Carcinogenic MDA-DNA adducts are sensitive biomarkers for cancer risk, which have been detected in human tissues. Antioxidants reduce cigarette smoke-related oxidative stress by quenching lipid peroxides. Previous studies indicated that Noni fruit juice, made from the tropical plant, Morinda citrifolia, is a strong antioxidant and cancer preventive nutritional supplement. Recently, we found that Noni juice is able to significantly reduce cancer risk by reducing aromatic DNA adducts in current smokers. In this study, we examined whether Noni juice was able to reduce MDA-DNA adduct level in current smokers. Current smokers volunteered to drink 1 or 4 ozs of Noni juice or 4 ozs of placebo juice daily for one month in a double-blinded placebo-controlled, IRB approved clinical trial. Male and female current smokers, age 18 to 60, with a 20 cigarettes per day habit for more than 1 year, were eligible for this study. MDA-DNA adduct level was analyzed by nuclease P1 procedure of 32P post-labeling assay. Two hundred forty five people among 317 enrolled smokers completed the trial. The average cigarette usage was 1.39 packs (27-28 cigarettes) per day (ranging from 1.3 to 1.44 PPD). The average age was 40±10.81 years. They had smoked on average 22-24 years, classifying them as heavy smokers. The paired Student T test was used for data analysis. The results indicated that the MDA-DNA adduct level in the lymphocytes was significantly reduced after drinking 1 or 4 ozs of Noni juice for one month: 84.45±8.45 x 10-9 vs 39.39±1.70 x 10-9 (a 53.36% reduction, n=203, PPD=1.37, p=0.000). After a dose-dependent analysis of drinking 1 or 4 ozs of Noni juice, we found that the MDA adduct level was significantly reduced in both groups: 89.26±12.32 x 10-9 vs 38.04±2.20 x 10-9 (a 57.36% reduction, n=118, age=42.5, PPD=1.3, p=0.000) and 77.761±10.74 x 10-9 vs 41.27±2.68 x 10-9 ( a 46.93% reduction, n=85, age=40.4, PPD=1.43, p=0.000), respectively. Further gender specific analysis indicated a 41.86% reduction in male smokers (n=43, p=0.002) and a 51.05% reduction (n=59, p=0.001) in female smokers in the 4 oz group. There was a 59.29% reduction in females (n=43, p=0.001) and a 55.02% reduction in males (n=59, p=0.002) in the 1 oz group. Although there is no significant dose and gender difference, we noted that the degree of MDA adduct level reduction was higher in female smokers compared to the male smokers in each category. Also observed in this study was an increase in the MDA-DNA adduct level and large variation in the placebo group before and after trial: 233.35±36.14 x 10-9 vs 945.70± 365.53 x 10-9 (305.27% increase, n=42, PPD=1.44, age=37, p=0.000). Due to the small number of participants in the placebo group we could not give any explanation for this without further investigation. In conclusion, Noni juice is able to reduce the MDA-DNA adduct level at an extremely significant level. Therefore, it may reduce cancer risk in current smokers.
98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA