Optimizing green approach to enhanced antioxidants from Thai pigmented rice bran using deep eutectic solvent-based ultrasonic-assisted extraction

Deep eutectic solvents (DES) have garnered significant attention as extraction media owing to their commendable attributes of being environmentally sustainable and the inherent adaptability of DES's versatile physical and chemical characteristics. The present study investigated the effects of deep eutectic solvents on the total contents of anthocyanin, phenolic, and flavonoids, as well as the antioxidant activity of Thai pigmented rice bran extract. The optimal extraction parameters for deep eutectic solvent-based ultrasonic-assisted extraction (DES-UAE) were also determined using the response surface methodology (RSM). The optimal conditions for the extraction of anthocyanins and other antioxidants from pigmented rice bran using a deep eutectic solvent were choline chloride: ethylene glycol (Ch:Eg) at a 1:2 ratio, mixed with 20 % water as a solvent. The ultrasonic-assisted extraction (UAE) at 37 kHz of frequency, 50 °C of temperature, 40 min of extraction time, and a 1:6 g/mL of solid-to-solvent ratio yielded a total anthocyanin content of 4.55 ± 0.09 mg C3G/g DW, a total phenolic content of 26.49 ± 0.62 mg GAE/g DW, a total flavonoid content of 6.57 ± 0.55 mg QE/g DW, and a percent inhibition of DPPH radical of 77.83 ± 1.51. By comparing the antioxidant content that was extracted from three cultivars of pigmented rice, it was found that Leum Pua black rice bran provided significantly higher antioxidant content compared to Hom Nin purple rice bran and Mali Dang red rice bran. This research suggests an achievable, eco-friendly, and effective method for preparing high-quality, consumer-safe Thai rice bran as a raw material for nutraceuticals.

Purification and characterization of crude fructooligosaccharides extracted from red onion (Allium cepa var. viviparum) by yeast treatment

BACKGROUND

Yeast treatment has been used for purification of fructooligosaccharides (FOSs). However, the main drawback of this approach is that yeast can only partially remove sucrose from crude FOSs. The main objective of this research was to screen yeast strains for the capability of selectively consuming unwanted sugars, namely fructose, glucose, and sucrose, in crude FOSs extracted from red onion (Allium cepa var. viviparum) with minimal effect on FOS content.

RESULTS

Among 43 yeast species isolated from Miang, ethnic fermented tea leaves, and Assam tea flowers, Candida orthopsilosis FLA44.2 and Priceomyces melissophilus FLA44.8 exhibited the greatest potential to specifically consume these unwanted sugars. In a shake flask, direct cultivation of C. orthopsilosis FLA44.2 was achieved in the original crude FOSs containing an initial FOSs concentration of 88.3 ± 1.2 g/L and 52.9 ± 1.2 g/L of the total contents of fructose, glucose, and sucrose. This was successful with 93.7% purity and 97.8% recovery after 24 h of cultivation. On the other hand, P. melissophilus FLA48 was limited by initial carbohydrate concentration of crude FOSs in terms of growth and sugar utilization. However, it could directly purify two-fold diluted crude FOSs to 95.2% purity with 92.2% recovery after 72 h of cultivation. Purification of crude FOSs in 1-L fermenter gave similar results to the samples purified in a shake flask. Extracellular β-fructosidase was assumed to play a key role in the effective removal of sucrose. Both Candida orthopsilosis FLA44.2 and P. melissophilus FLA44.8 showed γ-hemolytic activity, while their culture broth had no cytotoxic effect on viability of small intestinal epithelial cells, preliminarily indicating their safety for food processing. The culture broth obtained from yeast treatment was passed through an activated charcoal column for decolorization and deodorization. After being freeze dried, the final purified FOSs appeared as a white granular powder similar to refined sugar and was odorless since the main sulfur-containing volatile compounds, including dimethyl disulfide and dipropyl trisulfide, were almost completely removed.

CONCLUSION

The present purification process is considered simple and straight forward, and provides new and beneficial insight into utilization of alternative yeast species for purification of FOSs.

