Author
Mitsuru Watanabe
Bio: Mitsuru Watanabe is an academic researcher from Japanese Ministry of Agriculture, Forestry and Fisheries. The author has contributed to research in topics: Rutin & Luteolin. The author has an hindex of 3, co-authored 3 publications receiving 511 citations.
Topics: Rutin, Luteolin, Fagopyrum, Vitexin, Echinochloa
Papers
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TL;DR: In this paper, four catechins and rutin were isolated from ethanol extracts of buckwheat (Fagopyrum esculentum Moench) groats by Sephadex LH-20 column chromatography and preparative HPLC with monitoring of the peroxyl radical scavenging activity.
Abstract: Four catechins and rutin were isolated from ethanol extracts of buckwheat (Fagopyrum esculentum Moench) groats by Sephadex LH-20 column chromatography and preparative HPLC with monitoring of the peroxyl radical scavenging activity. The antioxidant activity of these catechins was higher than that of rutin. The structures of these catechins were established as (−)-epicatechin, (+)-catechin 7-O-β-d-glucopyranoside, (−)-epicatechin 3-O-p-hydroxybenzoate, and (−)-epicatechin 3-O-(3,4-di-O-methyl)gallate on the basis of 1H, 13C, and two-dimensional nuclear magnetic resonance techniques and fast atom bombardment mass spectrometry. The yields of these antioxidant compounds suggest that they are abundant, as is rutin, which is known as a biological phytochemical in buckwheat groats. Keywords: Fagopyrum esculentum; antioxidant activity; flavonoids; (−)-epicatechin; (+)-catechin 7-O-β-d-glucopyranoside; (−)-epicatechin 3-O-p-hydroxybenzoate; (−)-epicatechin 3-O-(3,4-di-O-methyl)gallate
221 citations
TL;DR: In this paper, the buckwheat hulls were separated by Sephadex LH-20 column chromatography into eight fractions and five antioxidant compounds were identified by preparative HPLC and identified as quercetin, hyperin, rutin, protocatechuic acid, and 3,4-dihydroxybenzaldehyde.
Abstract: Ethanolic extracts of buckwheat (Fagopyrum esculentum Moench) hulls were separated by Sephadex LH-20 column chromatography into eight fractions. Five of the fractions exhibited peroxyl radical-scavenging activity by inhibiting the oxidation of methyl linoleate in solution. Two of the antioxidant fractions contained proanthocyanidins (condensed tannins) from the color reaction of these fractions with HCl under heat treatment. Five antioxidant compounds were isolated by preparative HPLC and identified as quercetin, hyperin, rutin, protocatechuic acid, and 3,4-dihydroxybenzaldehyde. The contents of these active compounds in the buckwheat hulls were as follows: protocatechuic acid (13.4 mg/100 g of dried hulls), 3,4-dihydroxybenzaldehyde (6.1 mg/100 g), hyperin (5.0 mg/100 g), rutin (4.3 mg/100 g), and quercetin (2.5 mg/100 g). Besides the isolation of these compounds, two major compounds that showed no peroxyl radical-scavenging activity in the extract were isolated and identified as vitexin and isovitexin.
177 citations
TL;DR: Three antioxidative phenolic compounds, one serotonin derivative and two flavonoids, were isolated from an ethanol extract of Japanese barnyard millet grains by Sephadex LH-20 chromatography and preparative high-performance liquid chromatography, and exhibited strong antioxidant activity almost equivalent to that of butylated hydroxyanisole at the same concentration.
Abstract: Three antioxidative phenolic compounds, one serotonin derivative and two flavonoids, were isolated from an ethanol extract of Japanese barnyard millet (cv. Kurohie) grains by Sephadex LH-20 chromatography and preparative high-performance liquid chromatography. Their structures were established to be N-(p-coumaroyl)serotonin, luteolin, and tricin on the basis of spectrometric data from (1)H and (13)C and two-dimensional nuclear magnetic resonance techniques, fast atom bombardment mass spectrometry, and Fourier transform infrared spectrophotometry. N-(p-Coumaroyl)serotonin exhibited a strong antioxidant activity almost equivalent to that of butylated hydroxyanisole at the same concentration (w/v). Although the antioxidant activity of luteolin was lower than that of N-(p-coumaroyl)serotonin, it was nearly equal to that of quercetin, whereas the activity of tricin was lower than that of luteolin. All of them were newly isolated from Japanese barnyard millet grains.
140 citations
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TL;DR: Phenolic compounds, ubiquitous in plants are an essential part of the human diet, and are of considerable interest due to their antioxidant properties as mentioned in this paper, and their structures may range from a simple phenolic molecule to a complex high-molecular weight polymer.
2,723 citations
TL;DR: A review of phenolic and polyphenolic compounds can be found in this article, which summarizes both the synthetic and natural phenolic antioxidants, emphasizing their mode of action, health effects, degradation products and toxicology.
1,800 citations
TL;DR: In this paper, the authors focus on the extraction of polyphenols from agricultural and industrial wastes, and summarize available data on the factors affecting their antioxidant activity and stability, and, in some cases, the reported major active compounds identified.
1,614 citations
TL;DR: This overview provides a cursory account of the source, extraction and analysis of phenolics in fruits, vegetables and cereals.
1,251 citations
TL;DR: The measurement of antioxidant activities, especially of antioxidants that are mixtures, multifunctional or are acting in complex multiphase systems, cannot be evaluated satisfactorily by a simple antioxidant test without due regard to the many variables influencing the results.
Abstract: Antioxidant activity has been assessed in many ways. The limitation of many newer methods is the frequent lack of an actual substrate in the procedure. The combination of all approaches with the many test methods available explains the large variety of ways in which results of antioxidant testing are reported. The measurement of antioxidant activities, especially of antioxidants that are mixtures, multifunctional or are acting in complex multiphase systems, cannot be evaluated satisfactorily by a simple antioxidant test without due regard to the many variables influencing the results. Several test procedures may be required to evaluate such antioxidant activities. A general method of reporting antioxidant activity independent of the test procedure is proposed.
1,145 citations