Gj. Hageman et al., REDUCING EFFECTS OF GARLIC CONSTITUENTS ON DNA ADDUCT FORMATION IN HUMAN-LYMPHOCYTES IN-VITRO, Nutrition and cancer, 27(2), 1997, pp. 177-185
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.