Mineral elements and their relation to anthocyanin content in pigmented rice plants using definitive screening design and self-organizing maps

BACKGROUND

Mineral elements are nutrients required by an organism to perform functions necessary for survival. Stress-induced metabolism following nutritional stress has been reported to increase levels of anthocyanin. However, the role of mineral elements commonly found in soil and their contribution to the accumulation of anthocyanin content in rice plants is uncertain.

RESULT

Amongst the ten mineral elements investigated, the cultivation of rice plants in clean sand showed that the Mg-, Se-, and Cu-treated plants had the highest accumulated anthocyanin content in the leaves, whereas B, Cr, and Se had the greatest effect on grains. Yield component data showed major positive effects from Mg, Cr, and B. The interaction of Zn*Se and Mg*Cu positively affected the anthocyanin content in grains. The self-organizing map indicated that the total anthocyanin content was relatively proportional to the concentration of Mn, B, and Cr, but disproportional to that of Se. However, rice plants with added Fe produced the smallest amount of total anthocyanin content, less than the control, in the four stages of rice growth.

CONCLUSION

The appropriate concentrations of mineral elements in soil could promote the proliferation of anthocyanin content in rice plants and grains. © 2023 Society of Chemical Industry.

Comparison of plasma technology for the study of herbicide degradation

The study aimed to investigate the effects of two different plasma systems, including pinhole plasma jet and gliding arc (GA) plasma, for the degradation of herbicide, diuron, in plasma activated solutions (PAS). In the GA plasma system, air was used to generate plasma, however, Ar, oxygen and nitrogen at different gas compositions were compared in the pinhole plasma jet system. The Taguchi design model was used to study the effects of gas compositions. Results revealed that the pinhole plasma jet system was able to degrade over 50% of the diuron in 60 minutes. The optimal plasma generation condition for the highest degradation of diuron used pure Ar gas. The highest degradation percentage of herbicide in PAS corresponded to the lowest hydrogen peroxide (H₂O₂) content, nitrite concentration and electrical conductivity (EC) of the PAS. The diuron degradation products were identified as 3,4-dichloro-benzenamine, 1-chloro-3-isocyanato-benzene and 1-chloro-4-isocyanato-benzene via gas chromatography-mass spectrometry (GC-MS). The GA plasma system was not adequate for the degradation of herbicide in PAS.

Resistant starch from black rice, Oryza sativa L. var. ameliorates renal inflammation, fibrosis and injury in insulin resistant rats

It has recently been reported that black rice (BR) extract has anti-obesity, anti-diabetic, and anti-osteoporosis effects. It has been shown to reduce obese-related kidney dysfunction in animal models. This study aimed to investigate the effect of resistant starch from BR (RS) on renal inflammation, oxidative stress, and apoptosis in obese insulin resistant rats. Male Wistar rats were divided into six groups: normal diet (ND), ND treated with 150 mg of RS (NDRS150), high-fat (HF) diet, HF treated with 100 and 150 mg of RS (HFRS100), (HFRS150), and HF treated with metformin as a positive control. Insulin resistance was shown in the HF rats by glucose intolerance, increased insulin, total area under the curve of glucose and homeostasis model assessment of insulin resistance and dyslipidemia. The resulting metabolic disturbance in the HF rats caused renal inflammation, fibrosis and apoptosis progressing to kidney injury and dysfunction. Prebiotic RS including anthocyanin from BR at doses of 100 and 150 mg ameliorated insulin resistance, dyslipidemia and liver injury. Treatment with RS reduced TGF-β fibrotic and apoptotic pathways by inhibition of NF-κB and inflammatory cytokines which potentially restore kidney damage and dysfunction. In conclusion, prebiotic RS from BR ameliorated obesity induced renal injury and dysfunction by attenuating inflammatory, fibrotic, and apoptotic pathways in insulin resistant rats induced by HF.

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.

