glucobrassicin and ascorbigen

Chemopreventive effects of broccoli, a highly valued vegetable, have been known for a long time. Several studies have demonstrated that broccoli might be beneficial by reducing the risk for the development of certain forms of cancer. These effects are generally attributed to glucosinolate-derived degradation products like isothiocyanates and indoles which are formed by the hydrolytic action of plant myrosinase and/or glucosidases deriving from the human microbial flora. However, recent in vitro and experimental animal studies indicate that broccoli, its extracts and the glucosinolate-derived degradation products might also have undesirable effects, especially genotoxic activities. However, the relevance of the genotoxic activities to human health is not known yet. This paper gives an overview on genotoxic, anti-genotoxic/chemopreventive, nutritive and antinutritive properties of broccoli, its ingredients and their degradation products. A qualitative comparison of the benefit and risk of broccoli consumption benefit-risk assessment shows that the benefit from intake in modest quantities and in processed form outweighs potential risks. For other preparations (fortified broccoli-based dietary supplements, diets with extraordinary high daily intake, consumption as a raw vegetable) further studies both for potential risks and beneficial effects are needed in order to assess the benefit and risk in the future.

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Brassica; DNA Damage; Glucosinolates; Glycoside Hydrolases; Humans; Indoles; Isothiocyanates; Models, Animal; Neoplasms; Plant Extracts; Risk Assessment; Sulfoxides; Thiocyanates; Vegetables

Searches for the natural compounds that determine the anticarcinogenic properties of a cruciferous-vegetable diet, revealed the products of alkaloid glucobrassicin biotransformations; among these, ascorbigen, an indole-containing derivative of L-ascorbic acid, was found to be the most abundant. Study of chemical properties of ascorbigen showed that it is capable of different transformations in acidic (including gastric juice) and slightly alkaline (including blood) media. The stable and unstable products of ascorbigen transformation determine the biological properties of the compound. The most important product of ascorbigen transformation in gastric juice is 5,11-dihydroindolo[3,2-b]-carbazole, with a binding affinity to the Ah receptor only 3.7 x 10(-2) lower than that of tetrachlorodibenzodioxin. This compound may be responsible for modifying P450 enzyme activities. Ascorbigen and its analogs are available synthetically. Their biological evaluation showed that some of the compounds of these series are immunomodulators. The most active is N-methylascorbigen, which demonstrates therapeutic effects (inhibition of tumor growth, protection of animals from bacterial and viral infections). The immunomodulatory activity of natural ascorbigen may be an additional factor of importance for the anticarcinogenic properties of a cruciferous-vegetable diet.

Topics: Adjuvants, Immunologic; Animals; Anticarcinogenic Agents; Ascorbic Acid; Biotransformation; Brassica; Glucosinolates; Humans; Hydrogen-Ion Concentration; Indoles; Molecular Sequence Data; Neoplasms, Experimental

The aim of the study was to investigate the effect of storage on the contents of glucosinolates (GLS) and their degradation products in a boiled white cabbage. A 24h storage at 4 °C resulted in a decrease in GLS content (20-40%, depending on the cooking time applied) in the edible parts. The most significant losses were observed for sinigrin (20-45%), and the least for glucobrassicin (12-32%). Storage had a diversified effect on GLS breakdown products (indole-3-acetonitrile, indole-3-carbinol, ascorbigen and 3,3'-diindolylmethane released from glucobrassicin and 4-methylsulfinylbutanenitrile released from glucoiberin) in the boiled cabbage. The increase in the content of indole-3-acetonitrile, especially considerable within the first 24h of storage (and a simultaneous decrease in glucobrassicin) clearly indicates that degradation of GLS may occur during storage or cooling to 4 °C.

Topics: Ascorbic Acid; Brassica; Drug Stability; Fermentation; Food Handling; Food Preservation; Glucosinolates; Hot Temperature; Indoles

The aim of the study was to investigate the effect of the pasteurization process on the content of ascorbigen, indole-3-carbinol, indole-3-acetonitrile, and 3,3'-diindolylmethane in fermented cabbage. Pasteurization was run at a temperature of 80 °C for 5-30 min. Significant changes were only observed in contents of ascorbigen and 3,3'-diindolylmethane. The total content of the compounds analyzed in cabbage pasteurized for 10-30 min was found to be decreased by ca. 20%, and the losses were due to thermal degradation of the predominating ascorbigen. Pasteurization was found not to exert any considerable effect on contents of indole-3-acetonitrile and indole-3-carbinol in cabbage nor did it affect contents of the compounds analyzed in juice.

Topics: Ascorbic Acid; Brassica; Fermentation; Glucosinolates; Hot Temperature; Indoles; Pasteurization

Topics: Ascorbic Acid; Carbohydrate Metabolism; Glucosinolates; Glycoside Hydrolases; Humans; In Vitro Techniques; Indoles