Nutrients in rice bran oil and their nutritional functions: a review.

Rice is an important food crop throughout the world. Rice bran, the outer layer of rice grain, is a by-product generated during the rice milling process. Rice bran oil (RBO) is extracted from rice bran and has also become increasingly popular. RBO is considered to be one of the healthiest cooking oils due to its balanced proportion of fatty acids, as well as high content of γ-oryzanol together with phytosterols, vitamin E, wax ester, trace and macro elements, carotenoids, and phenolics. The existence of these compounds provides RBO with various functions, including hypotensive and hypolipidemic functions, antioxidant, anticancer, and immunomodulatory functions, antidiabetic function, anti-inflammatory and anti-allergenic functions, hepatoprotective activity function, and in preventing neurological diseases. Recently, research on the nutrients in RBO focused on the detection of nutrients, functions, and processing methods. However, the processing and utilization of rice bran remain sufficiently ineffective, and the processing steps will also affect the nutrients in RBO to different degrees. Therefore, this review focuses on the contents and nutritional functions of different nutrients in RBO and the possible effects of processing methods on nutrients.

Added γ-oryzanol boosted anti-inflammatory effects of canola oil in adult subjects with type 2 diabetes: a randomized controlled clinical trial.

PURPOSE: This study was conducted to examine the effects of daily intake of γ-oryzanol (ORZ)-fortified canola oil, as compared with plain canola and sunflower oils, on certain inflammatory and oxidative stress biomarkers in adult subjects with Type 2 Diabetes (T2D). METHODS: We randomly allocated 92 adult subjects with T2D from both sexes to one of the following groups to receive: (a) ORZ-fortified canola oil (ORZO; n1 = 30); (b) unfortified canola oil (CANO; n2 = 32); or (c) sunflower oil (SUFO; n3 = 30) for 12 weeks. Dietary and laboratory evaluations were performed initially and finally. RESULTS: Serum hs-CRP concentrations significantly decreased in ORZO group (from 3.1 ± 0.2 to 1.2 ± 0.2 mg/L), as compared with CANO (p = 0.003) and SUFO (p < 0.001) groups. Serum IL-6 significantly decreased just in ORZO (- 22.8%, p = 0.042) and CANO groups (- 19.8%, p = 0.038). However, the between-group differences were not significant. Serum IL-1ß slightly decreased in ORZO (- 28.1%, p = 0.11) and increased in SUFO (+ 20.6%, p = 0.079) but between-group difference was statistically significant (p = 0.017). Serum IFN-γ concentrations decreased significantly only in ORZO (from 3.3 ± 0.08 to 2.9 ± 0.21 IU/mL, p = 0.044). Salivary IgA concentrations increased significantly in all three intervention groups. Notwithstanding, only the difference between ORZO and CANO groups was statistically significant (p = 0.042). Similarly, circulating malondialdehyde concentrations significantly decreased in all three groups but with no between-group significant difference. CONCLUSIONS: Daily consumption of ORZ-fortified canola oil, compared with unfortified canola and sunflower oils, for 12 weeks resulted in boosting of certain anti-inflammatory effects of canola oil. These findings may have preventive implications for both clinicians and policy makers. This clinical trial was registered at clinicaltrials.gov (03.08.2022; NCT05271045).

Lipid concomitant γ-oryzanol decreased oil absorbency of French fries by changing the microstructure of French fries and physical properties of frying oil.

BACKGROUND: The aim of this research was to evaluate the possibility of lipid concomitant γ-oryzanol reducing oil absorbency of fried foods and the underlying mechanism. Therefore, the influence of γ-oryzanol on moisture and oil content, and distribution and micromorphology of French fries and the viscosity, fatty acid composition and total polar compounds content of rice bran oil (RBO) after frying were studied. RESULTS: Our results showed that the incorporation of low concentration of γ-oryzanol [low addition group (LAG)] (5.754 g/kg) decreased the oil absorbency and porous structure of French fries during frying. Additionally, LAG incorporation inhibited the degradation of linoleic acid, decreased the growth rate of saturated fatty acids, total polar compounds and viscosity of frying oil. CONCLUSIONS: Consequently, it was recommended to incorporate a small amount of γ-oryzanol in frying oil because it could inhibit oil absorption behavior of French fries. © 2023 Society of Chemical Industry.

