Anthocyanin content and antioxidant capacity in bran extracts of some Thai black rice varieties

A comprehensive review of the impact of anthocyanins from purple/black Rice on starch and protein digestibility, gut microbiota modulation, and their applications in food products

This review explores the impact of anthocyanins derived from purple and black rice on starch and protein digestibility, gut microbiota modulation, and their applications in food production. Anthocyanins are shown to reduce starch digestibility by forming complexes with starch, thereby inhibiting key digestive enzymes. Additionally, they can influence protein digestion by inducing structural changes that enhance resistance to digestive processes. Evidence suggests that black rice anthocyanins positively modulate gut microbiota composition, potentially improving overall gut health. The incorporation of anthocyanin-rich extracts into various food products, such as bread and beverages, underscores their potential as functional ingredients. This review provides valuable insights into the health benefits associated with rice anthocyanins and identifies areas for future research to optimize their application in functional foods aimed at managing metabolic health.

Melatonin differentially refines the metabolome to improve seed formation during grain developmental stages and enhances yield in two contrasting rice cultivars, grown in arsenic-contaminated soil

The manuscript revealed the ameliorative effects of exogenous melatonin in two distinct reproductive stages, i.e., developing grains (20 days after pollination) and matured grains (40 days after pollination) in two contrasting indica rice genotypes, viz., Khitish (arsenic-susceptible) and Muktashri (arsenic-tolerant), irrigated with arsenic-contaminated water throughout their life-cycle. Melatonin administration improved yield-related parameters like rachis length, primary and secondary branch length, number of grains per panicle, number of filled and empty grains per panicle, grain length and breadth and 1000-grain per weight. Expression of GW2, which negatively regulates grain development, was suppressed, along with concomitant induction of positive regulators like GIF1, DEP1 and SPL14 in both Khitish and Muktashri. Melatonin lowered arsenic bioaccumulation in grains and tissue biomass, more effectively in Khitish. Unregulated production of reactive oxygen species, leading to cellular necrosis caused by arsenic, was reversed in presence of melatonin. Endogenous melatonin level was stimulated due to up-regulation of the key biosynthetic genes, SNAT and ASMT. Melatonin enhanced the production of diverse antioxidants like anthocyanins, flavonoids, total phenolics and ascorbic acid and also heightened the production of thiol-metabolites (cysteine, reduced glutathione, non-protein thiols and phytochelatin), ensuring effective chelation and arsenic detoxification. Altogether, our observation, supported by principal component analysis, proved that melatonin re-programs the antioxidative metabolome to enhance plant resilience against arsenic stress to mitigate oxidative damages and reduce arsenic translocation from the soil to tissue biomass and edible grains.

Productivity and profitability of black rice as affected by transplanting methods and crop geometry

Black rice is a highly nutritious cereal that has been introduced to Nepal recently. Due to its late introduction, only a few agronomic research have been conducted so far. Hence, farmers are not aware about the appropriate transplanting methods and cropping geometry for profitable black rice cultivation. To fulfill the research gap and to establish a basic benchmark for further studies, the research focuses on responses of two black rice genotypes at different transplanting methods and cropping geometry. The profitability analysis with respect to transplanting methods and cropping geometry revealed, transplanting 21 days old seedlings with any geometrical pattern would yield and profit more as compared to SRI. Similarly, farmers can get a highest net revenue of 9379.3 $ at the B/C ratio of 12.07 from fine black rice as compared to coarse black rice that has a net revenue of 4485.7 $ at the B/C of 7.38. The highest productivity (2.70 t ha-1), net revenue (6018.5 $), and B/C ratio (13.7) were observed at the crop geometry of 20 cm × 15 cm for coarse black rice. Whereas, the highest yield (4.60 t ha-1), net revenue (10889.8 $), and B/C ratio (19.5) was observed in 20 cm × 10 cm for fine black rice. The higher net revenue and B/C ratio of premium black rice genotypes was due to their higher market price. The correlation analysis suggested tillering index (Ti) and net biomass accumulated up to 60 days after transplanting (DAT) had the highest positive correlation with yield of both black rice genotypes. Hence, the authors recommend researchers to work on additional agronomic practices that enhance the tillering index and net biomass production up to 60 DAT considering transplanting methods yield more as compared to SRI and crop geometry of 20 cm × 15 cm and 20 cm × 10 cm are the most productive and profitable cropping geometry for coarse and fine black rice genotypes, respectively.

