Pharmacological properties of plant sterols - In vivo and in vitro observations

Plant sterols have been investigated as one of the safe potential alternati ve methods in lowering plasma cholesterol levels. Several human studies hav e shown that plant sterols/stanols significantly reduce plasma total and LD L cholesterol. In this article, pharmacological characteristics of plant st erols/stanols have been summarized and discussed. In particular, experiment al data that demonstrate the effects of dietary phytosterols on lipid metab olism and development of atherosclerotic lesions have been critically revie wed. Despite their similar chemical structures, phytosterols and cholestero l differ markedly from each other in regard to their pharmacological charac teristics including intestinal absorption and metabolic fate. Compared to c holesterol, plant sterols have poor intestinal absorption. The most and bes t studied effects of plant sterols are their inhibition of intestinal chole sterol absorption. Other biological activities of phytosterols such as effe cts on lecithin:cholesterol acyltransferase activity, bile acid synthesis, oxidation and uptake of lipoproteins, hepatic and lipoprotein lipase activi ties and coagulation system have been linked to their anti-atherogenic prop erties, Moreover, evidence for beneficial effects of plant sterols on disor ders such as cutaneous xanthomatosis, colon cancer and prostate hyperplasia has been discussed. Finally, the potential adverse effects of plant sterol s as well as pathophysiology of hereditary sitosterolemia are also reviewed . In conclusion, more pharmacokinetic data are needed to better understand metabolic fate of plant sterols/stanols and their fatty acid esters as well as their interactions with other nutraceutical/pharmaceutical agents. (C) 2000 Elsevier Science Inc. All rights reserved.