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

Biological and Pharmacological Effects of Gamma-oryzanol: An Updated Review of the Molecular Mechanisms

BACKGROUND

Gamma-oryzanol (γ-oryzanol) is one of the rice bran oil (RBO) compounds, known as a principal food source throughout the world. In recent numerous experimental studies, γ-oryzanol has been revealed to have several useful pharmacological properties, such as anti-oxidant, anti-inflammatory, anti-cancer, anti-diabetic, ameliorating unpleasant menopausal symptoms, cholesterol-lowering, improving plasma lipid pattern, etc. Methods: In this study, we reviewed the scientific literature published up until 2020, which has evaluated the biological and pharmacological activity of gamma-oryzanol. This review summarizes the published data found in PubMed, Science Direct, and Scopus.

RESULTS AND CONCLUSION

The present review attempts to summarize the most related articles about the pharmacological and therapeutic potential from recent studies on γ-oryzanol to gain insights into design further studies to achieve new evidence that confirm the observed effects.

Exploring The Interactions of a Natural Gamma-Oryzanol with Human Serum Albumin: Surface Plasmon Resonance, Fluorescence, and Molecular Modeling Studies

γ-oryzanol (ORY) is the vital bioactive compound, which is a mixture of ferulic acid ester and plant sterols. In the present work, the binding of ORY to human serum albumin (HSA) was investigated at the molecular level using fluorescence spectroscopy and surface plasmon resonance (SPR) as well as molecular modeling studies. Based on the fluorescence data analysis, ORY can form a non-fluorescent complex with HSA and induce static quenching of the emission intensity of HSA. Also, the high value of K _SV (34.69 × 10⁴ M^-1) confirmed a high sensitivity of HSA toward ORY. The real-time monitoring of the binding of ORY to HSA was carried out using the SPR technique. The small K _D value (1.23 × 10^-6 M) calculated by SPR analysis indicated a high affinity of ORY toward HSA. The molecular modeling studies confirmed that ORY has only one binding site on HSA and binds HSA in a cavity between subdomain IIA and IIIA.

Gamma-oryzanol reduces renal inflammation and oxidative stress by modulating AGEs/RAGE axis in animals submitted to high sugar-fat diet

Introduction:

The receptor for AGEs (RAGE) is a multiligand member of the immunoglobulin superfamily of cell surface receptors expressed in many organs, among them, the kidneys. When activated, RAGE leads to a sequence of signaling that results in inflammation and oxidative stress, both involved in kidney disease pathogenesis. Gamma-oryzanol (γOz) comprises a mixture of ferulic acid (FA) esters and phytosterols (sterols and triterpene alcohols) mainly found in rice, with antioxidant and anti-inflammatory activities.

Aim:

To evaluate the effect of γOz to reduce renal inflammation and oxidative stress by modulating AGEs/RAGE axis in animals submitted to a high sugar-fat diet.

Methods:

Male Wistar rats (±187g) were randomly divided into two experimental groups: control (n = 7 animals) and high sugar-fat diet (HSF, n = 14 animals) for 20 weeks. After this period, when the presence of renal disease risk factors was detected in the HSF group (insulin resistance, dyslipidemia, increased systolic blood pressure and obesity), the HSF animals were divided to begin the treatment with γOz or continue receiving only HSF for 10 more weeks.

Results:

No effect of γOz on obesity and metabolic parameters was observed. However, kidney inflammation and oxidative stress decreased as soon as RAGE levels were reduced in HSF + γOz.

Conclusion:

It is possible to conclude that the gamma- oryzanol was effective in reducing inflammation and oxidative stress in the kidney by modulating the AGEs/RAGE axis.

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.

