Arctostaphylos Uva-Ursi

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F. Mortier - One of the best experts on this subject based on the ideXlab platform.

D. Beaux - One of the best experts on this subject based on the ideXlab platform.

J. Fleurentin - One of the best experts on this subject based on the ideXlab platform.

Ryszard Amarowicz - One of the best experts on this subject based on the ideXlab platform.

  • CHROMATOGRAPHIC SEPARATION OF TANNIN FRACTIONS FROM A BEARBERRY-LEAF (Arctostaphylos Uva-Ursi L. SPRENGEL) EXTRACT BY SE-HPLC : A SHORT REPORT
    Polish Journal of Food and Nutrition Sciences, 2020
    Co-Authors: Ronald B. Pegg, Anna Rybarczyk, Ryszard Amarowicz
    Abstract:

    Phenolic compounds from the leaves of the bearberry plant (Arctostaphylos Uva-Ursi L. Sprengel) were extracted into 95% (v/v) ethanol. Tannin fractions were obtained by Sephadex LH-20 column chromatography using 50% (v/v) acetone as the mobile phase. The tannin fraction was then further characterised by size exclusion high-performance liquid chromatography (SE-HPLC) on a TSK G2000SWXL column with a mobile phase comprising 45% acetonitrile and 0.1% (v/v) TFA. The chromatography revealed the presence of additional phenolic compounds in the tannin fractions which are not proanthocyanidins (i.e. condensed tannins).

  • Antioxidant activity of polyphenolics from a bearberry-leaf (Arctostaphylos Uva-Ursi L. Sprengel) extract in meat systems.
    2020
    Co-Authors: R.b. Pegg, Ryszard Amarowicz, Marian Naczk, Fereidoon Shahidi, Chi-tang Ho
    Abstract:

    Bearberry-leaf (Arctostaphylos Uva-Ursi L. Sprengel) extract possesses marked antioxidant activity in model and meat systems. A crude ethanolic extract ofbearberry leaves was dechlorophyllized using a silicic acid column,and then fractionated by Sephadex LH-20 column chromatography using ethanol (95%, v/v) and acetone (50%, v/v) as the mobile phases. According to a mass balance, the ethanol fraction comprised 79.2% of the starting material, while the acetone fraction consisted of 9.7%. The content of total phenolics for the fractions and subtractions ranged from 2135 to 9110 Abs 7 2 5 units/g extract. Even though the acetone fraction was only ca. 10% of the crude extract, its vanillin response was five times greater than that of the ethanol fraction. According to a mass balance of this fraction, ca. 50% of the polyphenolics remained in the aqueous phase when partitioned between water and ethyl acetate. refrigerated storage by 97.0,49.1 and 100%, respectively, when added at a 200-ppm concentration. The ethanol fraction exhibited a classical dose response: when incorporated in meat systems at levels of 200- and 500-ppm before thermal processing, TBARS development was inhibited by 49.7 and 93.9%, respectively, after seven days. This [ethanol] fraction was further subdivided into vanillin-positive constituents; the vanillin-positive fraction possessed weak antioxidant activity in meat model systems, and in some cases demonstrated a slight pro-oxidant effect. The acetone fraction also showed a classical dose response. When added to meat systems at levels of 25-, 50- and 100-ppm, TBARS formation was inhibited by 36.7, 91.4 and 100%, respectively, after seven days of refrigerated storage. It was interesting to note that a subfraction from the acetone product, which was soluble in ethyl acetate but did not have a positive reaction with vanillin, imparted strong antioxidant activity in meat systems. Therefore, vanillin-positive reaction constituents (i.e., condensed tannins) are not solely responsible for the antioxidant activity observed from the bearberry-leaf extract.

