BIOAVAILABILITY OF SOYBEAN ISOFLAVONES DEPENDS UPON GUT MICROFLORA IN WOMEN
BIOAVAILABILITY OF SOYBEAN ISOFLAVONES DEPENDS UPON GUT MICROFLORA IN WOMEN
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DOI：
10.1093/jn/125.9.2307
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发表时间：
1995-09-01
影响因子：
4.2
通讯作者：
HENDRICH, S
中科院分区：
文献类型：
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作者：
XU, X;HARRIS, KS;HENDRICH, S
大豆异黄酮被认为具有抗癌作用，但其有效剂量尚未确定。为了研究其生物利用度，7名妇女消耗3.4，6.9，或10.3 μ mol/kg体重豆浆中的每一个三餐的流质饮食的三个喂养日之一，间隔2周的洗脱期。受试者以交叉设计随机分配剂量。通过反相HPLC测定血浆、尿液和粪便中的孕酮。在两名受试者中，粪便排泄物回收率是其他五名受试者的10-20倍。在所有三种剂量下，仅在粪便中排泄少量异黄酮的五名受试者中，摄入的大豆苷元和染料木黄酮的平均48小时尿液回收率分别为16 +/- 4和10 +/-4%，而在排泄大量粪便异黄酮的两名受试者中，大豆苷元和染料木黄酮的尿液回收率分别为32 +/- 5和37 +/-6%。给药后48 h，所有受试者的尿肌酐排泄量几乎为零。在早餐后24小时，排泄大量粪便异黄酮的受试者的平均血浆染料木黄酮浓度显著高于排泄少量粪便异黄酮的受试者2.5倍（P < 0.05）。体外厌氧孵育的人粪便中的大豆黄酮和染料木素的肠道半衰期可能分别为7.5和3.3小时。这些数据表明，人类的生物利用度取决于肠道微生物菌群降解这些化合物的相对能力。
Soybean isoflavones have been proposed to be anticarcinogenic, but their effective doses have not been established. To study their bioavailability, seven women consumed 3.4, 6.9, or 10.3 mu mol isoflavones/kg body wt in soymilk in each of three meals of a liquid diet on one of three feeding days that were separated by 2-wk washout periods. Subjects were randomly assigned to doses in a cross-over design. Plasma, urine and fecal isoflavones were measured by reverse phase HPLC. In two subjects, fecal isoflavone recovery was 10-20 times that in the other five subjects. Average 48-h urinary recoveries of ingested daidzein and genistein were 16 +/- 4 and 10 +/- 4%, respectively, at all three doses among the five subjects excreting only small amounts of isoflavones in feces, whereas urinary recoveries of daidzein and genistein in the two subjects who excreted large amounts of fecal isoflavones were 32 +/- 5 and 37 +/- 6%, respectively. Urinary isoflavone excretion was nearly zero in all subjects at 48 h after dosing. Average plasma concentration of genistein at 24 h after the breakfast isoflavone dose in subjects excreting large amounts of fecal isoflavones was significantly greater by 2.5-fold than in subjects who excreted small amounts of fecal isoflavones (P < 0.05). In vitro anaerobic incubation of isoflavones with human feces showed that intestinal half-life of daidzein and genistein may be as little as 7.5 and 3.3 h, respectively. These data suggest that human isoflavone bioavailability depends upon the relative ability of gut microflora to degrade these compounds.