Polygonum hydropiper extract attenuates ethanol-induced gastric damage through antioxidant and anti-inflammatory pathways

The present study was conducted to investigate the underlying mechanisms and effective components of Polygonum hydropiper in ethanol-induced acute gastric mucosal lesions. The ethanol extract was purified on an AB-8 macroporous resin column and eluted with 60% ethanol and was then injected into the HPLC system for quantitative analysis. Sprague-Dawley rats were orally pretreated with P. hydropiper extract (PHLE; 50, 100, and 200 mg/kg) for 5 days and then absolute ethanol was administered to induce gastric mucosal damage. One hour after ethanol ingestion, the rats were euthanized and stomach samples were collected for biochemical analysis. Antioxidant enzymes and anti-inflammatory cytokines were quantified. Western blotting was used to detect the expression levels of proteins. Cell proliferation was assayed by CCK-8 assays. The proportion of total flavonoids in the final extract of P. hydropiper was 50.05%, which contained three major bioactive flavonoid constituents, including rutin, quercitrin, and quercetin. PHLE significantly increased cell viability and effectively protected human gastric epithelial cells-1 against alcohol-induced damage in vitro. PHLE pretreatment attenuated gastric mucosal injuries in a dose-dependent manner in rats, and increased the activity of superoxide dismutase, glutathione peroxidase, and glutathione, and decreased the levels of malondialdehyde in gastric tissue. Pretreatment with PHLE also reduced the generation of the pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1β in gastric tissue by downregulating the expression of nuclear factor-kappa B. PHLE exerted protective effects against gastric injury through antioxidant and anti-inflammatory pathways. Flavonoids might be the main effective components of P. hydropiper against gastric mucosal injury.

Protective effect of gamma-oryzanol against manganese-induced toxicity in Drosophila melanogaster

Manganese (Mn) is an essential element that, in excess, seems to be involved in the development of different neurodegenerative conditions. Gamma-oryzanol (Ory) was previously reported to possess antioxidant and neuroprotective properties. Thus, we conducted this study to test the hypothesis that Ory can also protect flies in an Mn intoxication model. Adult wild-type flies were fed over 10 days with Mn (5 mM) and/or Ory (25 μM). Flies treated with Mn had a decrease in locomotor activity and a higher mortality rate compared to those in controls. Mn-treated flies also had a significant increase in acetylcholinesterase (AChE) activity, in Mn accumulation and in oxidative stress markers. Moreover, flies treated with Mn exhibited a significant decrease in dopamine levels and in tyrosine hydroxylase activity, as well as in mitochondrial and cellular viability. Particularly important, Ory protected against mortality and avoided locomotor and biochemical changes associated with Mn exposure. However, Ory did not prevent the accumulation of Mn. The present results support the notion that Ory effectively attenuates detrimental changes associated with Mn exposure in Drosophila melanogaster, reinforcing its neuroprotective action/potential.

Protective Effects of Radix Sophorae Flavescentis Carbonisata-Based Carbon Dots Against Ethanol-Induced Acute Gastric Ulcer in Rats: Anti-Inflammatory and Antioxidant Activities

AIM

To explore the effects of Radix Sophorae Flavescentis carbonisata-based carbon dots (RSFC-CDs) on an ethanol-induced acute gastric ulcer rat model.

METHODS

The structure, optical properties, functional groups and elemental composition of RSFC-CDs synthesized by one-step pyrolysis were characterized. The gastric protective effects of RSFC-CDs were evaluated and confirmed by applying a rat model of ethanol-induced acute gastric ulcers. The underlying mechanisms were investigated through the nuclear factor-kappa B (NF-κB) signalling pathway and oxidative stress.

RESULTS

RSFC-CDs with a diameter ranging from 2-3 nm mainly showed gastric protective effects by reducing the levels of NF-κB, tumour necrosis factor-α (TNF-α), interleukin (IL)-6, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione (GSH), malondialdehyde (MDA) and inducible nitric oxide synthase (iNOS) to inhibit ethanol-induced inflammation and oxidative stress.

CONCLUSION

RSFC-CDs have anti-inflammatory and anti-oxidative effects, making them promising for application in ethanol-induced gastric injury.

The Landscape of Interactions between Hypoxia-Inducible Factors and Reactive Oxygen Species in the Gastrointestinal Tract

The gastrointestinal tract (GT) is the major organ involved in digestion, absorption, and immunity, which is prone to oxidative destruction by high levels of reactive oxygen species (ROS) from luminal oxidants, such as food, drugs, and pathogens. Excessive ROS will lead to oxidative stresses and disrupt essential biomolecules, which also act as cellular signaling molecules in response to growth factors, hormones, and oxygen tension changes. Hypoxia-inducible factors (HIFs) are critical regulators mediating responses to cellular oxygen tension changes, which are also involved in energy metabolism, immunity, renewal, and microbial homeostasis in the GT. This review discusses interactions between HIF (mainly HIF-1α) and ROS and relevant diseases in the GT combined with our lab's work. It might help to develop new therapies for gastrointestinal diseases associated with ROS and HIF-1α.