Effect of γ-oryzanol/ß-sitosterol-based oleogels on the physicochemical and gel properties of Nemipterus virgatus myofibrillar protein.

BACKGROUND: The effect of oleogels prepared with peanut oil and different concentrations of γ-oryzanol and ß-sitosterol mixture (γ/ß; 20, 40, 60, 80 and 100 g kg-1) on the physicochemical and gel properties of myofibrillar protein (MP) was investigated. RESULTS: The solubility and average particle size of MP first decreased and then increased with increasing γ/ß concentration. Peanut oil or oleogels could induce the exposure of hydrophobic amino acids and the unfolding of MP, thus significantly increasing the surface hydrophobicity, sulfhydryl content and absolute value of zeta potential, which reached maximum values when the γ/ß concentration was 60 g kg-1 (P < 0.05). The addition of peanut oil decreased the gel strength and water holding capacity of MP gel. However, oleogels prepared with 60 g kg-1 γ/ß could significantly increase the hydrophobic interactions and disulfide bond content of MP gel (P < 0.05), which promoted the crosslinking and aggregation of MP, enhancing the gel properties. Peanut oil had no significant influence on the secondary structure of MP, while oleogels promoted the transition of MP conformation from α-helix to ß-sheet structure. The results of light microscopy and confocal laser scanning microscopy indicated that oleogels prepared with 60 g kg-1 γ/ß filled in the pores of MP gel network to form denser and more uniform structure. CONCLUSION: Oleogels prepared with 60 g kg-1 γ/ß could effectively improve the quality of MP gel and have promising application prospects in surimi products. © 2024 Society of Chemical Industry.

Nanoparticles Encapsulated γ-Oryzanol as a Natural Prodrug of Ferulic Acid for the Treatment of Oxidative Liver Damage.

Antioxidants are promising therapeutics for treating oxidative stress-mediated liver diseases. Previously, we studied a potent natural antioxidant, ferulic acid, and developed a liposomal formulation of ferulic acid (ferulic-lipo) to improve its solubility. Ferulic-lipo significantly attenuated oxidative damage in the liver by inhibiting reactive oxygenase species (ROS). However, antioxidative liposomes must be less reactive with ROS prior to reaching the target sites to effectively neutralize existing ROS. But ferulic-lipo tends to be oxidized before reaching the liver. Besides, γ-oryzanol has been reported to decompose into ferulic acid in vivo; accordingly, we hypothesized that γ-oryzanol could be employed as a natural prodrug of ferulic acid to improve stability and antioxidative effectiveness. Therefore, in this study, we prepared a liposomal formulation of γ-oryzanol (γ-ory-lipo) and investigated its therapeutic effects in a CCl4-induced rat model of liver injury. We found that γ-ory-lipo has a higher chemical stability than does free γ-oryzanol. Although the antioxidative effect of γ-ory-lipo was lower than that of ferulic-lipo, pretreatment of the HepG2 cells with γ-ory-lipo improved the viability of CCl4-treated cells to a similar level as treatment with ferulic-lipo. γ-Oryzanol was shown to be converted into ferulic acid in vitro and in vivo. Furthermore, intravenous administration of γ-ory-lipo exhibited a similar effectiveness as ferulic-lipo against CCl4-induced hepatotoxicity, which should be the due to the conversion of γ-oryzanol into ferulic acid. These findings demonstrated that γ-ory-lipo could be a good natural prodrug of ferulic acid for eradicating its stability problem.

Characterization of encapsulated γ-oryzanol powder by spray drying using whey protein and maltodextrin as wall materials.

