title: Pharmacokinetics of cycloalliin, an organosulfur compound found in garlic and onion, in rats.
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.
authors.affiliation: Healthcare Research Institute, Wakunaga Pharmaceutical Company, Ltd., 1624 Shimokotachi, Kodacho, Akitakata, Hiroshima 739-1195, Japan. ichikawa_m@wakunaga.co.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Ichikawa
authors.forename: Ikuko
authors.initials: I
authors.lastname: Mizuno
authors.forename: Jiro
authors.initials: J
authors.lastname: Yoshida
authors.forename: Nagatoshi
authors.initials: N
authors.lastname: Ide
authors.forename: Mitsuyasu
authors.initials: M
authors.lastname: Ushijima
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Kodera
authors.forename: Minoru
authors.initials: M
authors.lastname: Hayama
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Ono
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D005243:Feces / Q000737:chemistry; D005737:Garlic / Q000737:chemistry*; D007700:Kinetics; D008297:Male; D013058:Mass Spectrometry; D019697:Onions / Q000737:chemistry*; D010875:Pipecolic Acids / Q000008:administration & dosage / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D010875:Pipecolic Acids; C015094:cycloalliin