Method Development for Purification of γ-oryzanol from Hydrolyzed Rice Bran Acid Oil by Semi-preparative Chromatography.

The objective of this study was to develop a method for isolation and purification of γ-oryzanol from hydrolyzed rice bran acid oil (RBAO) using semi-preparative chromatography by first applying silica coated-thin layer chromatography (TLC) to determine the suitable mobile phase. Subsequently, column chromatography was carried out to determine the effects of purification conditions such as the amount of and particle sizes of the sample silica gel, and elution modes, on the percentage of γ-oryzanol yield and recovery. The results from the TLC suggested that 75:25 (v/v) hexane to ethyl acetate mixture was a suitable mobile phase. The semi-chromatographic results indicated that the column containing 10 g of 25-40 µm silica gel with isocratic elution gave the highest yield (84%) of purified γ-oryzanol (> 95% purity). Further application of a step-gradient elution with 85:15 (v/v), followed by 75:25 (v/v) hexane to ethyl acetate mixture increased chromatographic resolution (Rs), resulting in enhanced separation efficiency, which in turn led to a higher yield of purified γ-oryzanol of 90%.

Estudio comparativo de la actividad anti-fúngica de extractos secuenciales de Fuchsia lycioides contra Candida sp / comparative study of the antifungal activity of sequencial extracts of Fuchsia lycioides against Candida sp

The genus Fuchsia is generally used in herbal preparations to treat conditions caused by microorganisms. Based on the popular use of this type of plants, the objective of this study was to obtain sequential extracts of increasing polarity from the branches of Fuchsia lycioides by maceration at room temperature and by the Soxhlet method at 60ºC, to later evaluate the antifungal capacity of the extracts against different clinical isolates of the Candida genus. The ethyl acetate extract exhibited strong anti-fungal activity, selectively inhibiting C. albicans strains with MIC and CMF values of 10 and 15 µg/mL, respectively; comparable with the drug itraconazole®. The analysis of the extract by GC-MS showed a high concentration of terpenoids (mainly phytol) and phenylpropanoids (mainly cinnamic acid), possibly responsible for the antifungal activity of the ethyl acetate extract of F. lycioides.

El género Fuchsia se usa generalmente en preparaciones de hierbas para tratar afecciones provocadas por microorganismos. En base al uso popular de este tipo de plantas, el objetivo de este estudio fue obtener los extractos secuenciales de polaridad creciente de las ramas de Fuchsia lycioides por maceración a temperatura ambiente y por el método Soxhlet a 60ºC, para luego evaluar la capacidad antifúngica de los extractos frente a diferentes aislados clínicos del genero Candida. El extracto de acetato de etilo exhibió una fuerte actividad antifúngica inhibiendo en forma selectiva las cepas de C. albicans con valores de CMI y de CMF de 10 y 15 µg/mL, respectivamente; comparables con el fármaco itraconazol®. El análisis del extracto por CG-EM mostró una alta concentración de terpenoides (principalmente fitol) y fenilpropanoides (principalmente ácido cinámico), posibles responsables de la actividad antifúngica del extracto de acetato de etilo de F. lycioides.

Functional Profiling and Future Research Direction of Rice Bran Oil in Bangladesh.

Rice bran oil (RBO) has been demonstrated to affect complex malfunctioned conditions such as oxidative stress, hyperlipidemia, hyperglycemia, hypertension, inflammation, abnormal cell growth (cancer), ulceration, immune and cognitive modulation. This unique effect of RBO is due to the presence of well-balanced fatty acid composition and several bioactive compounds, γ- oryzanol (cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, campesterol ferulate, and ß-sitosteryl ferulate), vitamin E (tocopherol and tocotrienol), phytosterols (ß-sitosterol, campesterol and stigmasterol) and other nutrients. The RBO composition of bioactive compounds varied geographically, thus the clear-cut mechanisms of action on complex disease cascades are still required. This review article summarized the RBO compositional profiling and compared it with other edible oils. This article also summarized Bangladesh RBO profiling and their proposed mechanism of action as well as the first line of defense in the prevention, management, and control of complex disease conditions. This review indicates how Bangladesh RBO increase their opportunity to be functional food for 21st century's ailment.

