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Author(s): Scavariello EMS ; Arellano DB

Title: Gamma-Oryzanol: an important component in rice bran oil

Source: ARCHIVOS LATINOAMERICANOS DE NUTRICION 1998, Vol 48, Iss 1, pp 7-12

Language: Spanish

Abstract: gamma-Oryzanol, a mixture of ferulic acid esters of sterol and triterpene alcohols, it occurs in rice bran oil at a level of to 2%,where it serves as natural antioxidant. Recent research has shown that gamma-Oryzanol can lower the cholesterol levels in the blood, lowering the risk of coronary heart disease, besides that also has been used in Japan like natural antioxidant in foods, beverages and cosmetics. This review refers to aspects about gamma-Oryzanol, like its physiochemical properties, its presence in the rice bran oil, its antioxidant and hypocholesterolemic activity, as well as, identification, quantitation and extraction methods.


Author(s): Rong N; Ausman LM; Nicolosi RJ

Title: Oryzanol decreases cholesterol absorption and aortic fatty streaks in hamsters

Source: LIPIDS 1997, Vol 32, Iss 3, pp 303-309

Language: English

Abstract:
Oryzanol is a class of nonsaponifiable lipids of rice bran oil (RBO). More specifically, oryzanol is a group of ferulic acid esters of triterpene alcohol and plant sterols. In experiment 1, the mechanisms of the cholesterol-lowering action of oryzanol were investigated in 32 hamsters made hypercholesterolemic by feeding chow based diets containing 5% coconut oil and 0.1% cholesterol with or without 1% oryzanol for 7 wk. Relative to the control animals, oryzanol treatment resulted in a significant reduction in plasma total cholesterol (TC) (28%, P < 0.01) and the sum of IDL-C, LDL-C, and VLDL-C (NON-HDL-C) (34%, P < 0.01). In addition, the oryzanol-treated animals also exhibited a 25% reduction in percent cholesterol absorption vs. control animals. Endogenous cholesterol synthesis, as measured by the liver and intestinal HMG-CoA reductase activities, showed no difference between the two groups. To determine whether a lower dose of oryzanol was also efficacious and to measure aortic fatty streaks, 19 hamsters in experiment 2 were divided into two groups and fed for 10 wk chow-based diets containing 0.05% cholesterol and10% coconut oil (w/w) (control) and the control diet plus 0.5% oryzanol (oryzanol). Relative to the control, oryzanol-treated hamsters had reduced plasma TC (44%, P < 0.001), NON-HDL-C (57%, P < 0.01), and triglyceride (TG) (46%, P < 0.05) concentrations. Despite a 12% decrease in high density lipoprotein cholesterol (HDL-C) (P < 0.01), the oryzanol-treated animals maintained a more optimum NON-HDL-C/HDL-C profile (1.1 +/-0.4) than the control (2.5 +/- 1.4; P < 0.0075). Aortic fatty streak formation, so defined by the degree of accumulation of Oil Red O-stained macrophage-derived foam cells, was reduced 67% (P < 0.01) in the oryzanol-treated animals. From these studies, it is concluded that a constituent of the nonsaponifiable lipids of RBO, oryzanol, is at least partially responsible for the cholesterol-lowering action of RBO. In addition, the cholesterol-lowering action of oryzanol was associated with significant reductions in aortic fatty streak formation.


Author(s): Sugano M; Tsuji E

Title: Rice bran oil and cholesterol metabolism

Source:
JOURNAL OF NUTRITION 1997, Vol 127, Iss 3, p S521-S524

Language:
English

Abstract:
A range of human and animal studies have shown that rice bran oil (RBO) is an edible oil of preference for improving serum cholesterol levels and lipoprotein profiles with similarity to the more commonly used vegetable oils such as com oil and safflower oil. Of particular interest is the observation that blending RBO with safflower oil at a definite proportion (7:3, wt/wt) magnifies the hypo-cholesterolemic efficacy, compared with the effect of each oil alone. Although the mechanism underlying this effect is not apparent at present, the blending may have a practical significance. The blending effect was reproduced in rats fed a cholesterol-enriched diet, and there was also a decrease in liver cholesterol. The occurrence of peculiar components such as gamma-oryzanol and tocotrienols could be responsible for the hypocholesterolemic effect of RBO.


