Characterization of triterpene alcohol and sterol ferulates in rice bran using LC-MS/MS

Current advances in phytosterol free forms and esters: Classification, biosynthesis, chemistry, and detection

Phytosterols are plant sterols that are important secondary plant metabolites with significant pharmacological properties. Their presence in the plant kingdom concerns many unrelated botanical families such as oleageneous plants and cereals. The structures of phytosterols evoke those of cholesterol. These molecules are composed of a sterane ring, also known as perhydrocyclopentanophenanthrene, along with a methyl or ethyl group at C-24 in their side chains, a hydroxyl group at C-3 on ring A, and one or two double bonds in the B ring. Phytosterols display different oxidation degrees at the sterane ring and at the side chain as well as varying numbers of carbons with complex stereochemistries. Fats and water solubilities of phytosterols have been achieved by physical, chemical and enzymatic esterifications to favor their bioavailability and to improve the sensory quality of food, and the efficiency of pharmaceutic and cosmetic products. This review aims to provide comprehensive information starting from the definition and structural classification of phytosterols, and exposes an update of their biogenic relationships. Next, the synthesis of phytosterol esters and their applications as well as their effective roles as hormone precursors are discussed. Finally, a concise exploration of the latest advancements in phytosterol / oxyphytosterols analysis techniques is provided, with a particular focus on modern hyphenated techniques.

Classification, biosynthesis, and biological functions of triterpene esters in plants

Triterpene esters comprise a class of secondary metabolites that are synthesized by decorating triterpene skeletons with a series of oxidation, glycosylation, and acylation modifications. Many triterpene esters with important bioactivities have been isolated and identified, including those with applications in the pesticide, pharmaceutical, and cosmetic industries. They also play essential roles in plant defense against pests, diseases, physical damage (as part of the cuticle), and regulation of root microorganisms. However, there has been no recent summary of the biosynthetic pathways and biological functions of plant triterpene esters. Here, we classify triterpene esters into five categories based on their skeletons and find that C-3 oxidation may have a significant effect on triterpenoid acylation. Fatty acid and aromatic moieties are common ligands present in triterpene esters. We further analyze triterpene ester synthesis-related acyltransferases (TEsACTs) in the triterpene biosynthetic pathway. Using an evolutionary classification of BAHD acyltransferases (BAHD-ATs) and serine carboxypeptidase-like acyltransferases (SCPL-ATs) in Arabidopsis thaliana and Oryza sativa, we classify 18 TEsACTs with identified functions from 11 species. All the triterpene-skeleton-related TEsACTs belong to BAHD-AT clades IIIa and I, and the only identified TEsACT from the SCPL-AT family belongs to the CP-I subfamily. This comprehensive review of the biosynthetic pathways and bioactivities of triterpene esters provides a foundation for further study of their bioactivities and applications in industry, agricultural production, and human health.

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.

Chemical Structure Diversity and Extensive Biological Functions of Specialized Metabolites in Rice

Rice (Oryza sativa L.) is thought to have been domesticated many times independently in China and India, and many modern cultivars are available. All rice tissues are rich in specialized metabolites (SPMs). To date, a total of 181 terpenoids, 199 phenolics, 41 alkaloids, and 26 other types of compounds have been detected in rice. Some volatile sesquiterpenoids released by rice are known to attract the natural enemies of rice herbivores, and play an indirect role in defense. Momilactone, phytocassane, and oryzalic acid are the most common diterpenoids found in rice, and are found at all growth stages. Indolamides, including serotonin, tryptamine, and N-benzoylserotonin, are the main rice alkaloids. The SPMs mainly exhibit defense functions with direct roles in resisting herbivory and pathogenic infections. In addition, phenolics are also important in indirect defense, and enhance wax deposition in leaves and promote the lignification of stems. Meanwhile, rice SPMs also have allelopathic effects and are crucial in the regulation of the relationships between different plants or between plants and microorganisms. In this study, we reviewed the various structures and functions of rice SPMs. This paper will provide useful information and methodological resources to inform the improvement of rice resistance and the promotion of the rice industry.

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.

