REDUCING EFFECTS OF GARLIC CONSTITUENTS ON DNA ADDUCT FORMATION IN HUMAN-LYMPHOCYTES IN-VITRO

A water extract of raw garlic (RGE) and two organosulfur compounds, di allyl sulfide and S-allylcysteine (SAC), were evaluated for their rela tive effectiveness in reducing benzo[a]pyrene (BaP)-DNA adduct formati on in stimulated human peripheral blood lymphocytes in vitro. In repli cate experiments, RGE significantly inhibited BaP-DNA adduct formation at concentrations of 0.001, 0.01, and 0.1 mg/ml. SAC also significant ly decreased BaP-DNA adduct formation at concentrations of 0.01 and 0. 1 mg/ml. For diallyl sulfide, no significant reduction in BaP-DNA addu ct formation was found. BaP-DNA adduct formation was not associated wi th cell viability or proliferation of peripheral blood lymphocytes aft er the various treatments. No clear scavenging activity was detected f or the garlic constituents. Aryl hydrocarbon hydroxylase activity was not decreased, nor was formation of sulfate and glucuronide conjugates of 3-hydroxy-BaP increased in the presence of RGE and SAG, indicating that increased glutathione S-transferase activity or a more efficient repair of BaP-DNA adducts may explain the observed effects. In additi on, reactive oxygen species-induced 8-oxodeoxyguanosine in DNA was red uced in the presence of SAG. It is concluded that raw garlic and SAC m ay be useful in the prevention of BaP-associated tumorigenesis and tha t further evaluation of their preventive potential in humans at risk a ppears feasible.