Author(s): Kahlon TS; Chow FI; Chiu MM; Hudson CA ; Sayre RN

Title:
Cholesterol-lowering by rice bran and rice bran oil unsaponifiable matter in hamsters

Source:
CEREAL CHEMISTRY 1996, Vol 73, Iss 1, pp 69-74

Language:
English

Abstract:
Unsaponfiable matter (U) was prepared from both raw and extrusion stabilized (130 degrees C) rice bran and tested for cholesterol-lowering activity in hamsters by addition to diets containing cellulose, raw rice bran, or stabilized rice bran at either the level found in the rice bran diet (0.4%,1X) or twice that level (2X). All diets contained 0.3% cholesterol,10% total dietary fiber,10.1% fat, and 3% N (same plant-to-animal N ratio). After 21 days, plasma cholesterol was significantly reduced by rice bran diets containing added U compared to the cellulose control diet, while the high density lipoprotein cholesterol -to-low density lipoprotein cholesterol ratio remained unchanged in all treatment groups. Liver cholesterol was significantly reduced by all rice bran-containing diets and with cellulose diets containing 2X added U when compared to the control diet. Rice bran diets plus added U resulted in cholesterol values lower than cellulose diets containing the same level of U. Stabilization of rice bran did not appear to affect the plasma and liver cholesterol responses to the unsaponifiable matter prepared from the extracted oil. There appears to be a dose response to rice bran unsaponifiable matter in plasma and liver cholesterol reductions. After 2 weeks, fecal fat and neutral sterol excretion were significantly greater with all treatment diets compared to the control diet. Fecal fat was negatively correlated with liver as well as plasma cholesterol (r = -0.97, P less than or equal to 0.0001 and -0.91, P less than or equal to 0.0006, respectively). Under the conditions of this study, cholesterol-lowering activity of rice bran is present in its unsaponifiable matter in addition to other components. Increased fecal excretion of fat and neutral sterols appears to be a possible mechanism for cholesterol-lowering by rice bran.


Author(s): Huang D, Ou B, Hampsch-Woodill M, Flanagan JA, Deemer EK.

Title: Development and validation of oxygen radical absorbance capacity assay for lipophilic antioxidants using randomly methylated beta-cyclodextrin as the solubility enhancer.

Source: Journal Agricultural and Chemistry, 2002, 50 (7), pp. 1815-1821

Language: English

Abstract: Brunswick Laboratories, 6 Thacher Lane, Wareham , Massachusetts 02571 , USA . We recently reported the improved oxygen radical absorbance capacity (ORAC) assay using fluorescein (FL) as the fluorescent probe. The current ORAC(FL) assay is limited in hydrophilic antioxidant due to the aqueous environment of the assay. Lipophilic antioxidants mainly include the vitamin E family and carotenoids, which play a critical role in biological defense systems. In this paper, we expanded the current ORAC(FL) assay to lipophilic antioxidants. Randomly methylated beta-cyclodextrin (RMCD) was introduced as the water solubility enhancer for lipophilic antioxidants. Seven percent RMCD (w/v) in a 50% acetone-H(2)O mixture was found to sufficiently solubilize vitamin E compounds and other lipophilic phenolic antioxidants in 75 mM phosphate buffer (pH 7.4). This newly developed ORAC assay (abbbreviated ORAC(FL-LIPO) was validated through linearity, precision, accuracy, and ruggedness. The validation results demonstrate that the ORAC(FL-LIPO) assay is reliable and robust. For the first time, by using 6-hydroxy-2,5,7,8-tetramethyl-2-carboxylic acid as a standard (1.0), the ORAC values of alpha-tocopherol, (+)-gamma-tocopherol, (+)-delta-tocopherol, alpha-tocopherol acetate, tocotrienols, 2,6-di-tert-butyl-4-methylphenol, and gamma-oryzanol were determined to be 0.5 +/- 0.02, 0.74 +/- 0.03, 1.36 +/- 0.14, 0.00, 0.91 +/- 0.04, 0.16 +/- 0.01, and 3.00 +/- 0.26, respectively. The structural information of oxidized alpha-tocopherol obtained by liquid chromatography/mass spectrometry reveals that the mechanism for the reaction between the vitamin E and the peroxyl radical follows the hydrogen atom transfer mechanism, which is in agreement with the notion that vitamin E is the chain-breaking antioxidant.


