Antioxidative and antimutagenic activities of 4-vinyl-2,6-dimethoxyphenol (canolol) isolated from canola oil

A potent antioxidative compound in crude canola oil, canolol, was recently identified, and reported herein are studies of its scavenging capacity against the endogenous mutagen peroxynitrite (ONOO(-)). ONOO(-) is generated by the reaction between superoxide anion radical and nitric oxide, both of which are produced by inflammatory leukocytes. Among various antioxidative substances of natural or synthetic origin, canolol was one of the most potent antimutagenic compounds when Salmonella typhimurium TA102 was used in the modified Ames test. Its potency was higher than that of flavonoids (e.g., rutin) and alpha-tocopherol and was equivalent to that of ebselen. Canolol suppressed ONOO(-)-induced bactericidal action. It also reduced intracellular oxidative stress and apoptosis in human cancer SW480 cells when used at a concentration below 20 microM under H(2)O(2)-induced oxidative stress. In addition, canolol suppressed plasmid DNA (pUC19) strand breakage induced by ONOO(-), as revealed by agarose gel electrophoresis.     

Antioxidative activities of volatile extracts from green tea, oolong tea, and black tea

Antioxidative activities of volatile extracts from six teas (one green tea, one oolong tea, one roasted green tea, and three black teas) were investigated using an aldehyde/carboxylic acid assay and a conjugated diene assay. The samples were tested at levels of 20, 50, 100, and 200 micrograms/mL of dichloromethane. The results obtained from the two assays were consistent. All extracts except roasted green tea exhibited dose-dependent inhibitory activity in the aldehyde/carboxylic acid assay. A volatile extract from green tea exhibited the most potent activity in both assays among the six extracts. It inhibited hexanal oxidation by almost 100% over 40 days at the level of 200 micrograms/mL. The extract from oolong tea inhibited hexanal oxidation by 50% in 15 days. In the case of the extract from roasted green tea, the lowest antioxidative activity was obtained at the level of 200 micrograms/mL, suggesting that the extract from roasted green tea contained some pro-oxidants. The extracts from the three black teas showed slight anti- or proactivities in both assays. The major volatile constituents of green tea and roasted green tea extracts, which exhibited significant antioxidative activities, were analyzed using gas chromatography-mass spectrometry. The major volatile chemicals with possible antioxidative activity identified were alkyl compounds with double bond(s), such as 3,7-dimethyl-1,6-octadien-3-ol (8.04 mg/kg), in the extract from green tea and heterocyclic compounds, such as furfural (7.67 mg/kg), in the extract from roasted green tea. Benzyl alcohol, which was proved to be an antioxidant, was identified both in a green tea extract (4.67 mg/kg) and in a roasted tea extract (1.35 mg/kg).     

Properties of extracts from defatted rice bran by its subcritical water treatment

Defatted rice bran was extracted with water and subcritical water at 50-250 degrees C for 5 min. The highest extract yield was achieved at 200 degrees C, at which the maximum amounts of protein and carbohydrate were also obtained. The total phenolic and furfural contents, radical scavenging activity, and antioxidative activity for the autoxidation of linoleic acid increased with increasing treatment temperature. The bran extracts exhibited emulsifying activity except for the extract prepared at 250 degrees C, which was concomitant with the disappearance of its high-molecular-mass substances. The extract prepared at 200 degrees C also had the highest emulsion-stabilizing activity.     

