Anti-diabetic activity of oryzanol and its relationship with the anti-oxidant property

Dietary Oryzanol (Ory) Improved the Survival and Growth of Large Yellow Croaker (Larimichthys crocea) Larvae via Promoting Activities of Digestive Enzymes, Antioxidant Capacity, and Lipid Metabolism

A feeding study lasting 30 days was carried out to determine the effects of dietary Oryzanol (Ory) on the survival, growth, antioxidant capacity, peptic enzymes, as well as lipid metabolism of Larimichthys crocea larvae (11.87 ± 0.59 mg) using four different Ory concentrations in microfeed formulations (0, 20, 40, and 80 mg/kg), all preserving isolipidic (18.25% crude lipid) and isonitrogenous (52.08% crude protein) conditions. Results revealed that larvae given 40 and 80 mg/kg Ory revealed markedly higher survival rates; in particular, the 80 mg/kg Ory larvae exhibited a considerably higher specific growth rate than the control. Furthermore, the 80 mg/kg dietary Ory resulted in increased peptic enzyme activity, indicating heightened digestive capabilities of larvae. Meanwhile, Ory supplementation at 20, 40, and 80 mg/kg also increased antioxidant enzyme activities and reduced malondialdehyde levels, indicating an enhanced antioxidant capacity. Moreover, the incorporation of 20 and 40 mg/kg Ory demonstrated efficacy in enhancing the lipid metabolism of the larvae. This was evident in the reduction of triglyceride and total cholesterol levels in the larval visceral mass, attributed to the downregulation of genes that participate in lipid synthesis, and the upregulation of genes associated with lipid catabolism. Overall, the study suggests that the addition of Ory (ranging from 40 to 80 mg/kg) significantly improves both survival and developmental aspects, possibly mediated by enhanced digestion and antioxidative effects, alongside the induction of lipid metabolism in Larimichthys crocea larvae.

Contemporary Views of the Extraction, Health Benefits, and Industrial Integration of Rice Bran Oil: A Prominent Ingredient for Holistic Human Health

Globally, 50% of people consume rice (Oryza sativa), which is among the most abundant and extensively ingested cereal grains. Rice bran is a by-product of the cereal industry and is also considered a beneficial waste product of the rice processing industry. Rice bran oil (RBO) is created from rice bran (20-25 wt% in rice bran), which is the outermost layer of the rice kernel; has a lipid content of up to 25%; and is a considerable source of a plethora of bioactive components. The main components of RBO include high levels of fiber and phytochemicals, including vitamins, oryzanols, fatty acids, and phenolic compounds, which are beneficial to human health and well-being. This article summarizes the stabilization and extraction processes of rice bran oil from rice bran using different techniques (including solvent extraction, microwaving, ohmic heating, supercritical fluid extraction, and ultrasonication). Some studies have elaborated the various biological activities linked with RBO, such as antioxidant, anti-platelet, analgesic, anti-inflammatory, anti-thrombotic, anti-mutagenic, aphrodisiac, anti-depressant, anti-emetic, fibrinolytic, and cytotoxic activities. Due to the broad spectrum of biological activities and economic benefits of RBO, the current review article focuses on the extraction process of RBO, its bioactive components, and the potential health benefits of RBO. Furthermore, the limitations of existing studies are highlighted, and suggestions are provided for future applications of RBO as a functional food ingredient.

Supplementation of media with gamma-oryzanol as a novel antioxidant to overcome redox imbalance during bovine oocyte maturation in vitro

This study evaluated the effect of supplementing IVM media with γ-oryzanol (ORY), a nutraceutical derived from rice bran oil, on the development of bovine oocytes and hindering the compromising effect of redox imbalance. An in vitro model of the bovine cumulus-oocyte complex was used for the evaluation of nuclear maturation and development. Antioxidant activity was investigated by assessing the level of ROS (Reactive Oxygen Species) and GSH (glutathione) in oocytes and quantitative changes in gene expression in matured oocytes and their respective cumulus cells. ORY supplementation increased the proportion of MII oocytes, cleaved embryos, and total blastocysts (p < .05) and was linked to higher and lower levels of intracellular GSH and ROS, respectively (p < .05). The treated oocytes and their respective cumulus-granulosa cells showed a modulation in the expression of genes related to apoptosis (downregulation of BAX and CHOP) and oxidative stress (upregulation of NRF2, CAT, and SOD). Also, relative upregulation of OCT-4 and IGF2R in treated oocytes was concomitant with higher subsequent development in terms of cleavage and total blastocyst rates (p < .05). Based on our findings, it appears that ORY supplementation can improve the nuclear maturation and development of bovine oocytes into blastocysts and augment their enzymatic and non-enzymatic antioxidant systems, maintaining the Redox balance and high enzymatic activity against ROS generation.

