Gamma-Oryzanol

DescriptionGamma oryzanol is a lipid fraction derived from rice-bran oil. Oryzanol was first isolated from rice-bran oil in the 1950s. Several lipid fractions were isolated from the oil.The third (gamma) fraction isolated was oryzanol.It is made up of a mixture of ferulic acid esters and plant sterols. Similar in structure to cholesterol, the phytosterols and triterpenes that comprise oryzanol include campesterol, stigmasterol, beta sitosterol, cycloartanol, and cycloartenol. Because phytosterols are poorly absorbed, it has been suggested that they may reduce blood cholesterol by inhibiting intestinal cholesterol absorption.In contrast, the ferulic acid portion of gamma oryzanol is easily absorbed into the body's tissues. Ferulic acid also has demonstrated antioxidant properties in vitro.

OccurrenceGamma oryzanol is found in rice-bran oil, which is commercially available in Japan for use in salad oils and frying.Crude rice-bran oil contains approximately 1.56% oryzanol.Of the 180 mg of plant sterols found in the typical American diet，about 4% is gamma-oryzanol.One cup of brown rice provides 18 mg gamma oryzanol, whereas white rice provides 4mg. The ferulic acid portion of gamma oryzanol is naturally found in the bran of cereals, and in fruits and vegetables.Ferulic acid is also a metabolite of caffeic acid found in coffee.

UsesGamma Oryzanol is a mixture of 6 substances derived from rice bran oil, including sterols and ferulic acid, called Cycloartanyl Ferulate or Triterpene alcohol ferulate. It has been approved in Japan for several conditions, including menopausal symptoms, mild anxiety, stomach upset, and high cholesterol. In the US, it is widely used as a sports supplement, as well as for reducing cholesterol. gamma oryzanol is widely used as a food additive, pharmaceutical material. In cosmetic area, the application to creams and sunscreens exploiting its skin age resistor function and ultraviolet absorbing effect.

General DescriptionGamma oryzanol is found in the by-products of the rice industry, such as rice bran and rice bran oil. It exhibits a wide range of biological activities, including anticarcinogenic, anti-inflammatory, antihyperlipidemic, and neuroprotective properties, which are primarily due to its high antioxidant capacity.

PreparationExtraction of gamma oryzanol from processes oil. Gamma oryzanol can be extracted by liquid-liquid extraction method by using organic solvent or by using supercritical extraction method. The following procedure was followed to extract gamma oryzanol from the oil.Rice Bran Oil (1 kg)→NaOH and water was added→Stirred and stored for one day at room temperature→Acidified to pH 4 using H2SO4→Heated to 80°C→50g NaCl was added→Oily layer was obtained→ Methanol was added→ Mixture was cooled to 0°C for 2 hrs.→ Waxy component precipitated→ Solution of 5g H2SO4 in 300 ml methanol→ Stored for one day→ Stirred at 40°C to remove/evaporate methanol→ To 100g residue 100g n-hexane was added→ Solvent Distillation→ Treatment of 100 ml methanol was given→ Residue was extracted 3 times with 50ml 0.5N→ methanolicNaOH→ Neutralised with methanolic acetic acid to pH 6.8-7→ Stored to precipitate gamma oryzanol.The yield of gamma oryzanol was found to be 2.2%