Joshi J V, Vaidya R A, Pandey S N, Agashe S, Chandrasekharan S, Menon S K, Vaidya A D B
Bharatiya Vidya Bhavan's Swami Prakashananda Ayurveda Research Center (SPARC) , Mumbai, India.
Indian J Med Res. 2007 Apr;125(4):534-41.
BACKGROUND & OBJECTIVE: Soy isoflavones are being used as therapy for menopausal syndrome in many countries. Marketed preparations show variability in bioavailability and there are variations in kinetics due to ethnicity and diet. Inspite of soy isoflavone being available in the Indian market there are no studies to show whether the preparation is likely to be effective in women. This study was carried out to determine circulating levels of genistein, a bioactive soy isoflavone, in Indian women after a single dose of soy extract.
Six healthy vegetarian women volunteers, between 36 and 62 yr and with a mean body mass index (BMI) 25.01+/-2.02 (kg/m2), were enrolled after an informed consent. Women with antibiotic or Soy food intake within 1 month of study were excluded. A single dose of standardized soy extract capsule containing 64.12 mg of total isoflavones (genistein content equivalent to 31.76 mg) was ingested under supervised fasting condition and multiple blood samples were collected at 0, 1, 2, 4, 6, 8 and 24 h. Genistein levels were measured by high performance liquid chromatography (HPLC) method with a detection level of 2.5 ng/100 microl of injection volume. The intra- and inter-assay coefficients of variation were < 5.32 per cent.
Genistein was detected (10.3 to 16.2 ng/ml) in 3 volunteers in baseline samples. Within one hour genistein levels rose from 42 ng to 215 ng/ml with a maximum concentration of 117 to 380 ng/ml at 4 to 8 h. A secondary peak suggestive of enterohepatic circulation was seen between 4 and 6 h in 2 out of 6 volunteers. The mean Cmax was 315.5 +/- 57.1 ng/ml. All women had detectable levels from 25.2 to 109.3 ng/ml at 24 h.
INTERPRETATION & CONCLUSION: Our study showed adequate circulating levels of genistein in Indian vegetarian women after a single dose of soy extract. Variability in plasma levels of the soy isoflavones may explain differences in responses to therapy.
在许多国家，大豆异黄酮正被用作更年期综合征的治疗药物。市售制剂的生物利用度存在差异，并且由于种族和饮食的原因，其动力学也有所不同。尽管印度市场上有大豆异黄酮产品，但尚无研究表明该制剂对女性是否有效。本研究旨在测定单剂量大豆提取物后印度女性体内生物活性大豆异黄酮染料木黄酮的循环水平。
6名年龄在36至62岁之间、平均体重指数（BMI）为25.01±2.02（kg/m²）的健康素食女性志愿者在签署知情同意书后被纳入研究。排除在研究前1个月内摄入过抗生素或大豆类食物的女性。在监督禁食条件下，志愿者服用一粒含有64.12mg总异黄酮（染料木黄酮含量相当于31.76mg）的标准化大豆提取物胶囊，并在0、1、2、4、6、8和24小时采集多份血样。采用高效液相色谱（HPLC）法测定染料木黄酮水平，检测限为每100微升进样体积2.5纳克。批内和批间变异系数均<5.32%。
在3名志愿者的基线样本中检测到了染料木黄酮（10.3至16.2纳克/毫升）。1小时内，染料木黄酮水平从42纳克/毫升升至215纳克/毫升，在4至8小时达到最高浓度，为117至380纳克/毫升。6名志愿者中有2名在4至6小时出现了提示肠肝循环的第二个峰值。平均最大浓度（Cmax）为315.5±57.1纳克/毫升。所有女性在24小时时的可检测水平为25.2至109.3纳克/毫升。
我们的研究表明，单剂量大豆提取物后，印度素食女性体内染料木黄酮的循环水平充足。大豆异黄酮血浆水平的差异可能解释了治疗反应的差异。