Dose-dependent anti-hyperglycemic & anti-dyslipidemic potential of aqueous leaves extract of Typha elephantina in-vivo and in-vitro

Diabetes mellitus is among the fundamental causes of illness and millions of deaths around the globe are directly attributed to it each year. Current antidiabetic medications often lack sustained glycemic control and carry significant risks of side effects. As a result, the use of plant-based treatments has gained popularity. In this experimental study, we evaluated the aqueous extracts (LQE) of Typha elephantina (also known as Elephant grass) leaves collected from freshwater marshes, for their potential anti-hyperglycemic and anti-hyperlipidemic antioxidant effects in healthy streptozotocin caused diabetic-mice. We employed glucose adsorption tests at different glucose levels and glucose diffusion tests to assess the in-vitro antidiabetic action of plant extract. For the in-vivo trail, we measured fasting blood glucose (FBG), glucose tolerance (GTT), as well as long-term anti-diabetic, anti-hyperlipidemic, and antioxidant activities. Our results from the glucose diffusion test indicated that the extract was highly effective at both low glucose concentrations (5 mmol L) and high glucose concentrations (100 mmol L). However, the glucose-diffusion ability reached its peaked at an excessively high dosage of the aqueous extract, suggesting a dose-related effect. Similarly, we observed that high doses of TEL.AQ extracts (400 mg/kg body weight) significantly reduced blood glucose levels in healthy mice during the glucose tolerance test (GTT) at 3 h and fasting blood glucose studies (FBG) at 6 h. Furthermore, the high-dose TEL.AQ extract effectively reduced liver-related serum markers and blood-glucose concentration (BGC) in severely chronic diabetic rats. The extract dosage also influenced lipid profile, conjugate and unconjugated bilirubin levels, cholesterol, triglycerides, HDL, and total bilirubin levels. Additionally, after administering a high extract dose, we observed considerable improvement in the liver homogenate markers CAT, POD, and SOD. In contrast, the extract at a low dosage (100 mg/kg), showed minimal, while a moderate dose (200 mg/kg), yielded promising results.

Daily consumption of γ-oryzanol-fortified canola oil, compared with unfortified canola and sunflower oils, resulted in a better improvement of certain cardiometabolic biomarkers of adult subjects with type 2 diabetes: a randomized controlled clinical trial

BACKGROUND

This study was undertaken to examine the effects of daily consumption of γ-oryzanol (ORZ)-fortified canola oil, as compared with plain canola and sunflower oils, on certain cardiometabolic indicators.

METHODS

Ninety-two adult subjects from both sexes with T2D were randomly assigned to one of the three groups to receive: (a) ORZ-fortified canola oil (Group 1; n1 = 30); (b) unfortified canola oil (Group 2; n2 = 32); or (c) sunflower oil (Group 3; n3 = 30) for 12 weeks. The participants were instructed to use only the given oils for all cooking (but frying) purposes. Anthropometric, dietary and biochemical assessments were done initially and finally.

RESULTS

Though body mass index (BMI) significantly decreased in all three groups, only in Groups 1 and 2 waist circumference (WC) showed a significant decrement (-2.6 ± 0.1 and -2.2 ± 0.1 cm in Groups 1 and 2 respectively, p < 0.001 for both) which was accompanied by a significant reduction of blood pressure just in Group 1. Fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) showed a significant decrease only in ORZ-fortified canola oil group (-7.7 ± 0.4 mg/dL, p = 0.039 and -0.7 ± 0.1%, p < 0.001, respectively). However, insulin resistance, as judged by HOMA-IR, did not change significantly. In addition, serum triglyceride (TG) concentrations decreased in all three groups but only in ORZ-fortified canola oil was this decrement statistically significant (-17.9 ± 2.1 mg/dL, p = 0.005). Other components of serum lipid profile did not change significantly in either group.

