The inhibitory effect of chlorophyllin was investigated against mutagenicity of 6-sulfooxymethylbenzo[
a]pyrene (SMBP) in S. Typhimurium TA100 and in Chinese hamster lung fibroblast (V79) cells.
Chlorophyllin (CHL) was quite effective in reducing mutagenicity for SMBP in dose-dependent manner up to 50
nmol in S. Typhimurium TA100 and 12.5 M in V79 cells. A μ similar but less effective prevention of CHL was
indicated in the mammalian and bacterial assays with 6-hydroxymethylbenzo[a]pyrene (HMBP), the proximate
precursor of SMBP. Intracellular accumulation of SMBP was decreased by CHL in a dose-dependent manner
and the treatment with 10 μM CHL reduced the accumulation of SMBP to almost 40% of control value. A dramatic
decrease in DNA adducts were also obtained by the treatment of CHL in dose- dependent manner. CHL at a
50 μM concentration reduced the DNA-SMBP adducts to 16% of control level with SMBP-treated group. SMBP
may be more stable in aqueous phase in the presence of CHL than in the absence of CHL. Furthermore, CHL
decreased the amount of eluted HMBP to 50% of control value in HPLC profiles. These results suggest that
the chemopreventive effect of CHL against the mutagenicity of SMBP are related to the complex formation
between CHL and SMBP. The hydroxysteroid sulfotransferase responsible for activation of HMBP to SMBP was
suppressed by the increased concentration of CHL. Besides adducts formation, CHL may have an effect on
production of SMBP and detoxifying systems.

Keywords: Chemoprevention, Chlorophyllin, 6-sulfooxymethylbenzo[a]pyrene, Mutagenicity