Analysis of low-volatility pesticides in cabbage by high temperature comprehensive two-dimensional gas chromatography

High-temperature comprehensive two-dimensional gas chromatography (HTGC × GC) using a longitudinally modulated cryogenic system (LMCS) was developed for the analysis of low-volatility pesticides in cabbage. The method applied DB-17HT and DB-5HT as the first and second dimensional (¹D and ²D) columns, respectively. Twelve pesticides, namely 6 organochlorines (4,4'-DDT, β-endosulfan, endosulfan sulfate, endrin, heptachlor, and dicofol), 4 carbamates (metolcarb, isoprocarb, methiocarb, and carbofuran), 1 organophosphate (chlorpyrifos), and 1 pyrethroid (permethrin), were spiked into cabbage samples and prepared using QuEChERS. The applied oven temperature was up to 340 °C, enabling the elution of all the target pesticides and the matrix. The effects of initial oven temperature program, temperature ramp rate, LMCS trap temperature, and modulation period (P_M) on the separation results were investigated, leading to the suitable conditions of 80 °C, 15 °C min^-1, 10 °C, and 12 s, respectively. The method detection limits, signal-to-noise ratio, and recoveries of the compounds were within the ranges of 0.01-0.09 mg kg^-1, 4.26-32.7, and 78-104%, respectively. Good linearity ranges within the concentration range of 0.1-1 ppm with R² > 0.9134 were also obtained with the intra and interday precisions of the peak areas of 0.4-9.8% and 1.0-10.2%, respectively.

Phytochemical Profile and Chemopreventive Properties of Cooked Glutinous Purple Rice Extracts Using Cell-Based Assays and Rat Model

Purple rice has gained attention for its health promoting potential due to a high content of bioactive phytochemicals. The heat generated during cooking alters the quality and quantity of nutrients and phytochemicals in food. This study aimed to investigate the phytochemical profile and chemopreventive properties of cooked glutinous purple rice using cell-based assays and a rat model. Purple rice was cooked in a rice cooker and was then further extracted with solvents to obtain dichloromethane and methanol extracts. The methanol extracts of glutinous purple rice contained great amounts of phenolics, flavonoids, and anthocyanins. Protocatechuic acid (2.26–5.40 mg/g extract) and cyanidin 3-glucoside (34.3–65.7 mg/g extract) were the major phenolic acid and anthocyanin contents, respectively. After cooking, the content of anthocyanins, γ-oryzanols, and phytosterols decreased, while the amount of some phenolic acid and tocol contents increased. Methanol extracts of glutinous purple rice inhibited reactive oxygen species production about 60% in PMA-treated peripheral blood mononuclear cells, reduced nitric oxide formation in LPS-induced RAW 264.7 cells (26–39% inhibition), and exhibited antimutagenicity against several mutagens using the Ames test, but dichloromethane extracts presented only mild anti-inflammatory activities. Although methanol extracts induced mild mutagenicity (mutagenic index 2.0–2.5), they did not induce micronucleated hepatocyte formation and certain hepatic CYP450 isozyme activities in rats. However, the mutagenicity of the methanol extract significantly declined after cooking. In summary, the methanol extract of the cooked glutinous purple rice might be a promising cancer chemopreventive fraction, which was neither genotoxic nor posing adverse effects on phytochemical–drug interaction in rats.

Determination of 2-Acetyl-1-pyrroline via a Color-Change Reaction Using Chromium Hexacarbonyl

At present, there is no colorimetric method for the quantitation of the aroma compound 2-acetyl-1-pyrroline (2AP). A novel colorimetric method was developed for the determination of 2AP content using chromium hexacarbonyl (Cr(CO)₆) as a reagent. The reaction of synthetic 2AP with chromium hexacarbonyl reagent solution in the presence of light produced a green product with an absorption maximum (λ_max) at 623 nm. GC–MS was used to confirm the color-change reaction, which showed the loss of 2AP after the addition of Cr(CO)₆. This novel method enables facile and cost-effective determination of 2AP in fragrant rice. A comparative analysis of fragrant and nonfragrant rice grain extracts showed that no color-change reaction occurred with the nonfragrant rice sample. A limit of detection (LOD) of 2.00 mg L⁻¹ was determined by method validation with an effective linear concentration ranging from 5.00 to 60.00 mg L⁻¹ of 2AP. The results obtained using the developed colorimetric method were consistent with those obtained by automated static headspace gas chromatography with nitrogen-phosphorus detection (SHS-GC–NPD).

