Erdman J W, Thatcher A J, Hofmann N E, Lederman J D, Block S S, Lee C M, Mokady S
Department of Food Science and Human Nutrition and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
J Nutr. 1998 Nov;128(11):2009-13. doi: 10.1093/jn/128.11.2009.
The algae Dunaliella bardawil and Dunaliella salina naturally contain large concentrations of all-trans and 9-cis beta-carotene (betaC). The purpose of this study was to compare the relative serum and tissue accumulation of all-trans and 9-cis betaC in ferrets fed different ratios of all-trans/9-cis betaC derived from two commercial sources, D. bardawil or D. salina (Betatene). Male ferrets (7 wk old) were fed carotene-free, pelleted diets for 27 d. Beginning on d 18, groups of ferrets (n = 6 or 7) received daily, one of six oral supplements varying in ratios of 9-cis and all-trans betaC mixed with approximately 1.0mL of Ensure. Four supplements containing 5.2-8.3 micromol total betaC were prepared from a 20% Betatene preparation, D. bardawil, a high-cis Betatene preparation, and Betatene further enriched in 9-cis betaC with all-trans betaC/9-cis betaC ratios of 2.2, 1.5, 0.6 and 0.4, respectively. Two control supplements, high and low betaC, were prepared from commercial betaC beadlets. The high control supplement had an all-trans/9-cis ratio of 19.0, whereas 9-cis betaC was not detected in the low supplement. On d 27, serum and tissues were obtained for HPLC analysis of betaC and its isomers. Analysis of livers showed that all-trans betaC was the primary isomer present, but 9-cis and other isomers were also detected in all groups. The hepatic all-trans/9-cis ratios were 5.9, 4.9, 2.5, 1.4, 52.2 and47.5, respectively, for the groups listed above. Lower amounts of all-trans and 9-cis betaC were found in kidneys compared with the liver, but ratios of all-trans/9-cis were not different among groups. Only trace amounts of 9-cis betaC were found in serum. These results demonstrate that the algae D. bardawil and D. salina provide a bioavailable source of betaC isomers, but, as in humans, absorption of 9-cis betaC is poor and any 9-cis betaC absorbed is apparently cleared by the liver.
巴氏杜氏藻（Dunaliella bardawil）和盐生杜氏藻（Dunaliella salina）天然含有高浓度的全反式和9-顺式β-胡萝卜素（βC）。本研究的目的是比较用来自两种商业来源（巴氏杜氏藻或盐生杜氏藻（β-胡萝卜素））的不同全反式/9-顺式βC比例喂养的雪貂中全反式和9-顺式βC在血清和组织中的相对积累情况。雄性雪貂（7周龄）喂食无胡萝卜素的颗粒饲料27天。从第18天开始，每组雪貂（n = 6或7）每天接受六种口服补充剂中的一种，这些补充剂中9-顺式和全反式βC的比例不同，并与约1.0mL的安素（Ensure）混合。四种含有5.2 - 8.3微摩尔总βC的补充剂由20%的β-胡萝卜素制剂、巴氏杜氏藻、高顺式β-胡萝卜素制剂以及进一步富含9-顺式βC且全反式βC/9-顺式βC比例分别为2.2、1.5、0.6和0.4的β-胡萝卜素制备而成。两种对照补充剂，即高βC和低βC，由商业βC小珠制备。高对照补充剂的全反式/9-顺式比例为19.0，而低补充剂中未检测到9-顺式βC。在第27天，获取血清和组织用于βC及其异构体的高效液相色谱分析。肝脏分析表明，全反式βC是主要存在的异构体，但所有组中也检测到了9-顺式和其他异构体。上述组的肝脏全反式/9-顺式比例分别为5.9、4.9、2.5、1.4、52.2和47.5。与肝脏相比，肾脏中全反式和9-顺式βC的含量较低，但各组间全反式/9-顺式比例无差异。血清中仅发现痕量的9-顺式βC。这些结果表明，巴氏杜氏藻和盐生杜氏藻提供了一种生物可利用的βC异构体来源，但与人类一样，9-顺式βC的吸收较差，且任何吸收的9-顺式βC显然都被肝脏清除。