Characterizations of encapsulated γ-oryzanol powder (EOP) using whey protein concentrate (WPC) and maltodextrin as wall materials were studied. Rice bran oil (RBO) with 2% γ-oryzanol was encapsulated using different concentrations of WPC (0.2-1.0%) combined with 10% of maltodextrin before spray drying. The physicochemical characteristics and reconstitution of EOP were investigated. The results found that different concentrations of WPC affected EOP characteristics. The EOP coated 1% WPC exhibited low moisture content and water activity (aw) containing high γ-oryzanol content and encapsulation efficiency. Morphology of EOP using SEM displayed spheroid shape with smooth and crack-free surface. However, EOP emulsion had relatively larger particle size and lower solubility index than the fresh emulsion after reconstitution, but a good creaming stability of reconstituted EOP was observed. Therefore, it can be concluded that using 1% WPC combined with 10% maltodextrin provided good performance of encapsulated RBO with 2% γ-oryzanol using spray drying. According to physicochemical characteristics, the EOP has good potential as a food ingredient for food industry and as an excipient for pharmaceutical and cosmetic industries.

Increased γ-Aminobutyric Acid Content of Germinated Brown Rice Produced in Membrane Reactor.

RESEARCH BACKGROUND: Rice germination is a natural approach to enhance the physical and functional properties of brown rice. Thus, the aim of this study is to investigate the influence of different germination methods on functional properties of germinated brown rice and evaluate the process feasibility. EXPERIMENTAL APPROACH: Brown rice of IPB 3S variety was germinated with three different methods: (i) complete soaking without water replacement, (ii) complete soaking with water replacement every six hours, and (iii) complete soaking with continuous washing in the developed membrane-facilitated soaking reactor. RESULTS AND CONCLUSIONS: The application of the membrane reactor for producing germinated brown rice maintained the pH of the soaking solution relatively constant (i.e. 6.8-7.0). This indicated the circumvention of natural fermentation during brown rice germination. Moreover, the mass fraction of γ-aminobutyric acid in germinated brown rice produced in the membrane reactor was about 4.5-fold higher (169.2 mg/100 mg) than in ungerminated brown rice (36.82 mg/100 mg), and also higher than that of the other two soaking methods. The γ-oryzanol mass fractions and the antioxidant capacity expressed as ascorbic acid equivalents of germinated brown rice obtained with the three soaking methods varied from 32 to 38 mg/100 mg and 18 to 28 mg/100 g, respectively. Within this study, germination could also slightly reduce the transition temperatures of germinated brown rice starch gelatinization (t o=73-74 °C, t p=76-77 °C and t c=~80 °C, where t o, t p and t c are onset, peak and conclusion (final) temperatures). In conclusion, the production of germinated brown rice in the membrane reactor could enhance its γ-aminobutyric acid mass fraction and reduce wastewater production and is therefore considered more feasible. NOVELTY AND SCIENTIFIC CONTRIBUTION: This study demonstrates the feasibility of germinated brown rice production using a membrane-facilitated soaking reactor with enhancement of bioactive compound content, especially γ-aminobutyric acid, and minimised wastewater production.

Preparation and Evaluation of Release Formulation of γ-Oryzanol/Algae Oil Self-Emulsified with Alginate Beads.

Self-emulsion improves solubility and bioavailability for γ-oryzanol/algae oil, and alginate beads can be used as controlled release carriers. In this study, self-emulsified alginate beads (SEABs) were prepared with different weight ratios of self-emulsion treatment (5%, 10%, 15%, 20%, and 30%) with alginate. We found that the microstructure with a surfactant of SEABs had a different appearance with alginate-based beads. The encapsulation of γ-oryzanol corresponded with the self-emulsion/alginate ratio, which was 98.93~60.20% with a different formulation of SEABs. During in vitro release, SEABs had the gastric protection of γ-oryzanol/algae oil, because γ-oryzanol and emulsion were not released in the simulated stomach fluid. When the SEABs were transferred to a simulation of the small intestine, they quickly began to swell and dissolve, releasing a higher content of the emulsion. We observed that the emulsion that formed had a bimodal distribution in the simulated intestinal fluid as a result of the hydrogel and emulsion droplets, leading to the formation of large aggregates. These results suggested that γ-oryzanol encapsulation within alginate beads via emulsification combined with gelation can serve as an effective controlled delivery system.

Diversity in γ-oryzanol profiles of Japanese black-purple rice varieties.

