Mutagenic, antimutagenic and antioxidant potency of leaf extracts from Nitraria retusa

Four extracts were prepared from the leaves of Nitraria retusa; methanol, ethyl acetate, chloroform and hexane extracts. An assay for the ability of these extracts to prevent mutations induced by various oxidants in Salmonella typhimurium TA102 and TA 104 strains was conducted. These extracts from leaf parts of N. retusa showed no mutagenicity either with or without the metabolic enzyme preparation (microsome fraction). The highest protection against methylmethanesulfonate induced mutagenicity was observed with chloroform and methanol extracts with inhibition percentages of 44.93% (at 50 μg/plate in the presence of TA102 strain) and 38% (at 10 μg/plate in the presence of TA104 strain), respectively. Whereas Hexane and chloroform extracts reduced the mutagenicity induced by 2-aminoanthracene by 83.4% (using the S. typhimurium TA104 assay system) and 65.3% (using the S. typhimurium TA 102 assay system), respectively. Antioxidant activity of N. retusa extracts was determined by the ability of each extract to protect plasmid DNA against strand scission induced by hydroxyl radicals. Chloroform extract exhibited the highest ability to protect plasmid DNA against hydroxyl radical induced DNA damages and exhibited the highest antioxidant capacity, with 0.95 mM trolox equivalent when tested by the ferric reducing/antioxidant method.