Chemical Composition, Antioxidant, and Antimicrobial Activities of Leaves of Ajuga Iva

The main objective of this research was to study the biological characteristics in terms of antioxidant and antimicrobial activities of Ajuga iva and determine the best analytical and extraction methods applicable to this specie and studied compounds. A short screening of its nutritional value in terms of chemical composition is also included. A. iva leaves were analyzed for crude protein (CP), cell wall [neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL)], minerals, fatty acids, essential oils, and phenolic compounds. Mature aerial parts of A. iva were randomly collected during the Spring season from Mograne-Zaghouan, Tunisia. Leaves of A. iva contained 13.4 ± 0.4% CP, 26.3 ± 0.35% NDF, 20.2 ± 0.42% ADF, and 5.13 ± 0.21% ADL. Mineral content (13.0 ± 0.45%) was mainly composed of potassium (4.5% g DM) and magnesium (4.25% DM). Leaves of A. iva had linolenic (26.29 ± 0.760%) and linoleic (37.66 ± 2.35%) acids as the main components of the acid profile. Thymol was found to be the most dominant (23.43%) essential oil, followed by 4-vinylguaiacol (14.27%) and linalool (13.66%). HPLC-PDA-ESI-MS/MS analysis pointed out the presence of phytoecdysteroids. Phenolic acids and flavonoids, such as glycosylated derivatives of naringenin, eriodyctiol, and apigenin, were detected in the methanol extract of A. iva leaves. Our results underline the importance of choosing proper extraction methods and solvents to extract and characterize the described compounds profile of A. iva leaves. Results also show A. iva leaves as a potential source of functional ingredients with beneficial health-promoting properties. Overall, leaves of A. iva have low biological activities (antioxidant and antimicrobial activities) with a chemical composition suitable as a feed for ruminants in rangeland pasture. It also has low-grade antibacterial or medicinal characteristics when fed to ruminants.

Natural variation and underlying genetic loci of γ-oryzanol in Asian cultivated rice seeds

γ-oryzanol is the most studied component in rice (Oryza sativa L.) bran oil. It is not only associated with physiological processes of rice growth and development but also grain quality that is related to human health. Previous studies focused mainly on γ-oryzanol composition and content in various rice cultivars, while its biosynthetic and regulatory pathways remain unknown. Here we present the quantitative identification of γ-oryzanol in rice seeds across 179 Asian cultivated accessions using ultra-performance liquid chromatography-time-of-flight mass spectrometry (UPLC-TOF/MS), which revealed a significant natural variation in γ-oryzanol content among these tested rice accessions. In addition, we present, for the first time, the genome-wide association study (GWAS) on rice seed γ-oryzanol, which identified 187 GWAS signal hot spots and 13 candidate genes that are associated with variable γ-oryzanol content and provided the top 10 rice haplotypes with high γ-oryzanol content for breeding. Collectively, our study provides valuable germplasms for breeding rice cultivars rich in γ-oryzanol and genetic resources for elucidating genetic and biochemical bases of variable γ-oryzanol in rice.

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.

Benefits of Anthocyanin-Rich Black Rice Fraction and Wood Sterols to Control Plasma and Tissue Lipid Concentrations in Wistar Kyoto Rats Fed an Atherogenic Diet

Background: This study reports on the relative effects of administrating a cyanidin-3-O-glucoside-rich black rice fraction (BRF), a standardized wood sterol mixture (WS), and a combination of both to lower plasma and target tissue lipid concentrations in Wistar Kyoto (WKY) rats fed atherogenic diets. Methods: Male WKY (n = 40) rats were randomly divided into five groups, which included a nonatherogenic control diet and atherogenic diets that included a positive control and atherogenic diets supplemented with BRF or WS, respectively, and a combination of both BRF + WS. Plasma and target tissue liver, heart and aorta cholesterol, and triacylglycerides (TAG) content were also measured. Results: Rats fed atherogenic diets exhibited elevated hyperlipidemia compared to counterparts fed nonatherogenic diets (p < 0.001); this effect was mitigated by supplementing the atherogenic diets with BRF and WS, respectively (p < 0.05). Combining BRF with WS to enrich the supplement lowered cholesterol similar to the WS effect (p < 0.05) and lowered TAG characteristic to the BRF effect (p < 0.05). Conclusions: Rats fed diets containing BRF or WS effectively mitigate the hypercholesterolemia and elevated TAG induced by feeding an atherogenic diet. The benefit of adding BRF + WS together is relevant to the lipid parameter measured and is target tissue-specific.