Microwave treatment of rice bran and its effect on phytochemical content and antioxidant activity

An alternative approach for rice bran stabilization is microwave treatment. However, the effects of the microwave treatment on the contents of bioactive compounds and antioxidant activities of the rice bran have rarely been reported in detail. In this study, microwave pretreatment (130-880 W for 0.5-5.0 min) of rice bran was proposed where the antioxidant activity, total flavonoids, and total phenolic contents were determined using UV-Vis spectrometry. Tocols, γ-oryzanols, squalene, phytosterols and phenolic compounds were quantified using high-performance liquid chromatography. The results showed an increase in the antioxidant activity (0.5 folds), total phenolic contents (1.3 folds), total flavonoid contents (0.9 folds), total tocols (2.6 folds), total γ-oryzanols (1.6 folds), and total phytosterols (1.4 folds). Phytochemicals were enhanced, especially trans-p-coumaric acid (10.3 folds) and kaempferol (8.6 folds). The microwave treatment at 440 W for 2.5 min provided the best contents of the bioactive compounds and antioxidant activity. This work revealed the microwave treatment as a potential tool for stabilizing rice bran and increasing the usability of its phytochemicals, which applies to several industries concerning the use of rice bran as an ingredient.

Smartphone digital image colorimetric determination of the total monomeric anthocyanin content in black rice via the pH differential method

In this research, the pH differential method was explored for the first time using a mobile phone as a detector, replacing UV-Vis spectrophotometry. A smartphone digital image colorimetric (SDIC) system was developed for the determination of the total monomeric anthocyanin content in black rice grains using colour values. The change in colour of anthocyanin cyanidin-3-glucoside (C3G) at pH 1.0 and pH 4.5 was investigated and described through colour model systems (RGB and CIELAB). Under optimum conditions, the quantitative method based on the chroma difference, was able to quantify the total amount of monomeric anthocyanins with a linear correlation (R² = 0.989) to that of UV-Vis spectrophotometry and high performance liquid chromatography (HPLC) (reference method). The SDIC system displayed good precision (≤1.88% RSD) and a low detection limit (2.2 ± 0.1 μg g^-1). The validated results demonstrated that the developed method was a cost-effective alternative for the quantitation of anthocyanins. In addition, the effect of six mineral elements on black rice cultivation was investigated. The results showed that the addition of the Ca fertiliser resulted in black rice grains with an anthocyanin content 2-fold higher than that of the control with a significant difference (p < 0.05).

Anthocyanin-rich fraction from black rice, Oryza sativa L. var. indica "Luem Pua," bran extract attenuates kidney injury induced by high-fat diet involving oxidative stress and apoptosis in obese rats

Obesity is acknowledged as being a world health problem and increases the risk of several chronic diseases including chronic kidney disease. High-fat diet consumption and obesity-related renal disease show a close correlation with increased oxidative stress. Black rice bran extract, (BRE) Oryza sativa L. variety "Luem Pua" contains a high anthocyanin content. This study evaluated the effects of an anthocyanin-rich fraction from BRE on renal function and oxidative stress in obese rats. Male Wistar rats were fed a normal diet (ND) or high-fat diet (HF) for 16 weeks. After this, the rats were given either vehicle (HF), BRE 100 (HF100) or BRE 200 mg/kg/day (HF200) orally for 8 weeks. The HF rats had increased body weight, visceral fat weight, plasma glucose, cholesterol and triglycerides. These parameters were normalized following HF100 administration and showed a decreasing trend with HF200. Serum creatinine and renal cortical MDA were increased in the HF group but these effects were attenuated by BRE. Negative kidney injury and histopathology changes were observed following a HF, but treatment with BRE reversed these deleterious effects. These results suggest that BRE could be used as a food supplement to improve metabolic disturbance and prevent kidney dysfunction in cases of obesity.

