Desmutagenic Effect of Pheophytin from Japanese Eggplant against Several Mutagens

Abstract

Using Salmonella typhimurium TA98 in the Ames test, we have identified desmutagens in Japanese eggplant juice. Most of the desmutagenic activity in the eggplant fruit is due to pheophytin, a Mg-free derivative of chlorophyll. Pheophytin inhibits mutagenesis to about 40% with or without metabolic activation of mutagens by S9 mix preparations. The mutagens employed were 2-aminoanthracene (2-AA), 2-aminofluorene (2-AF), 2-amino-3-methyl-9H-pyrido [2, 3-b] indole (MeAαC), 3-amino-1-methyl-5H-pyrido [4, 3-b] indole (Trp-P-2) and 2-nitro-fluorene (2-NF). Pheophytin did not influence enzymes involved in metabolic activation or interfere with the activation process when S9 was added. Therefore pheophytin appears to be a desmutagen acting directly on the mutagens. Trp-P-2-pheophytin reaction products could not be isolated by HPLC or determined by 1H-NMR under various conditions owing to their instability. The desmutagenicity of pheophorbide, the phorbin skeleton of pheophytin, against Trp-P-2 was approximately 40%, but phytol, the carbon chain of pheophorbide, showed no desmutagenicity. This suggests that the desmutagenicity of pheophytin is derived from the pyrole rings.