ASCORBIGEN AND OTHER INDOLE-DERIVED COMPOUNDS FROM BRASSICA VEGETABLES AND THEIR ANALOGS AS ANTICARCINOGENIC AND IMMUNOMODULATING AGENTS

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, a n 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 gastr ic juice) and slightly alkaline (including blood) media. The stable an d unstable products of ascorbigen transformation determine the biologi cal properties of the compound. The most important product of ascorbig en transformation in gastric juice is 5,11-dihydroindolo[3,2-b]-carbaz ole, with a binding affinity to the Ah receptor only 3.7 x 10(-2) lowe r than that of tetrachlorodibenzodioxin. This compound may be responsi ble for modifying P450 enzyme activities. Ascorbigen and its analogs a re available synthetically. Their biological evaluation showed that so me of the compounds of these series are immunomodulators. The most act ive is N-methylascorbigen, which demonstrates therapeutic effects (inh ibition of tumor growth, protection of animals from bacterial and vira l infections). The immunomodulatory activity of natural ascorbigen may be an additional factor of importance for the anticarcinogenic proper ties of a cruciferous-vegetable diet.