The γ-oryzanol contents and the composition of steryl ferulates distributed in Japanese pigmented rice varieties were investigated using the high-performance liquid chromatography-ultraviolet detection method for the purpose of expanding their utilisation. The average γ-oryzanol content in nine black-purple, four red, four green and three brown rice varieties was 54.2, 47.3, 44.3 and 43.3 mg γ-oryzanol equivalent/100 g dried weight, respectively. Among the nine varieties of black-purple rice, five varieties showed steryl ferulate composition similar to that of brown, red and green varieties. In contrast, the composition of steryl ferulates in other four black-purple rice varieties was partially specific and was characterised by a low amount of campesteryl ferulate and high of campestanyl ferulate and stigmastanyl ferulate. The latter two steryl ferulates have been recognised as minor components of γ-oryzanol in rice and as major components in wheat and corn. These results indicate that the compositions of steryl ferulates vary among Japanese black-purple rice varieties.

Improved Physicochemical Properties of Yogurt Fortified with Fish Oil/γ-Oryzanol by Nanoemulsion Technology.

Fish oil has several dietary benefits, but its application in food formulations is limited because of its poor water-solubility, easy oxidation and strong odor. The purposes of this study were to produce a fish oil/γ-oryzanol nanoemulsion and to evaluate the effect of adding this nanoemulsion on the physicochemical and sensory characteristics of yogurts. Adding fish oil/γ-oryzanol nanoemulsion resulted in a significant reduction in the acidity and syneresis of yogurt. Yogurt with the nanoemulsion had significantly lower peroxide value (0.28 mmol/L after 21 days) and higher retention of eicosapentaenoic acid and docosahexaenoic acid contents (decreased to 95% and 94% of its initial value, respectively) than yogurt with fish oil/γ-oryzanol (peroxide value = 0.65 mmol/L; eicosapentaenoic acid and docosahexaenoic acid contents decreased to 72% and 53% of its initial value, respectively). Fish oil/γ-oryzanol nanoemulsion incorporated into yogurt had closer sensory attributes scores to plain yogurt. This study may have important implications for the application of fish oil/γ-oryzanol nanoemulsion in yogurt.

γ-Oryzanol suppresses COX-2 expression by inhibiting reactive oxygen species-mediated Erk1/2 and Egr-1 signaling in LPS-stimulated RAW264.7 macrophages.

Cyclooxygenase (COX)-2 produces prostanoids, which contribute to inflammatory responses. Nuclear factor (NF)-κB is a key transcription factor mediating COX-2 expression. γ-Oryzanol is an active component in rice bran oil, which inhibits lipopolysaccharide (LPS)-mediated COX-2 expression by inhibiting NF-κB. However, the inhibition of COX-2 expression by γ-oryzanol independently of NF-κB is poorly understood. We found that LPS upregulated Egr-1 expression at the transcriptional level. Forced expression of Egr-1 trans-activated the Cox-2 promoter independently of NF-κB. In contrast, silencing of Egr-1 abrogated LPS-mediated COX-2 expression. LPS produced reactive oxygen species (ROS), which, in turn, induced Egr-1 expression via the Erk1/2 MAPK pathway. ROS scavenging activity of γ-oryzanol suppressed Egr-1 expression by inhibiting the Erk1/2 MAPK pathway. Our results suggest that γ-oryzanol inhibits LPS-mediated COX-2 expression by suppressing Erk1/2-mediated Egr-1 expression. This study supports that γ-oryzanol may be useful for ameliorating LPS-mediated inflammatory responses.

Rice bran nutraceutics: A comprehensive review.