Effect of processing methods and storage on the bioactive compounds of black rice (Oryza sativa L.): a review

Compared to brown and white rice, black rice contains more nutrients and numerous unique bioactive substances, such as essential amino acids, dietary fiber, γ-oryzanols, γ-aminobutyric acid, phenolic compounds, and anthocyanins, which makes it highly valuable for development and use. Whole-grain black rice typically requires a certain amount of processing prior to consumption, with the primary goal of enhancing the taste and texture of whole grains and their products. However, various new processing technologies have been effectively applied to the processing of black rice and the enhancement of its qualitative characteristics, but they also have both positive and negative effects on its nutritional quality. Therefore, evaluation of changes in concentrations of the bioactive substances as natural antioxidants due to processing and storage conditions is critical for establishing dietary guidelines for rice. This review highlights the primary bioactive components of black rice and provides a discussion of the impact of processing methods and storage on the bioactive components of black rice. Furthermore, we summarized the issues that currently exist in the processing and storage of black rice.

Black rice and its by-products: anthocyanin-rich extracts and their biological potential

Recently, growing demand for products enriched with natural compounds that support human health has been observed. Black rice, its by-products, and residues are known to have in their composition a large amount of these compounds with biological potential, mainly anthocyanins. These compounds have reported effects on anti-obesity, antidiabetic, antimicrobial, anticancer, neuroprotective, and cardiovascular disease. Therefore, the extract from black rice or its by-products have great potential for application as ingredients in functional foods, supplements, or pharmacological formulations. This overview summarizes the methods employed for the extraction of anthocyanins from both black rice and its by-products. In addition, trends in applications of these extracts are also evaluated regarding their biological potential. Commonly, the extraction methods used to recover anthocyanins are conventional (maceration) and some emerging technologies (Ultrasound-Assisted Extraction - UAE, and Microwave-Assisted Extraction - MAE). Anthocyanin-rich extracts from black rice have presented a biological potential for human health. In vitro and in vivo assays (in mice) showed these compounds mainly with anti-cancer properties. However, more clinical trials are still needed to prove these potential biological effects. Extracts from black rice and its by-products have great potential in applying functional products with beneficial characteristics to humans and reducing agro-industrial residues.

Effect of gelatin and acacia gum on anthocyanin coacervated microcapsules using double emulsion and its characterization

The present study was aimed to develop a stable microencapsulated anthocyanin from black rice bran using double emulsion complex coacervation technique. Nine microcapsule formulations were prepared using gelatin, acacia gum and anthocyanin at ratios of 1:1:0.5, 1:1:0.75 and 1:1:1 respectively. The concentration of gelatin and acacia gum used were 2.5, 5 and 7.5 % w/v. Subsequently, the coacervated microcapsules were obtained at different pH (3, 3.5 and 4), freeze-dried and evaluated for their physicochemical properties, morphology, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction pattern (XRD), thermal behaviour and stability of anthocyanin. The results obtained for encapsulation efficiency of anthocyanin with high values (72.70 to 83.65 %) indicated that the encapsulation process was effective. The morphology of the microcapsule powder was analysed and exhibited round, hard, agglomerated structures and relatively smooth surface. The thermal degradation behaviour of microcapsules displayed endothermic reaction confirming the thermostability of the microcapsules where the peak ranged from 83.7 to 97.6 °C. The stability studies in terms of retention of total anthocyanin content were observed at different storage conditions; both under refrigerated condition (7 °C) and at room temperature (37 °C). The results indicated that the microcapsules obtained through coacervation can be an alternative source to develop stable nutraceuticals.