Gamma-oryzanol as a potential modulator of oxidative stress and inflammation via PPAR-y in adipose tissue: a hypothetical therapeutic for cytokine storm in COVID-19?

The literature has reported a higher prevalence of negative clinical outcomes due to Coronavirus disease 19 (COVID-19) in obese individuals. This can be explained by the cytokine storm, result from the cytokine production from both obesity and viral infection. Gamma-oryzanol (γOz) is a compound with anti-inflammatory and antioxidant activities. However, little is known about the γOz action as a possible agonist of peroxisome proliferator-activated receptor gamma (PPAR-γ). The aim of this study was to test the hypothesis that γOz attenuates the cytokine storm by stimulating PPAR-γ in the adipose tissue.

METHODS

Male Wistar rats were randomly divided into three experimental groups and fed ad libitum for 30 weeks with control diet (C, n = 6), high sugar-fat diet (HSF, n = 6) or high sugar-fat diet + γOz (HSF + γOz, n = 6). HSF groups also received water + sucrose (25%). The γOz dose was 0.5% in the chow. Evaluation in animals included caloric intake, body weight, adiposity index, plasma triglycerides, and HOMA-IR. In adipose tissue was evaluated: PPAR-γ gene and protein expression, inflammatory and oxidative stress parameters, and histological analysis.

RESULTS

Adipose tissue dysfunction was observed in HSF group, which presented remarkable PPAR-γ underexpression and increased levels of cytokines, other inflammatory markers and oxidative stress. The γOz treatment prevented adipose tissue dysfunction and promoted PPAR-γ overexpression.

CONCLUSION

Natural compounds as γOz can be considered a coadjutant therapy to prevent the cytokine storm in COVID-19 patients with obesity conditions.

Cereal grain-based functional beverages: from cereal grain bioactive phytochemicals to beverage processing technologies, health benefits and product features

Increased consumer awareness of health and wellness has promoted a high demand for foods and beverages with functional and therapeutic properties. Cereals, apart from being important staple crops and primary sources of energy and nutrition, are replete with bioactive phytochemicals with health properties. Cereal grains contain a diverse range of bioactive phytochemicals including phenolic compounds, dietary fibers, carotenoids, tocols, phytosterols, γ-oryzanol, and phytic acid and therefore have great potential for processing into functional beverages. Although there are a variety of cereal grain-based beverages produced world-wide, very little scientific and technological attention has been paid to them. In this review, we have discussed cereal grain-based functional beverages based on 3 main categories: cereal grain-based milk alternatives, roasted cereal grain teas, fermented nonalcoholic cereal grain beverages. The processing techniques, health properties and product features of these beverages are elaborated, and the challenges and future perspectives are proposed. As the food market becomes increasingly diverse, cereal grain-based beverages could be a promising new category of health functional beverages in our daily life.

Isolation and structural elucidation of unique γ-oryzanol species in rice bran oil

Even though γ-oryzanol (OZ) such as 24-methylenecycloartanyl ferulate (24MCAFA) is abundant in purified rice bran oil, we realized that the oil contained the prospect of two additional novels of OZ species. To identify this, we isolated and analyzed their chemical structures by using HPLC-UV-MS, NMR, and IR. We revealed for the first time that the oil had also contained cyclobranyl ferulate (CBFA) and cyclosadyl ferulate (CSFA) which are likely to be exist due to the isomerism of 24MCAFA under acid condition. OZ profile including CBFA and CSFA was roughly similar between commercial rice bran oils and processed foods containing the oils, suggesting that people might have often consumed CBFA and CSFA from rice bran oils and/or processed foods. Since different OZ species are known to have different functionality, this study opens the chance to explore more the contribution of CBFA and CSFA for human health and wellness.

