Protective effects of vitamins C and E on the number of micronuclei in lymphocytes in smokers and their role in ascorbate free radical formation in plasma

Cigarette smoke is widely believed to increase free radical concentrations causing subsequent oxidative processes that lead to DNA damage and hence, t o several diseases including lung cancer and atheroselerosis. Vitamin C is a reducing agent that can terminate free-radical-driven oxidation by being converted to a resonance-stabilized free radical. To investigate whether sh ort-term supplementation with the antioxidants vitamin C and E decreases fr ee-radical-driven oxidation and thus decreases DNA damage in smokers, we de termined the frequency of micronuclei in lymphocytes in 24 subjects and mon itored the electron paramagnetic resonance signal of ascorbate free radical formation in plasma. Further parameters comprised sister-chromatid exchang es and thiobarbituric acid-reactive substances. Twelve smokers and twelve n on-smokers took 1000 mg ascorbic acid daily for 7 days and then 1000 mg asc orbic acid and 335.5 mg RRR-alpha -tocopherol daily for the next 7 days. Ba seline concentrations of both vitamins C and E were lower and baseline numb ers of micronuclei were higher (p < 0.0001) in smokers than in non-smokers. After 7 days of vitamins C and E, DNA damage as monitored by the number of micronulei was decreased in both, smokers and non-smokers, but it was more decreased in smokers as indicated by fewer micronuclei in peripheral lymph ocytes (p < 0.05). Concomitantly, the plasma concentrations of vitamin C (p < 0.001) as well as the ascorbate free radical (p < 0.05) were increased. The corresponding values in non-smokers, however, did not change. Our findi ngs show that increased ascorbate free radical formation in plasma after sh ort-term supplementation with vitamins C and E can decrease the number of m icronuclei in blood lymphocytes and thus DNA damage in smokers.