Comparative RNA-Seq analysis unravels molecular mechanisms regulating therapeutic properties in the grains of traditional rice Kavuni

Developing rice varieties with enhanced levels of functional bioactives is an important intervention for achieving food and nutritional security in Asia where rice is the staple food and Type II diabetes incidences are higher. The present study was aimed at dissecting out the molecular events underlying the accumulation of bio active compounds in pigmented traditional rice Kavuni. Comparative transcriptome profiling in the developing grains of Kavuni and a white rice variety ASD 16 generated 37.7 and 29.8 million reads respectively. Statistical analysis identified a total of 9177 exhibiting significant differential expression (DEGs) between the grains of Kavuni and ASD 16. Pathway mapping of DEGs revealed the preferential up-regulation of genes involved in the biosynthesis of amylose and dietary fibres in Kavuni accounting for its low glycemic index (GI). Transcripts involved in the biosynthesis of carotenoids, flavonoids, anthocyanins, phenolic acids and phenylpropanoids were also found to be up-regulated in the grains of Kavuni. This study identified up-regulation of key transcripts involved in the accumulation of phenolic acids having potential for inhibiting major hydrolytic enzymes α-amylase and α-glucosidase and thus accounting for the slow digestibility leading to low GI. Overall, this study has identified molecular targets for the genetic manipulation of anti-diabetic and anti-oxidant traits in rice.

Influence of black rice (Oryza sativa L.) bran derived anthocyanin-extract on growth rate, immunological response, and immune-antioxidant gene expression in Nile tilapia (Oreochromis niloticus) cultivated in a biofloc system

This study investigated the effects of dietary supplementation with anthocyanin extracted from black rice bran (AR) on the growth rate, immunological response, and expression of immune and antioxidant genes in Nile tilapia raised in an indoor biofloc system. A total of 300 Nile tilapia fingerlings (15.14 ± 0.032 g) were maintained in 150 L tanks and acclimatized for two weeks. Five experimental AR diets (0, 1, 2, 4, and 8 g kg^-1) with various anthocyanin doses were used to feed the fish. We observed that the growth and feed utilization of fish fed with different dietary AR levels increased significantly after eight weeks (p < 0.05). In addition, the serum immunity of fish fed AR diets was much greater than that of those fed non-AR diets (p < 0.05). However, there were little or no difference in between fish fed AR enriched diets and the control AR-free diet (p > 0.05). After eight weeks, fish fed AR-supplemented diets had significantly higher mRNA transcript levels in immune (interleukin [IL]-1, IL-8, and liposaccharide-binding protein [LBP]) and antioxidant (glutathione transferase-alpha [GST-α] and glutathione reductase [GSR]) genes compared to control fish fed the AR-free diet, with the greatest enhancement of mRNA transcript levels (in the case of IL-8 by up to about 5.8-fold) in the 4 g kg^-1 AR diet. These findings suggest that dietary inclusion of AR extract from black rice bran at 4-8 g kg^-1 could function as a herbal immunostimulant to enhance growth performance, feed consumption, and immunity in Nile tilapia.

Enhancement of the Colorectal Chemopreventive and Immunization Potential of Northern Thai Purple Rice Anthocyanin Using the Biotransformation by β-Glucosidase-Producing Lactobacillus

This study aimed to study the biotransformation of indigenous northern Thai purple rice using β-glucosidase-producing Lactobacillus (BGPL) to increase the content of bioactive anthocyanin for colorectal chemoprevention and immunization. BGPL, namely, Lactobacillus FR 332, was first isolated from Thai fermented foods. Indigenous northern Thai purple rice, namely, Khao’ Gam Leum-Phua (KGLP), was selected to study bioactive anthocyanin using biotransformation by L. plantarum FR332 according to the highest amounts of cyanidin-3-glucoside. The determination of anthocyanin quantities revealed that the highest cyanidin was detected after 12 h of biotransformation, corresponding to the highest β-glucosidase activity of L. plantarum FR332 and a decrease in cyanidin-3-glucoside. The anthocyanin extract, after 12 h of biotransformation, exhibited the most potent in vitro antioxidative activity. Additionally, it showed potent anti-inflammatory activity by inhibiting cyclooxygenase-2 (COX-2), nitric oxide, and inducible nitric oxide synthase (iNOS) production in interferon-γ-stimulated colon adenocarcinoma (HT-29) cells without exerting cytotoxicity. Moreover, it also showed a potent inhibitory effect on proinflammatory cytokine interleukin-6 (IL-6) secretion and an induction effect on anti-inflammatory cytokine IL-10 secretion. These documents highlight the potential to be used of the anthocyanin extract after 12 h of biotransformation by L. plantarum FR332 as a natural active pharmaceutical ingredient (NAPI) for colorectal chemoprevention and immunization.

