虾青素是一种叶黄素类型的类胡萝卜素，它是特定的细胞膜反应和不同临床益处的养分。该分子通过接受或失去电子来中和自由基或其他氧化剂，在这个过程中不会变性或者成为氧化剂。它的线性，极性-非极性极性分子布局确保它精确地插入到膜中并横跨整个宽度。在这种情况下，虾青素沿着亲水性头部为界限来拦截活性分子，阻断其到达膜的疏水性内部。在临床上，虾青素显示了不同的优点，具有优异的安全性和耐受性。在双隐形随机对照试验中，虾青素可以降低偏胖、肥胖或者吸烟患者的氧化应激性。同时，它还可以阻断DNA氧化损伤，降低C反应蛋白等炎症的标志物，提高结核菌素皮试的免疫力。在另一项实验中，研究发现虾青素可以降低甘油三酯，提高高密度脂蛋白胆固醇；在微循环模式中发现其可以改善血流。在一项小的临床实验中发现虾青素可以提高认知，促进神经干细胞分化。日本人研究的几个随机对照试验，发现虾青素可以改善视力和保护眼睛。它能够提高人体的生育能力，减轻幽门螺旋杆菌的病人的症状。初步试验显示，它也可以提高运动能力（例如足球）。在培养的细胞中，虾青素能够抵御线粒体的内源性氧自由基，保护它们的氧化还原（抗氧化剂）能力，提高产能效率。这些在细胞培养过程中使用的虾青素浓度可以通过人体的适度饮食摄入。虾青素临床上成功不仅仅为抗氧化和消炎提供帮助，而且为研究减缓年龄相关的功能性衰退指明了方向。

  Astaxanthin, a xanthophyll carotenoid, is a nutrient with unique cell membrane actions and diverse clinical benefits. This molecule neutralizes free radicals or other oxidants by either accepting or donating electrons, and without being destroyed or becoming a pro-oxidant in the process. Its linear, polar-nonpolar-polar molecular layout equips it to precisely insert into the membrane and span its entire width. In this position, astaxanthin can intercept reactive molecular species within the membrane's hydrophobic interior and along its hydrophilic boundaries. Clinically, astaxanthin has shown diverse benefits, with excellent safety and tolerability. In double-blind, randomized controlled trials (RCTs), astaxanthin lowered oxidative stress in overweight and obese subjects and in smokers. It blocked oxidative DNA damage, lowered C-reactive protein (CRP) and other inflammation biomarkers, and boosted immunity in the tuberculin skin test. Astaxanthin lowered triglycerides and raised HDL-cholesterol in another trial and improved blood flow in an experimental microcirculation model. It improved cognition in a small clinical trial and boosted proliferation and differentiation of cultured nerve stem cells. In several Japanese RCTs, astaxanthin improved visual acuity and eye accommodation. It improved reproductive performance in men and reflux symptoms in H. pylori patients. In preliminary trials it showed promise for sports performance (soccer). In cultured cells, astaxanthin protected the mitochondria against endogenous oxygen radicals, conserved their redox (antioxidant) capacity, and enhanced their energy production efficiency. The concentrations used in these cells would be attainable in humans by modest dietary intakes. Astaxanthin's clinical success extends beyond protection against oxidative stress and inflammation, to demonstrable promise for slowing age-related functional decline.

Altern Med Rev. 2011, 16(4):355-364. 

Kidd P