  • SE-HPLC separation of myosin complex with tannins of bearberry (Arctostaphylos Uva-Ursi L. Sprengel) leaves - a short report.
    Czech Journal of Food Sciences, 2018
    Co-Authors: Ryszard Amarowicz, Ronald B. Pegg, Agnieszka Kosinska
    Abstract:

    Amarowicz R., Pegg R.B., Kosinska A . (2009): SE-HPLC separation of myosin complex with tannins from bearberries (Arctostaphylos Uva-Ursi L. Sprengel) leaves – a short communication. Czech J. Food Sci., 27: 386–391. Phenolic compounds were extracted from bearberry (Uva-Ursi L. Sprengel) leaves into 95% (v/v) etha nol. The tannin constituents were separated from the crude extract using Sephadex LH-20 column chromatography with 95% (v/v) ethanol and 50% (v/v) acetone as the mobile phases. Myosin was isolated and purified from excised pork knuckle muscles using the standard salt-solution extraction procedure followed by gel filtration chromatogra phy. Myosin was precipitated from the solution with bearberry-leaf tannins at pH 5.0. The recovered complex was washed, lyophilised, and subjected to size-exclusion high performance liquid chromatography (SE-HPLC). Based on the basic conditions of the HPLC analysis, a portion of the tannin constituents was liberated from the complex. The UV spectra of these compounds were characterized by a maximum at ~ 300 nm. A portion of the tannins was present in the complex with myosin, and this was confirmed by UV spectra.

  • Protein-precipitating capacity of bearberry-leaf (Arctostaphylos Uva-Ursi L. Sprengel) polyphenolics
    Food Chemistry, 2011
    Co-Authors: Marian Naczk, Ronald B. Pegg, Ryszard Amarowicz
    Abstract:

    Abstract Polyphenolics (PP) from bearberry (Arctostaphylos Uva-Ursi L. Sprengel) leaves were extracted with 70% (v/v) acetone. The lyophilised crude PP extract was then separated on a Sephadex LH-20 column using first 95% (v/v) ethanol as a mobile phase to elute fraction I low in tannins, and then 50% (v/v) acetone to elute fraction II rich in hydrolysable and condensed tannins. Bovine serum albumin (BSA) was effectively precipitated by PP in the bearberry-leaf crude extract and fraction II at pH values between 3.8 and 4.5. A statistically significant (P = 0.0001) linear relationship exists between the amount of PP-protein complex formed and the quantity of PP added to the reaction mixture. The slope values of these lines indicate that fraction II from the crude extract was a more effective precipitant of proteins than other examined preparations. Based on the quantity of gelatine, fetuin, and BSA required to inhibit 50% of dye-labelled PP–BSA complex precipitation, gelatine was 3–6 times more effective as a precipitation inhibitor than both unlabelled BSA and fetuin.

  • Free-radical scavenging capacity and antioxidant activity of selected plant species from the Canadian prairies
    Food Chemistry, 2004
    Co-Authors: Ryszard Amarowicz, Ronald B. Pegg, Branka Barl, P. Rahimi-moghaddam, J.a. Weil
    Abstract:

    Ethanolic extracts from the roots of wild licorice (Glycyrrhiza lepidota), narrow-leaved echinacea (Echinacea angustifolia), senega (Polygala senega), leaves of bearberry (Arctostaphylos Uva-Ursi) and aerial parts of two varieties of horsetail (Equisetum spp.) were prepared and evaluated for their free-radical scavenging capacity and their antioxidant activity, by a number of chemical assays. Assays employed included a b-carotene-linoleic acid (linoleate) model system, reducing power, scavenging effect on the DPPH � free radical and capacity to scavenge hydroxyl free radicals (HO � ), by use of electron paramagnetic resonance (EPR) spectroscopy. The bearberry-leaf extract consistently exhibited the highest antioxidant activity based on the tests performed, and seems to be a promising source of natural antioxidants. The polyphenolic constituents appear to be responsible, at least in part, for the extract’s radical-scavenging capacity. Research is progressing to characterize the antioxidant compounds in the bearberry-leaf extract and their mode of action in imparting antioxidant activity to various food systems. # 2003 Elsevier Ltd. All rights reserved.