Synthesis of Steryl Hydroxycinnamates to Enhance Antioxidant Activity of Rapeseed Oil and Emulsions

In recent years, steryl esters have found potential applications in food, pharmaceutical and cosmetic industries. Therefore, three hydroxycinnamate steryl esters (HSEs): β-sitosteryl sinapate (β-SSA), β-sitosteryl caffeate (β-SCA), and β-sitosteryl ferulate (β-SFA) were synthesized by chemical approach and their antioxidant activity (AA) were analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. The values of inhibitory concentration (IC₅₀) of each ester needed to inhibit 50% of the DPPH radical (IC_50(DPPH) = 238.9, 78.3, 290.0 µmol/L for β-SSA, β-SCA, and β-SFA, respectively) and ABTS radical cation (IC_50(ABTS) = 174.6, 106.7, 206.0 µmol/L for β-SSA, β-SCA, and β-SFA, respectively) were estimated and compared with antioxidant potential of phenolic acids. Moreover, the effect of HSEs addition in the concentrations range between 0.01% and 0.5% on the AA of refined rapeseed oil, mayonnaise and margarine was evaluated. Chemical structures of the synthesized HSEs and their concentrations strongly affect the AA of fat products. Oil and emulsions supplemented with higher concentrations of HSEs had significantly higher AA than control samples. Unfortunately, lower concentrations of HSEs (0.01% and 0.02%) did not increase the AA of fat products. However, steryl phenolates added in higher amounts can be considered as potential antioxidants delaying the oxidation processes of studied fats.

Immunostimulatory Activity of Black Rice Bran in Cyclophosphamide-Induced Immunosuppressed Rats

Black rice bran extract (BRBE), containing various biologically active compounds, such as anthocyanin, has antioxidant activity and numerous pharmacological effects. Here, we aimed to confirm the immunostimulatory effects of BRBE in cyclophosphamide (CP)-induced immunosuppressed cells. Our results confirmed that BRBE exerted an immunostimulatory effect. In vitro, BRBE treatment enhanced cell proliferation, activity of natural killer cells and cytotoxic T lymphocytes, and production of CP-repressed cytokines, such as tumor necrosis factor-α, interferon-γ, interleukin (IL)-2, and IL-12, and immunoglobulins G and A in isolated splenocytes. Additionally, in vivo, BRBE treatment increased the number of immune cells, such as white blood cells, lymphocyte counts, mid-range absolute counts, and neutrophils in CP-induced immunosuppressed rats. Furthermore, BRBE increased the serum levels of abovementioned inflammatory cytokines and immunoglobulins in CP-induced immunosuppressed rats. In addition, BRBE protected against CP-mediated spleen and thymic tissue damage. Our findings suggest that BRBE could be potentially used as a component of functional food for immunity enhancement.

Comparison of Blood Profiles of γ-Oryzanol and Ferulic Acid in Rats after Oral Intake of γ-Oryzanol

γ-Oryzanol (OZ), a bioactive phytochemical abundant in cereals such as rice, has been reported to be mainly hydrolyzed to ferulic acid (FA) in the body. Meanwhile, in our previous study, we revealed that a part of OZ is absorbed into the body and exists in its intact form. However, the comprehensive absorption profile of OZ and its metabolites (e.g., FA) after OZ intake has not been fully elucidated yet. Therefore, in this study, we measured the concentrations of OZ, FA, and FA conjugates (i.e., FA sulfate and glucuronide) in the blood of rats with the use of HPLC-MS/MS after a single oral administration of 300 µmol/kg body weight of rice bran OZ (RBOZ). As a result, intact OZ along with FA and FA conjugates existed in the blood, which implied that these constituents may all contribute to the physiological effects under OZ intake. Additionally, when an equimolar amount of FA (300 µmol/kg body weight) was administered, it was found that the absorption profile of FA was significantly different from that when RBOZ was administered.

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.

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.