Alpha glucosidase inhibitory properties of a few bioactive compounds isolated from black rice bran: combined in vitro and in silico evidence supporting the antidiabetic effect of black rice

Alpha glucosidase inhibitors reduce post prandial hyperglycemia and are the drugs of choice for the treatment of type 2 diabetes. As synthetic α-glucosidase inhibitors often produce undesirable side effects, less toxic inhibitors from natural sources are in high demand.

A rice bran phytochemical, cyanidin 3-glucoside, inhibits the progression of PC3 prostate cancer cell

Prostate cancer is one of the high incidences and the most invasive cancer that is also highly resistant to chemotherapy. Currently, several natural products have been considering using as the supplements for anti-cancer therapy. This study aims to identify the potential active anti-cancer ingredients in the bran extracts of the native Thai rice (Luempua cultivar). Rice bran fraction enriched in anthocyanins was successively isolated and processed until the major purified compound obtained. The sub-fractions and the purified, rice bran, cyanidin 3-glucoside (RBC3G), were studied for biological effects (cell viability, migration, and invasion assays) on human prostatic cancer (PC3) cells using immunohistochemical-staining and immuno-blotting approaches. The sub-fractions and the purified RBC3G inhibited epithelial mesenchymal transition (EMT) characteristics of PC3 cells by blocking the expression of several cytoskeletal associate proteins in a concentration dependent manner, leading to decreasing of the cancer cell motility. RBC3G reduced the expression of Smad/Snail signaling molecules but enhanced the expression of cell surface protein, E-cadherin, leading to a delay tumor transformation. The RBC3G also inhibited matrix metalloproteinase-9 and nuclear factor-kappa B expression levels and the enzymes activity in PC3 cells, leading to a slow cell migration/invasion process. The results suggested that RBC3G blunt and/or delay the progressive cancer cell behaviors by inhibit EMT through Smad signaling pathway(s) mediating Snail/E-cadherin expression.

Production and development of vinegar fermentation from broken Riceberry rice using raw starch-degrading enzyme hydrolysis

Broken Riceberry rice was used as a substrate for sugar syrup production by the hydrolysis of raw starch-degrading enzyme as a low-temperature amylase (iKnowZyme^® LTAA, Thailand). Response surface methodology (RSM) with a central composite design (CCD) showed that an optimized substrate concentration of 250 g/L yielded 13°Brix of total soluble solid (TSS) content when incubated at 50 °C for 12 h. The major product from the broken Riceberry rice hydrolysis was glucose with lesser amounts of maltose and maltotriose. Maximum alcohol content (16% w/v) for broken Riceberry rice wine was obtained after fermentation with two mixed strains of Saccharomyces cerevisiae for 10 days. Scanning electron micrographs showed that yeast strains could grow on the solid residue of broken Riceberry rice that supported yeast cell survival under stress conditions. Broken Riceberry rice wine was used as the substrate for vinegar fermentation by Acetobacter aceti TISTR 354. Maximum acetic acid concentration was achieved at 5.4% when incubated at room temperature for 6 days, containing 10.92 mg/L and 965.53 ± 7.74 mL sample/g DPPH of anthocyanin content and antioxidant assay, respectively. Our finding revealed the feasibility of broken Riceberry rice substrate for sugar syrup, wine and vinegar production by raw starch-degrading enzyme hydrolysis which increased the value of low-cost agricultural crops through biotechnological processes.

