MODULATION OF CARCINOGEN-INDUCED DNA-DAMAGE AND REPAIR ENZYME-ACTIVITY BY DIETARY RIBOFLAVIN

Formation of single strand breaks in nuclear DNA induced by hepatocarc inogens aflatoxin B-1 and N-nitrosodimethylamine was observed to be mo re pronounced in rats maintained on a riboflavin-deficient diet compar ed to that on a normal diet. This increased damage was reversed on rib oflavin supplementation. The induction of repair enzymes poly(ADP-ribo se) polymerase, DNA polymerase beta and DNA ligase was significantly h igher in riboflavin-deficient rats following DNA damage caused by the administration of carcinogens. Riboflavin supplementation brought down the induction to the levels found in rats maintained on normal diet. Since damage to DNA and its altered repair may relate to carcinogenesi s, modulation of these parameters by riboflavin suggests a potential c hemopreventive role of this vitamin.