Categories
BLOG

alpha 17 seeds

First identification of α-glucosidase inhibitors from okra (Abelmoschus esculentus) seeds

Affiliation

  • 1 Program of Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
  • PMID: 24079173

First identification of α-glucosidase inhibitors from okra (Abelmoschus esculentus) seeds

  • Search in PubMed
  • Search in NLM Catalog
  • Add to Search

Authors

Affiliation

  • 1 Program of Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
  • PMID: 24079173

Abstract

Infusion of roasted okra seeds has long been consumed in Turkey for diabetes mellitus therapy. Previous reports of a hypoglycemic effect observed in rats administrated with okra seed extract indicated a possible connection with inhibition of intestinal alpha-glucosidase. An attempt to identify active components was first herein conducted using alpha-glucosidase-inhibition-guided isolation, yielding two major flavonol glucosides named isoquercetin (2) and quercetin-3-O-beta-glucopyranosyl-(1″‘ –> 6″)-glucoside (3). They selectively inhibited rat intestinal maltase and sucrase, in which isoquercetin (2) was 6-10 times more potent than its related diglucoside 3. This result suggested that an increase in hydrophilicity by the additional glucose residue in 3 led to a significant decline in the inhibitory effect and raised the possible involvement of the free 3-OH in exerting the inhibition. Our postulation was evaluated by examining alpha-glucosidase inhibition of quercetin (1), and the aglycone of 2 and 3, whose 3-OH is free from any glucose moiety. Interestingly, 1 displayed a broad inhibitory effect toward rat intestinal and baker’s yeast alpha-glucosidases, with improved potency. A kinetic study of 1 indicated that it inhibited maltase by two distinct mechanisms, in competitive (K(i) 462 microM) and noncompetitive (K(i) 2153 microM) manners, whereas the mechanism underlying the inhibition of sucrase was verified as being of a competitive behavior (K(i) 218 microM).

Infusion of roasted okra seeds has long been consumed in Turkey for diabetes mellitus therapy. Previous reports of a hypoglycemic effect observed in rats administrated with okra seed extract indicated a possible connection with inhibition of intestinal alpha-glucosidase. An attempt to identify activ …

Expression of a bacterial alpha-amylase gene in transgenic rice seeds

Affiliation

  • 1 Institute of Insect Sciences and National Key Laboratory of Rice Biology, School of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
  • PMID: 17926139
  • DOI: 10.1007/s11248-007-9144-5

Expression of a bacterial alpha-amylase gene in transgenic rice seeds

  • Search in PubMed
  • Search in NLM Catalog
  • Add to Search

Authors

Affiliation

  • 1 Institute of Insect Sciences and National Key Laboratory of Rice Biology, School of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
  • PMID: 17926139
  • DOI: 10.1007/s11248-007-9144-5

Abstract

An alpha-amylase gene from Bacillus stearothermophilus under the control of the promoter of a major rice-seed storage protein was introduced into rice. The transgenic line with the highest alpha-amylase activity reached about 15,000 U/g of seeds (one unit is defined as the amount of enzyme that produces 1 mumol of reducing sugar in 1 min at 70 degrees C). The enzyme produced in the seeds had an optimum pH of 5.0-5.5 and optimum temperature of 60-70 degrees C. Without extraction or purification, the power of transgenic rice seeds was able to liquify 100 times its weight of corn powder in 2 h. Thus, the transgenic rice could be used for industrial starch liquefaction.

An alpha-amylase gene from Bacillus stearothermophilus under the control of the promoter of a major rice-seed storage protein was introduced into rice. The transgenic line with the highest alpha-amylase activity reached about 15,000 U/g of seeds (one unit is defined as the amount of enzyme that prod …