亚临界丙烷萃取米糠油及其微量活性组分动力学模型

为了揭示亚临界流体萃取米糠油及其微量活性组分的动力学规律,该文以亚临界丙烷为萃取介质,研究了米糠油、γ-谷维素及α-生育酚等活性组分在不同萃取温度和时间的萃取率,并基于 Baümler 模型对目标物的萃取率进行模型拟合,建立相应的动力学模型并验证。结果表明,亚临界萃取过程中目标物的相对萃取率随时间增长递增,且在初始阶段（洗涤过程）的增长速率快于第二阶段（扩散过程）的增长速率;同时,升高萃取温度可同时提高目标产物的扩散系数和相对萃取率;基于Baümler模型可较好拟合亚临界丙烷萃取米糠油、γ-谷维素和α-生育酚的动力学过程（R2>0.95）,所得动力学模型具有较好的预测准确性。由Arrhenius方程可计算出米糠油、α-生育酚和γ-谷维素的亚临界萃取反应活化能,其中米糠油的活化能最低（5.23 kJ/mol）,α-生育酚次之（7.05 kJ/mol）,γ-谷维素最高（9.11 kJ/mol）,表明γ-谷维素最难萃取且对温度依赖程度最高;根据拟合所得动力学模型,对米糠油提取率进行预测,结果表明,该模型对米糠油萃取率的预测准确率达95.8%,而对γ-谷维素和α-生育酚萃取率的预测准确度稍低,分别达94.7%和94.4%,对三者均具有很好的预测准确性。总之,基于 Baümler 模型可以较好地建立米糠油及其有益伴随物的亚临界萃取动力学模型,从而较为准确的预测米糠油及其微量活性组分的萃取率,对米糠油的亚临界萃取工艺具有一定的理论指导意义。     

Antioxidative capacity of extracts and constituents in Cornus capitata adventitious roots

Radical scavenging activities of extracts and constituents in Cornus capitata adventitious root cultures were evaluated by using 1,1-diphenyl-2-pycrylhydrazyl (DPPH) and superoxide anion radicals. Inhibitory activity against peroxidation of linoleic acid was assayed by using the thiobarbituric acid (TBA) method. Ethyl acetate and aqueous fractions were prepared from adventitious roots cultured in Murashige-Skoog liquid medium with 0.1 microM Cu(2+) (0.1CuMS) or 10 microM Cu(2+) (10CuMS). The highest scavenging activities on DPPH and superoxide anion radicals were observed in the ethyl acetate fraction from 0.1CuMS. In the inhibitory activity against linoleic acid oxidation, the ethyl acetate fraction from 10CuMS was highest among the fractions tested. The ethyl acetate fraction of adventitious roots cultured in 0.1CuMS contained mainly galloylglucoses (1,2,3,6-tetragalloylglucose and 1,2,3,4,6-pentagalloylglucose). The ethyl acetate fraction of adventitious roots cultured in 10CuMS contained mainly ellagic acid derivatives [3,3'-di-O-methylellagic acid 4-(5"-acetyl)-alpha-L-arabinofuranoside and stenophyllin H1]. Aqueous fractions prepared from both media contained iridoid glycosides (dihydrocornin and cornin). Tetra- and pentagalloylglucoses showed strong inhibitory activities (61.9 and 85.2%, respectively) against linoleic acid oxidation relative to those of butylated hydroxytoluene (BHT) (91.1%) or alpha-tocopherol (49.5%) at 50 microM concentration. Although both ellagic acid derivatives had weak activities (<50%) on DPPH and superoxide anion radical scavenging, 3,3'-di-O-methylellagic acid 4-(5"-acetyl)-alpha-L-arabinofuranoside was stronger (74.7%) than alpha-tocopherol (49.5%) in inhibiting linoleic acid oxidation at 50 microM concentration. Iridoid glycosides exhibited little activity against DPPH and superoxide anion radicals or against oxidation of linoleic acid.     

Preparation and functional properties of rice bran protein isolate

Rice bran protein isolate (RBPI) containing approximately 92.0% protein was prepared from unstabilized and defatted rice bran using phytase and xylanase. The yield of RBPI increased from 34% to 74.6% through the use of the enzymatic treatment. Nitrogen solubilities of RBPI were 53, 8, 62, 78, 82, and 80% at pHs 2.0, 4.0, 6.0, 8.0, 10.0, and 12.0, respectively. Differential scanning calorimetry showed that RBPI had denaturation temperature of 83.4 degrees C with low endotherm (0.96 J/g of protein). RBPI had similar foaming properties in comparison to egg white. But emulsifying properties of RBPI were significantly lower than those of bovine serum albumin. The result of amino acid analysis showed that RBPI had a similar profile of essential amino acid requirements for 2-5-year-old children in comparison to that of casein and soy protein isolate.     