ORY supplementation mitigates acetaminophen-induced acute liver failure in male mice: role of oxidative stress and apoptotic markers

The aim of the present study was to assess the possible protective effect of γ-oryzanol (ORY) supplementation in a model of acute liver failure (ALF) induced by acetaminophen (APAP) in mice. Male Swiss strain mice were supplemented with ORY (10 and 50 mg/kg, per oral route) daily for 7 days. One hour after the last supplementation, animals received APAP (300 mg/kg, intraperitoneal). Twenty-four hours after APAP administration, mice were euthanized, and biochemical and histopathological determinations were performed. Histopathological analysis revealed that APAP caused vascular congestion, loss of cellular structure, and cellular infiltration in hepatocytes. Moreover, it caused oxidative damage (enzymatic and non-enzymatic analysis of oxidative stress), with loss of hepatic function leading to cell apoptosis (apoptotic parameters). ORY supplementation (ORY-10 and ORY-50) protected against all changes in ALF model. Thus, the protective effect of ORY supplementation was due to modulation of antioxidant defenses avoiding the apoptotic process.

γ-Oryzanol alleviates acetaminophen-induced liver injury: roles of modulating AMPK/GSK3β/Nrf2 and NF-κB signaling pathways

Acetaminophen (APAP) overdose is a major cause of drug-induced liver injury worldwide. Our current study was performed to assess the potential protective effects of γ-oryzanol (ORY) on APAP-induced liver injury in mice and explore the underlying molecular mechanisms. We unveiled that ORY alleviated the APAP-induced death of HL-7702 hepatocytes in vitro and liver injury in mice. Moreover, ORY promoted the nuclear translocation of Nrf2, increased the expressions of Nrf2-downstream antioxidative enzymes, including HO-1, NQO1, GCLC, and GCLM, and thereby restrained APAP-induced oxidative stress in hepatocytes. Moreover, ORY modulated the AMPK/GSK3β axis that acts upstream of Nrf2 in hepatocytes. Compound C, an inhibitor of AMPK, prevented the ORY-mediated activation of Nrf2 and protection against APAP toxicity in HL-7702 hepatocytes. Additionally, in the liver of mice receiving APAP, ORY suppressed the nuclear translocation of the NF-κB p65 subunit, downregulated the expressions of iNOS and COX-2, and reduced the levels of pro-inflammatory factors including TNF-α, IL-1β, IL-6, and NO. Taken together, our findings revealed that ORY is capable of ameliorating APAP-induced liver injury. The modulation of AMPK/GSK3β/Nrf2 and NF-κB signaling pathways is implicated in the hepatoprotective activity of ORY.

γ-Oryzanol mitigates oxidative stress and prevents mutant SOD1-Related neurotoxicity in Drosophila and cell models of amyotrophic lateral sclerosis

Oxidative stress plays a critical role in mutant copper/zinc superoxide dismutase 1 (SOD1)-linked amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease characterized by selective loss of motor neurons. Thus, an anti-oxidative stress remedy might be a promising means for the treatment of ALS. The aim of the present study is to investigate the neuroprotective effects of γ-oryzanol (Orz) and elucidate its relevant molecular mechanisms in mutant hSOD1-linked Drosophila and cell models of ALS. Orz treatment provided neuroprotection in flies with expression of hSOD1-G85R in motor neurons, as demonstrated by the prolonged survival, improvement of motor deficits, reduced oxidative damage and regulated redox homeostasis when compared with those in controls. Moreover, Orz significantly decreased neuronal apoptosis and upregulated the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutamate-cysteine ligase catalytic subunit (GCLC) antioxidant pathway via activating Akt in hSOD1-G93A-expressing NSC-34 cells. In addition, our results showed that both in vivo and in vitro, Akt served as an upstream regulator of signal transducers and activators of transcription (Stat) 3 stimulated by Orz, which further increased the level of another anti-oxidative stress factor heat-shock protein 70 (HSP70). Altogether, these findings provide evidence that Orz has potential neuroprotective effects that may be beneficial in the treatment of ALS disease with SOD1 mutations.