Presence of orally administered rice bran oil γ-oryzanol in its intact form in mouse plasma

Although the beneficial effects (e.g., lipid-lowering activity) of γ-oryzanol (OZ), a mixture of ferulic acid esters of plant sterols and triterpene alcohols, have been extensively investigated, few studies have evaluated the absorption and metabolism of OZ. Moreover, it is unclear whether OZ, once ingested, is directly absorbed by the intestine into the bloodstream at a sufficient level to exhibit activity. Here, we prepared OZ concentrate from purified rice bran oil (Rice Oil OZ), determined the concentration of OZ in the preparation (cycloartenyl ferulate equivalent concentration; 52.2%), and then carried out chromatography-mass spectrometry analysis of plasma samples from mice after oral administration of Rice Oil OZ. The OZ concentrations of plasma from the control (vehicle-treated) mice were low (trace levels); however, at 5 h after a single oral administration of the Rice Oil OZ (600 mg per kg body weight), the levels significantly increased, reaching 17.6 ng mL^-1 for cycloartenyl ferulate, 28.2 ng mL^-1 for 24-methylenecycloartanyl ferulate isomers, 15.6 ng mL^-1 for campesteryl ferulate, and 5.1 ng mL^-1 for β-sitosteryl ferulate, respectively, expressed in equivalence of cycloartenyl ferulate in plasma. These results provided the first mass spectrometric evidence suggesting that a portion of orally administered OZ is directly absorbed by the intestine and is present in the intact form in plasma. The presence of a significant amount of OZ in its intact form in plasma may explain the beneficial effects of OZ in vivo.

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.

Chemical Components, Biological Activities, and Toxicological Evaluation of the Fruit (Aril) of Two Precious Plant Species from Genus Taxus

The fruit (aril) of the endangered genus Taxus plants is an abandoned herbal resource. Traditionally, people enthusiastically focus on its bark, its renewable, tremendous arils fall into the soil with seeds after they are mature. The present research investigated the fruit of two species from the genus Taxus, Taxus chinensis var. mairei, and Taxus media, with regards to their antioxidant and antihyperglycaemic activities, safety, and bioactive constituents. Results showed that T. chinensis var. mairei and T. media both had certain biological activities with T. chinensis var. mairei better in antioxidant activity and T. media better in antihyperglycaemic activity. Correlation analysis revealed that the differences in bioactivities depended on content of their mainly chemical components. The mice acute oral toxicity test indicated that the methanol extracts of the two biotypes of Taxus were safe. And nineteen compounds were tentatively assigned from the two varieties, via tandem mass spectrometry using a LC-ESI-Q-TOF-MS instrument, which included phenols, flavonoids, and terpenes. These results indicate a possible application of Taxus fruit extracts in various fields like in food industry, however, this still needs further investigations.

Phytochemicals in whole grain wheat and their health-promoting effects

Accumulated evidence in epidemiological studies has consistently shown that consumption of whole grains (WGs) is inversely associated with risk of major chronic diseases such as certain types of cancer, type 2 diabetes, and cardiovascular diseases. Dietary fiber (DF) has been reported to be responsible for the health effects of WG consumption. Evidence from in vitro and in vivo studies is emerging that, in addition to DF and minerals, the unique phytochemicals in WGs may in part contribute to these health-promoting effects. WGs are rich sources of various phytochemicals. However, phytochemical contents and profiles in WG wheat are not systematically summarized yet, and the rapid rate of discovery of wheat phytochemicals necessitates an update on the current state of this field. Furthermore, the biological roles of phytochemicals in protective effects of WGs are also relatively underestimated compared to DFs. This manuscript summarized current research literature regarding phytochemicals that have been identified and characterized from wheat grains and wheat bran, and their corresponding contributions to the major health benefits of WG wheat consumption.

Ninety-day oral toxicity study of rice-derived γ-oryzanol in Sprague-Dawley rats

A 90-day oral toxicity study of γ-oryzanol, a rice-derived triterpenoid ferulate, was performed by oral gavage administration to male and female Sprague-Dawley rats at doses of 0, 1000, and 2000 mg/kg body weight/day. All rats administered γ-oryzanol survived throughout the study period. Both male and female rats showed no toxicologically significant changes of the general signs, examination findings, body weight, food consumption, functional observational battery results, ophthalmological findings, urinalysis, hematology tests, clinical chemistry tests, organ weights, and necropsy findings. Moreover, there were no histopathological changes related to administration of γ-oryzanol in males and females from the 2000 mg/kg body weight/day group. In conclusion, the no observed adverse effect level (NOAEL) of γ-oryzanol exceeded 2000 mg/kg body weight/day for both male and female rats under the conditions of this study.