Antioxidative activities of heterocyclic compounds formed in brewed coffee

Typical volatile heterocyclic compounds found in brewed coffee extracts-pyrroles, furans, thiophenes, and thiazoles-were examined for antioxidative activity, which was determined by measuring the oxidative conversion of hexanal to hexanoic acid using gas chromatography. 2-Acetylpyrrole, 1-methylpyrrole, and pyrrole inhibited hexanal oxidation by 98, 87, and 78%, respectively, at a concentration of 500 microgram/mL over a period of 30 days. 2-Methylfuran, which inhibited hexanal oxidation by 90% at all concentrations tested (500, 200, and 100 microgram/mL) for a 30-day period, exhibited the greatest activity among furans tested. Similarly, 2-methylthiophene, which inhibited hexanal oxidation by almost 100% at a concentration of 500 microgram/mL over 30 days, exhibited the greatest activity among the thiophenes tested. In general, thiazoles were ineffective antioxidants at all concentrations tested. However, 4,5-dimethylthiazole was able to inhibit hexanal oxidation by 50% at the highest level tested (500 microgram/mL). 2-Acetylpyrrole, 2-methylfuran, and 2-methylthiophene at concentrations of 500, 200, and 100 microgram/mL and furan at a concentration of 500 microgram/mL exhibited antioxidative activities comparable to that of the synthetic antioxidant butylated hydroxytoluene at a concentration of 50 microgram/mL.     

Quantification of vitamin E and gamma-oryzanol components in rice germ and bran

Rice bran is a rich natural source of vitamin E and gamma-oryzanol, which have been extensively studied and reported to possess important health-promoting properties. However, commercial rice bran is a mixture of rice bran and germ, and profiles of vitamin E and gamma-oryzanol components in these two different materials are less well-studied. In the current study, vitamin E and gamma-oryzanol components in rice bran and germ were analyzed by liquid chromatography/mass spectrometry/mass spectrometry. The components were identified by electrospray ionization mass spectrometry (ESI-MS) with both positive- and negative-ion modes. Both deprotonated molecular ion [M - H](-) and protonated molecular ion [M + H](+) found as the base peaks in spectra of vitamin E components made ESI-MS a valuable analytic method in detecting vitamin E compounds, especially when they were at very low levels in samples. Ultraviolet absorption was used for quantification of vitamin E and gamma-oryzanol components. While the level of vitamin E in rice germ was 5 times greater than in rice bran, the level of gamma-oryzanol in rice germ was 5 times lower than in rice bran. Also, the major vitamin E component was alpha-tocopherol in rice germ and gamma-tocotrienol in rice bran. These data suggest that rice bran and germ have significantly different profiles of vitamin E and gamma-oryzanol components. The method enables rapid and direct on-line identification and quantification of the vitamin E and gamma-oryzanol components in rice bran and germ.     

Antioxidant activity of steryl ferulate extracts from rye and wheat bran

Antioxidant activity of steryl ferulates from other sources than rice have not yet been studied much, despite the fact that rice steryl ferulates (gamma-oryzanol) have been shown to possess good antioxidant activity. In this study, steryl ferulate extracts from wheat or rye bran were studied for their capability to inhibit hydroperoxide formation in bulk methyl linoleate and methyl linoleate emulsion. Further, their activity to scavenge DPPH radicals was analyzed. The activities were compared to synthetic steryl ferulates, rice steryl ferulates, ferulic acid, and alpha-tocopherol. Nonrice cereal extracts of steryl ferulates exhibited good antioxidant activity, especially in the bulk lipid system. The radical scavenging activity was similar to that of nonesterified ferulic acid, indicating that the ferulic acid moiety is responsible for the antioxidant properties. This study illustrates a new aspect to the health-promoting properties of rye and wheat.     

Prevention of hydrolytic rancidity in rice bran during storage.

