Human metabolic fate of glucosinolates from kailan-hybrid broccoli. Differences between raw and microwaved consumption

• Published in: Food research international 2013-08, Vol.53 (1), p.403-408
• Main Authors: Martinez-Hernandez, Gines B, Gomez, Perla A, Garcia-Talavera, Noelia V, Artes-Hernandez, Francisco, Monedero-Saiz, Tamara, Sanchez-Alvarez, Carmen, Artes, Francisco
• Format: Article
• Language: English
• Subjects: acids; Biological and medical sciences; blood; Brassica; Brassica oleracea Italica Group × Alboglabra Group; Broccoli; chemoprevention; colon; Cooking; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; glucosinolates; high performance liquid chromatography; humans; Ingestion; Isothiocyanates; Myrosinase; Raw; Samples; small intestine; Statistical analysis; Statistical methods; Sulforaphane; thioglucosidase; urine; Vegetables
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2013.05.002

Glucosinolates are sulphur-containing compounds present in Brassica species that are hydrolyzed by the plant enzyme myrosinase to isothiocyanates (ITC), which have previously reported chemopreventive properties. In vivo, ITC are metabolized and excreted in urine as mercapturic acids. A cross-over-design study of 7 subjects after ingestion of 200-g raw or microwaved kailan-hybrid broccoli was conducted. Total ITC equivalents in the vegetable, urine and blood samples were determined by HPLC as the cyclocondensation product of 1,2-benzenedithiol. The highest ITC metabolization (53.6±15.7% over the total ITC ingested) was observed during the first 4h after ingestion of raw product. However, the highest ITC metabolization after consumption of microwaved samples was delayed to 4–10h, with 23.2±27.6%. The high ITC metabolization during the first 4h was most likely due to absorption in the small intestine, while the second peak (4–8h) could be presumably attributed to an ITC absorption in the colon. The total ITC metabolization after raw kalian-hybrid consumption (79.1±18.8%) was approximately 2-fold higher than that from microwaved broccoli (41.3±8.8%), which was statistically significant (P, t test=0.005). The ITC absorption of the kailan-hybrid was 2 times higher for raw and 3–9 times higher for cooked samples than the values previously reported in the bibliography with conventional broccoli varieties. Compared to other brassicas, kailan-hybrid can be presented as a vegetable with both, a high concentration and a great ITC metabolization. •The isothiocyanates (ITC) absorption of kailan-hybrid, a new vegetable, was studied.•Microwaving delayed ITC metabolization up to 6h comparing to the raw broccoli•Raw broccoli consumption led 2-fold higher ITC metabolization than the cooked one.•ITC absorption from kailan-hybrid was 2–9-fold higher than conventional broccoli.