Aim: Recent studies have made it clear that brassica vegetables contain 2-thiothiazolidine-4-carboxylic acid (TTCA), which is the most widely used biological monitoring index of exposure to carbon disulfide (CS2). This study aimed to assess the time-course of TTCA excretion in urine (TTCA-U) after eating brassica vegetables. Methods: After a 1-d break from eating brassica vegetables, ten volunteers (6 males and 4 females) ingested 100 grams of chopped raw cabbage containing 4.3 mg/kg of TTCA, and the TTCA concentration in urine samples was determined over 24 h. TTCA concentrations in brassica vegetables purchased from a local supermarket were also measured. Results: TTCA-U reached peak concentrations 3-9 h after cabbage intake, gradually decreased, and was below the detection limit (<0.1 mg/l) in 8 of 10 volunteers in the last urine samples. The total amount of TTCA excreted in 24 h ranged from 0.19 to 0.42 mg, and half of the total TTCA was excreted within 6.5 h on average (range: 4.5-10.1). The excretion profiles of young and middle-aged volunteers seemed to differ, but not those of young males and young females. TTCA was detected in both raw and boiled cabbage, Japanese radish, turnip, and broccoli, but was not detected in Chinese cabbage or chingentsuai. Conclusion: TTCA-U may be overestimated as an index of CS2 exposure when brassica vegetables are ingested within approximately 24 h before collection of the urine sample.
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