Anthocyanins: A Comprehensive Review of Their Chemical Properties and Health Effects on Cardiovascular and Neurodegenerative Diseases

Anthocyanins are a class of water-soluble flavonoids widely present in fruits and vegetables. Dietary sources of anthocyanins include red and purple berries, grapes, apples, plums, cabbage, or foods containing high levels of natural colorants. Cyanidin, delphinidin, malvidin, peonidin, petunidin, and pelargonidin are the six common anthocyanidins. Following consumption, anthocyanin, absorption occurs along the gastrointestinal tract, the distal lower bowel being the place where most of the absorption and metabolism occurs. In the intestine, anthocyanins first undergo extensive microbial catabolism followed by absorption and human phase II metabolism. This produces hybrid microbial-human metabolites which are absorbed and subsequently increase the bioavailability of anthocyanins. Health benefits of anthocyanins have been widely described, especially in the prevention of diseases associated with oxidative stress, such as cardiovascular and neurodegenerative diseases. Furthermore, recent evidence suggests that health-promoting effects attributed to anthocyanins may also be related to modulation of gut microbiota. In this paper we attempt to provide a comprehensive view of the state-of-the-art literature on anthocyanins, summarizing recent findings on their chemistry, biosynthesis, nutritional value and on their effects on human health.

In Vitro and in Vivo Anti-Hyperglycemic Activities of Taxifolin and Its Derivatives Isolated from Pigmented Rice (Oryzae sativa L. cv. Superhongmi)

Superhongmi is a new rice variety, which was developed for the enrichment of bioactive compounds through cross-breeding three varieties of rice breeds in Korea. The high-performance liquid chromatography coupled with a photodiode array detector quadrupole and tandem time-of-flight mass spectrometry (HPLC/PDA/QTOF-MS) analysis has revealed that superhongmi bran extract contained four taxifolin derivatives as well as cyanidin 3-glucoside. The high-performance countercurrent chromatography (CCC) and reversed-phase HPLC led to the isolation of aforementioned five compounds, and spectroscopic analysis identified cyanidin 3-glucoside (1), along with (2R,3R)-taxifolin 3-O-β-d-glucopyranoside (2), (2R,3R)-4'-O-methyltaxifolin 3-O-β-d-glucopyranoside (a novel compound) (3), (2R,3R)-taxifolin (4), and (2R,3R)-4'-O-methyltaxifolin (5). Compound 2 had the highest rat small intestinal sucrase inhibitory activity (0.54 mM) relevant for potentially managing postprandial hyperglycemia, followed by compound 1 (0.97 mM) and compound 4 (1.74 mM, IC₅₀). The anti-hyperglycemic effect of compound 4 (taxifolin), a main peak in HPLC analysis was investigated using a Sprague-Dawley (SD) rat model. Compared to a control, taxifolin treatment (p < 0.001) reduced significantly after sucrose loading the observed postprandial blood glucose and the maximum blood glucose (C_max) by 15% (203.60 ± 15.86 to 172.30 ± 12.74). These results indicate that taxifolin derivatives that inhibit the activity of carbohydrate-hydrolyzing enzymes resulting in reduced dietary carbohydrate absorption can potentially be used as a strategy to manage diabetes.

Promoting water deficit tolerance and anthocyanin fortification in pigmented rice cultivar (Oryza sativa L. subsp. indica) using arbuscular mycorrhizal fungi inoculation

