Yao L, Liang Y, Trahanovsky W S, Serfass R E, White W S
Department of Food Science and Human Nutrition, Iowa State University, Ames 50011, USA.
Lipids. 2000 Mar;35(3):339-48. doi: 10.1007/s11745-000-0531-0.
Increased intake of lutein from vegetables promotes increased density of the macular pigment and therefore may protect against age-related macular degeneration. Our objective was to use a 13C tracer and high-precision gas chromatography-combustion interfaced-isotope ratio mass spectrometry (GC-C-IRMS) to investigate metabolism of a lutein dose equivalent to that absorbed from vegetables. Biosynthetic per-labeled (>99% 13C) lutein was purified from a commercially available extract of algal biomass. Subjects (n = 4) ingested 3 mg of [13C]lutein with a standardized low-carotenoid breakfast. Blood samples were collected at baseline and then hourly for 12 h; additional blood samples were drawn at 16, 24, 48, 72, 96, 192, 360, and 528 h. To produce perhydro-beta-carotene suitable for analysis by GC-C-IRMS, the plasma lutein fraction was hydrogenated on palladium-on-carbon catalyst with acid-catalyzed hydrogenolysis. The stable carbon isotope (13C/12C) ratio measured by GC-C-IRMS was used to calculate the plasma concentration of [13C]lutein. There was a rapid increase in [13C]lutein in plasma until peak enrichment at 16 h followed by a decline to the next measurement at 24 h. At 528 h, small changes in 13C enrichment from baseline could still be measured in plasma lutein. High-precision GC-C-IRMS enables complete definition of the appearance and disappearance of [13C]lutein in plasma after ingestion of a dose similar to that absorbed from foods.
增加蔬菜中叶黄素的摄入量可提高黄斑色素密度，因此可能预防年龄相关性黄斑变性。我们的目标是使用13C示踪剂和高精度气相色谱-燃烧接口-同位素比率质谱法（GC-C-IRMS）来研究与从蔬菜中吸收的叶黄素剂量相当的叶黄素的代谢情况。从市售藻类生物质提取物中纯化出生物合成全标记（>99% 13C）的叶黄素。受试者（n = 4）在食用标准化低类胡萝卜素早餐时摄入3 mg [13C]叶黄素。在基线时采集血样，然后每小时采集一次，共采集12小时；在16、24、48、72、96、192、360和528小时采集额外的血样。为了制备适合GC-C-IRMS分析的全氢-β-胡萝卜素，将血浆叶黄素部分在钯-碳催化剂上进行氢化，并进行酸催化氢解。通过GC-C-IRMS测量的稳定碳同位素（13C/12C）比率用于计算血浆中[13C]叶黄素的浓度。血浆中[13C]叶黄素迅速增加，直至16小时达到峰值富集，随后在24小时下降至下一次测量值。在528小时时，仍可测量到血浆叶黄素中13C富集相对于基线的微小变化。高精度GC-C-IRMS能够完整地定义摄入与从食物中吸收的剂量相似的叶黄素后，血浆中[13C]叶黄素的出现和消失情况。
