GENOTOXIC EFFECTS OF CRUDE JUICES FROM BRASSICA VEGETABLES AND JUICESAND EXTRACTS FROM PHYTOPHARMACEUTICAL PREPARATIONS AND SPICES OF CRUCIFEROUS PLANTS ORIGIN IN BACTERIAL AND MAMMALIAN-CELLS

Crude juices of eight Brassica vegetables as well as juices and extrac ts of spices and phytopharmaceutical preparations from cruciferous veg etables were tested for induction of point mutations in Salmonella TA9 8 and TA100, repairable DNA damage in E.coli K-12 cells and clastogeni c effects in mammalian cells. In bacterial assays, all juices caused g enotoxic effects in the absence of metabolic activation, the ranking o rder being: Brussels sprouts > white cabbage > cauliflower > green cab bage > kohlrabi > broccoli > turnip > black radish. In experiments wit h mammalian cells, six juices induced structural chromosome aberration s. Brussels sprouts, white and green cabbage caused the strongest effe cts (800 mu l of juice induced a 5-fold increase over the background). In sister chromatid exchange assays, positive results were measured a s well, but the effects were less pronounced. With all juices the geno toxic effects seen in mammalian cells were paralleled by a pronounced decrease in cell viability. Column fractionation experiments showed th at 70-80% of the total genotoxic activity of the juices is found in th e fraction which contains isothiocyanates and other breakdown products of glucosinolates, whereas phenolics and flavonoids contributed to a lesser extent to the overall effects. On the basis of these findings, and considering the negative results obtained with non-cruciferous veg etables (tomato, carrot and green pepper), it seems likely that the ge notoxic effects of the juices are due to specific constituents of cruc iferous plants such as glucosinolates and/or their breakdown products, in particular, isothiocyanates, which we found previously to be poten t genotoxins in bacterial and mammalian cells. Finally, spices (mustar ds and horse radish paste) and phytopharmaceutical preparations were t ested in bacterial assays. Mustards and horse radish caused very weak effects while most of the pharmaceutical preparations gave negative re sults, except cabbage tablets, which caused a strong and dose dependen t induction of his(+) revertants in Salmonella TA100. The present find ings clearly indicate that cruciferous vegetables Contain DNA damaging constituents. These observations are in contrast to earlier findings, which emphasized the antimutagenic effects of vegetable juices and al so raise the question whether greatly increased consumption of Brassic a vegetables or their concentrated constituents as a means for cancer prevention is indeed recommendable.