Author(s): Packer L, Weber SU,Rimbach G.

Title:
Molecular aspects of alpha-tocotrienol antioxidant action and cell signalling.

Source:
The Journal of Nutrition, Vol. 131, Iss. 2, p. 369-73.

Abstract:
Packer L.et al. described antioxidant activity.Vitamin E was the most important lipid-soluble antioxidant. Although the antioxidant activity of tocotrienols is higher than that of tocopherols, tocotrienols have a lower bioavailability after oral ingestion. Tocotrienols penetrate rapidly through skin and efficiently combat oxidative stress induced by UV or ozone. Tocotrienols have beneficial effects in cardiovascular diseases both by inhibiting LDL oxidation and by down-regulating 3-hydroxyl-3-methylglutaryl-coenzyme A(HMG CoA) reductase, a key enzyme of the mevalonate pathway.


Author(s): Gen Y., Tsutomu K., Masohiko A., Makoto T., Tomio Y., Shuji T., Masahide I., Hiroshi H., Shigeaki B.

Title:
Effects of gamma-oryzanol on hyperlipidemic subjects

Source:
Current therapeutic, Vol. 4, No. 4, april, 1989

Abstract:
Gen Y. et al. studied on the hypercholesterolemic effect of gamma-oryzanol which was investigated in 67 patients with hyperlipidemia. Three milligrams of gamma-oryzanol were administered daily, for 3 months. Plasma cholesterol and plasma triglyceride levels decreased significantly from the second month and after three months, respectively. High-density lipoprotein(HDL)-cholesterol was also significantly elevated after three months. The reduction in plasma-cholesterol was attributable to the decrease in low-density lipoprotein(LDL) cholesterol. Together with a long-term history of clinical use, this indicates the potential use of this drug as a treatment of first choice for mild hypercholesterolemic.


Author(s): Tong W., Kevin B.H., Robert M

Title:
Antioxidant activity of phytosterols, oryzanol and other phytosterol conjugates

Source:
JAOCS, Vol.79, No.12, 2002

Abstract:
Tong W. et al. studied on antioxidant activity of phytosterols, oryzanol, ferulic acid ester of sterols, corn fiber oil and rice bran oil. At low concentration, these materials (phytosterols, oryzanol, ferrulic acid ester of sterols) did not improve the oxidative stability of the oil. The oxidative stability of oil was significantly affected by type of compounds tested and other concentration. Rice bran oil had significantly better antioxidant activity than the other. Viscosity of the oil was also significantly affected by type of the compounds. Rice bran oil was the most effective agent in preventing polymerization, and its activity increased dramatically with an initial increase in concentration but tended to level off an higher concentration. This experiment  also suggest that  the good antioxidant and antipolymerization of rice bran oil may not be due to is oryzanol content alone but to other minor lipid components, such as avenasterols. Rice bran oil showed very good antioxidant and antipolymerization ativity.


Author(s): Caudia Juliano, Massima Cossee, Maria Cristina, Luisella Pia

Title:
Antioxidant activity of gamma-oryzanol mechanism of action and its effect  on oxidative stability of pharmaceutical

Source:
International Journal of   pharmaceutics, Vol.299, Issue 1-2, 11August 2005, 146-154.

Abstract:
Claudia et al. studied in antioxidant activity of gamma-oryzanol. In this research, gamma-oryzanol was extracted from rice bran oil. The molecular mechanism(s) of antioxidant activity of gamma-oryzanol by utilising different in vitro were investigated, such as scavenging at stable DPPH radical, OH radical and O2 radicals scavenging, and azocompound AMVN-initiated lipid peroxidation. The effect of scavenging on the oxidative stability of vegetable oils of pharmaceutical and cosmetic was evaluated in a oxidation accelerate test and compared with the effect of BHA and BHT. It was found that gamma-oryzanol is able to prevent AMVN-triggered lipoperoxidation. Moreover, when added to oil at concentration ranging between 2.5 and 10 mmol/kg, gamma-oryzanol shows a dose-dependant increase of induction time of oil, gamma-oryzanol improved the oxidative stability of oil.


