Different Polyphenolic Components of Soft Fruits Inhibit α-Amylase and α-Glucosidase

G.J. McDougall, F Shpiro, P. Dobson, P. Smith, A. Blake, D. Stewart

    Research output: Contribution to journalArticle

    Abstract

    Polyphenol-rich extracts from soft fruits were tested for their ability to inhibit a-amylase and a-glucosidase. All extracts tested caused some inhibition of a-amylase, but there was a 10-fold difference between the least and most effective extracts. Strawberry and raspberry extracts were more effective a-amylase inhibitors than blueberry, blackcurrant, or red cabbage. Conversely, a-glucosidase was more readily inhibited by blueberry and blackcurrant extracts. The extent of inhibition of a-glucosidase was related to their anthocyanin content. For example, blueberry and blackcurrant extracts, which have the highest anthocyanin content, were the most effective inhibitors of a-glucosidase. The extracts most effective in inhibiting a-amylase (strawberry and raspberry) contain appreciable amounts of soluble tannins. Other tannin-rich extracts (red grape, red wine, and green tea) were also effective inhibitors of a-amylase. Indeed, removing tannins from strawberry extracts with gelatin also removed inhibition. Fractionation of raspberry extracts on Sephadex LH-20 produced an unbound fraction enriched in anthocyanins and a bound fraction enriched in tannin-like polyphenols. The unbound anthocyanin-enriched fraction was more effective against a-glucosidase than the original extract, whereas the a-amylase inhibitors were concentrated in the bound fraction. The LH-20 bound sample was separated by preparative HPLC, and fractions were assayed for inhibition of a-amylase. The inhibitory components were identified as ellagitannins using LC-MS-MS. This study suggests that different polyphenolic components of fruits may influence different steps in starch digestion in a synergistic manner.
    Copyright © 2005 American Chemical Society
    Original languageEnglish
    Pages (from-to)2760-2766
    Number of pages7
    JournalJournal of Agricultural and Food Chemistry
    Volume53
    Issue number7
    DOIs
    Publication statusPublished - 2005

    Fingerprint

    glucosidases
    amylases
    small fruits
    polyphenols
    extracts
    black currants
    tannins
    anthocyanins
    raspberries
    blueberries
    strawberries
    green tea
    red wines
    gelatin
    cabbage
    grapes
    fractionation
    digestion
    starch

    Keywords

    • α-Amylase
    • α-glucosidase
    • anthocyanins
    • ellagitannins
    • inhibition
    • starch digestion

    Cite this

    McDougall, G.J. ; Shpiro, F ; Dobson, P. ; Smith, P. ; Blake, A. ; Stewart, D. / Different Polyphenolic Components of Soft Fruits Inhibit α-Amylase and α-Glucosidase. In: Journal of Agricultural and Food Chemistry. 2005 ; Vol. 53, No. 7. pp. 2760-2766.
    @article{7ef85728c5c04f98bcd1684730f1fba8,
    title = "Different Polyphenolic Components of Soft Fruits Inhibit α-Amylase and α-Glucosidase",
    abstract = "Polyphenol-rich extracts from soft fruits were tested for their ability to inhibit a-amylase and a-glucosidase. All extracts tested caused some inhibition of a-amylase, but there was a 10-fold difference between the least and most effective extracts. Strawberry and raspberry extracts were more effective a-amylase inhibitors than blueberry, blackcurrant, or red cabbage. Conversely, a-glucosidase was more readily inhibited by blueberry and blackcurrant extracts. The extent of inhibition of a-glucosidase was related to their anthocyanin content. For example, blueberry and blackcurrant extracts, which have the highest anthocyanin content, were the most effective inhibitors of a-glucosidase. The extracts most effective in inhibiting a-amylase (strawberry and raspberry) contain appreciable amounts of soluble tannins. Other tannin-rich extracts (red grape, red wine, and green tea) were also effective inhibitors of a-amylase. Indeed, removing tannins from strawberry extracts with gelatin also removed inhibition. Fractionation of raspberry extracts on Sephadex LH-20 produced an unbound fraction enriched in anthocyanins and a bound fraction enriched in tannin-like polyphenols. The unbound anthocyanin-enriched fraction was more effective against a-glucosidase than the original extract, whereas the a-amylase inhibitors were concentrated in the bound fraction. The LH-20 bound sample was separated by preparative HPLC, and fractions were assayed for inhibition of a-amylase. The inhibitory components were identified as ellagitannins using LC-MS-MS. This study suggests that different polyphenolic components of fruits may influence different steps in starch digestion in a synergistic manner.Copyright {\circledC} 2005 American Chemical Society",
    keywords = "α-Amylase, α-glucosidase, anthocyanins, ellagitannins, inhibition, starch digestion",
    author = "G.J. McDougall and F Shpiro and P. Dobson and P. Smith and A. Blake and D. Stewart",
    year = "2005",
    doi = "10.1021/jf0489926",
    language = "English",
    volume = "53",
    pages = "2760--2766",
    journal = "Journal of Agricultural and Food Chemistry",
    issn = "0021-8561",
    publisher = "American Chemical Society",
    number = "7",

    }

    Different Polyphenolic Components of Soft Fruits Inhibit α-Amylase and α-Glucosidase. / McDougall, G.J.; Shpiro, F; Dobson, P.; Smith, P.; Blake, A.; Stewart, D.

