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本文研究了猕猴桃汁对N-二甲基亚硝胺体外合成的阻断作用,以鼠伤寒沙门氏菌致突变试验检验。 将二甲基亚硝胺的前体物质-亚硝酸钠和氨基比林,在体外模拟胃液条件下(pH3.3,37％℃)保温一小时,以鼠伤寒沙门氏菌变异株TA100,按常规方法(平皿掺入试验)检验致突变性。当两种前体浓度达5mg/ml以上时,如不加阻断剂,均显示出突变阳性反应,提示反应体系中形成了有致突变性的亚硝胺。如果同时加入猕猴桃汁,可以阻断亚硝胺合成,在5mg/ml和8mg/ml两个浓度的测定结果均未出现致突变作用。在5mg/ml反应体系中,分别加入桃汁和维生素C溶液进行对比,发现桃汁的阻断效率高于维生素C,每皿菌落数均值分别为252±4.2(桃汁),和445±81.2(同浓度维生素C),两者差异有显著性(P<0.01)。结果证明猕猴桃汁对体外亚硝胺合成的阻断作用优于同浓度的维生素C溶液。同样条件下单独保温的亚硝酸钠氨基比林或磷酸缓冲液均无致突变作用。 同样条件下处理的样品(亚硝酸钠,氨基比林各5mg/ml,加到pH3.3磷酸缓冲液中,37℃混合保温1小时)经水蒸气蒸馏,二氯甲烷萃取,浓缩后用气相色谱—质谱联机分析,确认为N-二甲基亚硝胺(NDMA)。
In this paper, kiwifruit juice on N- dimethylnitrosamine in vitro blocking the synthesis of Salmonella typhimurium mutagenicity test. The precursors of dimethylnitrosamine, sodium nitrite and aminopyrine, were incubated in in vitro simulated gastric fluid (pH3.3, 37% ℃) for one hour, Salmonella typhimurium strain TA100, according to the conventional method (Plate Inclusion Test) to check for mutagenicity. When the two precursors concentration of 5mg / ml or more, such as without blocking agent, showed a positive mutation, suggesting that the reaction system has a mutagenic nitrosamines. If you also join the kiwi juice, can block nitrosamine synthesis, 5mg / ml and 8mg / ml two concentrations of the determination results were not mutagenic effect. In the 5mg / ml reaction system, peach juice and vitamin C solution were added separately for comparison. The results showed that the blocking efficiency of peach juice was higher than that of vitamin C, and the average number of colonies was 252 ± 4.2 (peach juice) and 445 ± 81.2 (With the same concentration of vitamin C), the difference was significant (P <0.01). The results show that kiwifruit juice on nitrosamine synthesis in vitro blocking effect is better than the same concentration of vitamin C solution. Under the same conditions, sodium nitrite aminopyrine or phosphate buffer alone did not cause any mutagenic effects. The samples treated with the same conditions (sodium nitrite, aminopyrine each 5mg / ml, added to pH3.3 phosphate buffer, incubated at 37 ℃ for 1 hour) by steam distillation, dichloromethane extraction, concentrated with a gas phase Chromatography - mass spectrometry online analysis, identified as N-dimethyl nitrosamines (NDMA).