Enzymatic synthesis of phytosteryl docosahexaneates and evaluation of their anti-atherogenic effects in apo-E deficient mice

Phytosterols have attracted much attention in recent years due to their health benefits, such as cholesterol lowering, anti-inflammatory, anti-atherogenicity, and anti-cancer potential. Docosahexaenoic acid (DHA) has been demonstrated to possess cardioprotective and immune-enhancing effects. Esterification of phytosterols with DHA may render improved physiochemical properties such as solubility, miscibility, oxidative stability and hence bioactivity and bioavailability. Thus, phytosteryl docosahexaneates (PS-DHA) may offer both the benefits of phytosterols and DHA, possibly in a synergistic manner. Here, we describe a method for enzymatic synthesis of phytosteryl docosahexaneates and evaluation of metabolic and cardiovascular benefits in apo-E deficient (apo E-KO) mice. The structures of phytosteryl docosahexaneates were confirmed by infrared (IR) and high performance liquid chromatography–mass spectrometry (HPLC–MS) using both normal and reverse phase chromatography. Apo E-KO mice were fed with an atherogenic diet containing 2% (w/w) PS-DHA for 7 weeks. Plasma lipid levels and the extent and complexity of atherosclerotic lesions were examined and compared with those in the control group. The PS-DHA-treated mice had significantly lower plasma cholesterol levels and three times smaller atherosclerotic lesions in the aortic roots. This pilot study suggests cardiovascular benefits for PS-DHA. Further experimental and clinical studies are needed to confirm such benefits of PS-DHA.