GC-MS and HPLC-DAD analysis of fatty acid profile and functional phytochemicals in fifty cold-pressed plant oils in Thailand

Cold-pressed oil is one of the healthiest plant extracts, but its use is limited only in some kinds of plants. Therefore, we aimed to investigate some potential cold-pressed oils with attractive fatty acid profiles and high amounts of functional phytochemicals. Fifty cold-pressed plant oils were prepared from various plant materials in Thailand, in which some of them were from uncommon or unattended plant materials. The oils included were nut oils (n = 9), pseudo-cereal oils (n = 9), legume oils (n = 3), amaranth oils (n = 3), marrow seed oils (n = 8), cruciferous seed oils (n = 7), and leafy green seed oils (n = 11). Gas-chromatography mass-spectrometry (GC-MS) and high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) were employed to analyze fatty acid profile and five functional phytochemicals (e.g., phytosterols, cholecalciferol, and squalene). Saturated fatty acids were detected around 7.87-36.04%, monounsaturated fatty acids 10.17-80.25%, and polyunsaturated fatty acids nondetectable (ND)-78.25%, phytosterols 663-15123 μg g-1, squalene 265-5979 μg g-1, and cholecalciferol ND-1287.75 μg g-1. The study showed chemical characteristic of the analyzed oils: some contained good fatty acid composition and some were rich in functional phytochemical content. Among the obtained oils, marrow seed oils are a good source of phytosterol, cholecalciferol, and linoleic acid. Pseudo-cereal oils are rich in squalene and linolenic acid. Legume oils are rich in phytosterols and oleic acid. Besides, principal component analysis (PCA) was applied to identify the significance of oils that share compositional similarity (e.g., the samples from pseudo-cereal oil were found on the lower side of the PCA space, which separated them from marrow and leafy green seed oils distributed on the upper part of the plot). In summary, the qualitative and quantitative data would provide a good foundation for further application or selection of those plant oils for health purposes.

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.

Antioxidant activities and volatile compounds in longan (Dimocarpus longan Lour.) wine produced by incorporating longan seeds

The seeds of dried longan, one of the major processed fruits in Thailand, contain several bioactive compounds. In this study, we developed longan wine by incorporating its seeds during juice preparation and evaluated the antioxidant activities and volatile compounds in different conditions. The results suggested that Saccharomyces cerevisiae EC-1118 was suitable for fermentation of longan juice supplemented with 50% seed and 20% initial soluble solids at an optimal temperature of 30 °C. Different yeast strains showed various extents of antioxidant activities; however, the fermentation temperature and initial soluble solids of longan juice had little effect on the inhibition of reactive species. Antioxidant activities were significantly increased with increasing seed content. Dominant volatile compounds, which were independent of the winemaking conditions, were found to be phenethyl alcohol, 2,3-butylene glycol, 5-hydroxymethyl-2-furaldehyde, ethyl hydrogen succinate, and 4-hydroxyphenethyl alcohol. These compounds highly influenced the antioxidant activities of longan wine produced by incorporating the seeds.

Estimation of Retention Time in GC/MS of Volatile Metabolites in Fragrant Rice Using Principle Components of Molecular Descriptors

A quantitative structure-retention relationship (QSRR) study was applied for an estimation of retention times of secondary volatile metabolites in Thai jasmine rice. In this study, chemical components in rice seed were extracted using solvent extraction, then separated and identified by gas chromatography-mass spectrometry (GC-MS). A set of molecular descriptors was generated for these substances obtained from GC-MS analysis to numerically represent the molecular structure of such compounds. Principal component analysis (PCA) and principal component regression analysis (PCR) were used to model the retention times of these compounds as a function of the theoretically derived descriptors. The best fitted regression model was obtained with R-squared of 0.900. The informative chemical properties related to retention time were elucidated. The results of this study demonstrate clearly that the combination of molecular weight and autocorrelation functions of two dimensional interatomic distance, which are molecular polarizability, atom identity, sigma charge, sigma electronegativity and polarizability, can be considered as comprehensive factors for predicting the retention times of volatile compounds in rice.