Synthesis, antitumor activity and in silico analyses of amino acid derivatives of artepillin C, drupanin and baccharin from green propolis.

Breast cancer has the highest incidence and mortality in females, while prostate cancer has the second-highest incidence in males. Studies have shown that compounds from Brazilian green propolis have antitumor activities and can selectively inhibit the AKR1C3 enzyme, overexpressed in hormone-dependent prostate and breast tumors. Thus, in an attempt to develop new cytotoxic inhibitors against these cancers, three prenylated compounds, artepillin C, drupanin and baccharin, were isolated from green propolis to synthesize new derivatives via coupling reactions with different amino acids. All obtained derivatives were submitted to antiproliferative assays against four cancer cells (MCF-7, MDA MB-231, PC-3, and DU145) and two normal cell lines (MCF-10A and PNT-2) to evaluate their cytotoxicity. In general, the best activity was observed for compound6e, derived from drupanin, which exhibited half-maximal inhibitory concentration (IC50) of 9.6 ± 3 µM and selectivity index (SI) of 5.5 against MCF-7 cells.In silicostudies demonstrated that these derivatives present coherent docking interactions and binding modes against AKR1C3, which might represent a possible mechanism of inhibition in MCF-7 cells.

A comparative study on root and bark extracts of Eleutherococcus senticosus and their effects on human macrophages.

BACKGROUND: Eleutherococcus senticosus or Siberian ginseng is a medicinal plant containing adaptogenic substances believed to regulate immune responses. Both, the root and stem bark are commonly used in traditional medicines. PURPOSE: The purpose of the present study is to chemically characterize E. senticosus root and bark extracts and to compare their effects on functions of human primary macrophages. STUDY DESIGN AND METHODS: HPLC-DAD-MS analysis was used to characterize chemical constituents of alcoholic extracts from E. senticosus root and bark. The data obtained and available databases were combined for network pharmacology analysis. Involvement of predicted pathways was further functionally confirmed by using monocyte-derived human macrophages and endotoxin-free E. senticosus root and bark extracts. RESULTS: Chemical analysis showed that the root extract contained more syringin, caffeic acid, and isofraxidin than the bark extract. At variance, bark extract contained more sesamin and oleanolic acid. Coniferyl aldehyde and afzelin were below the limit of quantification in both extracts. Network pharmacology analysis indicated that constituents of E. senticosus might affect the immune cell phenotype and signaling pathways involved in cell metabolism and cytoskeleton regulation. Indeed, both extracts promoted actin polymerization, migration, and phagocytosis of E. coli by macrophages pointing to macrophage polarization towards the M2 phenotype. In addition, treatment with E. senticosus root and bark extracts decreased phosphorylation of Akt on Ser473 and significantly reduced expression of the hemoglobin scavenger receptor CD163 by macrophages. Neither extract affected expression of CD11b, CD80, or CD64 by macrophages. In addition, macrophages treated with the bark extract, but not with the root extract, exhibited activated p38 MAPK and NF-κB and released increased, but still moderate, amounts of proinflammatory TNF-α and IL-6, anti-inflammatory IL-10, and chemotactic CCL1, which all together point to a M2b-like macrophage polarization. Differently, the root extract increased the IL-4-induced expression of anti-inflammatory CD200R. These changes in monocytes are in agreement with an increased M2a macrophage polarization. CONCLUSION: The ability of E. senticosus root and bark extracts to promote polarization of human macrophages towards anti-inflammatory M2a and M2b phenotypes, respectively, might underlay the immunoregulatory activities and point to potential wound healing promoting effects of this medicinal plant.

Determination of γ-Oryzanol in Refined Rice Bran Oil by Nuclear Magnetic Resonance Method.

γ-Oryzanol contained as a minor component in rice bran oil (RBO) is a group of phytosterol ferulates. The existence of γ-oryzanol in rice bran oil is very interesting because of the special biological functions. The methods to determine γ-oryzanol in crude RBO include the absorptiometry, thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). However, those methods need much solvent and long operating time. Moreover, some of those methods are not able to apply to refined RBO because of the low sensitivity. We have developed the method to determine γ-oryzanol in refined RBO using proton nuclear magnetic resonance (1H-NMR). Refined RBO had a specific chemical shift due to the methoxy group of ferulate in γ-oryzanol at 3.9 ppm on the 1H-NMR spectrum. The intensity of the chemical shift due to the methoxy group of ferulate was consistent with the amounts of γ-oryzanol in refined RBO. This NMR method was able to quickly and easily determine γ-oryzanol in refined RBO.