CONCLUSIONS

Consumption of either sunflower or canola oils for 12 weeks improved certain studied biomarkers. However, only ORZ-fortified canola oil resulted in a significant decrease of blood pressure, WC, FBG, HbA1c and TG. These findings can help both clinicians and public health authorities for dietary recommendations to subjects with T2D and presumably the whole community.

TRIAL REGISTRATION

number at clinicaltrials.gov (NCT05271045).

Inhibitory Efficacy of Cycloartenyl Ferulate against α-Glucosidase and α-Amylase and Its Increased Concentration in Gamma-Irradiated Rice (Germinated Rice)

Cycloartenyl ferulate is a derivative of γ-oryzanol with varied biological activity, including diabetes mellitus treatment. This research focused on improving the cycloartenyl ferulate accumulation in germinated rice by gamma irradiation under saline conditions. Moreover, the inhibitory potential of cycloartenyl ferulate against carbohydrate hydrolysis enzymes (α-glucosidase and α-amylase) was investigated through in vitro and in silico techniques. The results revealed that cycloartenyl ferulate increased in germinated rice under saline conditions upon gamma irradiation. A suitable condition for stimulating the highest cycloartenyl ferulate concentration (852.20±20.59 μg/g) in germinated rice was obtained from the gamma dose at 100 Gy and under 40 mM salt concentration. The inhibitory potential of cycloartenyl ferulate against α-glucosidase (31.31±1.43%) was higher than against α-amylase (12.72±1.11%). The inhibition mode of cycloartenyl ferulate against α-glucosidase was demonstrated as a mixed-type inhibition. A fluorescence study confirmed that the cycloartenyl ferulate interacted with the α-glucosidase's active site. A docking study revealed that cycloartenyl ferulate bound to seven amino acids of α-glucosidase with a binding energy of -8.8 kcal/mol and a higher binding potential than α-amylase (-8.2 kcal/mol). The results suggested that the gamma irradiation technique under saline conditions is suitable for stimulating γ-oryzanol, especially cycloartenyl ferulate. Furthermore, cycloartenyl ferulate demonstrated its potential as a candidate compound for blood glucose management in diabetes mellitus treatment.

Nutrigenomic Effects of White Rice and Brown Rice on the Pathogenesis of Metabolic Disorders in a Fruit Fly Model

Consumption of white rice (WR) has been shown to predispose individuals to metabolic disorders. However, brown rice (BR), which is relatively richer in bioactive compounds, possesses anti-glycaemic and antioxidant effects. In this study, fifteen cultivars of paddy rice that are predominantly consumed in North West Nigeria were analysed for their nutritional composition, bioactive contents and effects on metabolic outcomes in a fruit fly model. Gene expression analyses were conducted on the whole fly, targeting dPEPCK, dIRS, and dACC. The protein, carbohydrate, and fibre contents and bioactives of all BR cultivars were significantly different (p < 0.05) from the WR cultivars. Moreover, it was demonstrated that the glucose and trehalose levels were significantly higher (p < 0.05), while glycogen was significantly lower (p < 0.05) in the WR groups compared to the BR groups. Similarly, the expression of dACC and dPEPCK was upregulated, while that of dIRS was downregulated in the WR groups compared to the BR groups. Sex differences (p < 0.05) were observed in the WR groups in relation to the nutrigenomic effects. Our findings confirm metabolic perturbations in fruit flies following consumption of WR via distortion of insulin signalling and activation of glycogenolysis and gluconeogenesis. BR prevented these metabolic changes possibly due to its richer nutritional composition.