The effect of microwave heating, packaging, and storage temperature on the production of free fatty acids (FFA) in rice bran was examined. Freshly milled raw rice bran was adjusted to 21% moisture content and heated in a microwave oven at 850 W for 3 min. Raw and microwave-heated rice bran were packed in zipper-top bags or vacuum-sealed bags and stored at 4-5 or 25 degrees C for 16 weeks. FFA content of bran was measured at 4-week intervals. Total FFA increased rapidly over the 16-week period from the initial value of 2.5% in raw bran stored at 25 degrees C to 54.9% in vacuum bags and 48.1% in zipper-top bags. However, total FFA of raw bran stored at 4-5 degrees C increased at a slower rate from an initial value of 2. 5 to 25.4% in vacuum bags and 19.5% in zipper-top bags. After 16 weeks of storage, total FFA of microwave-heated bran stored at 25 degrees C increased from 2.8 to 6.9 and 5.2%, respectively, for samples stored in vacuum bags and zipper-top bags. Total FFA of microwave-heated samples stored at 4-5 degrees C did not change significantly with storage time. Results showed that hydrolytic rancidity of rice bran can be prevented by microwave heating and that the recommended storage condition for microwaved rice bran is 4-5 degrees C in zipper-top bags.     

Prevention of oxidative rancidity in rice bran during storage.

The effect of microwave heat on lipoxygenase (LOX) activity in rice bran under various storage conditions was examined. Raw rice bran from the long-grain variety Lemont was adjusted to 21% moisture content and heated in a microwave oven at 850 W for 3 min. Raw and microwave-heated rice bran samples were packed in zipper-top bags or vacuum packs and stored at room temperature (25 degrees C) or in the refrigerator (4-5 degrees C) for 16 weeks. Samples were analyzed for LOX activity at 4-week intervals. LOX activity did not significantly change from its initial value at week 0 for zipper-top and vacuum-packed samples while stored at 4-5 degrees C for 12 weeks, but decreased at week 16. Vacuum packing did not show a significant impact on LOX activity during 16 weeks of storage. Microwave-heated samples stored in the refrigerator did not show significant change in LOX activity for up to 12 weeks but showed a significant (p < 0. 05) decrease at 16 weeks. Results showed that oxidative rancidity of rice bran could be prevented by microwave heating the samples, packing in zipper-top bags, and storing at 4-5 degrees C for up to 16 weeks.     

Purification and identification of components of gamma-oryzanol in rice bran Oil.

High-purity gamma-oryzanol was obtained from crude rice bran oil using a normal-phase preparative scale HPLC. A reverse-phase HPLC method was used for separating the individual components of gamma-oryzanol present in rice bran oil. Ten fractions were isolated and collected using the reverse-phase HPLC method, and their structures were identified. Identification was accomplished using GC/MS with an electron impact mass spectrum after components were transformed into trimethylsilyl ether derivatives. The 10 components of gamma-oryzanol were identified as Delta(7)-stigmastenyl ferulate, stigmasteryl ferulate, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, Delta(7)-campestenyl ferulate, campesteryl ferulate, Delta(7)-sitostenyl ferulate, sitosteryl ferulate, compestanyl ferulate, and sitostanyl ferulate. Three of these, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, and campesteryl ferulate, were major components of gamma-oryzanol.     

Study of the chemical composition and antimicrobial activities of ethanolic extracts from roots of Scutellaria baicalensis Georgi

Scutellaria baicalensis Georgi (SBG), commonly named Huangqin, showed strong in vitro antimicrobial effects. However, limited research is available to systematically evaluate the effects of extraction methods on the phytochemical composition of SBG and its associated antimicrobial effects. In addition, limited studies have tested SBG as a natural antimicrobial agent on fresh produce such as tomatoes. In the current study, powered roots of SBG were extracted with 60, 80, and 100% ethanol, and their antiviral and antibacterial activities were evaluated. SBG ethanol extracts (SBGEEs) at 6.25 mg/mL showed limited antiviral activities against coliphage MS2 and hepatitis A virus. The SBG 80% ethanol extract (SBG80%EE) exhibited the lowest minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) against six foodborne pathogens. SBG80%EE had the highest contents of flavonoids and phenolic acids determined by high-performance liquid chromatography (HPLC). Among these bioactive compounds, ferulic acid had the lowest MIC and MBC values, 0.4 and 1.0 mg/mL, respectively, followed by baicalein and baicalin. Washing with SBG80%EE (12.5 mg/mL) resulted in >1 log reduction of Salmonella enterica serovars Typhimurium, Kentucky, Senftenberg, and Enteritidis on surface-inoculated grape tomatoes. None of SBGEE solutions changed the total phenolic content, color, or pH values of grape tomatoes. The quantification of these antimicrobial flavonoids and phenolic acids is important to maintain the quality and antimicrobial efficacy of SBG extracts. In addition, the application of SBG on tomatoes has provided valuable insights on the potential usage of this antimicrobial extract.     

