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Purification and Characterization of Polyphenols from Chestnut Astringent Skin
- Tsujita, Takahiro, Yamada, Misato, Takaku, Takeshi, Shintani, Tomoyoshi, Teramoto, Kanae, Sato, Takafumi
- Journal of agricultural and food chemistry 2011 v.59 no.16 pp. 8646-8654
- Castanea, alpha-amylase, antioxidant activity, blood glucose, corn starch, dialysis, ellagic acid, gallic acid, oral administration, proanthocyanidins, procyanidins, rats, tannins
- Polyphenolic compounds from chestnut astringent skin (CAS) were purified by dialysis, using Diaion HP-20 and Sephadex LH-20 columns. During purification, specific alpha-amylase inhibitory activities were increased about 3.4-fold, and the 50% inhibition value was 5.71 micrograms/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.