Agro-industry yields ample quantity of several byproducts with considerable importance. These byproducts are mostly under-utilized, often used as animal feed or rejected as waste; hence their true potential is not harnessed. The use of such superfluous resources is of not only economic significance but also a form of commercial recycling. Rice bran is an important byproduct of rice milling industry with a global potential of 29.3 million tons annually. It is gaining great attention of the researchers due to its nutrient-rich composition, easy availability, low cost, high antioxidant potential, and promising effects against several metabolic ailments. Bioactive components of rice bran, mainly γ-oryzanol, have been reported to possess antioxidant, anti-inflammatory, hypocholesterolemic, anti-diabetic, and anti-cancer activities. Rice bran oil contains appreciable quantities of bioactive components and has attained the status of "Heart oil" due to its cardiac-friendly chemical profile. Nutraceutics have successfully been extracted from rice bran using several extraction techniques such as solvent extraction, supercritical fluid extraction, microwave-, and ultrasonic-assisted extraction. Current paper is an attempt to highlight bioactive moieties of rice bran along with their extraction technologies and health benefits.

Genetic variation of carotenoids, vitamin E and phenolic compounds in Provitamin A biofortified maize.

BACKGROUND: Biofortified maize is not only a good vehicle for provitamin A carotenoids for vitamin A deficient populations in developing countries but also a source of vitamin E, tocochromanols and phenolic compounds, which have antioxidant properties. Using high-performance liquid chromatography and a total antioxidant performance assay, the present study analyzed the antioxidant variation and antioxidant activity of 36 provitamin A improved maize hybrids and one common yellow maize hybrid. RESULTS: The ranges of major carotenoids in provitamin A carotenoids biofortified maize were zeaxanthin [1.2-13.2 µg g-1 dry weight (DW)], ß-cryptoxanthin (1.3-8.8 µg g-1 DW) and ß-carotene (1.3-8.0 µg g-1 DW). The ranges of vitamin E compounds identified in provitamin A carotenoids biofortified maize were α-tocopherol (3.4-34.3 µg g-1 DW), γ-tocopherol (5.9-54.4 µg g-1 DW), α-tocotrienol (2.6-19.5 µg g-1 DW) and γ-tocotrienol (45.4 µg g-1 DW). The ranges of phenolic compounds were γ-oryzanol (0.0-0.8 mg g-1 DW), ferulic acid (0.4-3.6 mg g-1 DW) and p-coumaric acid (0.1-0.45 mg g-1 DW). There was significant correlation between α-tocopherol and cis isomers of ß-carotene (P < 0.01). Tocotrienols were correlated with α-tocopherol and γ-oryzanol (P < 0.01). CONCLUSION: Genotype was significant in determining the variation in ß-cryptoxanthin, ß-carotene, α-tocopherol and γ-tocopherol contents (P < 0.01). A genotype × environment interaction was observed for γ-tocopherol content (P < 0.01). © 2016 Society of Chemical Industry.

Dietary gamma oryzanol plays a significant role in the anti-inflammatory activity of rice bran oil by decreasing pro-inflammatory mediators secreted by peritoneal macrophages of rats.

Ricebran oil (RBO) is promoted as heart friendly oil because of its ability to maintain serum lipids at desirable levels. Inflammation also plays an important role on cardiovascular health. The role of minor constituents present in unsaponifiable fraction (UF) of RBO on inflammatory markers is not well understood. To evaluate this, we have taken RBO with UF (RBO-N), RBO stripped of UF (RBO-MCR) and RBO-MCR supplemented with UF from RBO (UFRBO) or Gamma-Oryzanol (γ-ORY) were added in AIN-93 diets which was then fed to Wistar rats for a period of 60 days. Groundnut oil with UF (GNO-N), UF removed GNO (GNO-MCR) and GNO-MCR supplemented with UF from RBO or γ-ORY was also used for comparison. The peritoneal macrophages from the rats were activated and pro-inflammatory mediators such as Reactive Oxygen Species (ROS), eicosanoids, cytokines, hydrolytic enzymes of lysosomal origin were monitored. The results indicated that UF of RBO and γ-ORY supplemented in the dietary oils play a significant role in reducing the secretion of pro-inflammatory mediators by macrophages. Hence γ-ORY in RBO significantly contributed to the anti-inflammatory properties of RBO.

Rice bran prevents high-fat diet-induced inflammation and macrophage content in adipose tissue.