Comparative study on amount of nutraceuticals in by-products from solvent and cold pressing methods of rice bran oil processing.

Rice bran oil (RBO) has become a popular oil globally. However, the RBO extraction process leaves various residue products, which contain bioactive substances of varying potency which could be significant sources of functional ingredients for both food production and pharmaceutical manufacture. The objective of our study was to compare the bioactive substances in various by-products derived from the two rice bran oil processing methods; solvent extraction and cold pressing. The residues from solvent extraction processing contained up to 97.37 mg/100 g of γ-aminobutyric acid in defatted rice bran, and the rice acid oil contained high levels of vitamin E (tocopherols, tocotrienols), up to 120.59 mg/100 g, as well as γ-oryzanol (3829.65 mg/100 g), phytosterol (599.40 mg/100 g), and policosanol compounds (332.79 mg/100 g). All of these values are higher than in the residues derived from cold pressing. Importantly, high amounts of total nutraceuticals (8.3 kg/100 kg) were found in residues from both processing methods, indicating the commercial potential of these residues as a source of functional ingredients for food production, as dietary supplements, and in pharmaceutical manufacture.

Thermal rice oil degradation evaluated by UV-Vis-NIR and PARAFAC.

Thermal rice oil degradation was evaluated by UV-Vis and NIR in three-way arrays assembled with samples, different temperatures, and the absorbance at different wavelengths by applying PARAFAC chemometric method. The loadings matrix of the mode corresponding to the samples (scores) contains the information related to the samples. The loadings on the temperature mode resemble kinetics profiles. These profiles change with the nature of the component responsible for the factor and evolve with the heating temperature. The loadings on the spectral mode reveal the antioxidants γ-oryzanol and tocopherol, and oxidation products are the components responsible for the two factors. The results achieved showed that the antioxidants concentration decreases starting at 70 °C while oxidation products start to increase more pronounced after 90 °C. The proposed method is shown to be a simple and fast way to obtain information about the oxidative stability of rice oils.

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.

Could Fecal Phenylacetic and Phenylpropionic Acids Be Used as Indicators of Health Status?

Although most of the health effects attributed to polyphenols may be linked to their phenolic-derived metabolites, the role of the intestinal derived-phenolics in human health is still far from being well understood. We determined the profile of fecal phenolic-derived metabolites, microbiota, biomarkers of oxidative stress and inflammation, and daily intake of bioactive compounds in 71 elderly volunteers. Phenylacetic and phenylpropionic acids were the main phenolic metabolites present in feces. From them, phenylacetic acid was related with a more pro-oxidant and immune stimulated status, and both were negatively associated with fecal propionate, whereas phenylpropionic acid was directly related with the fecal concentration of acetate. Moreover, phenylacetic acid was negatively associated with the Bacteroides group and Clostridium cluster XIVa and positively with Lactobacillus. These results provide a rationale to explore the potential of fecal microbial phenolic-derived metabolites as possible biomarkers of health status in future studies focused on the elderly population.

Bioavailability, composition and functional characterization of extracts from Oryza sativa L. bran.

The aim of this study has been to assess the composition and antioxidant activities of rice bran extracts submitted to a human simulated digestion, which extraction process was previously optimized. In order to adjust the optimum values for the extraction, D-optimal experimental design and response surface methodology have been applied. Phenolic compounds and γ-oryzanol contents have been used as response parameters. In this way, two different extracts have been obtained. The first one, was obtained with 100% water as solvent, and it was mainly composed by phenolic acids. Ferulic acid was the majority compound found with a concentration of 1.00 ±â€¯0.03 mg/g extract, followed by p-coumaric acid (0.19 ±â€¯0.02 mg/g), The second extract, extracted with ethanol as solvent, was a γ-oryzanol enriched fraction with a content of 14.41 ±â€¯0.26 mg/g extract. The optimized rice bran extracts thus obtained were subjected to a process of human in-vitro digestion. In the first extract, with high polyphenol content, the phenolic content was oscillating during the digestion, like antioxidant activity. The oryzanol content found in this fraction (0.079 ±â€¯0.002 mg/g) has not been detected in any phase of digestion. In the second extract, with a high oryzanol content at the beginning, oryzanol content was not detected in any of digestion steps. However, phenolic composition was stable in all phases of simulation (ranging from 0.117 and 0.094 mg/g in the case of ferulic acid). This fact evidence that oryzanol is not a bioavailability fraction, while phenolic compounds support to some extent, the conditions of digestion.