The content and distribution of steryl ferulates in wheat produced in Japan

Oryzanol contained in rice bran is a complex mixture of steryl ferulates (SFs) with many identified health benefits. Recently, SF has been shown to exist in other cereals such as wheat, rye, and corn. In this study, SFs in several wheats produced in Japan were analyzed. For instance, SF content of whole wheat grain, Yumekaori (Japan) was 15.2 ± 1.4 mg-oryzanol-equivalent/100 g grain, while that of the imported one, 1CW (Canada) was 11.4 ± 1.3 mg-oryzanol-equivalent/100 g grain. The main SF components in the examined wheats were campesteryl ferulate, campestanyl ferulate, and sitostanyl ferulate. SF distribution in whole wheat grain was investigated using 14 fractions produced by a conventional test milling machine. SF was intensively accumulated in the four bran fractions (24 - 95 mg-oryzanol-equivalent/100 g bran fraction). These results suggest that the wheat bran would be an important source of SF.

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.

A Blend of Sesame and Rice Bran Oils Lowers Hyperglycemia and Improves the Lipids

BACKGROUND

Considering the health benefits of sesame oil and rice bran oil, the study was conducted to determine the extent to which the daily use of this blend of oils controls hyperglycemia and improves the lipid profile.

METHODS

In this 8-week open-label randomized dietary intervention study, 300 type 2 diabetes mellitus patients and 100 normoglycemic subjects were grouped as 1) normoglycemic subjects (n = 100) treated with sesame oil blend Vivo (Adani Wilmar, Ahmedabad, Gujarat, India), 2) type 2 diabetes mellitus patients treated with sesame oil blend (n = 100), 3) type 2 diabetes mellitus patients treated with glibenclamide (n = 100; 5 mg/d), and 4) type 2 diabetes mellitus patients treated in combination of glibenclamide (5 mg/d) and sesame oil blend (n = 100). Twelve-hour fasting blood glucose, glycated hemoglobin (HbA1c), and lipid profile followed by postprandial blood glucose were measured at baseline. Sesame oil blend was supplied to the respective groups, who were instructed to use as cooking oil for 8 weeks. Fasting and postprandial blood glucose was measured at week 4 and week 8, while HbA1c and lipid profile were measured at week 8.

RESULTS

At week 4 and week 8, type 2 diabetes mellitus patients treated with sesame oil blend or glibenclamide or combination of glibenclamide and sesame oil blend showed significant reduction of fasting and postprandial blood glucose (P <.001). HbA1c, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol were significantly reduced (P <.001), while high-density lipoprotein cholesterol was significantly increased at week 8 (P <.001) in type 2 diabetes mellitus patients treated with the sesame oil blend or combination of glibenclamide and sesame oil blend; whereas glibenclamide-alone-treated type 2 diabetes mellitus patients showed a significant reduction of HbA1c (P <.001) only.

CONCLUSIONS

A novel blend of 20% cold-pressed unrefined sesame oil and 80% physically refined rice bran oil as cooking oil, lowered hyperglycemia and improved the lipid profile in type 2 diabetes mellitus patients.

Differentiation of Whole Grain from Refined Wheat (T. aestivum) Flour Using Lipid Profile of Wheat Bran, Germ, and Endosperm with UHPLC-HRAM Mass Spectrometry

A comprehensive analysis of wheat lipids from milling fractions of bran, germ, and endosperm was performed using ultrahigh-performance liquid chromatography-high-resolution accurate-mass multistage mass spectrometry (UHPLC-HRAM-MS(n)) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in both positive and negative modes. About 155 lipid compounds, including free fatty acids (FA), oxylipins, alk(en)ylresorcinols (ARs), γ-oryzanol, sphingolipids, triglycerides (TGs), diglycerides (DGs), phospholipids, and galactolipids were characterized from the three milling fractions. Galactolipids and phospholipids were proposed to be potential discriminatory compounds for refined flour, whereas γ-oryzanols, ARs, TGs, and DGs could distinguish whole wheat flour from a refined one based on principal component analysis (PCA).