BACKGROUND: The inflammatory process associated with obesity mainly arises from white adipose tissue (WAT) alterations. In the last few years, nutritional-based strategies have been positioned as promising alternatives to pharmacological approaches against these pathologies. Our aim was to determine the potential of a rice bran enzymatic extract (RBEE)-supplemented diet in the prevention of metabolic, biochemical and functional adipose tissue and macrophage changes associated with a diet-induced obesity (DIO) in mice. METHODS: C57BL/6J mice were fed high-fat diet (HF), 1 and 5 % RBEE-supplemented high-fat diet (HF1 % and HF5 %, respectively) and standard diet as control. Serum cardiometabolic parameters, adipocytes size and mRNA expression of pro-inflammatory biomarkers and macrophage polarization-related genes from WAT and liver were evaluated. RESULTS: RBEE administration significantly decreased insulin resistance in obese mice. Serum triglycerides, total cholesterol, glucose, insulin, adiponectin and nitrites from treated mice were partially restored, mainly by 1 % RBEE-enriched diet. The incremented adipocytes size observed in HF group was reduced by RBEE treatment, being 1 % more effective than 5 % RBEE. Pro-inflammatory biomarkers in WAT such as IL-6 and IL-1ß were significantly decreased in RBEE-treated mice. Adiponectin, PPARγ, TNF-α, Emr1 or M1/M2 levels were significantly restored in WAT from HF1 % compared to HF mice. CONCLUSIONS: RBEE-supplemented diet attenuated insulin resistance, dyslipidemia and morphological and functional alterations of adipose tissue in DIO mice. These benefits were accompanied by a modulating effect in adipocytes secretion and some biomarkers associated with macrophage polarization. Therefore, RBEE may be considered an alternative nutritional complement over metabolic syndrome and its complications.

Antioxidant Activity of γ-Oryzanol: A Complex Network of Interactions.

γ-oryzanol (Orz), a steryl ferulate extracted from rice bran layer, exerts a wide spectrum of biological activities. In addition to its antioxidant activity, Orz is often associated with cholesterol-lowering, anti-inflammatory, anti-cancer and anti-diabetic effects. In recent years, the usefulness of Orz has been studied for the treatment of metabolic diseases, as it acts to ameliorate insulin activity, cholesterol metabolism, and associated chronic inflammation. Previous studies have shown the direct action of Orz when downregulating the expression of genes that encode proteins related to adiposity (CCAAT/enhancer binding proteins (C/EBPs)), inflammatory responses (nuclear factor kappa-B (NF-κB)), and metabolic syndrome (peroxisome proliferator-activated receptors (PPARs)). It is likely that this wide range of beneficial activities results from a complex network of interactions and signals triggered, and/or inhibited by its antioxidant properties. This review focuses on the significance of Orz in metabolic disorders, which feature remarkable oxidative imbalance, such as impaired glucose metabolism, obesity, and inflammation.

Performance of Different Natural Antioxidant Compoundsin Frying Oil.

In this study, the natural green tea extract, purified lycopene, purified resveratrol and purified γ-oryzanol were added into peanut oil and their antioxidant performances were evaluated during frying. Moreover, the sensory properties of fried dough were evaluated to determine the consumption feasibility. All natural antioxidants led to significant increase in the stability of the oil samples. The ranges of measurements in the treatment groups were as follows: free acidity 0.1-2.9 g of oleic acid per 100 g of oil, conjugated dienes 0.01-0.40 g per 100 g of oil, total polar material 8.8-73.8 g per 100 g of oil, total phenolics 0.1-4.2 mg of gallic acid equivalents per 100 g of oil, and antioxidant capacity 0.5-11.0 mM of Trolox equivalents per 100 g of oil. The fatty acid and sterol compositions indicated that antioxidant supplementation could slow the oxidative degradation of unsaturated fatty acids and reduce trans-acid formation. Frying oil enriched with purified γ-oryzanol had higher sterol levels than the other enriched oil samples. The obtained quality of oil protection was in descending order: purified γ-oryzanol, green tea extract and purified lycopene.

Effect of natural compounds on Fusarium graminearum complex.