Simultaneous determination of tocols, γ-oryzanols, phytosterols, squalene, cholecalciferol and phylloquinone in rice bran and vegetable oil samples

In this study, a simultaneous analytical method of tocols, γ-oryzanols, phytosterols, squalene, cholecalciferol and phylloquinone were developed using HPLC-DAD-FLD. The developed method allowed the quantification of 18 compounds in 30 min. Method validation showed linearity of calibration curves (α = 0.05). RSD of intra-day, inter-day and inter-laboratory precision were less than 4.88%. The limit of detections (LODs) and limit of quantifications (LOQs) were low (0.009-2.166 μg g^-1) with recoveries around 96.0-102.9%. Results derived from the established method demonstrated a wide variation of detected compounds in rice bran and vegetable oil samples (22.4-1774.6 μg g^-1 tocols, ND-26484 μg g^-1 γ-oryzanols, ND-12655 μg g^-1 phytosterols, ND-3189 μg g^-1 squalene, ND-105.3 μg g^-1 cholecalciferol, and ND-54.4 μg g^-1 phylloquinone). Thus, the developed HPLC-DAD-FLD method is a powerful analytical tool for the above mentioned compounds useful in food and pharmaceutical application.

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.

A deletion of the gene encoding amino aldehyde dehydrogenase enhances the "pandan-like" aroma of winter melon (Benincasa hispida) and is a functional marker for the development of the aroma

The gene conferring a "pandan-like" aroma of winter melon was identified. The sequence variation (804-bp deletion) found in the gene was used as the target for functional marker development. Winter melon (Benincasa hispida), a member of the Cucurbitaceae family, is a commonly consumed vegetable in Asian countries that is popular for its nutritional and medicinal value. A "pandan-like" aroma, which is economically important in crops including rice and soybean, is rarely found in most commercial varieties of winter melon, but is present in some landraces. This aroma is a value-added potential trait in breeding winter melon with a higher economic value. In this study, we confirmed that the aroma of winter melon is due to the potent volatile compound 2-acetyl-1-pyrroline (2AP) as previously identified in other plants. Based on an analysis of public transcriptome data, BhAMADH encoding an aminoaldehyde dehydrogenase (AMADH) was identified as a candidate gene conferring aroma of winter melon. A sequence comparison of BhAMADH between the aromatic and non-aromatic accessions revealed an 804-bp deletion encompassing exons 11-13 in the aromatic accession. The deletion caused several premature stop codons and could result in a truncated protein with a length of only 208 amino acids compared with 503 amino acids in the normal protein. A functional marker was successfully developed based on the 804-bp deletion and validated in 237 F₂ progenies. A perfect association of the marker genotypes and aroma phenotypes indicates that BhAMADH is the major gene conferring the aroma. The recently developed functional marker could be efficiently used in breeding programs for the aroma trait in winter melon.

Anthocyanin-rich Riceberry bran extract attenuates gentamicin-induced hepatotoxicity by reducing oxidative stress, inflammation and apoptosis in rats

Liver plays an important role in the detoxification and metabolic elimination of various drugs and harmful substances. The damaging effects on the liver tissue treated with gentamicin are multi-factorial and their mechanisms remain unclear. This study aimed to investigate the possible protective effects of anthocyanin-rich Riceberry bran extract on gentamicin-induced hepatotoxicity in rats. Riceberry bran extract was given by oral administration 30min before gentamicin injection for 15 consecutive days. Serum levels of liver marker enzymes, AST and ALT, were significantly elevated and the total serum protein level was markedly reduced in gentamicin-treated rats. Gentamicin injection led to the significant increase in hepatic MDA level and decrease SOD expression. Liver inflammation and apoptosis were observed in gentamicin-treated rats as indicated by the increases in NF-κB, TNF-αR1, COX2, and iNOS, caspase-3, Bax, and decrease in Bcl-XL expressions. Riceberry bran extract significantly prevented gentamicin-induced the elevations of serum AST, ALT and the reduction of serum total protein. These were related to the inhibition of oxidative stress, inflammation and apoptosis in Riceberry bran extract treatment. These findings suggest that anthocyanin-rich Riceberry bran extract can prevent liver dysfunction and damage induced by gentamicin, possibly through its antioxidant, anti-inflammatory and anti-apoptotic effects.