Author(s): Mohammad Minhajuddin, Zafarul H. Beg, Jahangir Iqbal

Title:
Hypolipidemic and antioxidant properties of tocotrienol rich fraction isolated from rice bran oil in experimentally induced hyperlipidemic rats

Source:
Food and Chemical Toxicology, 43, 2005, 747-753

Abstract:
Mohammad et al. studied on hypolipidemic and antioxidant effect of tocotrienol rich fraction (TRF) isolated from rice bran oil on experimentally induced hyperlipidemic rats. Hyperlipidemic rats were supplemented with different doses of TRF of one week. It was found that TRF supplementation decreased the lipid parameters with the optimum effect at a dose of 8 mg TRF /kg/day. HMG-CoA reductas activity, TBARS and conjugated dienes decreased significantly  during the TRF treatment. These results suggest that TRF supplementation has health benefits through the modulation of physiological functions that include various atherogenic lipid profiles and antioxidants in hypercholesterolemic.


Author(s): Baliarsingh S, Beg ZN, Ahmad J

Title:
The therapeutic impacts of tocotrienols in type 2 diabetic patients with hyperlipidemia

Source:
Atherosclerosis, 2005, October; 182(2) : 867-74

Abstract:
Baliarsingh S et al. investigated the theropeutic impacts of tocotrienols on serum and lipoprotein lipid levels in type 2 diabetic patients. Tocotrienol rich fraction(TRF) mediated decrease on elevated blood glucose and glucated hemoglobin A(1C)(HbA(1C)) in diabetic rats.  They investigated effect of TRF on these parameters. After 60 days of TRF treatment, subjects showed an average decline of 20, 30 and 42% in serum total lipids, TC and LDL-C, respectively. In conclusion, daily intake of dietary TRF by type 2 diabetics will be useful in the prevention and treatment of hyperlipidemia and atherogenesis.


Author(s): Most MM., Tulley R., Morales S., Lefevre M.

Title:
Rice bran oil, not fiber, lower cholesterol in humans

Source:
American Journal of Clinical Nutrition, Vol. 81, No.1, 64-68, January 2005

Abstract:
Most MM studied to assess the effects of defatted rice bran and rice bran oil in an average American diet on blood lipid in moderately hypercholesterolemic persons. It was found that defatted  rice bran did not lower lipid concentrations. Total cholesterol was significantly lower with comsumption of the diet containing rice bran oil than with consumption of the control diet. The consumption of the rice bran oil diet, LDL cholesterol decreased by 7%, whereas HDL cholesterol was unchanged. In conclusion, rice bran oil, not fiber, lowers cholesterol in healthy, moderately hypercholesterolemic adults. There were no substantial differences in the fatty acid composition of the diets; therefore, the reduction of cholesterol was due to other components present in the rice bran oil, such as unsaponifiable compounds.


Author(s): Murase Y., Ishima H

Title:
Clinical studies of oral administration of gamma-oryzanol on climacteric complaints and its syndrome

Source:
Obstetrical and gynecological practice, 1963; 12: 147-9.

Abstract:
Murase Y and Ishima H studies on effect of gamma-oryzanol for menopause. In this research gave 13 women who had hysterectomies, also called surgical menopouse, 100 mg gamma-oryzanol three daily for 38 days. It was found that it halved menopausal symptoms such as hot flashes in more than 67 percent of the women.


ข้อมูลเพิ่มเติมเกี่ยวกับคุณค่าของน้ำมันรำข้าว ทั้งในเรื่องการลดคอเลสเตอรอล และเรื่องสารต้านอนุมูลอิสระ สามารถค้นหาเพิ่มเติมได้ในเอกสารทางวิชาการ วารสารต่างๆ และในเว็บไซต์
http://www.americanheart.org/presenter.jhtml?identifier=1466
http://www.fao.org/WAICENT/OIS/PRESS_NE/PRESSENG/2000/pren0017.htm
http://brunswicklabs.com
http://www.americanheart.org/presenter.jhtml?identifier=1872
http://www.tatnews.org/emagazine/1941.asp
http://www.diabetes.org/uedocuments/ADACardioReview4.pdf
http://www.americanheart.org/presenter.jhtml?identifier=1466

 
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