Isolation and identification of novel tocotrienols from rice bran with hypocholesterolemic, antioxidant, and antitumor properties

Two novel tocotrienols were isolated from stabilized and heated rice bran, apart from the known alpha-, beta-, gamma-, and delta-tocopherols and tocotrienols. These new tocotrienols were separated by HPLC, using a normal phase silica column. Their structures were determined by ultraviolet, infrared, nuclear magnetic resonance, circular dichroism, and high-resolution mass spectroscopies and established as desmethyl tocotrienol [3, 4-dihydro-2-methyl-2-(4,8,12-trimethyltrideca-3'(E),7'(E), 11'-trienyl)-2H-1-benzopyran-6-ol] and didesmethy tocotrienol [3, 4-dihydro-2-(4,8,12-trimethyltrideca-3'(E),7'(E), 11'-trienyl)-2H-1-benzopyran-6-ol]. These tocotrienols significantly lowered serum total and LDL cholesterol levels and inhibited HMG-CoA reductase activity in chickens. They had much greater in vitro antioxidant activities and greater suppression of B16 melanoma cell proliferation than alpha-tocopherol and known tocotrienols. Results indicated that the number and position of methyl substituents in tocotrienols affect their hypocholesterolemic, antioxidant, and antitumor properties.     

Physicochemical,including spectroscopic,and biological analyses during composting of green tea waste and rice bran

The aims of this study were to monitor the changes in physicochemical, including spectroscopic, and biological characteristics during composting of green tea waste–rice bran compost (GRC) and to define parameters suitable for evaluating the stability of GRC. Compost pile temperature reflected the initiation and stabilization of the composting process. The pH, electrical conductivity, NO₃ ⁻-N content, and carbon-to-nitrogen ratio were measured as chemical properties of the compost. The color (CIELAB variables), humification index (the absorption ratio Q _4/6 = A ₄₇₂ / A ₆₆₄ of 0.5 M NaOH extracts), absorption at 665 nm of acetone extracts, and Fourier-transform infrared (FT-IR) spectra were measured to evaluate the organic matter transformation; germination of komatsuna or tomato seeds was measured to assess the potential phytotoxicity of composting materials during composting. No single parameter was capable of giving substantial information on the composting process, the nutrient balance, phytotoxicity, and organic matter decomposition. The FT-IR spectra at 3,300, 2,930, 2,852, and 1,065 cm⁻¹ provided information on the molecular transformation of GRC during composting and they decreased over the composting. Most of the assayed parameters showed no further change after about 90 days of composting suggesting that GRC can be used for agricultural purposes after this period.     

Effects of microwave heat, packaging, and storage temperature on fatty acid and proximate compositions in rice bran

The effect of microwave heat, packaging methods, and storage temperatures on proximate and fatty acid compositions of rice bran during 16 weeks of storage was examined. Freshly milled raw rice bran was adjusted to 21% moisture content and microwave heated for 3 min. Raw and microwave-heated brans were packed in zipper-top bags and/or vacuum-sealed bags and stored at 4-5 and/or 25 degrees C for 16 weeks. The moisture content decreased significantly from an initial 8.4 to 6.4% in microwave-heated samples regardless of packaging methods and storage temperatures. Protein, fat, linoleic, and linolenic contents did not change significantly in all raw and microwave-heated samples during 16 weeks of storage. The microwave-heated rice bran packed in zipper-top bags can be stored at 4-5 degrees C for up to 16 weeks without adverse effect on proximate and fatty acid composition quality under the conditions employed in this study.     

