Bioavailability of Chemopreventive and Nutritional Compounds in Broccoli

Bioavailability of Bioactive Compounds in Broccoli

The aim of this study was to determine the absorption of isothiocyanates (ITC) after ingestion of kailan-hybrid broccoli through the analysis of the correspondent urinary biomarkers. Furthermore, the effect of cooking (microwave) on the mentioned metabolic fate of these ITC was studied comparing to the uncooked vegetable.

Background Glucosinolates (sulphur-containing compounds) are hydrolyzed by the plant enzyme myrosinase to ITC, which have chemopreventive properties. No information has been reported about the metabolic fate of ITC in the kailan-hybrid broccoli, which physicochemical characteristics could greatly influence that metabolic fate. Previous studies have shown that cooking process of vegetables may vary the human absorption of the correspondent nutritional and bioactive compounds.

Research Methods & Procedures 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.

Inclusion Criteria:

• Subjects with a body mass index between 19 and 28.
• Subjects age: 22-50 years-old.
• Good health of subjects: confirmed by medical history, physical examination and clinical laboratory analysis of urine and blood (complete blood count and liver function markers including serum glutamic-pyruvic transaminase bilirubin test and glucose-6-phosphate dehydrogenase).

Exclusion Criteria:

• Tobacco smoking.
• Use of regular medications.
• Had taken antibiotics for 4 weeks immediately preceding the study.
• History of kidney stones, diabetes mellitus, bleeding disorders or family history of iron overload/hemochromatosis.