Gamma-Oryzanol - A Multi-Purpose Steryl Ferulate

For the last couple of decades, there has been a surge of global interest pertaining to the beneficial nutritive effects of bioactive phytochemicals like gamma-oryzanol (gamma-OZ), obtained from crude rice bran oil (RBO), which is manufactured from rice bran, a by-product of rice processing. Oryzanol, although presumed to be a single component initially, was shown to be a mixture of ferulic acid esters of triterpene alcohols and plant sterols. The gamma-OZ component can be simultaneously separated and quantified by high performance liquid chromatography, once the RBO has been extracted from rice bran by solvent extraction using food grade n-hexane or by supercritical fluid extraction technology. A number of potentially therapeutically useful biological activities have been reported for gamma-OZ, in terms of improvement of the plasma lipid pattern of rodents, rabbits, non-human primates and humans, reducing total plasma cholesterol and triglyceride concentration and cholesterol absorption from cholesterol-enriched diets and aortic fatty streaks and simultaneously increasing the high density lipoprotein cholesterol level. Other potential properties of gamma-OZ, that have been studied both in vitro as well as in vivo are the modulation of the pituitary secretion, inhibition of the gastric acid secretion, antioxidant action and inhibition of the platelet aggregation. However, these studies were unable to produce unequivocal conclusions and had been conducted on animal species very different from each other, and using diverse experimental methodologies and targets. The current contribution provides a comprehensive review of the chemical constituents, pharmacological profile and the healthcare properties of gamma-OZ as a nutraceutical.