Capsinoids, non-pungent capsaicin analogs, reduce body fat accumulation without weight rebound unlike dietary restriction in mice.

Enhancing energy expenditure and reducing energy intake are both crucial for weight control. Capsinoids, which are non-pungent capsaicin analogs, are known to suppress body fat accumulation and reduce body weight by enhancing energy expenditure in both mice and humans. However, it is poorly understood whether the suppression of body fat accumulation by capsinoids has an advantage over dietary restriction. This study shows that the oxygen consumption was increased in mice administered with capsinoids but not in dietary-restricted mice, although there was a similar suppression of body fat accumulation in both groups. The weight rebound was more notable in the dietary-restricted mice than in the mice administered with capsinoids. These results indicate that suppressing body fat accumulation by capsinoids was more beneficial than a restricted diet for maintaining body weight.

Ultra sensitive determination of limaprost, a prostaglandin E1 analogue, in human plasma using on-line two-dimensional reversed-phase liquid chromatography-tandem mass spectrometry.

A highly sensitive and selective method has been developed and validated to determine limaprost, a prostaglandin (PG) E(1) analogue, in human plasma by on-line two-dimensional reversed-phase liquid chromatography-tandem mass spectrometry (2D-LC/MS/MS) due to the lack of efficient methods to determine very low levels of limaprost in plasma. Limaprost and its deuterium derivatives, used as internal standard, were extracted by protein precipitation and following three-step solid phase extractions. After extraction procedure, samples were analyzed by on-line 2D-LC/MS/MS with electrospray ionization in negative mode. The 2D-LC system consists of Phenyl column at first dimension and ODS at second dimension with a trapping column placed between the separation columns. The linear dynamic range of this method was 0.1-10 pg/ml with 3 ml of plasma (r >0.9987). Acceptable precision and accuracy were obtained over the calibration curve ranges. The assay has been successfully used in analyses of human plasma samples to support clinical pharmacokinetics studies.

Capsiate, a nonpungent capsaicin analog, increases endurance swimming capacity of mice by stimulation of vanilloid receptors.

We investigated the effect of capsiate, a nonpungent natural capsaicin analog, on the swimming capacity of mice in an adjustable-current water pool. Male BALB/c mice orally given capsiate (10 mg/kg) were able to keep swimming longer before exhaustion than the control mice. After 30 min of swimming, the residual glycogen in the gastrocnemius muscle was higher, the serum free fatty acid concentration tended to be higher, and the serum lactic acid concentration was significantly lower in the capsiate-administered mice. The value for the respiratory exchange ratio of the capsiate group was significantly lower during both resting and treadmill running. These physiological differences were abolished by administering the vanilloid receptor antagonist, capsazepin (0.17 mmol/kg, i.p.). The mice were not averse to the capsiate solution during a 4-h two-bottle choice test. These results suggest that the oral administration of capsiate enhanced fat oxidation and spared carbohydrate utilization, and consequently increased the endurance swimming capacity of the mice via stimulation of their vanilloid receptors. Practical application of capsiate is expected.

Upregulation of uncoupling proteins by oral administration of capsiate, a nonpungent capsaicin analog.

Capsiate is a nonpungent capsaicin analog, a recently identified principle of the nonpungent red pepper cultivar CH-19 Sweet. In the present study, we report that 2-wk treatment of capsiate increased metabolic rate and promoted fat oxidation at rest, suggesting that capsiate may prevent obesity. To explain these effects, at least in part, we examined uncoupling proteins (UCPs) and thyroid hormones. UCPs and thyroid hormones play important roles in energy expenditure, the maintenance of body weight, and thermoregulation. Two-week treatment of capsiate increased the levels of UCP1 protein and mRNA in brown adipose tissue and UCP2 mRNA in white adipose tissue. This dose of capsiate did not change serum triiodothyronine or thyroxine levels. A single dose of capsiate temporarily raised both UCP1 mRNA in brown adipose tissue and UCP3 mRNA in skeletal muscle. These results suggest that UCP1 and UCP2 may contribute to the promotion of energy metabolism by capsiate, but that thyroid hormones do not.