大豆异黄酮转化菌株在ICR小鼠体内定植研究

Colonization of isoflavone biotransforming bacterium in the intestinal tract of ICR mice

健康ICR小鼠肠道菌群对大豆异黄酮有稳定转化作用。本研究选用合适抗生素对健康ICR小鼠进行连续灌服,使ICR小鼠在不影响其正常生理活动状况下完全丧失对大豆异黄酮的转化能力,并对该类完全丧失转化能力的ICR小鼠灌服大豆异黄酮还原菌株Niu-O16的微胶囊,用高效液相色谱检测菌株Niu-O16在ICR小鼠体内定植情况。结果表明:用420mg/mL浓度的阿奇霉素连续灌服1周,可使ICR小鼠完全丧失对大豆异黄酮的转化能力,停药后20d左右,ICR小鼠恢复其对大豆异黄酮的转化能力;经抗生素处理的ICR小鼠在停止灌菌后,2周内可检测到其粪便菌群具有与菌株Niu-O16完全相同的转化作用,而同样经抗生素处理未灌菌的对照则未检测到转化活性,表明菌株Niu-O16已在ICR小鼠体内进行定植。

Abstract： The intestinal microflora of ICR mice is able to biotranform isoflavones to different metabolites stably. In order to completely kill or inhibit the isoflavone biotransforming bacteria in the intestine of ICR mice, we screened different varieties of antibiotics and chose a suitableone to feed healthy ICR mice. Strain Niu-O16 capable of biotransforming isoflavones was coa- ted in microcapsules before it was fed to the healthy ICR mice which have totally lost the ability to biotransform isoflavones through intragastric administration after being treated with thesuitable antibiotics. High-performance liquid chromatography （HPLC） was used to detect whether strain Niu-O16 colonized in the intestinal tract of ICR mice or not. The results showed that ICR mice completely lost the ability to transform isoflavones after being fed with azithro-mycin （AZI） continuously for one week through intragastric administration, the concentrationof AZI was 420 mg/mL. The ICR mice fed with AZI recovered their capacity to biostransformisoflavones about 20 days after they were fed with AZI. Furthermore, the ICR mice fed the mi-crocapsules of Niu-O16 were detected the ability to biotransform isoflavones within two weeksafter they were fed with the microcapsules of Niu-O16. Based on HPLC detection profiles, theICR mice which were fed with the microcapsules of strain Niu-O16 showed exactly the samebiotransforming activity as that of the strain Niu-O16. However, we did not detect any isofla-vone biotransforming activity from the control. Our study indicated that bacterium Niu-O16coated in the microcapsule colonized in the intestinal tract of the ICR mice.