Ascorbigen is formed by indole-3-carbinole and ascorbic acid in brassica vegetables
February 1 2017

J Agric Food Chem. 2012. Effect of the pasteurization process on the contents of ascorbigen, indole-3-carbinol, indole-3-acetonitrile, and 3,3'-diindolylmethane in fermented cabbage. 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.

Clin Dermatol. 2009 . Ascorbigen: chemistry, occurrence, and biologic properties. Institute of Human Nutrition and Food Science, Christian-Albrechts-University, Kiel, Germany. Ascorbigen belongs to the glucosinolate family and occurs mainly in Brassica vegetables. It is formed by its precursor glucobrassicin. Glucobrassicin is enzymatically hydrolyzed to indole-3-carbinol, which in turn reacts with L-ascorbic acid to ABG. The degradation of glucobrassicin is induced by plant tissue disruption. The Ascorbigen  formation depends on pH and temperature. The degradation in acidic medium causes a release of l-ascorbic acid and a formation of methylideneindolenine, not diindolemethane; in more alkaline medium, the degradation of Ascorbigen  causes the formation of 1-deoxy-1-(3-indolyl)-alpha-L-sorbopyranose and 1-deoxy-1-(3-indolyl)-alpha-l-tagatopyranose. Ascorbigen may partly mediate the known anticarcinogenic effect of diets rich in Brassicacae. Furthermore, it is able to induce phase I and II enzymes that are centrally involved in the detoxification of xenobiotics. Cosmeceuticals containing it as an active principle are becoming increasingly popular, although the underlying cellular and molecular mechanisms regarding its potential antiaging and ultraviolet-protective properties have not been fully established.

Altern Med Rev. 2000. The use of ascorbigen in the treatment of fibromyalgia patients: a preliminary trial. National College of Naturopathic Medicine, USA.  Twelve female fibromyalgia syndrome (FMS) patients were given 500 mg per day of a blend containing 100 mg ascorbigen and 400 mg broccoli powder in a preliminary, one-month, open-label trial. This group of patients showed a mean 20 percent decrease in their physical impairment score and a mean 17.8 percent decrease in their total fibromyalgia impact scores as measured by the Fibromyalgia Impact Questionnaire. The mean physical impairment score two weeks post-treatment showed a significant return to near pre-treatment level. Analysis of ten of the patients' mean threshold pain levels at the 18 possible tender points obtained before and at the end of treatment showed a strong trend toward an increase in the mean threshold pain level. The reduced sensitivity to pain and improvement in quality of life measured in this study appear to be clinically relevant and a larger, double-blind study is warranted.

Exp Dermatol. 2010. Sulforaphane but not ascorbigen, indole-3-carbinole and ascorbic acid activates the transcription factor Nrf2 and induces phase-2 and antioxidant enzymes in human keratinocytes in culture. Institute of Human Nutrition and Food Science, Christian-Albrechts-University, Kiel, Germany. Nrf2 is a basic leucine zipper transcriptional activator essential for the coordinated transcriptional induction of phase-2 and antioxidant enzymes. Brassica vegetables contain phytochemicals including glucoraphanin, the precursor of sulforaphane (SFN) and glucobrassicin, the precursor of indole-3-carbinole (I3C) and ascorbigen (ABG). The degradation products SFN, I3C and ABG may be capable of inducing cytoprotective genes in skin. In this study, we tested the potency of SFN, ABG and I3C in affecting Nrf2-dependent gene expression in human keratinocytes in culture. SFN but not ABG and its precursors I3C and ascorbic acid induced Nrf2 dependent gene expression at a relatively low concentration (5 micromol/l). Induction of Nrf2 due to SFN was accompanied by an increase in mRNA and protein levels of NADPH quinone oxidoreductase 1, heme oxygenase 1 and gamma-glutamylcysteine-synthetase. Furthermore, SFN elevated cellular glutathione levels and antagonized tumor necrosis factor-alpha-induced NFkappaB transactivation. Therefore, SFN treatment may present a strategy for enhancing the cellular defense mechanisms in skin.