Antioxidant activities of phenolic,proanthocyanidin, and flavonoid components in extracts of Cassia fistula

Cassia fistula L., a semi-wild Indian Labernum, is widely cultivated in Mauritius as an ornamental tree for its beautiful bunches of yellow flowers and also used in traditional medicine for several indications. The total phenolic, proanthocyanidin, and flavonoid contents, and the antioxidant activities, of fresh vegetative and reproductive organs of Cassia fistula harvested at different stages of growth were determined using the Trolox equivalent antioxidant capacity (TEAC) and ferric-reducing antioxidant power (FRAP) assays. The antioxidant activities were strongly correlated with total phenols (TEAC r = 0.989; FRAP r = 0.951) in all organs studied, and with proanthocyanidins (TEAC r = 0.980; FRAP r = 0.899) in reproductive organs including fruits. The antioxidant activities of reproductive parts were higher than those of the vegetative organs, with the pods having highest total phenolic, proanthocyanidin, and flavonoid contents and antioxidant potentials (TEAC = 992 +/- 0.4 micromol/g dry weight; FRAP = 811 +/- 23 micromol/g dry weight).     

Use of microscopy to assess bran removal patterns in milled rice

During rice milling, the bran and germ are successively removed from the caryopsis (kernel). Because bran and germ contain large quantities of lipid, the amount of lipid remaining on the kernel surface may be used as a method for the assessment of milling quality. Bulk samples of rice pureline varieties and an experimental hybrid were milled for 0, 10, 20, 30, and 40 s. Scanning electron microscopy (SEM) revealed that brown rice kernels had large contours of linear protuberances and depressions running lengthwise along the kernel surface. The protuberances were abraded successively during milling, but varying amounts of material remained in the depressions. Light microscopy combined with the lipid-specific probes Nile Blue A or Sudan Black B demonstrated that the material in the depressions observed with SEM was lipid. Sections of whole, milled rice kernels, prepared using a modified sectioning technique and stained with Nile Blue A, showed that portions of the embryo remain after milling and that lipid is located on or near the surface of the kernel. Differences in quantity and distribution of residual lipid as milling duration increased were documented photographically to indicate the extent to which the bran and embryo components were removed during milling. This paper provides proof of concept that residual lipid is a robust measure of the degree of milling.     

Impact of browning reactions and bran pigments on color of parboiled rice

Rice color changes from white to amber during parboiling (soaking and steaming). Color parameters indicated that, during soaking, yellow bran pigments leached out in the water. The levels of the Maillard precursors (i.e., reducing sugars (RS) and free alpha-amino nitrogen (FAN)) depended on soaking temperature and time: leaching of RS was compensated by enzymic formation for long soaking times (>60 min), while proteolytic activity was too low to compensate for FAN leaching. Rice soaking under nitrogen, oxygen, or ambient conditions and determination of polyphenol oxidase activity allowed us to conclude that the effect of enzymic color changes on the soaked rice color was rather small. Color measurements of brown and milled mildly, intermediately, and severely parboiled rice samples showed that both brown and milled rice samples were darker and more red and yellow after parboiling and that the effect depended on the severity of parboiling conditions. Furthermore, steaming affected the rice color more and in a way opposite to that observed in soaking. The changes in RS and the loss of FAN during parboiling suggested that Maillard type reactions occur during brown rice steaming. Analyses of furosine levels confirmed Maillard browning of outer bran layers and endosperm during steaming. The level of this Maillard indicator increased with the severity of parboiling conditions in both brown and milled parboiled rice. Measurements of the levels of bran pigments indicated that bran pigments diffuse into the endosperm during parboiling and contribute to the parboiled rice color.     

Functional properties of protein isolates extracted from stabilized rice bran by microwave, dry heat, and parboiling

Protein isolates extracted from differently stabilized rice bran were analyzed to work out the food use potential. Bulk density remained higher for isolates obtained from heat stabilized bran, the treatments were found to have positive impact on the oil absorption properties, while the water absorption was slightly impaired owing to some possible configurational changes. Surface hydrophobicity and emulsion properties were improved with bran stabilization. Isolates exhibited better foaming properties owing to the flexible nature of protein molecules, with less intensive disulfide bonding, that were slightly affected by the stabilization treatment. Nitrogen solubility index followed a curved pattern with the least value near isoelectric point that showed an increasing trend toward basic pH, and parboiled protein isolates exhibited better gelling properties among the isolates.