BACKGROUND: A search is underway for new solutions to counter farm loss caused by fungal contamination of grains, since the active agents of fungicides can remain in the environment and contribute to the development of resistant and toxigenic species. In this study, the antifungal activity of natural compounds (γ-oryzanol, phenolic extract of neem seeds and of rice bran) was assessed on three toxigenic strains of Fusarium graminearum isolated from wheat, rice and barley. Their efficacy was compared to that of synthetic fungicides. The halo diameters were measured and the susceptible pathways were determined by the levels of structural compounds and activities of enzymes involved in the primary metabolism of the microorganisms. Moreover, mycotoxin production and gene expression were examined. RESULTS: Phenolic extracts were more effective at inhibiting F. graminearum than was γ-oryzanol, as evidenced by the minimum inhibitory concentration. This work contributed to the elucidation of the mechanism of action of natural antifungal agents. CONCLUSION: Natural antifungals effectively inhibited fungal growth, especially via the inactivation of the enzymatic systems of F. graminearum. Natural antifungals inhibited mycotoxin production by the fungi. A correlation between the levels of deoxynivalenol and the expression of Tri5 gene was observed, indicating that the natural compounds could be considered alternatives to synthetic antifungals. © 2015 Society of Chemical Industry.

Comparative study on conventional, ultrasonication and microwave assisted extraction of γ-oryzanol from rice bran.

In present study, conventional, ultrasonic and microwave assisted extraction methods were compared with the aim of optimizing best fitting solvent and method, solvent concentration and digestion time for high yield of γ-oryzanol from rice bran. Petroleum ether, hexane and methanol were used to prepare extracts. Extraction yield were evaluated for giving high crude oil yield, total phenolic content (TPC) and γ-oryzanol content. Gas chromatography-mass spectrophotometry was used for the determination of γ-oryzanol concentration. The highest concentration of γ-oryzanol was detected in methanolic extracts of microwave treatment (85.0 ppm) followed by ultrasonication (82.0 ppm) and conventional extraction method (73.5 ppm). Concentration of γ-oryzanol present in the extracts was found to be directly proportional to the total phenolic content. A combination of 80 % methanolic concentration and 55 minutes digestion time of microwave treatment yielded the best extraction method for TPC and thus γ-oryzanol (105 ppm).

γ-Oryzanol reduces caveolin-1 and PCGEM1 expression, markers of aggressiveness in prostate cancer cell lines.

BACKGROUND: Prostate cancer is a leading cause of death among men due to the limited number of treatment strategies available for advanced disease. γ-oryzanol is a component of rice bran, rich in phytosterols, known for its antioxidant, anti-carcinogenic and endocrinological effects. It is known that γ-oryzanol may affect prostate cancer cells through the down regulation of the antioxidant genes and that phytosterols have anti-proliferative and apoptotic effects. There are evidences showing that some of the components of γ-oryzanol can modulate genes involved in the development and progression of prostate cancer, as caveolin-1 (Cav-1) and prostate specific androgen-regulated gene (PCGEM1). METHODS: To determine the effects of γ-oryzanol on prostate cancer cell survival we evaluated the cell viability and biomass by MTT and sulforhodamine B assays, respectively. Cell death, cell cycle and pERK1/2 activity were assessed by flow cytometry. The changes in gene expression involved in the survival and progression of prostate cancer cav-1 and PCGEM1 genes were evaluated by quantitative real time reverse transcriptase polymerase chain reaction (RT-PCR) and cav-1 protein by immunofluorescence followed by confocal microscopy analysis. RESULTS: We found that γ-oryzanol decreases cell viability and culture biomass by apoptosis and/or necrosis death in androgen unresponsive (PC3 and DU145) and responsive (LNCaP) cell lines, and signals through pERK1/2 in LNCaP and DU145 cells. γ-oryzanol also appears to block cell cycle progression at the G2/M in PC3 and LNCaP cells and at G0/G1 in DU145 cells. These effects were accompanied by a down regulation in the expression of the cav-1 in both androgen unresponsive cell lines and PCGEM1 gene in DU145 and LNCaP cells. CONCLUSION: In summary, we used biochemical and genetics approaches to demonstrate that γ-oryzanol show a promising adjuvant role in the treatment of prostate cancer.