Using metabolomic approaches to explore chemical diversity in rice

Rice (Oryza sativa) is an excellent resource; it comprises 25% of the total caloric intake of the world's population, and rice plants yield many types of bioactive compounds. To determine the number of metabolites in rice and their chemical diversity, the metabolite composition of cultivated rice has been investigated with analytical techniques such as mass spectrometry (MS) and/or nuclear magnetic resonance spectroscopy and rice metabolite databases have been constructed. This review summarizes current knowledge on metabolites in rice including sugars, amino and organic acids, aromatic compounds, and phytohormones detected by gas chromatography-MS, liquid chromatography-MS, and capillary electrophoresis-MS. The biological properties and the activities of polar and nonpolar metabolites produced by rice plants are also presented. Challenges in the estimation of the structure(s) of unknown metabolites by metabolomic approaches are introduced and discussed. Lastly, examples are presented of the successful application of metabolite profiling of rice to characterize the gene(s) that are potentially critical for improving its quality by combining metabolite quantitative trait loci analysis and to identify potential metabolite biomarkers that play a critical role when rice is grown under abiotic stress conditions.

Fat-soluble bioactive components in colored rice varieties

Bioactive components in rice vary depending on the variety and growing condition. Fat-soluble components such as γ-oryzanol, tocopherols, tocotrienols, carotenoids, and fatty acids were analyzed in brown, sugary brown, red, and black rice varieties using established high-performance liquid chromatography (HPLC) and GC methodologies. In addition, these colored rice varieties were further analyzed using a high-resolution liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) (LTQ-Orbitrap XL) to identify the [M-H](-) ions of γ-oryzanol, ranging from m/z 573.3949 to 617.4211. The highest content of tocopherols (α-, 1.5; γ-, 0.5 mg/100 g) and carotenoids (lutein 244; trans-β carotene 25 μg/100 g) were observed in black rice; tocotrienols (α-, 0.07; γ-, 0.14 mg/100 g) in red rice, and γ-oryzanol (115 mg/100 g) in sugary brown rice. In all colored rice varieties, the major fatty acids were palmitic (16:0), oleic (18:1n-9), and linoleic (18:2n-6) acids. When the γ-oryzanol components were further analyzed by LC-MS/MS, 3, 10, 8, and 8 triterpene alcohols or sterol ferulates were identified in brown, sugary brown, red, and black rice varieties, respectively. Such structural identification can lead to the elucidation of biological function of each component at the molecular level. Consumption of colored rice rich in beneficial bioactive compounds may be a useful dietary strategy for achieving optimal health.

Infrared stabilization of rice bran and its effects on γ-oryzanol content, tocopherols and fatty acid composition

BACKGROUND

Rice bran is a nutritionally valuable by-product of paddy milling. In this study an experimental infrared (IR) stabilization system was developed to prevent rice bran rancidity. The free fatty acid content of raw and IR-stabilized rice bran samples was monitored every 15 days during 6 months of storage. In addition, energy consumption was determined.

RESULTS

The free fatty acid content of rice bran stabilized at 600 W IR power for 5 min remained below 5% for 165 days. No significant change in γ-oryzanol content or fatty acid composition but a significant decrease in tocopherol content was observed in stabilized rice bran compared with raw bran. IR stabilization was found to be comparable to extrusion with regard to energy consumption.

CONCLUSION

IR stabilization was effective in preventing hydrolytic rancidity of rice bran. By optimizing the operational parameters of IR stabilization, this by-product has the potential for use in the food industry in various ways as a value-added commodity.

Rice antioxidants: phenolic acids, flavonoids, anthocyanins, proanthocyanidins, tocopherols, tocotrienols, γ-oryzanol, and phytic acid

Epidemiological studies suggested that the low incidence of certain chronic diseases in rice-consuming regions of the world might be associated with the antioxidant compound contents of rice. The molecules with antioxidant activity contained in rice include phenolic acids, flavonoids, anthocyanins, proanthocyanidins, tocopherols, tocotrienols, γ-oryzanol, and phytic acid. This review provides information on the contents of these compounds in rice using a food composition database built from compiling data from 316 papers. The database provides access to information that would have otherwise remained hidden in the literature. For example, among the four types of rice ranked by color, black rice varieties emerged as those exhibiting the highest antioxidant activities, followed by purple, red, and brown rice varieties. Furthermore, insoluble compounds appear to constitute the major fraction of phenolic acids and proanthocyanidins in rice, but not of flavonoids and anthocyanins. It is clear that to maximize the intake of antioxidant compounds, rice should be preferentially consumed in the form of bran or as whole grain. With respect to breeding, japonica rice varieties were found to be richer in antioxidant compounds compared with indica rice varieties. Overall, rice grain fractions appear to be rich sources of antioxidant compounds. However, on a whole grain basis and with the exception of γ-oryzanol and anthocyanins, the contents of antioxidants in other cereals appear to be higher than those in rice.