    In: Journal of Agricultural and Food Chemistry, Vol. 53, No. 7, 2005, p. 2760-2766.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Different Polyphenolic Components of Soft Fruits Inhibit α-Amylase and α-Glucosidase

    AU - McDougall, G.J.

    AU - Shpiro, F

    AU - Dobson, P.

    AU - Smith, P.

    AU - Blake, A.

    AU - Stewart, D.

    PY - 2005

    Y1 - 2005

    N2 - Polyphenol-rich extracts from soft fruits were tested for their ability to inhibit a-amylase and a-glucosidase. All extracts tested caused some inhibition of a-amylase, but there was a 10-fold difference between the least and most effective extracts. Strawberry and raspberry extracts were more effective a-amylase inhibitors than blueberry, blackcurrant, or red cabbage. Conversely, a-glucosidase was more readily inhibited by blueberry and blackcurrant extracts. The extent of inhibition of a-glucosidase was related to their anthocyanin content. For example, blueberry and blackcurrant extracts, which have the highest anthocyanin content, were the most effective inhibitors of a-glucosidase. The extracts most effective in inhibiting a-amylase (strawberry and raspberry) contain appreciable amounts of soluble tannins. Other tannin-rich extracts (red grape, red wine, and green tea) were also effective inhibitors of a-amylase. Indeed, removing tannins from strawberry extracts with gelatin also removed inhibition. Fractionation of raspberry extracts on Sephadex LH-20 produced an unbound fraction enriched in anthocyanins and a bound fraction enriched in tannin-like polyphenols. The unbound anthocyanin-enriched fraction was more effective against a-glucosidase than the original extract, whereas the a-amylase inhibitors were concentrated in the bound fraction. The LH-20 bound sample was separated by preparative HPLC, and fractions were assayed for inhibition of a-amylase. The inhibitory components were identified as ellagitannins using LC-MS-MS. This study suggests that different polyphenolic components of fruits may influence different steps in starch digestion in a synergistic manner.Copyright © 2005 American Chemical Society

    AB - Polyphenol-rich extracts from soft fruits were tested for their ability to inhibit a-amylase and a-glucosidase. All extracts tested caused some inhibition of a-amylase, but there was a 10-fold difference between the least and most effective extracts. Strawberry and raspberry extracts were more effective a-amylase inhibitors than blueberry, blackcurrant, or red cabbage. Conversely, a-glucosidase was more readily inhibited by blueberry and blackcurrant extracts. The extent of inhibition of a-glucosidase was related to their anthocyanin content. For example, blueberry and blackcurrant extracts, which have the highest anthocyanin content, were the most effective inhibitors of a-glucosidase. The extracts most effective in inhibiting a-amylase (strawberry and raspberry) contain appreciable amounts of soluble tannins. Other tannin-rich extracts (red grape, red wine, and green tea) were also effective inhibitors of a-amylase. Indeed, removing tannins from strawberry extracts with gelatin also removed inhibition. Fractionation of raspberry extracts on Sephadex LH-20 produced an unbound fraction enriched in anthocyanins and a bound fraction enriched in tannin-like polyphenols. The unbound anthocyanin-enriched fraction was more effective against a-glucosidase than the original extract, whereas the a-amylase inhibitors were concentrated in the bound fraction. The LH-20 bound sample was separated by preparative HPLC, and fractions were assayed for inhibition of a-amylase. The inhibitory components were identified as ellagitannins using LC-MS-MS. This study suggests that different polyphenolic components of fruits may influence different steps in starch digestion in a synergistic manner.Copyright © 2005 American Chemical Society

    KW - α-Amylase

    KW - α-glucosidase

    KW - anthocyanins

    KW - ellagitannins

    KW - inhibition

    KW - starch digestion

    U2 - 10.1021/jf0489926

    DO - 10.1021/jf0489926

    M3 - Article

    VL - 53

    SP - 2760

    EP - 2766

    JO - Journal of Agricultural and Food Chemistry

    JF - Journal of Agricultural and Food Chemistry

    SN - 0021-8561

    IS - 7

    ER -