Analysis of loxoprofen in tablets, patches, and equine urine as tert-butyldimethylsilyl derivative by gas chromatography-mass spectrometry.

Loxoprofen is a non-steroidal anti-inflammatory drug of the 2-arylpropionic acid type, which has used to treat musculoskeletal disorders in the horse racing industry. However, it has also used illicitly to mask clinical signs of inflammation and pain in racehorses. Thus, its accurate analysis has become an important issue in horse doping laboratories. In this study, an analytical method of loxoprofen was developed as tert-butyldimethylsilyl (TBDMS) derivative by gas chromatography-mass spectrometry (GC-MS). Characteristic fragment ions of [M-15], [M-57], and [M-139] permitted the accurate and selective detection of loxoprofen. Under optimal conditions, this method showed good linearity (r ≥ 0.999) in the range of 10-500 ng/mL, repeatability (% relative standard deviation = 5.6-8.5), and accuracy (% relative error = - 0.3-0.9) with a detection limit of 1.0 ng. When applied to the analysis of loxoprofen in tablet and patch products, loxoprofen was positively identified as TBDMS derivative by GC-MS. The present method provided rapid and accurate determination of loxoprofen in patch and tablet products. Levels of loxoprofen were highest in equine urine at 0.5 and 1 h after oral administration with single dose (3 mg/kg) to three horses, and then rapidly reduced to below the lower limit of quantification at 24 h. Therefore, the present method will be useful for the pharmacokinetic study and doping tests for loxoprofen and other similar acidic drugs in horses.

Stabilization of immature rice grain using infrared radiation.

Immature rice grain is one of the underutilized by-products of paddy milling process. Despite its high potential of use as a food ingredient, it is mainly utilized as feed due to the rancidity problem. In the present study, the composition of immature rice grain, the potential of using infrared (IR) radiation for stabilization, and the effects of IR stabilization on color, fatty acid composition, tocopherol and γ-oryzanol contents of the grain were investigated. The free fatty acid (FFA) value of the unprocessed immature rice grain was 5.49% and increased to 35.71% at the end of 3 months of storage at room temperature. However, FFA content of the grains stabilized with IR radiation at specific conditions remained unchanged throughout the storage period. Moreover, IR stabilization did not caused a negative effect on the noted components of the immature rice grain.

Rapid Characterization and Identification of Non-Diterpenoid Constituents in Tinospora sinensis by HPLC-LTQ-Orbitrap MSn.

Tinospora sinensis, a kind of Chinese folk medicine, has functions of harmonizing qi and blood, dredging the channels and collaterals, calming and soothing the nerves. In the present study, a method based on high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry (HPLC-LTQ-Orbitrap) was developed for the systematical characterization of the non-diterpenoid constituents which possessed remarkable biological activities in T. sinensis, like anti-tumor, anti-inflammatory, hypoglycemic activity and immunomodulatory activity. Based on the accurate mass measurement (<5 ppm), retention times and MS fragmentation ions, 60 non-diterpenoid constituents were unambiguously or tentatively characterized from T. sinensis extract, including 27 alkaloids, 23 phenylpropanoids, seven sesquiterpenoids and three other constituents. Among them, 13 compounds were tentatively identified as new compounds. Finally, three of the non-diterpenoid constituents were purified and identified, which further confirmed the validity of the results. This study demonstrated that the HPLC-LTQ-Orbitrap MSn platform was a useful and efficient analytical tool to screen and identify constituents in natural medicine.