Phytochemical Profiles and Biological Studies of Selected Botanical Dietary Supplements Used in the United States

Based on their current wide bioavailability, botanical dietary supplements have become an important component of the United States healthcare system, although most of these products have limited scientific evidence for their use. The most recent American Botanical Council Market Report estimated for 2020 a 17.3% increase in sales of these products when compared to 2019, for a total sales volume of $11,261 billion. The use of botanical dietary supplements products in the United States is guided by the Dietary Supplement Health and Education Act (DSHEA) from 1994, enacted by the U.S. Congress with the aim of providing more information to consumers and to facilitate access to a larger number of botanical dietary supplements available on the market than previously. Botanical dietary supplements may be formulated for and use only using crude plant samples (e.g., plant parts such as the bark, leaves, or roots) that can be processed by grinding into a dried powder. Plant parts can also be extracted with hot water to form an "herbal tea." Other preparations of botanical dietary supplements include capsules, essential oils, gummies, powders, tablets, and tinctures. Overall, botanical dietary supplements contain bioactive secondary metabolites with diverse chemotypes that typically are found at low concentration levels. These bioactive constituents usually occur in combination with inactive molecules that may induce synergy and potentiation of the effects observed when botanical dietary supplements are taken in their different forms. Most of the botanical dietary supplements available on the U.S. market have been used previously as herbal remedies or as part of traditional medicine systems from around the world. Their prior use in these systems also provides a certain level of assurance in regard to lower toxicity levels. This chapter will focus on the importance and diversity of the chemical features of bioactive secondary metabolites found in botanical dietary supplements that are responsible for their applications. Many of the active principles of botanical dietary substances are phenolics and isoprenoids, but glycosides and some alkaloids are also present. Biological studies on the active constituents of selected botanical dietary supplements will be discussed. Thus, the present chapter should be of interest for both members of the natural products scientific community, who may be performing development studies of the products available, as well as for healthcare professionals who are directly involved in the analysis of botanical interactions and evaluation of the suitability of botanical dietary supplements for human consumption.

High Value Compounds and Bioactivity of Rice Bran, Rice Bran Protein: A Review

Rice bran and rice bran protein are important sources of minerals, energy, and vitamins. Other bioactive compounds are abundantly available to exert therapeutical activity. Healthpromoting activities of high-value compounds of rice bran were significant, as observed in recent studies. A variety of bioactive components present in rice bran and rice bran extract are responsible to exhibit therapeutical potential like chemopreventive, cardioprotective, hepatoprotective, immunomodulatory, neuroprotective, and lipid-lowering activity. Several bioactivity representative compounds like γ-oryzanol, ferulic acid, caffeic acid, tricin, protocatechuic acid, vanillic acid, coumaric acid, phytic acid, isoferulic acid, gallic acid, γ-amino butyric acid, sinapic acid, saturated and unsaturated fatty acids, vitamin E complexes, β-sitosterol, stigmasterol, campesterol, cyanidin-3-glucoside, peonidin-3-glucoside, quercetin, rutin, kaemferol, β-carotene, lutein, vitamin B and lycopene are known to display significant health benefits. The bioactive components produced therapeutical effects by regulation of different mechanisms like increasing faecal excretion, reducing oxidative stress, reducing the level of malondialdehyde (MDA), regulation of NF-kb activation, reduction of proinflammatory cytokines production, suppression of SREBP-1, reduction in the expression of anti-apoptotic protein Bcl-2, elevated the expression of proapoptotic protein Bax, up-regulating P53 expression and suppressing COX-2. Several research engines like PubMed, google scholar, science direct, etc. were used to collect the data on the mentioned keywords. Recent scientific works were included in this article. In this review paper, we profiled the high-value compounds and focused on their antioxidant, anti-hyperlipidemic, antidiabetic, and anticancer activity with their possible mechanism of action.

Gamma-oryzanol protects human liver cell (L02) from hydrogen peroxide-induced oxidative damage through regulation of the MAPK/Nrf2 signaling pathways

