Radical Scavenging Activity against 1,1-Diphenyl-2-picrylhydrazyl of Ascorbic Acid 2-Glucoside (AA-2G) and 6-Acyl-AA-2G.

Fujinami, Yoshihito; Tai, Akihiro; Yamamoto, Ichiro

doi:10.1248/cpb.49.642

Cited by 81 publications

(53 citation statements)

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“…A calibration curve was constructed using gallic acid as the standard. 2.3.5 DPPH radical scavenging activity The DPPH radical scavenging activity of the defatted rice bran extracts was determined according to the method developed by Fujinami et al 30 with some modifications.…”

Section: Total Phenolic Contentmentioning

confidence: 99%

Characteristics and antioxidative ability of defatted rice bran extracts obtained using several extractants under subcritical conditions

Chiou¹,

Ogino²,

Kobayashi³

et al. 2013

J. Oleo Sci.

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Section: Total Phenolic Contentmentioning

confidence: 99%

Characteristics and antioxidative ability of defatted rice bran extracts obtained using several extractants under subcritical conditions

Chiou¹,

Ogino²,

Kobayashi³

et al. 2013

J. Oleo Sci.

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“…DPPH radical scavenging activity The DPPH radical scavenging activity of the reaction mixture was evaluated (Fujinami et al, 2001). A 0.2 mL aliquot of 0.5 mmol/ L DPPH in ethanol was added to 0.8 mL of the adequately diluted reaction mixture or L-ascorbic acid as the standard.…”

Section: Introductionmentioning

confidence: 99%

“…at 0.4 mL/ min. The elution profile was monitored using the RID-10A refractometer.pH measurement The pH of the reactor effluent was measured at room temperature using a Horiba F-13 pH meter (Kyoto, Japan).UV-Vis absorption spectra The reactor effluents for GlcNAc and glucosamine were diluted 240 and 100 times, respectively, with distilled water to measure the UV-Vis absorption spectra at 200 to 350 nm using a Shimadzu UV-1600 spectrophotometer (Kyoto, Japan).DPPH radical scavenging activity The DPPH radical scavenging activity of the reaction mixture was evaluated (Fujinami et al, 2001). A 0.2 mL aliquot of 0.5 mmol/ L DPPH in ethanol was added to 0.8 mL of the adequately diluted reaction mixture or L-ascorbic acid as the standard.…”

mentioning

confidence: 99%

Degradation of N-Acetyl-D-glucosamine and D-Glucosamine in Subcritical Water and Properties of the Degradation Products

Wang

Kobayashi

Adachi

2011

FSTR

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The degradation processes of N-acetyl-d-glucosamine (GlcNAc) and d-glucosamine in subcritical water were measured using a continuous tubular reactor at 170 to 210℃, and at 190 to 230℃, respectively. The degradation processes obeyed first-order kinetics in the tested temperature ranges. The temperature dependences of the degradation rate constants could be expressed by the Arrhenius equation, and the activation energies and the pre-exponential factors for GlcNAc and glucosamine were estimated to be 126 kJ/mol and 2.83 × 10 12 s -1 , and 130 kJ/mol and 2.11 × 10 12 s -1 , respectively. The pH values of the reaction mixtures, which were measured at room temperature, decreased for both substrates during degradation.The main degradation product of glucosamine was determined to be 5-(hydroxymethyl)-furfural. The degradation product of glucosamine possessed weak radical-scavenging ability, while that of GlcNAc did not. Keywords: N-acetyl-d-glucosamine, degradation kinetics, d-glucosamine, 5-(hydroxyl-methyl)-furfural, subcritical water*To whom correspondence should be addressed. E-mail: adachi@kais.kyoto-u.ac.jp IntroductionWater that maintains its liquid state at elevated temperatures lower than its critical temperature under pressurized conditions is referred as to subcritical water. Subcritical water has two features distinct from ambient water: a low relative dielectric constant and a high ion product (Marshal and Franck, 1981). The relative dielectric constant of water decreases as the temperature increases (Archer and Wang, 1990). Because subcritical water is non-toxic and non-flammable, it holds promise as an extractant for recovering useful substances from agricultural resources or waste (Hartone et al., 1997;Herrero et al., 2006;Hata et al., 2008;Wiboonsirikul and Adachi, 2008).The ion product of subcritical water is higher by three orders of magnitude than that of ambient water (Marshal and Franck, 1981). This feature indicates that subcritical water can act as an acid or base catalyst, and indeed, the hydrolyses of biological substances such as cellulose (Sasaki et al., 1998), proteins (Yoshida et al., 1999 and fatty acid esters (Khuwijitjaru et al., 2004) have been reported. Subcritical water also catalyzes isomerizations (Usuki et al., 2007) and other chemical reactions (Holliday et al., 1998;Asano et al., 2005).Subcritical water extraction has been extensively investigated for the effective utilization of agricultural or food wastes . Chemical reactions can occur simultaneously during the extraction due to the high ion product of the subcritical water. Detailed knowledge of these reactions is crucial for the reasonable design and operation of the extraction processes. However, our knowledge of reactions in subcritical water is rather limited compared to application-oriented studies. Since saccharides are major components in the wastes, we investigated the degradation or hydrolysis kinetics of neutral mono- (Haghighart Khajavi et al., 2005a), di-(Oomori et al., 2004 Haghighart Khajavi et al., 2005b), tri...

