acid oxidation. We also compared the plasma concentrations of energy substrates in the group administered anti-TGF-beta antibody and the control group during running. We found that the plasma concentrations of nonesterified fatty acids and ketone bodies in the group administered anti-TGF-beta antibody were lower than in the control group at the end of running. In the same way, we carried out respiratory gas analysis during treadmill running after depressing corticotropin-releasing factor activity in the brain using intracisternal administration of astressin, an inhibitor of the corticotropin-releasing factor receptor. However, there were no significant differences in respiratory exchange ratio or oxygen consumption in moderate running (60% maximum oxygen consumption). These results suggest that brain TGF-beta has a role in enhancing fatty acid oxidation during endurance exercise and that this regulation is executed at least partly via the type 1 TGF-beta receptor signal transduction system.

Metabolically active functional food ingredients for weight control

The scale of the obesity epidemic creates a pressing consumer need as well as an enormous business opportunity for successful development and marketing of food products with added benefits for weight control. A number of proposed functional food ingredients have been shown to act post-absorptively to influence substrate utilization or thermogenesis. Characteristics and supporting data on conjugated linoleic acid, diglycerides, medium-chain triglycerides, green tea, ephedrine, caffeine, capsaicin and calcium, are reviewed here, giving examples of how these could act to alter energy expenditure or appetite control. Consideration is also given to other factors, in addition to efficacy, which must be satisfied to get such ingredients into foods. We conclude that, for each of the safe, putatively metabolically active agents, there remain gaps in clinical evidence or knowledge of mechanisms, which need to be addressed in order to specify the dietary conditions and food product compositions where these ingredients could be of most benefit for weight control.

Green tea extract improves endurance capacity and increases muscle lipid oxidation in mice

Green tea contains a high level of polyphenolic compounds known as catechins. We investigated the effects of green tea extract (GTE), which is rich in catechins, on endurance capacity, energy metabolism, and fat oxidation in BALB/c mice over a 10-wk period. Swimming times to exhaustion for mice fed 0.2–0.5% (wt/wt) GTE were prolonged by 8–24%. The effects were dose dependent and accompanied by lower respiratory quotients and higher rates of fat oxidation as determined by indirect calorimetry. In addition, feeding with GTE increased the level of β-oxidation activity in skeletal muscle. Plasma lactate concentrations in mice fed GTE were significantly decreased after exercise, concomitant with increases in free fatty acid concentrations in plasma, suggesting an increased lipid use as an energy source in GTE-fed mice. Epigallocatechin gallate (EGCG), a major component of tea catechins, also enhanced endurance capacity, suggesting that the endurance-improving effects of GTE were mediated, at least in part, by EGCG. The β-oxidation activity and the level of fatty acid translocase/CD36 mRNA in the muscle was higher in GTE-fed mice compared with control mice. These results indicate that GTE are beneficial for improving endurance capacity and support the hypothesis that the stimulation of fatty acid use is a promising strategy for improving endurance capacity.

Protocol for measuring the endurance capacity of mice in an adjustable-current swimming pool

We re-examined the methods used in an adjustable-current swimming pool for evaluating the endurance capacity of mice to improve the sensitivity and reproducibility. We found that the BALB/c strain was most suitable to minimize the variation in time taken to swim to the point of fatigue. We found that precise adjustment of the apparatus and the use of three primary swimming trials to select mice before a study made the swimming time more uniform. This procedure was used to establish a more precise evaluation protocol.

Enzymatic synthesis of a capsinoid by the acylation of vanillyl alcohol with fatty acid derivatives catalyzed by lipases

Capsinoids are a novel group of compounds produced by the Capsicum plant. We synthesized a capsinoid by the lipase-catalyzed esterification of vanillyl alcohol with fatty acid derivatives in an organic solvent. The use of seven out of 17 commercially available lipases, especially Novozym 435, was applicable to the synthesis of vanillyl nonanoate, a model compound of capsinoids. The yield of vanillyl nonanoate under the optimum conditions of 50 mM vanillyl alcohol and 50 mM methyl nonanoate in 500 microl of dioxane, using 20 mg of Novozym 435 and 50 mg of 4 A molecular sieves at 25 degrees C, was 86% in 20 h. Several capsinoid homologues having various acyl chain lengths (C6-C18) were synthesized at 64-86% yields from the corresponding fatty acid methyl ester. The natural capsinoids, capsiate and dihydrocapsiate, were obtained by a 400-fold-scale reaction at these optimum conditions in 60% and 59% isolated yields, respectively.

Chronic (-)-hydroxycitrate administration spares carbohydrate utilization and promotes lipid oxidation during exercise in mice

(-)-Hydroxycitrate (HCA) is an active ingredient that is extracted from the rind of the Indian fruit, Garcinia cambogia, which is available as an herbal supplement and is used to lose weight. In this study, the acute and chronic effects of HCA on energy metabolism were examined in male Std ddY mice. Mice were placed into metabolic chambers and administered 10 mg HCA or water (control) orally. Serum free fatty acid levels were significantly higher 100 min after administration in the HCA group, but the respiratory exchange ratio was not different from that in the control group. The concentration of glycogen in the gastrocnemius muscle was higher in the HCA group 16 h after administration, and in a separate study, the maximum swimming time until fatigue was slightly longer (P: = 0. 21) than that in the control group on d 1. The difference was significant on d 3 after 3 d of HCA or water administration. Other mice were administered 10 mg HCA or water orally twice a day for 25 d. On d 26, they were placed into metabolic chambers after administration and allowed to rest for 1 h, followed by 1 h of running at 15 m/min. Respiratory gas was monitored. The respiratory exchange ratio was significantly lower in the HCA group during both resting and exercising conditions. These results suggest that chronic administration of HCA promotes lipid oxidation and spares carbohydrate utilization in mice at rest and during running.