Drought or water deficit is a major abiotic stress that can reduce growth and productivity in the rice crop especially in the rain-fed areas, which face long-term water shortage. The objective of this investigation was to promote the drought tolerant abilities in pigmented rice cv. 'Hom Nil' at booting stage using arbuscular mycorrhizal fungi (AMF)-inoculation, mixed spores of Glomus geosporum, G. etunicatum and G. mosseae in the soil before rice seedling transplantation. At booting stage, the AMF-inoculated (+AMF) and AMF-uninoculated plants (-AMF) were subjected to control (well-watering; 46.6% SWC) and water deficit condition (14 days water withholding; 13.8% SWC). Colonization percentage in the AMF-inoculated root tissues were evidently proved in both with and without water deficit conditions, leading to elevate total phosphorus in root and leaf tissues. Interestingly, sucrose and total soluble sugar concentration in the flag leaf were increased by 5.0 folds and 1.5 folds, respectively in the plants under water deficit (WD). Free proline was accumulated in flag leaf when exposure to water deficit, subsequently regulated by AMF-inoculation. Total soluble sugar and free proline enrichment in 'Hom Nil' was a major mode of osmotic adjustment to control osmotic potential in the cellular level when exposed to water deficit, leading to maintained photosynthetic abilities and growth performances. Concentration of chlorophyll b in AMF-inoculated plants under water deficit stress was retained, causing to improve chlorophyll fluorescence and net photosynthetic rate. Shoot height and number of tillers were significantly declined by 12.5% and 11.6%, respectively, when subjected to WD. At the harvest, grain yield, panicle dry weight and fertility percentage of AMF-inoculated rice from WD were greater than those without AMF by 1.5, 3.9 and 2.4 folds, respectively. Cyanidin-3-glucoside and peonidin-3-glucoside concentrations in pericarp were enriched in the grain derived from AMF-inoculation with water deficit stress. Overall growth characters and physiological adaptations in 'Hom Nil' grown under water deficit condition were retained by AMF inoculation, resulting in enhanced yield attributes and anthocyanin fortification in rice grain.

Cold plasma treatment to improve germination and enhance the bioactive phytochemical content of germinated brown rice

The changes in the bioactive phytochemicals of six cultivars of Thai germinated brown rice (GBR) were monitored in parallel to those of cold plasma-treated GBR (PGBR). After treatment with the optimal plasma conditions, the germination percentage, root length, and seedling height measurements of the most sensitive rice cultivar increased by 84%, 57%, and 69%, respectively. For all of the rice cultivars, there were no significant differences in the antioxidant activities of the GBRs and PGBRs. Conversely, higher contents of γ-oryzanols were observed in the PGBR group than in the GBR group during the 2-day germination period. Certain cultivars in the PGBR group reached their maximum values for total phenolic compounds, total vitamin E, certain simple phenolics, phytosterols, triterpenoids, and anthocyanins one day earlier than the same values for GBR. In contrast, the concentrations of 2-acetyl-1-pyrroline in both the GBR and PGBR samples were reduced significantly with increased germination time.

Extraction and Analysis of Phenolic Compounds in Rice: A Review

Rice represents the main source of calorie intake in many world countries and about 60% of the world population include rice in their staple diet. Whole grain rice, also called brown rice, represent the unpolished version of the more common white rice including bran, germ, and endosperm. Many health-promoting properties have been associated to the consumption of whole grain rice and, for this reason, great attention has been paid by the scientific community towards the identification and the quantification of bioactive compounds in this food item. In this contribution, the last five years progresses in the quali-quantitative determination of phenolic compounds in rice have been highlighted. Special attention has been devoted to the most recent strategies for the extraction of the target compounds from rice along with the analytical approaches adopted for the separation, identification and quantification of phenolic acids, flavonoids, anthocyanins, and proanthocyanidins. More specifically, the main features of the “traditional” extraction methods (i.e., maceration, ultrasound-assisted extraction) have been described, as well as the more innovative protocols involving advanced extraction techniques, such as MAE (microwave-assisted extraction). The predominant role of HPLC in the definition of the phenolic profile has been examined also presenting the most recent results obtained by using mass spectrometry-based detection systems. In addition, the most common procedures aimed to the quantification of the total amount of the cited classes of phenolic compounds have been described together with the spectrophotometric protocols aimed to the evaluation of the antioxidant properties of rice phenolic extracts (i.e., FRAP, DPPH, ABTS and ORAC).

The evaluation of Oryza sativa L (Black rice) extracts for detection of spermatozoa on the clothing and vaginal swab samples