Gamma-oryzanol (Orz), a mixture of the ferulic acid ester of triterpene alcohols and phytosterols, was found abundantly in rice bran and rice bran oil which could be available and served as an antioxidant. The present study was to explore the potential protective effects of Orz on oxidative stress and cell apoptosis in human hepatic cells (L02 cells) induced by hydrogen peroxide (H₂ O₂ ). Flow cytometry detection and Hoechst 33258 staining showed that Orz significantly restored cell cycle and ameliorated apoptosis in H₂ O₂ -challenged L02 cells. Orz pretreatment inhibited H₂ O₂ -induced cell apoptosis by increasing the scavenging of hydroxyl radicals (OH·), and efficiently decreasing the production of nitric oxide (NO). Moreover, a loss of total antioxidant capacity (T-AOC) and adenosine triphosphatase (ATPase) were enhanced in H₂ O₂ -mediated L02 cells pretreated with Orz. Furthermore, preincubation with Orz reduced H₂ O₂ -mediated the proapoptotic protein of Bak expression and the phosphorylation of ASK1, p38, JNK, and ERK, and increased the anti-apoptotic protein of Bcl-xl expression and anti-oxidative stress proteins of Nrf2 and HO-1 expression. The findings suggested that Orz exerts the cytoprotective effects in H₂ O₂ -induced L02 cells apoptosis by ameliorating oxidative stress via inhibiting MAPK signaling pathway and activating Nrf2 signaling pathway. PRACTICAL APPLICATIONS: Gamma-oryzanol (Orz), a mixture of the ferulic acid ester of triterpene alcohols and phytosterols, was found abundantly in rice bran and rice bran oil which could be availably served as an antioxidant. In this study, it was found that Orz exerts the cytoprotective effects in H₂ O₂ -induced L02 cell apoptosis by ameliorating oxidative stress via the inhibition of MAPK signaling pathway and the activation of Nrf2 signaling pathway, which provides a theoretical basis for dietary adding natural products to prevent or treat oxidative stress-related diseases.

Rice bran, an off-shoot to newer therapeutics in neurological disorders

Normal brain functioning involves the interaction of interconnected molecular and cellular activities, which appear to alter normal to abnormal brain functioning when worsened, contributing to the emergence of neurological disorders. There are currently millions of people who are living with brain disorders globally and this will rise if suitable prevention strategies are not explored. Nutraceutical intended to treat numerous health goals with little adverse effect possible together can be more beneficial than pharmaceutical monotherapy for fostering balanced brain functioning. Nutraceutical provides a specific composition of effective macronutrients and micronutrients that are difficult to synthesize in the laboratory. Numerous elements of rice fibers in rice bran are characterized as natural anti-oxidant and having potential anti-inflammatory activity. The rice bran captures interest among the researchers as it is widespread, affordable, and rich in nutrients including protein, fat, carbohydrates, bioactive components, and dietary fiber. This review covers the neuroprotective multiplicity of rice bran and its constituents to deter pathological conditions of the brain and to facilitate balanced brain functioning at the same time.

Rice Bran By-Product: From Valorization Strategies to Nutritional Perspectives

The aim of this study is to review the innovative techniques based on bioprocessing, thermal or physical treatments which have been proposed during the last few decades to convert rice bran into a valuable food ingredient. Rice bran (Oryza sativa) is the main by-product of rice grain processing. It is produced in large quantities worldwide and it contains a high amount of valuable nutrients and bioactive compounds with significant health-related properties. Despite that, its application in food industry is still scarce because of its sensitivity to oxidation processes, instability and poor technological suitability. Furthermore, the health-related effects of pretreated rice bran are also presented in this review, considering the up-to-date literature focused on both in vivo and in vitro studies. Moreover, in relation to this aspect, a brief description of rice bran arabinoxylans is provided. Finally, the application of rice bran in the food industry and the main technology aspects are concisely summarized.

Comparative Evaluation of the Nutritional, Antinutritional, Functional, and Bioactivity Attributes of Rice Bran Stabilized by Different Heat Treatments

The objective of this study was to evaluate the effects of different stabilization treatments—namely, dry-heating, infrared-radiation, and microwave-heating—on the nutritional, antinutritional, functional, and bioactivity attributes of rice bran (RB). Among the heating treatments, infrared-radiation exerted the strongest inactivation, resulting in 34.7% residual lipase activity. All the stabilization methods were found to be effective in the reduction of antinutrients, including phytates, oxalate, saponins, and trypsin inhibitors. No adverse effect of stabilization was noted on chemical composition and fatty acid profile of RB. Instead, stabilization by all heat treatments caused a significant decrease of vitamin E and total phenolics content in RB; the same trend was observed for the antioxidant activity as evaluated by the DPPH test. The antioxidant activity, as evaluated by ABTS and FRAP tests, and water absorption capacity were improved by the stabilization of RB, whereas the oil absorption capacity and emulsifying properties decreased. Microwave-heating enhanced the foaming properties, whereas infrared-radiation improved the water solubility index and swelling power of RB. Consequently, treatment of RB with infrared-radiation has a potential for industrialization to inactivate the lipase and improve some functional properties of this material for uses as a nutraceutical ingredient in food and cosmetic products.

