title: Purification and characterization of polyphenols from chestnut astringent skin.
abstract: Polyphenolic compounds from chestnut astringent skin (CAS) were purified by dialysis, using Diaion HP-20 and Sephadex LH-20 columns. During purification, specific α-amylase inhibitory activities were increased about 3.4-fold, and the 50% inhibition value was 5.71 μg/mL in the Sephadex LH-20 fraction (SE-fraction). The SE-fraction contained about 67% of the total polyphenols, 57.3% of the flavanol-type tannins, and 51.3% of the procyanidins. Strong antioxidant activity was observed in the SE-fraction. Oral administration of the SE-fraction in rats fed corn starch significantly suppressed an increase in blood glucose levels. The SE-fraction contained gallic acid and ellagic acid. The MALDI-TOF spectrum showed a peak series exhibiting a mass increment of 288 Da, reflecting the variation in the number of catechin/epicatechin units. Our results suggest CAS contains polyphenols with strong α-amylase inhibitory activity. The data also suggest CAS polyphenols might be oligomeric proanthocyanidins with gallic acid and ellagic acid.
authors.affiliation: Bioscience, Integrated Center for Sciences, Ehime University, Shitsukawa, Toon, Ehime, Japan. tsujita@m.ehime-u.ac.jp
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsujita
authors.forename: Misato
authors.initials: M
authors.lastname: Yamada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takaku
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Shintani
authors.forename: Kanae
authors.initials: K
authors.lastname: Teramoto
authors.forename: Takafumi
authors.initials: T
authors.lastname: Sato
mesh_terms: D031319:Aesculus / Q000737:chemistry*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry; D059808:Polyphenols / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D044945:Proanthocyanidins / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D012639:Seeds / Q000737:chemistry*; D013552:Swine; D013634:Tannins / Q000302:isolation & purification; D000516:alpha-Amylases / Q000037:antagonists & inhibitors
chemical_list: D001786:Blood Glucose; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D059808:Polyphenols; D044945:Proanthocyanidins; D013634:Tannins; D000516:alpha-Amylases