Dummy-surface molecularly imprinted polymers as a sorbent of micro-solid-phase extraction combined with dispersive liquid-liquid microextraction for determination of five 2-phenylpropionic acid NSAIDs in aquatic environmental samples.

A highly binding dummy template surface of molecularly imprinted polymers (MWNTs-MIPs) was synthesized on multi-walled carbon nanotubes surface using 2-phenylpropionic acid as dummy template, 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, and DMF as porogen by precipitation polymerization method. MIPs were characterized by FT-IR spectroscopy, scanning electron microscope, thermo-gravimetric analysis, and nitrogen adsorption-desorption experiment. Adsorption and selectivity experiments of MIPs and non-imprinted polymers (NIPs) verified that the MIPs had a good selectivity and adsorption properties for five 2-phenylpropionic acid nonsteroidal anti-inflammatory drugs (NSAIDs). Imprinted polymer was used as a sorbent material for µSPE in current work and µSPE-DLLME method was selected for pretreatment of water samples. The µSPE-DLLME method was successfully used for the pre-concentration of five non-steroidal anti-inflammatory drugs in different environmental water samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry. Efficiencies of µSPE and DLLME were thoroughly investigated and optimized in this study. The optimal results were obtained by using 3 mL of 1% formic acid-acetonitrile as elution solvent and dichloroethane and acetonitrile as extractant and disperser solvent, respectively. Limits of detection and quantification of five NSAIDs for different water matrices varied from 0.50 to 1.10 ng L-1 and 0.93 to 2.20 ng L-1, respectively. Each target analyte had a good linearity in its corresponding concentration range. Enrichment factors of target analytes ranged from 91 to 215. Recoveries of the target analytes were between 72.43 and 113.99% at the concentration levels of 0.02, 0.1, and 0.5 µg L-1. The developed method was successfully applied to extraction and analysis of NSAIDs in different water samples with satisfactory results which could help us better understand their environmental fate and risk to ecological health. Graphical abstract Dummy-surface molecularly imprinted polymers as a sorbent of micro-solid-phase extraction combined with dispersive liquid-liquid microextraction for determination of five 2-phenylpropionic acid NSAIDs in aquatic environmental samples.

Brown rice and retrograded brown rice alleviate inflammatory response in dextran sulfate sodium (DSS)-induced colitis mice.

The present study was aimed to investigate the impacts of brown rice (BR) and retrograded brown rice (R-BR) consumption on colonic health and gut microbiota in dextran sulfate sodium (DSS) induced colitis mice. Thirty two female C57Bl/6Mlac mice were fed with modified AIN 93G diets by replacing cornstarch in the original composition with white rice (WR), BR and R-BR powder. The mice were divided into 4 groups and fed with the following experimental diets for 4 weeks: (1) negative control (WR: diet with WR), (2) positive control (DSS_WR: DSS and diet with WR), (3) DSS_BR: DSS and diet with BR, and (4) DSS_R-BR: DSS and diet with R-BR. BR and R-BR had a greater content of fat, dietary fiber, GABA, γ-oryzanol, γ-tocotrienol, ferulic acid and p-coumaric acid than WR (p < 0.05). No significant difference in the level of these bioactive compounds was noted between BR and R-BR. Nevertheless, R-BR had a 1.8 fold resistant starch (RS) content of BR (p < 0.05). The DSS_BR and DSS_R-BR groups showed a lower ratio of colonic weight to length, and a lower content of iNOS, COX-2, MPO, IL-6 and INF-γ in colonic homogenates than the DSS_WR group. However, the DSS treated mice fed with the R-BR diet had significantly milder histopathological inflammatory injury and lower colonic iNOS expression than the DSS_BR and DSS_WR groups. The percentage of mesenteric regulatory T cells significantly increased in the DSS_R-BR group compared to that in the DSS_WR group. The DSS treated mice fed with the R-BR diet showed a significant increase in cecal bacterial diversity and abundance of genera Prevotella, Ruminococcus, Dorea, Coprococcus and Dehalobacterium but a significant decrease in pathogenic bacteria including Bacteroides and Enterococcus compared to the DSS_WR group. Thus, the present data indicate that BR and R-BR ameliorate colonic inflammation in experimental colitis induced by DSS in mice by suppressing inflammatory mediators and modulating regulatory T cell responses as well as bacterial diversity in the cecum.