Self-Nanoemulsifying Drug Delivery Systems (SNEDDS) Containing Rice Bran Oil for Enhanced Fenofibrate Oral Delivery: In Vitro Digestion, Ex Vivo Permeability, and In Vivo Bioavailability Studies

Lipid-based drug delivery systems (LbDDS), such as self-nanoemulsifying drug delivery systems (SNEDDS), constitute a prominent formulation approach for enhancing the aqueous solubility and oral bioavailability of poorly water-soluble compounds. Utilization of biorefinery wastes, such as oil from rice bran, may prove advantageous to both improving drug solubilization and absorption and to achieving sustainable agri-food waste valorization. Here, we assessed the effect of four SNEDDS compositions differing in the oil (rice bran oil and corn oil) and surfactant type (Kolliphor RH40 and EL) on the oral bioavailability of fenofibrate, a BCS class II compound. Prior to the in vivo oral administration of the SNEDDS in rats, drug solubilization was tested in vitro using the static digestion model, followed by the ex vivo permeability study of the predigested SNEDDS using the non-everted gut sac model. No significant variation was observed in the solubilization capacity within the different SNEDDS formulations. On the other hand, the ex vivo permeability data of the predigested SNEDDS correlated well with the in vivo bioavailability data designating the superiority of rice bran oil with Kolliphor EL as the surfactant, to enhance the oral absorption of fenofibrate. Results indicated that valorization of agro-industrial waste such as rice bran oil may prove useful in enhancing the oral performance of LbDDS in the case of fenofibrate, while at the same time maximizing the use of agricultural by-products via the creation of new sustainable value chains in the pharmaceutical field.

γ-Oryzanol suppresses cell apoptosis by inhibiting reactive oxygen species-mediated mitochondrial signaling pathway in H2O2-stimulated L02 cells

γ-Oryzanol, a mixture of ferulic acid esters of plant sterols and triterpene alcohols existed in rice bran oil, can ameliorate lipid metabolism and enhance antioxidant activity. In this study, we used hydrogen peroxide (H₂O₂)-induced injury in human hepatic L02 cells to investigate the mechanisms involved in the hepatoprotective activity of γ-oryzanol. The injuries produced by H₂O₂ in L02 cells include increased levels of malondialdehyde (MDA) and intracellular reactive oxygen species (ROS), decreased activities of superoxide dismutase (SOD) and catalase (CAT), loss of mitochondrial membrane potential (MMP), increased protein expressions of caspase-9 and caspase-3, and induced apoptosis. Pretreatment with γ-oryzanol enhanced the ROS scavenging activity of endogenous antioxidant enzymes and decreased lipid peroxidation in H₂O₂ treated cells. Moreover, pretreatment with γ-oryzanol inhibited H₂O₂-induced apoptosis by restoring MMP, upregulating the expression ratio of Bcl-2/Bax, and inhibiting the activation of caspase-9 and caspase-3. These findings show that γ-oryzanol can prevent H₂O₂-induced apoptosis by suppressing intracellular accumulation of ROS and impeding ROS-activated mitochondrial apoptotic pathway.

Contribution of momilactones A and B to diabetes inhibitory potential of rice bran: Evidence from in vitro assays

This study was the first to detect the presence of the two compounds momilactone A (MA) and momilactone B (MB) in rice bran using liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). By in vitro assays, both MA and MB exhibited potent inhibitory activities on pancreatic α-amylase and α-glucosidase which were significantly higher than γ-oryzanol, a well-known diabetes inhibitor. Remarkably, MA and MB indicated an effective inhibition on trypsin with the IC50 values of 921.55 and 884.03 µg/mL, respectively. By high-performance liquid chromatography (HPLC), quantities of MA (6.65 µg/g dry weight) and MB (6.24 µg/g dry weight) in rice bran were determined. Findings of this study revealed the α-amylase, α-glucosidase and trypsin inhibitors MA and MB contributed an active role to the diabetes inhibitory potential of rice bran.