Definitive evidence of the presence of 24-methylenecycloartanyl ferulate and 24-methylenecycloartanyl caffeate in barley

γ-Oryzanol (OZ), which has a lot of beneficial effects, is a mixture of ferulic acid esters of triterpene alcohols (i.e., triterpene alcohol type of OZ (TTA-OZ)) and ferulic acid esters of plant sterols (i.e., plant sterol type of OZ (PS-OZ)). Although it has been reported that OZ is found in several kinds of cereal typified by rice, TTA-OZ (e.g., 24-methylenecycloartanyl ferulate (24MCA-FA)) has been believed to be characteristic to rice and has not been found in other cereals. In this study, we isolated a compound considered as a TTA-OZ (i.e., 24MCA-FA) from barley and determined the chemical structure using by HPLC-UV-MS, high-resolution MS, and NMR. Based on these results, we proved for the first time that barley certainly contains 24MCA-FA (i.e., TTA-OZ). During the isolation and purification of 24MCA-FA from barley, we found the prospect that a compound with similar properties to OZ (compound-X) might exist. To confirm this finding, the compound-X was also isolated, determined the chemical structure, and identified as a caffeic acid ester of 24-methylenecycloartanol (24MCA-CA), which has rarely been reported before. We also quantified these compounds in various species of barley cultivars and found for the first time the existence of 24MCA-FA and 24MCA-CA in various barley. Through these findings, it opens the possibility to use barley as a new source of 24MCA-FA and 24MCA-CA.

Design of balanced COX inhibitors based on anti-inflammatory and/or COX-2 inhibitory ascidian metabolites

The aim of this study was to design and synthesize COX-1/COX-2 balanced inhibitors incorporating the structural motifs of anti-inflammatory ascidian metabolites. We designed a series of substituted indole analogs that incorporate the key structures of the ascidian metabolites, herdmanines C and D. The synthesized analogs were tested for their inhibitory activity against COX-1 and COX-2, and compound 5m, which displayed balanced inhibition, was further evaluated for in vitro anti-inflammatory activity. Compound 5m suppressed the expression of pro-inflammatory factors, including iNOS, COX-2, TNF-α, and IL-6 in LPS-stimulated murine RAW264.7 macrophages. The reduction of PGE₂, NO, and ROS was also observed, together with the suppression of NF-κB, IKK, and IκBα phosphorylation. Our results characterized 5m as a COX-1/COX-2 balanced inhibitor that subsequently caused ROS inhibition and NF-κB suppression, and culminated in the suppression of iNOS, COX-2, TNF-α, and IL-6 expression.

γ-Oryzanol Improves Cognitive Function and Modulates Hippocampal Proteome in Mice

Rice (Oryza sativa L.) is the richest source of γ-oryzanol, a compound endowed with antioxidant and anti-inflammatory properties. γ-Oryzanol has been demonstrated to cross the blood-brain barrier in intact form and exert beneficial effects on brain function. This study aimed to clarify the effects of γ-oryzanol in the hippocampus in terms of cognitive function and protein expression. Adult mice were administered with γ-oryzanol 100 mg/kg or vehicle (control) once a day for 21 consecutive days following which cognitive behavior and hippocampal proteome were investigated. Cognitive tests using novel object recognition and Y-maze showed that long-term consumption of γ-oryzanol improves cognitive function in mice. To investigate the hippocampal proteome modulated by γ-oryzanol, 2D-difference gel electrophoresis (2D-DIGE) was performed. Interestingly, we found that γ-oryzanol modulates quantitative changes of proteins involved in synaptic plasticity and neuronal trafficking, neuroprotection and antioxidant activity, and mitochondria and energy metabolism. These findings suggested γ-oryzanol as a natural compound able to maintain and reinforce brain function. Although more intensive studies are needed, we propose γ-oryzanol as a putative dietary phytochemical for preserving brain reserve, the ability to tolerate age-related changes, thereby preventing clinical symptoms or signs of neurodegenerative diseases.

