Marisiddaiah Raju, Baskaran Vallikannan
Department of Biochemistry and Nutrition, Central Food Technological Research Institute, CSIR, Mysore-570 020, India.
Nutr Res. 2009 Aug;29(8):588-95. doi: 10.1016/j.nutres.2009.07.005.
beta-Carotene (BC) is a potent dietary source of vitamin A for populations at risk of vitamin A deficiency, yet its bioavailability is influenced by several factors such as dietary fat, carotenoids type, and other components. We hypothesize that type of micellar phospholipids influence bioefficacy of carotenoids and activity of carotenoid metabolizing enzymes. This study determined the BC bioefficacy in rats (n = 5/time point) after an equimolar dose of BC and lutein (Lut) solubilized in micelles containing either phosphatidylcholine (PC) or lysophosphatidylcholine (LPC), or no phospholipid (NoPL). Results show that no BC and Lut was detected in the plasma of rats at 0 hour, but after gavage, the mean (SD) area under the curve (AUC; in picomoles per milliliter) of plasma BC for 6 hours in PC, LPC, and NoPL groups were 1145 (132), 965 (199), and 2136 (112), respectively. The AUC value of plasma Lut in LPC group (183 +/- 23 pmol mL(-1) h(-1)) was higher than the other 2 groups. Similarly, liver BC and Lut levels in the LPC group were significantly higher than the other groups. The activity of BC 15,15'-monooxygenase in the intestinal mucosa of LPC and PC groups was higher than NoPL group. Plasma retinyl palmitate level in LPC (AUC, 647 +/- 89 pmol mL(-1) h(-1)) group was 2-fold higher than that of PC and NoPL groups. Results indicate that phospholipids enhanced the BC and Lut absorption. beta-Carotene uptake was not affected by Lut when given with micellar phospholipids, but reduced plasma Lut level was observed, which may be due to the conversion of absorbed Lut into its metabolites.
β-胡萝卜素（BC）是维生素A缺乏风险人群维生素A的重要膳食来源，但其生物利用度受多种因素影响，如膳食脂肪、类胡萝卜素类型及其他成分。我们推测胶束磷脂类型会影响类胡萝卜素的生物效能及类胡萝卜素代谢酶的活性。本研究测定了在含有磷脂酰胆碱（PC）、溶血磷脂酰胆碱（LPC）或无磷脂（NoPL）的胶束中溶解的等摩尔剂量的BC和叶黄素（Lut）后大鼠（每组n = 5）的BC生物效能。结果显示，0小时时大鼠血浆中未检测到BC和Lut，但灌胃后，PC组、LPC组和NoPL组血浆BC 6小时的平均（标准差）曲线下面积（AUC；单位为皮摩尔每毫升）分别为1145（132）、965（199）和2136（112）。LPC组血浆Lut的AUC值（183±23 pmol mL⁻¹ h⁻¹）高于其他两组。同样，LPC组肝脏中BC和Lut水平显著高于其他组。LPC组和PC组肠黏膜中BC 15,15'-单加氧酶的活性高于NoPL组。LPC组血浆视黄醇棕榈酸酯水平（AUC，647±89 pmol mL⁻¹ h⁻¹）比PC组和NoPL组高2倍。结果表明磷脂增强了BC和Lut的吸收。与胶束磷脂一起给予时，Lut不影响BC的摄取，但观察到血浆Lut水平降低，这可能是由于吸收的Lut转化为其代谢产物所致。