Simultaneous HPLC quantification of five major triterpene alcohol and sterol ferulates in rice bran oil using a single reference standard

A high performance liquid chromatography (HPLC) method was developed for simultaneous quantification of five major triterpene alcohol and sterol ferulates in rice bran oils (RBO) with a single internal standard, cycloartenyl ferulate. The five compounds are cycloartenyl ferulate (1), 24-methylene cycloartanyl ferulate (2), campesteryl ferulate (3), sitosteryl ferulate (4) and stigmastanyl ferulate (5). All five compounds had good linear concentration-measurement relationships (r(2) ≥ 0.9995) and possessed similar relative response factors. The relative deviation of this method was less than 2.5% for intra- and inter-day assays, and the average recovery varied from 95.1% to 99.4%. The new method was validated by comparing the amount of 24-methylene cycloartanyl ferulate (2) in 17 RBO samples obtained with this method and that with an external standard method. This method was also successfully applied to determine five major triterpene alcohol and sterol ferulates in 17 batches of RBO samples. The results demonstrated that the present method could be utilised for quality control of RBO since some of the reference standards are not commercially available.

γ-Oryzanols of North American Wild Rice (Zizania palustris)

γ-Oryzanol, a natural mixture of ferulic acid esters of triterpene alcohols and sterols, are an important bioactive components present in rice bran oil. In light of the recent increase in the popularity of wild rice among consumers, and the possibility of a direct relationship between γ-oryzanol composition and its bioactivity, the oryzanol profile of major wild rice (Zizania palustris) grown in North America was studied and compared to regular brown rice (Oryza sativa L.). A total of twenty-three γ-oryzanol components were separated, identified and quantified by HPLC coupled to an Orbitrap MS. The distribution of individual γ-oryzanols was similar for all the wild rice but significantly different from those of the regular brown rice. Unlike in the regular brown rice, a significant amount of steryl caffeate and cinnamate were found in the wild rice samples. Generally, the amounts of γ-oryzanol in the wild rice were higher compared to the regular brown rice, 1,352 vs. 688 μg/g. The results from this study showed that wild rice had a more diverse γ-oryzanol composition and the higher amounts compared to the regular brown rice.

Evaluation of γ-oryzanol content and composition from the grains of pigmented rice-germplasms by LC-DAD-ESI/MS

Background

Rice is the staple food and one of the world’s three major grain crops. Rice contains more than 100 bioactive substances including phytic acid, isovitexin, γ-oryzanol, phytosterols, octacosanol, squalene, γ-aminobutyric acid (GABA), tocopherol, tocotrienol derivatives, etc. Out of them, γ-oryzanol is known to have important biological profile such as anti-oxidants, inhibitor of cholesterol oxidation, reduce serum cholesterol levels in animals, effective in the treatment of inflammatory diseases, inhibit tumor growth, reduce blood pressure and promotes food storage stability when used as a food additive, etc. Hence in the present investigation, we aimed to evaluate the content and composition of γ-oryzanol from pigmented rice germplasms using a liquid chromatography with diode array detection and electrospray ionization-mass spectrometry (LC-DAD-ESI/MS).

