Antioxidant Compounds from Buckwheat (<i>Fagopyrum esculentum</i> Möench) Hulls
Mitsuru Watanabe, Yasuo Ohshita, Tojiro Tsushida
Journal of Agricultural and Food Chemistry
Abstract
Ethanolic extracts of buckwheat (Fagopyrum esculentum Möench) 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. Keywords: Fagopyrum esculentum; antioxidant activity; flavonoids; phenolic compounds; proanthocyanidin
Extracted Claims
3 claims extracted from this paper into the knowledge graph
Two antioxidant fractions contained proanthocyanidins (condensed tannins)
“Two of the antioxidant fractions contained proanthocyanidins (condensed tannins) from the color reaction of these fractions with HCl under heat treatment”
Ethanolic extracts of buckwheat (Fagopyrum esculentum Möench) hulls exhibited peroxyl radical-scavenging activity
“Five of the fractions exhibited peroxyl radical-scavenging activity by inhibiting the oxidation of methyl linoleate in solution”
Buckwheat hulls contained 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), rut...”