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“…The calibration curve was constructed using standard BSA solutions. Every extract was assayed at least in triplicate.DPPH radical scavenging activity The DPPH radical scavenging activity of the defatted rice bran extracts was evaluated following the method reported by Fujinami et al (2001) with some modifications. Approximately 39.4 mg of DPPH was made up to 200 mL with ethanol.…”

mentioning

confidence: 99%

Properties of Extract Obtained from Defatted Rice Bran by Extraction with Aqueous Ethanol under Subcritical Conditions

Chiou

Neoh

Kobayashi

et al. 2012

FSTR

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Defatted rice bran was treated with water or aqueous ethanol under subcritical conditions to recover materials with antioxidative activity. The extraction conditions, namely ethanol concentration (10 − 100% (v/v)), temperature (120 − 237℃) and time after attainment of a desired temperature (5 − 60 min), were studied. On the basis of the determinations of total carbohydrate, protein and phenolic contents, yield, DPPH radical scavenging activity, and antioxidative activity against oxidation of bulk linoleic acid, the extraction with 20% (v/v) ethanol at 237℃ for 5 min was concluded to be comparatively more efficient than that by subcritical water at the same extraction temperature for the same length of time.Keywords: defatted rice bran, extraction, subcritical water, antioxidative activity, ethanol *To whom correspondence should be addressed. E-mail: adachi@kais.kyoto-u.ac.jp IntroductionRice bran (Oryza sativa) is a byproduct from the rice milling or polishing process of brown rice to produce more visually appealing white rice. In Japan, about 0.88 million tons of rice bran are produced every year, which accounts for approximately 10% of the annual rice production of the country. Defatted rice bran finds uses in animal feeds and fertilizers, but still most of it is discarded as an agricultural waste. Despite its considerable contents of several useful substances, this resource has yet to be fully utilized. The dietary fiber from defatted rice bran was found to exhibit higher water-binding, fat-binding, and emulsifying capacities than that from sugar beet (Abdul-Hamid and Luan, 2000). Defatted rice bran also contains phenolic compounds that have antioxidative (Cuvelier et al., 1992;Graf, 1992), ultraviolet absorbing (Castelluccio et al., 1995), and anti-tumor activities (Han et al., 2001). Several extraction methods, namely the extraction by organic solvents such as methanol (Iqbal et al., 2005), ethanol (Kaneda et al., 2004), and acetone (Chung and Woo, 2001) and non-organic solvents such as supercritical carbon dioxide (Kim et al., 1999), have been the subject of study to recover these functional substances. The organic solvent extraction is a time consuming process and the extensive use of organic solvents also causes pollution. Likewise, the treatment with supercritical carbon dioxide involves a great amount of carbon dioxide which is a predominant anthropogenic greenhouse gas. On the contrary, subcritical water treatment provides an environmentally friendly option for effective extraction of functional substances from food and agricultural wastes (Hata et al., 2008;Pourali et al., 2009;Watchararuji et al., 2008;Wiboonsirikul et al., 2007a;2007b).Subcritical water is water at over 100℃ that is compressed to maintain its liquid state below the critical point. The dielectric constant of water decreases from 80 to 27 with heating from room temperature to 250℃, which is similar to that of ethanol under ordinary pressure (Herrero et al., 2006;Miller and Hawthorne, 2000). At high temperatures, the substantially inc...

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Radical Scavenging Activity against 1,1-Diphenyl-2-picrylhydrazyl of Ascorbic Acid 2-Glucoside (AA-2G) and 6-Acyl-AA-2G.

Cited by 81 publications

References 11 publications

Characteristics and antioxidative ability of defatted rice bran extracts obtained using several extractants under subcritical conditions

Characteristics and antioxidative ability of defatted rice bran extracts obtained using several extractants under subcritical conditions

Degradation of N-Acetyl-D-glucosamine and D-Glucosamine in Subcritical Water and Properties of the Degradation Products

Properties of Extract Obtained from Defatted Rice Bran by Extraction with Aqueous Ethanol under Subcritical Conditions

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