Miro-Casas Elisabet, Covas Maria-Isabel, Farre Magi, Fito Montserrat, Ortuño Jordi, Weinbrenner Tanja, Roset Pere, de la Torre Rafael
Unitat de Farmacologia de l'Institut Municipal d'Investigació Mèdica (URAF-IMIM), Doctor Aiguader No. 80, 08003 Barcelona, Spain.
Clin Chem. 2003 Jun;49(6 Pt 1):945-52. doi: 10.1373/49.6.945.
Animal and in vitro studies suggest that phenolic compounds in virgin olive oil are effective antioxidants. In animal and in vitro studies, hydroxytyrosol and its metabolites have been shown to be strong antioxidants. One of the prerequisites to assess their in vivo physiologic significance is to determine their presence in human plasma.
We developed an analytical method for both hydroxytyrosol and 3-O-methyl-hydroxytyrosol in plasma. The administered dose of phenolic compounds was estimated from methanolic extracts of virgin olive oil after subjecting them to different hydrolytic treatments. Plasma and urine samples were collected from 0 to 12 h before and after 25 mL of virgin olive oil intake, a dose close to that used as daily intake in Mediterranean countries. Samples were analyzed by capillary gas chromatography-mass spectrometry before and after being subjected to acidic and enzymatic hydrolytic treatments.
Calibration curves were linear (r >0.99). Analytical recoveries were 42-60%. Limits of quantification were <1.5 mg/L. Plasma hydroxytyrosol and 3-O-methyl-hydroxytyrosol increased as a response to virgin olive oil administration, reaching maximum concentrations at 32 and 53 min, respectively (P <0.001 for quadratic trend). The estimated hydroxytyrosol elimination half-life was 2.43 h. Free forms of these phenolic compounds were not detected in plasma samples.
The proposed analytical method permits quantification of hydroxytyrosol and 3-O-methyl-hydroxytyrosol in plasma after real-life doses of virgin olive oil. From our results, approximately 98% of hydroxytyrosol appears to be present in plasma and urine in conjugated forms, mainly glucuronoconjugates, suggesting extensive first-pass intestinal/hepatic metabolism of the ingested hydroxytyrosol.
动物和体外研究表明，初榨橄榄油中的酚类化合物是有效的抗氧化剂。在动物和体外研究中，羟基酪醇及其代谢产物已被证明是强抗氧化剂。评估它们体内生理意义的前提之一是确定它们在人体血浆中的存在情况。
我们开发了一种分析血浆中羟基酪醇和3 - O - 甲基 - 羟基酪醇的方法。通过对初榨橄榄油的甲醇提取物进行不同的水解处理来估计酚类化合物的给药剂量。在摄入25 mL初榨橄榄油前后0至12小时收集血浆和尿液样本，该剂量接近地中海国家的日常摄入量。样本在进行酸性和酶水解处理前后通过毛细管气相色谱 - 质谱法进行分析。
校准曲线呈线性（r>0.99）。分析回收率为42 - 60%。定量限<1.5 mg/L。血浆中羟基酪醇和3 - O - 甲基 - 羟基酪醇随着初榨橄榄油的摄入而增加，分别在32分钟和53分钟达到最大浓度（二次趋势的P<0.001）。估计的羟基酪醇消除半衰期为2.43小时。在血浆样本中未检测到这些酚类化合物的游离形式。
所提出的分析方法允许在实际剂量的初榨橄榄油摄入后对血浆中的羟基酪醇和3 - O - 甲基 - 羟基酪醇进行定量。根据我们的结果，大约98%的羟基酪醇似乎以结合形式存在于血浆和尿液中，主要是葡糖醛酸结合物，这表明摄入的羟基酪醇在肠道/肝脏有广泛的首过代谢。
