Both dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), and its peptic hydrolysates exhibited angiotensin converting enzyme inhibitory activities

Feng-Lin Hsu, Yaw Huei Lin, Mei Hsien Lee, Chuen Liang Lin, Wen Chi Hou

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

Dioscorin, the tuber storage protein of yam (Dioscorea alata cv. Tainong No. 1), was purified to homogeneity by DE-52 ion-exchange chromatography. This purified dioscorin was shown by spectrophotometric methods to inhibit angiotensin converting enzyme (ACE) in a dose-dependent manner (12.5-750 μg, respectively, 20.83-62.5% inhibitions) using N-[3-(2-furyl)acryloyl]-Phe-Gly-Gly (FAPGG) as substrates. The 50% inhibition (IC50) of ACE activity was 6.404 μM dioscorin (250 μg corresponding to 7.81 nmol) compared to that of 0.00781 μM (0.0095 nmol) for captopril. The commercial bovine serum albumin and casein (bovine milk) showed less ACE inhibitory activity. The use of qualitative TLC also showed dioscorin as ACE inhibitors. Dioscorin showed mixed noncompetitive inhibitions against ACE; when 31.25 μg of dioscorin (0.8 μM) was added, the apparent inhibition constant (Ki) was 2.738 μM. Pepsin was used for dioscorin hydrolysis at 37 °C for different times. It was found that the ACE inhibitory activity was increased from 51.32% to about 75% during 32 h hydrolysis. The smaller peptides were increased with increasing pepsin hydrolytic times. Dioscorin and its hydrolysates might be a potential for hypertension control when people consume yam tuber.

Original languageEnglish
Pages (from-to)6109-6113
Number of pages5
JournalJournal of Agricultural and Food Chemistry
Volume50
Issue number21
DOIs
Publication statusPublished - Oct 9 2002

Keywords

  • Angiotensin converting enzyme (ACE)
  • Dioscorin
  • Mixed-type inhibition
  • N-[3-(2-furyl)acryloyl]-Phe-Gly-Gly (FAPGG)
  • Pepsin
  • Yam

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Food Science
  • Chemistry (miscellaneous)

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