Inhibition of 伪-Amylase and Glucoamylase by Tannins Extracted from Cocoa, Pomegranates, Cranberries, and Grapes
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- 作者：Ann Barrett ; Tshinanne Ndou ; Christine A. Hughey ; Christine Straut ; Amy Howell ; Zifei Dai ; Gonul Kaletunc
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2013
- 出版时间：February 20, 2013
- 年：2013
- 卷：61
- 期：7
- 页码：1477-1486
- 全文大小：465K
- 年卷期：v.61,no.7(February 20, 2013)
- ISSN：1520-5118
文摘
Proanthocyanidins and ellagitannins, referred to as 鈥渢annins鈥? exist in many plant sources. These compounds interact with proteins due to their numerous hydroxyl groups, which are suitable for hydrophobic associations. It was hypothesized that tannins could bind to the digestive enzymes 伪-amylase and glucoamylase, thereby inhibiting starch hydrolysis. Slowed starch digestion can theoretically increase satiety by modulating glucose 鈥渟piking鈥?and depletion that occurs after carbohydrate-rich meals. Tannins were isolated from extracts of pomegranate, cranberry, grape, and cocoa and these isolates tested for effectiveness to inhibit the activity of 伪-amylase and glucoamylase in vitro. The compositions of the isolates were confirmed by NMR and LC/MS analysis, and tannin鈥損rotein interactions were investigated using relevant enzyme assays and differential scanning calorimetry (DSC). The results demonstrated inhibition of each enzyme by each tannin, but with variation in magnitude. In general, larger and more complex tannins, such as those in pomegranate and cranberry, more effectively inhibited the enzymes than did less polymerized cocoa tannins. Interaction of the tannins with the enzymes was confirmed through calorimetric measurements of changes in enzyme thermal stability.