The antigenotoxic and chemopreventive effect of Aloe barbadensis Mille
r (polysaccharide fraction) on benzo[a]pyrene (B[a]P)-DNA adducts was
investigated in vitro and in vivo. Aloe showed a time-course and dose-
dependent inhibition of [H-3]B[a]P-DNA adduct formation in primary rat
hepatocytes (1x10(6) cells/ml) treated with [H-3]B[a]P (4 nmol/ml). A
t concentrations of 0.4-250 mu g/ml aloe, the binding of [H-3]B[a]P me
tabolites to rat hepatocyte DNA was inhibited by 9.1-47.9%. Also, in r
at hepatocytes cultured for 3-48 h with aloe (250 mu g/ml) and [H-3]B[
a]P (4 nmol/ml), [H-3]B[a]P-DNA adducts were significantly reduced by
36% compared with [H-3]B[a]P alone. Aloe also inhibited cellular uptak
e of [H-3]B[a]P in a dose-dependent manner at a concentration of 0.4-2
50 mu g/ml by 6.3-34.1%. After a single oral administration of B[a]P t
o male ICR mice (10 mg/mouse), benzo[a]pyrene diol epoxide I(BPDE-I)-D
NA adduct formation and persistence for 16 days following daily treatm
ent with aloe (50 mg/mouse) were quantitated by enzyme-linked immunoso
rbent assay using monoclonal antibody 8E11. In this animal model, BPDE
-I-DNA adduct formation was significantly inhibited in various organs
(liver, kidney, forestomach and lung) (P < 0.001), When mice were pret
reated with aloe for 16 days before B[a]P treatment, inhibition of BPD
E-I-DNA adduct formation and persistence was enhanced, Glutathione S-t
ransferase activity was slightly increased in the liver but cytochrome
P450 content was not affected by aloe, These results suggest that the
inhibitory effect of aloe on BPDE-I-DNA adduct formation might have a
chemopreventive effect by inhibition of B[a]P absorption.