Rice Secondary Metabolites: Structures, Roles, Biosynthesis, and Metabolic Regulation

Rice (Oryza sativa L.) is an important food crop providing energy and nutrients for more than half of the world population. It produces vast amounts of secondary metabolites. At least 276 secondary metabolites from rice have been identified in the past 50 years. They mainly include phenolic acids, flavonoids, terpenoids, steroids, alkaloids, and their derivatives. These metabolites exhibit many physiological functions, such as regulatory effects on rice growth and development, disease-resistance promotion, anti-insect activity, and allelopathic effects, as well as various kinds of biological activities such as antimicrobial, antioxidant, cytotoxic, and anti-inflammatory properties. This review focuses on our knowledge of the structures, biological functions and activities, biosynthesis, and metabolic regulation of rice secondary metabolites. Some considerations about cheminformatics, metabolomics, genetic transformation, production, and applications related to the secondary metabolites from rice are also discussed.

Phytosterol and γ-Oryzanol Conjugates: Synthesis and Evaluation of their Antioxidant, Antiproliferative, and Anticholesterol Activities

Fifteen new multifunctional conjugates were designed and synthesized by chemically linking the steroidal framework of natural occurring γ-oryzanol and γ-oryzanol-derived phytosterols to a wide range of bioactive natural compounds (fatty acids, phenolic acids, amino acids, lipoic acid, retinoic acid, curcumin, and resveratrol). Starting from γ-oryzanol, which is the main component of rice bran oil, this study was aimed at assessing if the conjugation strategy might enhance some γ-oryzanol bioactivities. The antioxidant activity was evaluated through three different mechanisms, namely, DPPH-scavenging activity, metal-chelating activity, and β-carotene-bleaching inhibition. Measurement of the in vitro cell growth inhibitory effects on three different human cancer cellular lines was also carried out, and the potential hypocholesterolemic effect was studied. Compounds 10 and 15 displayed an improved antioxidant activity, with respect to that of γ-oryzanol. Compounds 2, 6, and 12 exerted an antiproliferative activity in the low micromolar range against HeLa and DAOY cells (GI₅₀ < 10 μM). As for the claimed hypocholesterolemic effect of γ-oryzanol, none of the synthesized compounds inhibited the 3-hydroxy-3-methylglutaryl-coenzyme A reductase, a key enzyme in cholesterol biosynthesis.

Potential Gastroprotective Activity of Rice Bran (Oryza sativa L.) Extracted by Ionic Liquid-Microwave-Assisted Extraction against Ethanol-Induced Acute Gastric Ulcers in Rat Model

The presence of gamma-oryzanol in rice bran oil can be 10⁻20-fold higher than tocopherol and tocotrienol. Gamma-oryzanol has various pharmacological properties. The objective of this study was to evaluate the effectiveness of rice bran extract as a gastroprotective in reducing lesions in ethanol-induced acute gastric ulcer models in rat, using the ionic liquid-microwave-assisted extraction (IL-MAE) method. Rice bran extract was obtained using the IL-MAE method with ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]BF₄ (concentration 0.7 M), and a ratio of solid/liquid of 15 g/mL, 15 min extraction time, and 10% microwave power. The rats were pretreated with rice bran extract at different doses (100, 200, and 400 mg/kg body weight; BW) for seven days and subsequently exposed to acute gastric lesions induced by 80% ethanol. Omeprazole (36 mg/kg BW) was used as a standard anti-ulcer drug. The ulcer index, gastric juice acidity, and mucus levels were measured to assess the degree of gastroprotection. The results showed that the oral administration of rice bran extract at a dose of 400 mg/kg BW significantly inhibited the development of ulcer formation by 66.75% and reduced gastric acid levels. Moreover, gamma oryzanol and omeprazole protected the gastric mucosa from ethanol-induced gastric lesions by increasing the level of gastric mucus. Rice bran extract is effective as a gastroprotective therapy sourced from natural ingredients in treating the incidence of gastric ulcers. Most likely, this is related to gamma oryzanol as a bioactive compound contained in rice bran (Oryza sativa L.).

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.