Supercritical CO2 Extraction of Rice Bran Oil -the Technology, Manufacture, and Applications

Rice bran is a good source of nutrients that have large amounts of phytochemicals and antioxidants. Conventional rice bran oil production requires many processes that may deteriorate and degrade these valuable substances. Supercritical CO₂ extraction is a green alternative method for producing rice bran oil. This work reviews production of rice bran oil by supercritical carbon dioxide (SC-CO₂) extraction. In addition, the usefulness and advantages of SC-CO₂ extracted rice bran oil for edible oil and health purpose is also described.

Riceberry bran extract prevents renal dysfunction and impaired renal organic anion transporter 3 (Oat3) function by modulating the PKC/Nrf2 pathway in gentamicin-induced nephrotoxicity in rats

PURPOSE

This study investigated the protective effects of Riceberry bran extract (RBBE) on renal function, and the function and expression of renal organic anion transporter 3 (Oat3) in gentamicin-induced nephrotoxicity in rats and explored the mechanisms for its protective effects.

MATERIAL AND METHODS

Male Sprague Dawley rats (n= 42) were divided into six groups to receive normal saline, gentamicin (100mg/kg), co-treatment of gentamicin and RBBE (at dose of 250, 500 and 1000mg/kg), and RBBE (at dose of 1000mg/kg) only, for consecutive fifteen days. Renal function, oxidative and antioxidative markers, the function and expression of Oat3 and histological changes in the kidney were evaluated.

RESULTS

Elevation of BUN, serum creatinine levels and reduction in urine creatinine and creatinine clearance indicated decreased renal function in the gentamicin-treated rats. The decrease of [³H]ES uptake in the renal cortical slices of these rats, reflecting the attenuation of Oat3 transport function that was accompanied by decreased expression of Oat3. Moreover, increased MDA level and reduced superoxide dismutase (SOD) and glutathione (GSH) activities were found in gentamicin-treated rats compared to the control group. These changes were associated with the upregulated PKCα, Nrf-2, Keap 1, NQO-1 and HO-1 expressions in kidneys. RBBE treatment improved the renal function and Oat3 transport function and expression in gentamicin-treated rats. The oxidative status was also restored by RBBE treatment.

CONCLUSION

RBBE protects kidney injury by its antioxidant effect, subsequently leading to modulation of the PKC/Nrf2 antioxidant defense pathway.

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.

Anti-Tumor and Immune Enhancing Activities of Rice Bran Gramisterol on Acute Myelogenous Leukemia

Background

Acute myelogenous leukemia (AML) is a cancer of the blood that most commonly affects human adults. The specific cause of AML is unclear, but it induces abnormality of white blood cells that grow rapidly and accumulate in bone marrow interfering with the production and functions of the normal blood cells. AML patients face poor prognosis and low quality of life during chemotherapy or transplantation of hematopoietic stem cells due to the progressive impairment of their immune system. The goal of this study is to find natural products that have the potential to delay growth or eliminate the abnormal leukemic cells but cause less harmful effect to the body’s immune system.

Methods and Findings

The unsaponified fraction of Riceberry rice bran (RBDS) and the main pure compound, gramisterol, were studied for cytotoxicity and biological activities in WEHI-3 cells and in the leukemic mouse model induced by transplantation of WEHI-3 cells intraperitoneally. In the in vitro assay, RBDS and gramisterol exerted sub-G1 phase cell cycle arrest with a potent induction of apoptosis. Both of them effectively decreased cell cycle controlling proteins (cyclin D1 and cyclin E), suppressed cellular DNA synthesis and mitotic division, and reduced anti-apoptosis Bcl-2 protein, but increased apoptotic proteins (p53 and Bax) and activated caspase-3 enzyme in the intrinsic cell death stimulation pathway. In leukemic mice, daily feeding of RBDS significantly increased the amount of immune function-related cells including CD3⁺, CD19⁺, and CD11b⁺, and elevated the serum levels of IFN-γ, TNF-α, IL-2, and IL-12β cytokines, but suppressed IL-10 level. At the tumor sites, CD11b⁺ cells were polarized and became active phagocytotic cells. Treatment of mice normal immune cells with gramisterol alone or a combination of gramisterol with cytokines released from RBDS-treated leukemic mice splenocytes culture synergistically increased pSTAT1 transcriptional factor that up-regulated the genes controlling cell survival and function. Phosphorylation of STAT1 was absent in WEHI-3. Instead, similar treatments significantly decreased pSTAT3 signaling that regulates transcription of genes controlling tumor growth and proliferation.