Comparative Studies between Conventional and Microwave Assisted Extraction for Rice Bran Oil.

The present work deals with comparison of microwave assisted extraction to that of conventional solvent extraction for the extraction of rice bran oil (RBO); focusing on extraction yield and oil composition. Microwave assisted extraction act as a green process over other method and proved that it is effective method for extraction of oil. The investigation also focuses on the study of functional group and component present in oil. Natural antioxidant component; its activity was confirmed by DPPH assay. The oryzanol content was also determined by measuring the optical density of the sample at 315 nm in n-heptane using UV visible spectrophotometer.

Identification of Free Radical Scavengers from Brazilian Green Propolis Using Off-Line HPLC-DPPH Assay and LC-MS.

Brazilian green propolis is known as an appreciable natural antioxidant with abundant polyphenolic compounds. For quality control, a fingerprint-efficacy study of Brazilian green propolis was carried out in this work. Chemical fingerprints of Brazilian green propolis from 22 different sources were determined by HPLC and investigated by similarity analysis. The fingerprint-efficacy relationships between chemical fingerprint and DPPH radical-scavenging activity were established. The results showed that 14 characteristic common peaks were identified, and 9 compounds were discovered with free radical-scavenging activities. Caffeoylquinic acids and artepillin C might be the major effective components for quality control of Brazilian green propolis due to their specificity and strong antioxidant activity. This study provides new markers for the quality assessment of Brazilian green propolis and its derived products.

Comparative Analysis of γ-Oryzanol, ß-Glucan, Total Phenolic Content and Antioxidant Activity in Fermented Rice Bran of Different Varieties.

Rice bran, a by-product derived from processing rice, is a rich source of bioactive compounds. Recent studies have suggested that the fermentation can improve their biological activities. This study aimed to determined the level of γ-oryzanol, ß-glucan and total phenol contents of fermented rice bran from 21 Korean varieties, as well as to evaluate their antioxidant activities. We also assessed the validation of the analytical method for determining γ-oryzanol content in fermented rice brans. Among the fermented rice brans, the Haedam rice bran contained the highest level of total phenol content (156.08 mg gallic acid equivalents/g), DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity (71.30%) and ORAC (Oxygen radical absorbance capacity) value (1101.31 µM trolox equivalents/g). Furthermore, the fermented Migwang rice bran showed the highest level of γ-oryzanol content (294.77 ± 6.74 mg/100 g).

Factors influencing antioxidant compounds in rice.

Epidemiological and clinical studies suggest that the additive/synergistic effects of several bioactive compounds are responsible for the health benefits of rice. Among the leading contenders are phenolic acids, flavonoids, anthocyanins, proanthocyanidins, tocotrienols, tocopherols, λ-oryzanol, and phytic acid, which all possess strong antioxidant activities in vitro. In this review, data related to health effects of rice antioxidants using cultured cells, rodents and humans models are first summarized. The evidence is strong that consumption of rice tocotrienols translates into improved health outcomes. Current research, however, does not strongly support the health-promoting effects of rice tocopherols and phenolic acids. The crucial limitations in studies using rice flavonoids, anthocyanins, proanthocyanidins, λ-oryzanol and phytic acid appear to be the appropriateness of the substance tested (i.e., purity), and the scarcity of animal and human interventions. In a second part, rice antioxidants are reviewed with an emphasis on their composition and contents. Taking into account the bioavailability of these compounds, it is evident that a number of factors affect the antioxidant composition of rice, making it difficult to estimate dietary intake. Before harvest, factors including soil type, atmospheric CO2, chemical inputs, temperature, and degree of ripening are important. After harvest, rice is subjected to processing methods that include drying, parboiling, storage, irradiation, milling, stabilization, soaking, germination, fermentation, boiling, steaming, roasting, baking, and extrusion. Quantitative knowledge about the effects of these processes is summarized in this review. Surprisingly, a high level of agreement was found among study results, which could be useful in manipulating the growing and processing techniques of rice grains to facilitate efficient and safe consumption of antioxidant compounds.