Thesis (M.Sc. in Pharm.)--Chulalongkorn University, 2015

The water extracts from unripe pulp, half-ripe pulp, fully ripe pulp and aril of gac fruit (Momordica cochinchinensis) were investigated for their mutagenicity using the Ames test with modified pre-incubation method on Salmonella typhimurium strains TA98 and TA100 without enzymatic activation. The modification effect of these fruit extracts on the mutagenicity of standard mutagen; nitrite treated 1-aminopyrene (1-AP) was also evaluated. The results showed that none of them exhibited mutagenicity on both strains of S. typhimurium either with or without nitrite treatment. For the modification on mutagenicity assay, the extracts from various parts of gac fruit, especially the extracts from unripe pulp inhibited the mutagenicity of nitrite treated 1-AP with dose response manner on S. typhimurium strain TA98. According to the results from S. typhimurium strain TA100, two amounts (100 and 200 µl) of the extracts from unripe pulp and half-ripe pulp showed weak to moderate degree of inhibition while the extracts from fully ripe pulp showed negligible effect. The extracts from aril also showed negligible effect by the study concentrations but they tend to enhance the mutagenicity of nitrite treated 1-AP. However, the mutagenicity of nitrite treated 1-AP can be inhibited by the addition of the extracts from unripe pulp and half-ripe pulp.