The aqueous extract from Artemisia capillaris inhibits acute gastric mucosal injury by inhibition of ROS and NF-kB

Artemisia capillaris, also called "InJin" in Korean, has been used as traditional oriental medicine in Korea because of its various pharmacological activities. These include hepatoprotective, analgesic, and antipyretic activities. The present study was designed to validate the beneficial effects of the aqueous extract of A. capillaris (AEAC) against acute gastric mucosal injury and investigate the underlying molecular mechanisms. The pharmacological efficacy of AEAC was evaluated using the gastric ulcer index and histological examination. AEAC decreased gastric mucosal lesions mediated by HCl/ethanol in vivo in a dose-dependent manner. Interestingly, the mucosal damage was almost prevented by pretreatment with 200 or 400?mg/kg AEAC. However, AEAC did not have acid-neutralizing activity in vitro and did not prevent histamine secretion in HMC-1 mast cells. In the gastric mucosa, AEAC also significantly inhibited lipid peroxide formation through superoxide dismutase (SOD) activation. Moreover, AEAC strongly reduced the generation of pro-inflammatory cytokines, such as interleukin-6 (IL-6) and interleukin-1? (IL-1?), through nuclear factor kappa B (NF-?B) downregulation. Taken together, our findings suggest that AEAC inhibits inflammation and maintains oxidant/antioxidant homeostasis, resulting in a gastro-protective effect against HCl/ethanol-induced gastric damage. Therefore, AEAC might be a promising drug or useful neutraceutical for treatment of gastritis and gastric ulcer.

Effect of Gamma-Oryzanol as Therapeutic Agent to Prevent Cardiorenal Metabolic Syndrome in Animals Submitted to High Sugar-Fat Diet

BACKGROUND

The high consumption of fat and sugar contributes to the development of obesity and co-morbidities, such as diabetes, and cardiovascular and kidney diseases. Different strategies have been used to prevent these diseases associated with obesity, such as changes in eating habits and/or the addition of dietary components with anti-inflammatory and anti-oxidant properties, such as gamma-oryzanol (γOz) present mainly in bran layers and rice germ.

METHODS

Animals were randomly divided into four experimental groups and fed ad libitum for 20 weeks with control diet (C, n = 8), control diet + γOz (C + γOz, n = 8), high-sugar and high-fat diet (HSF, n = 8), and high-sugar and high-fat diet + γOz (HSF + γOz, n = 8). HSF groups also received water + sucrose (25%). The dose of γOz was added to diets to reach 0.5% of final concentration (w/w). Evaluation in animals included food and caloric intake, body weight, plasma glucose, insulin, triglycerides, uric acid, HOMA-IR, glomerular filtration rate, protein/creatinine ratio, systolic blood pressure, and Doppler echocardiographic.

RESULTS

Animals that consumed the HSF diet had weight gain compared to group C, increased insulin, HOMA, glucose and triglycerides, there were also atrial and ventricular structural alterations, deterioration of systolic and diastolic function, decreased glomerular filtration rate, and proteinuria. Gamma-oryzanol is significantly protective against effects on body weight, hypertriglyceridemia, renal damage, and against structural and functional alteration of the heart.

CONCLUSION

Gamma-oryzanol shows potential as a therapeutic to prevent Cardiorenal Metabolic Syndrome.

Minor Constituents in Rice Bran Oil and Sesame Oil Play a Significant Role in Modulating Lipid Homeostasis and Inflammatory Markers in Rats

The effects of feeding rats with groundnut oil (GNO), rice bran oil (RBO), and sesame oil (SESO) on serum lipids, liver lipids, and inflammatory markers were evaluated in rats. Male Wistar rats were fed with AIN-93 diet supplemented with 10 wt% of GNO, RBO, and SESO in the form of native (N) and minor constituent-removed (MCR) oils. Rats given RBO and SESO showed significant reduction in serum and liver lipids, 8-hydroxy-2-deoxyguanosine, cytokines in liver, and eicosanoids in leukocytes as compared with the rats given GNO and MCR oils. The rats fed with native oils of RBO and SESO showed an upregulation of sterol regulatory element-binding protein (SREBP)-2 and peroxisome proliferator-activated receptor gamma (PPARγ) and downregulation of nuclear factor-kappa B (NF-κB) p65. These effects of native oil were significantly compromised when rats were given MCR oils. In conclusion, the minor constituents significantly support the hypolipidemic and anti-inflammatory properties of RBO and SESO.