Findings

In the present study, 33 exotic pigmented rice accessions (red, white and purple) have been evaluated. Among them, the contents of γ-oryzanol varied from 3.5 to 21.0Âmg/100Âg with a mean of 11.2Âmg/100Âg. A total of ten components of γ-oryzanol including ∆⁷-stigmastenyl ferulate were identified of which, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, campesteryl ferulate and sitosteryl ferulate were identified as the major components. The mean proportions of steryl ferulates were in the descending order of 24-methylenecycloartanyl ferulate > cycloartenyl ferulate > campesteryl ferulate > sitosteryl ferulate > ∆⁷-campestenyl ferulate > campestanyl ferulate > sitostanyl ferulate > ∆⁷-stigmastenyl ferulate > stigamsteryl ferulate > ∆⁷-sitostenyl ferulate. Almost 11 accessions (33%) showed higher content than the control rice Chucheongbyeo and higher proportions ranged from 10 to 15Âmg/100Âg. Interestingly, the red rice accession Liberian Coll. B11/B-11 (21.0Âmg/100Âg) showed higher content γ-oryzanol than control rice Jeokjinjubyeo (19.1Âmg/100Âg) and the purple rice accession Padi Adong Dumarat, Mardi No.4376 (20.3Âmg/100Âg) showed a similar content with control rice Heugjinjubyeo (21.4Âmg/100Âg).

Conclusions

Most of analyzed rice accessions were found to possess higher contents of γ-oryzanol than the control rice, Chucheongbyeo. In particular, the red accessions showed highest content than the white and purple accessions. The content and composition of γ-oryzanol in 33 exotic pigmented rice accessions have been evaluated and compared significantly by the present investigation.

Unusual immuno-modulatory triterpene-caffeates in the skins of russeted varieties of apples and pears

Three triterpene-caffeates have been isolated from skins of a russeted apple cultivar "Merton Russet" and identified by LC-MS and NMR as betulinic acid-3-cis-caffeate, betulinic acid-3-trans-caffeate, and oleanolic acid-3-trans-caffeate. Betulinic acid-3-trans-caffeate and oleanolic acid-3-trans-caffeate were also found in russeted pear skins. These compounds have not been previously reported in apples or pears, or in any other foods. Their presence was related to suberized tissue as they were only found in russet portions of the partially russeted apple cultivar "Cox's Orange Pippin" and were not detected in the waxy apple cultivar "Royal Gala". High concentrations of betulinic acid-3-trans-caffeate were found in the bark of both "Merton Russet" and "Royal Gala" trees. The three triterpene-caffeates showed anti-inflammatory activity in vitro, inhibiting NF-κB activation with IC50's of 6-9 μM. Betulinic acid-3-trans-caffeate, the predominant compound in the apples, was immuno-modulatory at around 10 μM in the in vitro and ex vivo bioassays, boosting production of the pro-inflammatory cytokine TNFα in cells stimulated with bacterial lipopolysaccharides.

Preparative separation of triterpene alcohol ferulates from rice bran oil using a high performance counter-current chromatography

A novel method for the separation of two major triterpene alcohol ferulates from rice bran oil (RBO) was developed using a high performance counter-current chromatography (HPCCC). A two-phase solvent system of n-hexane-acetonitrile (1:1, v/v) was applied to purify cycloartenyl ferulate (CAF) and 24-methylene cycloartanyl ferulate (24-mCAF) from RBO. The yields were 20.50±2.60 mg CAF and 12.62±1.15 mg 24-mCAF from 390 mg RBO through a two-step separation procedure. The purities of the two compounds were 97.97±0.90% and 95.50±0.75%, respectively, as determined by high performance liquid chromatography (HPLC). Their chemical structures were confirmed by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), and (1)H, (13)C and 2D nuclear magnetic resonance (NMR). This represents the first report on direct separation of CAF and 24-mCAF from RBO by HPCCC.

Quantification of flavonoids in black rice by liquid chromatography-negative electrospray ionization tandem mass spectrometry

Systematic identification and structural characterization of flavonoids and their glycosides in bran extracts of seven Thai black rice varieties were performed by sequential uses of reversed-phase HPLC with a photodiode array detector and a combined electrospray ionization tandem mass spectrometer. Eleven flavonoids were detected, and six of these were found for the first time in rice bran. These were taxifolin-7-O-glucoside, myricetin-7-O-glucoside, isorhamnetin-3-O-acetylglucoside, isorhamnetin-7-O-rutinoside, 5,6,3',4',5'-pentahydroxyflavone-7-O-glucoside, and 5,3',4',5'-tetrahydroxyflavanone-7-O-glucoside. The quantitative results revealed that different rice varieties possessed flavonoids in different concentrations. The most abundant glycoside derivative of flavonoids widely distributed among the rice varieties was monoglucoside, such as quercetin-3-O-glucoside, isorhamnetin-3-O-glucoside, and isorhamnetin-3-O-glucoside.