Investigation of sexual assault cases from the evidence involving vaginal swab, clothing and others is examined by a forensic scientist. The explanation of trace findings on spermatozoa on clothing is often problematic due to the use of different staining methods. Conventional staining method used either Papanicolaou (PAP) or Dip quick® stain as synthetic dyes which are expensive imported material and harmful to human health. Therefore, the present study aims to determine the ability of Oryza sativa L (black rice) extract as a natural dye to detect spermatozoa on the clothing and vaginal swab casework samples for routine forensic examination. Results revealed that black rice extract has a highly effective for detecting spermatozoa on cloth and vaginal swab casework samples. There was no significantly different in the detection of spermatozoa compared with rapid PAP stain and Dip quick® stain. Results also showed that the staining of vaginal swab casework with black rice extracted can be used for PCR amplification of centromeric alphoid repeat gene on chromosome Y for 60 days. Moreover, the DNA extracted from stained semen slide generates a full profile of 16 alleles of STR typing. The results indicate that a new natural staining dye which extracted from black rice can be used to detect spermatozoa and identify a person from the trace evidence. The application of natural dyes for routine staining of spermatozoa from forensic specimens will decrease the expense to be spent in purchasing the synthetic dye and reduce their side effects on human and environment.

Some Strategies for Utilization of Rice Bran Functional Lipids and Phytochemicals

Rice bran contains a great amount of functional lipids and phytochemicals including γ-oryzanols, tocotrienols, and tocopherols. However, utilization of those compounds is limited and needs some proven guidelines for better implementation. We introduce some effective strategies for the utilization of rice functional lipids, including an introduction of pigmented rice varieties for better bioactive compounds, biofortification of rice tocotrienols, plasma technology for improving rice phytochemicals, supercritical CO₂ extraction of high quality rice bran oil, and an example on the development of tocotrienol-fortified foods.

Dietary supplementation of Thai black rice bran extract and yeast beta-glucan protects the dextran sodium sulphate mediated colitis induced rat

The present study was employed to evaluate the impact of black rice bran (RB) extract, and yeast β-glucan (YBG) supplementation on a dextran sodium sulfate (DSS)-induced colitis rat model.

Simultaneous quantification of vitamin E, γ-oryzanols and xanthophylls from rice bran essences extracted by supercritical CO2

Since the nutrition value of rice is diminished during rice processing, technology that can preserve and sustain functional compounds is necessary. In this study, supercritical carbon dioxide (SC-CO2) extraction was optimized for operational conditions (time, temperature, pressure and modifier) to extract vitamin E, γ-oryzanols and xanthophylls from rice bran. The simultaneous quantification of the compounds was developed using high-performance liquid chromatography with diode array and fluorescence detectors. Central composite design and respond surface methodology were applied to achieve optimum extraction conditions. The optimized conditions were 60min, 43°C, 5420psi with 10% ethanol as a modifier. Pigmented rice bran extracts contained greater amounts of functional phytochemicals than non-pigmented rice bran extracts (0.68, 1410, and non-detectable μg/g compared with 16.65, 2480, and 0.10μg/g of vitamin E, γ-oryzanols and xanthophylls in pigmented and non-pigmented ones, respectively). SC-CO2 extraction with modifier would be promising for preparation of phytochemical essences for therapeutic purpose.

Structures of phytosterols and triterpenoids with potential anti-cancer activity in bran of black non-glutinous rice

Structures of some bioactive phytochemicals in bran extract of the black rice cv. Riceberry that had demonstrated anti-cancer activity in leukemic cell line were investigated. After saponification with potassium hydroxide, separation of the unsaponified fraction by reversed-phase high performance liquid chromatography (HPLC) resulted in four sub-fractions that had a certain degree of anti-proliferation against a mouse leukemic cell line (WEHI-3 cell), this being IC50 at 24 h ranging between 2.80-467.11 μg/mL. Further purification of the bioactive substances contained in these four sub-fractions was performed by normal-phase HPLC. Structural characterization by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR) resulted in, overall, the structures of seven phytosterols and four triterpenoids. Four phytosterols, 24-methylene-ergosta-5-en-3β-ol, 24-methylene-ergosta-7-en-3β-ol, fucosterol, and gramisterol, along with three triterpenoids, cycloeucalenol, lupenone, and lupeol, were found in the two sub-fractions that showed strong anti-leukemic cell proliferation (IC50 = 2.80 and 32.89 μg/mL). The other sterols and triterpenoids were campesterol, stigmasterol, β-sitosterol and 24-methylenecycloartanol. Together with the data from in vitro biological analysis, we suggest that gramisterol is a significant anti-cancer lead compound in Riceberry bran extract.

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.