Recovery of γ-Oryzanol from Rice Bran Acid Oil by an Acid-base Extraction Method with the Assistance of Response Surface Methodology

A rapid and low energy consumption method for the recovery of γ-oryzanol from rice bran acid oil (RBAO), a byproduct of rice bran oil (RBO) refining, is presented. The RBAO was converted to the fatty acid ethyl ester (FAEE) and was used as the starting material. The dissolved γ-oryzanol was separated from the FAEE using an acid-base extraction method with alkaline aqueous ethanol and hexane as extraction media. A systematic investigation of the extraction yield was carried out by applying response surface methodology (RSM) based on central composite design (CCD) and Derringer's desirability function. The concentration of NaOH, the percentage of ethanol in water, the hexane content and their interactions showed significant effects on the yield of γ-oryzanol and FAEE. The optimal extraction conditions were as follows: extraction time of 1 min at room temperature (28-32°C); extraction medium: 1.855 M NaOH; 75.91% ethanol in water and 20.59% hexane in the total volume of the extractant; and FAEE to extractant ratio of 1:10 corresponding to a maximum γ-oryzanol yield of 75.82±3.44% and the desired FAEE yield of 54.42±7.80%. The γ-oryzanol-rich fraction was further purified by washing with a 2% Na₂CO₃ solution, obtaining 69.94% recovery yield with 89.90% purity of γ-oryzanol. The purified γ-oryzanol showed good scavenging activity on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and the ABTS radical and was comparable to the commercial product, clearly suggesting that the presented process was efficient and feasible.

Redox Homeostasis and Natural Dietary Compounds: Focusing on Antioxidants of Rice (Oryza sativa L.)

Redox homeostasis may be defined as the dynamic equilibrium between electrophiles and nucleophiles to maintain the optimum redox steady state. This mechanism involves complex reactions, including nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, activated by oxidative stress in order to restore the redox balance. The ability to maintain the optimal redox homeostasis is fundamental for preserving physiological functions and preventing phenotypic shift toward pathological conditions. Here, we reviewed mechanisms involved in redox homeostasis and how certain natural compounds regulate the nucleophilic tone. In addition, we focused on the antioxidant properties of rice and particularly on its bioactive compound, γ-oryzanol. It is well known that γ-oryzanol exerts a variety of beneficial effects mediated by its antioxidant properties. Recently, γ-oryzanol was also found as a Nrf2 inducer, resulting in nucleophilic tone regulation and making rice a para-hormetic food.

Hypolipidemic and Antioxidant Properties of Oryzanol Concentrate in Reducing Diabetic Nephropathy via SREBP1 Downregulation Rather than β-Oxidation

SCOPE

Diabetic nephropathy (DN) is a micro-vascular complication of chronic diabetes. Sterol regulatory element binding protein1 (SREBP1) participation in the development of DN is reported. Oryzanol concentrate (OC) at 0.1% and 0.3% is tested for its antioxidant and hypolipidemic effects. The aim of the work is to study the involvement of OC in the amelioration of DN in STZ-induced diabetic animal model.

METHODS AND RESULTS

Animals were grouped into starch, high-fat, and OC-treated control/diabetic groups (SFC/SFD, HFC/HFD, OFC/OFD). The markers of DN, increased glomerular filtration rate and kidney weight, were evident in HFD and reduced in OFD group by ≈1.09 and ≈1.3 fold, respectively. The amelioration of defensive antioxidant enzyme activities and lipid peroxidation, expressions of lipid-associated biomolecules (SREBP1 and FAS) were also observed. HFD showed increased ECM accumulation of glycoproteins, particularly Type IV collagen, fibronectin. SREBP1-associated gene transforming growth factor-β (TGF-β) was reduced on treatment (OFD ≈ 1.3 fold) as to HFD (≈2.7 fold).

CONCLUSION

Oryzanol concentrate, having hypolipidemic and antioxidant properties, also downregulated the lipid biosynthesis through reduced SREBP1-TGF-β interactions (EMSA) and could effectively ameliorate DN. Gene (ACC2, Cpt1, and ACOX) expression studies showed that β-oxidation was not involved in reducing DN.

