Effect of dietary chlorophyll derivatives on mutagenesis and tumor cell growth

Much attention in recent years has been given to the antigenotoxicity of ch lorophyll. 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 tumori cidal 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 mutage n. It does not exclude, however, another mechanism of activity involving in activation the enzymatic transformation of 3-MC. In contrast, the action of N'-nitro-N'-nitrosoguanidine (MNNG) depends upon structural differences be tween the chlorophyll derivatives. It is significantly lower when the phyto l-containing pheophytin and pyropheophytin are tested as to that of the phy tol-lacking pheophorbide. The higher concentrations of the chlorophyll deri vatives were required to reduce the mutagenicity of MNNG than needed for 3- MC. The cytotoxicity of chlorophyll derivatives against tumor cells also wa s evaluated. The cellular uptake and inhibition of myeloma cell multiplicit y were found to be greater for pheophorbide than for pheophytin. Calculated on the amount of cell associated chlorophyll derivative, however, pheophyt in was more cytostatic/cytotoxic than pheophorbide. The results presented i n 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. (C) 1999 Wiley-Liss,Inc.