ABSTRACT
Phytosterols are found in all plant cells and tissues. In the same way that cholesterol stabilizes animal organelle membranes, phytosterols stabilize plant organelle membranes. In all plant tissues, phytosterols occur in five common lipid classes, that is, as the free alcohol, as fatty-acyl esters, as hydroxycinnamate steryl esters, as steryl glycosides, and as acylated steryl glycosides. Phytosterols are thought to stabilize plant membranes, with an increase in the sterol/phospholipid ratio leading to membrane rigidification; however, individual phytosterols differ in their effect on membrane stability. Natural phytostanols occur at trace levels in many plants and at high levels in com and some other grains. Several studies indicated that phytosterols may have health-promoting effects such as anticancer activity. Tremendous research and development efforts have focused on understanding and harnessing the cholesterol-lowering properties of phytosterols. In addition to natural phytosterols, there has also been an effort to design more potent artificial phytosterol analogs.
