No abstract

Cycloalliin, an organosulfur compound found in garlic and onion, has been reported to exert several biological activities and also to remain stable during storage and processing. In this study, we investigated the pharmacokinetics of cycloalliin in rats after intravenous or oral administration. Cycloalliin and its metabolite, (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid, in plasma, urine, feces, and organs was determined by a validated liquid chromatography-mass spectrometry method. When administered intravenously at 50 mg/kg, cycloalliin was rapidly eliminated from blood and excreted into urine, and its total recovery in urine was 97.8% +/- 1.3% in 48 h. After oral administration, cycloalliin appeared rapidly in plasma, with a tmax of 0.47 +/- 0.03 h at 25 mg/kg and 0.67 +/- 0.14 h at 50 mg/kg. Orally administered cycloalliin was distributed in heart, lung, liver, spleen, and especially kidney. The Cmax and AUC0-inf values of cycloalliin at 50 mg/kg were approximately 5 times those at 25 mg/kg. When administered orally at 50 mg/kg, cycloalliin was excreted into urine (17.6% +/- 4.2%) but not feces. However, the total fecal excretion of (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid was 67.3% +/- 5.9% (value corrected for cycloalliin equivalents). In addition, no (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid was detected in plasma (<0.1 microg/mL), and negligible amounts (1.0% +/- 0.3%) were excreted into urine. In in vitro experiments, cycloalliin was reduced to (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid during anaerobic incubation with cecal contents of rats. These data indicated that the low bioavailability (3.73% and 9.65% at 25 and 50 mg/kg, respectively) of cycloalliin was due mainly to reduction to (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid by the intestinal flora and also poor absorption in the upper gastrointestinal tract. These findings are helpful for understanding the biological effects of cycloalliin.

ABSTRACT. In order to assess the functional role of the polyamines spermidine and spermine in pancreatic betacells, we examined the effect of spermidine and spermine synthase inhibitors, trans-4-methylcyclohexylamine (MCHA) and N-(3-aminopropyl)cyclohexylamine (APCHA), on cellular polyamine and insulin contents, insulin secretion, and cytoplasmic Ca 2+ concentration ([Ca 2+ ]i) in mouse insulin-secreting Beta-TC6 cells. The cellular spermidine and spermine contents were reduced 90% and 64% by cultivation of cells in the presence of MCHA and APCHA for 3 days, respectively. Addition of spermidine or spermine reversed the polyamine level reduced by MCHA or APCHA, respectively. Insulin secretion was decreased 40~60% in the cells treated with MCHA or APCHA. The reduction by MCHA was reversed to the untreated level by adding spermidine exogenously, while the effect of APCHA was not reversed by treatment with spermine. The cellular insulin content was also reduced by treatment with MCHA but not the expression of insulin 1 and 2 genes, suggesting that spermidine was involved in the translation of insulin mRNAs. The elevation of [Ca 2+ ]i, a key event triggering insulin secretion induced by glucose, was reduced in Beta-TC6 cells by MCHA treatment. The spermidine synthase inhibitor also augmented the sustained [Ca 2+ ]i rise induced by carbamylcholine but not by a high concentration of KCl or nicotine. These results suggested that spermidine rather than spermine plays an important role in the regulation of insulin synthesis and the glucose-induced [Ca 2+ ]i rise in Beta-TC6 cells.

Background: This study evaluated the effect of exercise training on body temperature and clarified the relationship between body temperature and body composition in the elderly. Methods: In this retrospective cohort study, a total of 91 elderly participants performed aerobic and anaerobic exercise training twice a week for 2 years. Non-contact infrared thermometer and bioelectrical impedance analysis were performed at baseline and at 2 years. Results: Mean age of study participants was 81.0 years. The participants were divided into two groups by baseline body temperature of 36.3 °C; lower body temperature group (n = 67) and normal body temperature group (n = 24). Body temperature rose significantly after exercise training in the lower body temperature group (36.04 ± 0.11 °C to 36.30 ± 0.13 °C, p < 0.0001), whereas there was no significant difference in the normal body temperature group (36.35 ± 0.07 °C to 36.36 ± 0.13 °C, p = 0.39). A positive correlation was observed between the amount of change in body temperature and baseline body temperature (r = −0.68, p < 0.0001). Increase in skeletal muscle mass was an independent variable related to the rise in body temperature by the multivariate logistic regression analysis (odds ratio: 4.77, 95% confidence interval: 1.29–17.70, p = 0.02). Conclusions: Exercise training raised body temperature in the elderly, especially those with lower baseline body temperature.