Conclusions

Rice bran gramisterol possesses a promising anti-cancer effect against a tumor of white blood cells and induces the production of anti-cancer immune-related cytokines. Gramisterol induces cell cycle arrest and apoptosis via suppression of pSTAT3 signaling control of tumor cells’ growth and progression. Gramisterol increased IFN-γ production and prevented the dysfunctional immune system of leukemic mice by enhancing pSTAT1 transcription signal controlling proliferation and functions of hematopoietic cells in the spleen. Together with IFN-γ, gramisterol efficiently facilitates leukemic mice immune system modulation leading to improvement of the AML condition. Administration of RBDS containing gramisterol potentiates immune recovery of leukemic mice and extends their survival. This finding encourages the medicinal application of rice bran gramisterol as a palliative treatment or an alternative agent for future drug development against AML.

Effects of Aqueous Extract of Unpolished Dark Purple Glutinous Rice, Var Luem Pua, on ROS in SK-N-SH Cells and Scopolamine-induced Memory Deficit in Mice

Purpose: To investigate the antioxidative and memory-enhancing effects of aqueous extract of unpolished Thai rice strain of Luem Pua (LP) in SK-N-SH cells and scopolamine-induced memory deficit in mice.Methods: In SK-N-SH cells, viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay while intracellular reactive oxygen species (ROS) levels were quantified after pretreatment with LP (0, 200, 600 and 1000 μg/mL) in the presence of hydrogen peroxide (H2O2). In mice, memory was impaired by injecting 2 mg/kg/day scopolamine, for 18 consecutive days. On each day, mice were also force-fed with LP 0, 90 or 180 mg/kg. On the last 5 days of treatment, memory was tested using passive avoidance (PA) and Morris water maze (MWM) tests.Results: At concentration up to 1,000 μg/mL LP had no effect on SK-N-SH cell viability and significantly reduce intracellular ROS levels of SK-N-SH cells with or without H2O2. Mice that received 90 or 180 mg/kg LP showed a significant decrease in latency time in PA test and an increase in escape latency time in MWM test. These  data suggest that LP antagonizes the effect of scopolamine on memory.Conclusion: LP extract has anti-oxidative and memory-enhancing effects in cell culture and mice. The rice may be a nutraceutical helpful for promoting brain health. Keywords: Dark purple rice, Leum Pua rice, Reactive oxygen species, Memory, Scopolamine, Cell culture

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.

Quantification of the rice aroma compound, 2-acetyl-1-pyrroline, in uncooked Khao Dawk Mali 105 brown rice

Volatile components of uncooked Khao Dawk Mali 105 brown rice were extracted using indirect steam distillation under reduced pressure and controlled temperature in order to prevent cooking. Analysis of the fresh extract by capillary gas chromatography-mass spectrometry revealed that there were >140 volatile constituents. Among these, 70 volatiles were identified, including 2-acetyl-1-pyrroline (2AP), a key aroma compound of cooked rice. Further study concentrated on an improved method for the quantification of 2AP in uncooked brown rice. The method was simplified by utilizing a solvent extraction procedure. Quantitative analysis was performed using a capillary gas chromatographic system employing a flame ionization detector with the aid of a more selective column, CP-Wax 51, for amines. This improved chromatographic system had remarkable detection sensitivity for 2AP in the rice extracts so that 2AP in an extract of only 0.5 g of uncooked Khao Dawk Mali 105 brown rice could be detected.