Much attention in recent years has been given to the antigenotoxicity of
chlorophyll.
Chlorophyll, however, is known to be converted into
pheophytin, pyropheophytin, and pheophorbide in processed vegetable food and following ingestion by humans. Studies were conducted on the antimutagenic and tumoricidal potencies of these compounds. All the
chlorophyll derivatives tested exhibit identical
antimutagenic effect towards
3-methylcholanthrene (3-MC), suggesting that the
porphyrin nucleus may complex directly with the
mutagen. It does not exclude, however, another mechanism of activity involving inactivation the enzymatic transformation of 3-MC. In contrast, the action of N'-nitro-N'-nitrosoguanidine (
MNNG) depends upon structural differences between the
chlorophyll derivatives. It is significantly lower when the
phytol-containing
pheophytin and pyropheophytin are tested as to that of the
phytol-lacking pheophorbide. The higher concentrations of the
chlorophyll derivatives were required to reduce the mutagenicity of
MNNG than needed for 3-MC. The cytotoxicity of
chlorophyll derivatives against
tumor cells also was evaluated. The cellular uptake and inhibition of myeloma cell multiplicity were found to be greater for pheophorbide than for
pheophytin. Calculated on the amount of cell associated
chlorophyll derivative, however,
pheophytin was more
cytostatic/cytotoxic than pheophorbide. The results presented in this report indicate that food sources that yield
chlorophyll derivatives may play a significant role in
cancer prevention.
Teratogenesis Carcinog.
Mutagen. 19:313-322, 1999.