Characterization of the Antioxidant Effects of γ-Oryzanol: Involvement of the Nrf2 Pathway

γ-Oryzanol (ORY) is well known for its antioxidant potential. However, the mechanism by which ORY exerts its antioxidant effect is still unclear. In this paper, the antioxidant properties of ORY were investigated for its potential effects as a reactive oxygen and nitrogen species (ROS/RNS) scavenger and in activating antioxidant-promoting intracellular pathways utilizing the human embryonic kidney cells (HEK-293). The 24 h ORY exposure significantly prevented hydrogen peroxide- (H₂O₂-) induced ROS/RNS production at 3 h, and this effect was sustained for at least 24 h. ORY pretreatment also enhanced the activity of antioxidant enzymes: superoxide dismutase (SOD) and glutathione peroxidase (GPX). Interestingly, ORY induced the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nuclear translocation and upregulation of Nrf2-dependent defensive genes such as NAD(P)H quinone reductase (NQO1), heme oxygenase-1 (HO-1), and glutathione synthetase (GSS) at mRNA and protein levels in both basal condition and after H₂O₂ insult. Thus, this study suggested an intriguing effect of ORY in modulating the Nrf2 pathway, which is also involved in regulating longevity as well as age-related diseases.

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.

The relationship between lipid phytochemicals, obesity and its related chronic diseases

This review focuses on phytochemicals in oils, and summarizes the mechanisms of the anti-obesity effects of these compounds in in vitro studies, animal models, and human trials.

Hypolipidemic activity of P-methoxycinnamic diester (PCO-C) isolated from Copernicia prunífera against Triton WR-1339 and hyperlipidemic diet in mice

Carnauba wax is extracted from the leaves of the Copernicia prunífera and contains approximately 80% of esters in its composition. The purpose of the present study was evaluate the hypolipidemic effect of p-methoxycinnamic diesters (PCO-C) extracted from Copernicia prunífera in a model of acute and chronic dyslipidemia in mice. The levels of total cholesterol and triglycerides were significantly reduced plasma levels in PCO-C at the dose of 100mg/kg in a model of acute and chronic dyslipidemia. Histological studies showed that PCO-C has no hepatotoxic effect and reduces hepatic steatosis in animals that consumed hyperlipidemic ration. Thus, it was concluded that PCO-C isolated from Copernicia Prunifera was effective in reducing total cholesterol and triglyceride levels in both dyslipidemia induction models. The finding indicates that PCO-C might be beneficial in treatment of hyperlipidemia and atherosclerosis.

Phenolic Compounds and Antioxidant Capacity of Brown Rice in China

The phenolic compounds and antioxidant activity of brown rice are well known but the extent to which phenolics and antioxidant activity varies within rice (Oryza sativa) is not known. This study evaluated the natural variation of phenolic compounds in brown rice of the major cultivars currently grown in China. Free phenolics were extracted with chilled methanol, while bound phenolics were released and extracted by alkaline hydrolysis. There were significant differences in phenolic and flavonoid content between these cultivars and significant differences in bound and total phenolics between japonica and indica samples. Ferulic and p-coumaric acids were the major phenolic acids and existed in both free and bound forms, with the bound form of ferulic acid being a dominant phenolic compound in brown rice. Phenolic compounds were the major contributor to the antioxidant capacity of brown rice and bound phenolics contributed more than free phenolics as estimated using ABTS+ radical scavenging method. This study provides additional information on brown rice from japonica and indica subspecies and may assist in retaining or increasing phenolics and antioxidant activity in rice.

Investigation of nutriactive phytochemical - gamma-oryzanol in experimental animal models

Gamma-oryzanol (GO) is an abundant dietary antioxidant that is considered to have beneficial effects in cardiovascular disease, cancer and diabetes. Other potential properties of GO include inhibition of gastric acid secretion and decreased post-exercise muscle fatigue. GO is a unique mixture of triterpene alcohol and sterol ferulates present in rice bran oil, a byproduct of rice processing. GO has been studied by many researchers over the last three decades. In particular, the utility of GO supplementation has been documented in numerous animal models. A large variety of species was examined, and various experimental methodologies and targets were applied. The aim of this study was to summarize the body of research on GO supplementation in animals and to examine possible mechanisms of GO action. Furthermore, while the safety of GO supplementation in animals has been well documented, studies demonstrating pharmacokinetics, pharmacodynamics and efficiency are less clear. The observed differences in these findings are also discussed.