Ronald B. Pegg - One of the best experts on this subject based on the ideXlab platform.

  • CHROMATOGRAPHIC SEPARATION OF TANNIN FRACTIONS FROM A BEARBERRY-LEAF (Arctostaphylos Uva-Ursi L. SPRENGEL) EXTRACT BY SE-HPLC : A SHORT REPORT
    Polish Journal of Food and Nutrition Sciences, 2020
    Co-Authors: Ronald B. Pegg, Anna Rybarczyk, Ryszard Amarowicz
    Abstract:

    Phenolic compounds from the leaves of the bearberry plant (Arctostaphylos Uva-Ursi L. Sprengel) were extracted into 95% (v/v) ethanol. Tannin fractions were obtained by Sephadex LH-20 column chromatography using 50% (v/v) acetone as the mobile phase. The tannin fraction was then further characterised by size exclusion high-performance liquid chromatography (SE-HPLC) on a TSK G2000SWXL column with a mobile phase comprising 45% acetonitrile and 0.1% (v/v) TFA. The chromatography revealed the presence of additional phenolic compounds in the tannin fractions which are not proanthocyanidins (i.e. condensed tannins).

  • CONTENT OF GALLIC ACID IN SELECTED PLANT EXTRACTS
    Polish Journal of Food and Nutrition Sciences, 2020
    Co-Authors: Magdalena Karamać, Agnieszka Kosinska, Ronald B. Pegg
    Abstract:

    Ethanolic extracts of phenolic compounds were prepared from green teas (Camellia sinensis L.), bearberry leaves (Arctostaphylos Uva-Ursi L.), hazelnuts (Corylus avellana), evening primrose (Oenothera biennis) and grape seeds (Vitis vinifera L.). All crude extracts were examined for their gallic acid content by HPLC. The bearberry-leaf preparation was also fractionated by a Sephadex LH-20 column chromatographic method with 95% (v/v) ethanol and acetone:water (1:1; v/v) as mobile phases: one fraction consisted of low molecular-weight phenolics and the other of tannins. To all samples tannase was applied in an effort to liberate gallic acid from the phenolic esters and hydrolysable tannins. The content of free gallic acid in the extracts ranged from 1 to 15 mg/g with the highest quantity being found in evening primrose. The content of gallic acid liberated by tannase ranged from 5 to 309 mg/g with the highest content being found in the tannin fraction from the bearberry-leaf extract.

  • SE-HPLC separation of myosin complex with tannins of bearberry (Arctostaphylos Uva-Ursi L. Sprengel) leaves - a short report.
    Czech Journal of Food Sciences, 2018
    Co-Authors: Ryszard Amarowicz, Ronald B. Pegg, Agnieszka Kosinska
    Abstract:

    Amarowicz R., Pegg R.B., Kosinska A . (2009): SE-HPLC separation of myosin complex with tannins from bearberries (Arctostaphylos Uva-Ursi L. Sprengel) leaves – a short communication. Czech J. Food Sci., 27: 386–391. Phenolic compounds were extracted from bearberry (Uva-Ursi L. Sprengel) leaves into 95% (v/v) etha nol. The tannin constituents were separated from the crude extract using Sephadex LH-20 column chromatography with 95% (v/v) ethanol and 50% (v/v) acetone as the mobile phases. Myosin was isolated and purified from excised pork knuckle muscles using the standard salt-solution extraction procedure followed by gel filtration chromatogra phy. Myosin was precipitated from the solution with bearberry-leaf tannins at pH 5.0. The recovered complex was washed, lyophilised, and subjected to size-exclusion high performance liquid chromatography (SE-HPLC). Based on the basic conditions of the HPLC analysis, a portion of the tannin constituents was liberated from the complex. The UV spectra of these compounds were characterized by a maximum at ~ 300 nm. A portion of the tannins was present in the complex with myosin, and this was confirmed by UV spectra.

  • Protein-precipitating capacity of bearberry-leaf (Arctostaphylos Uva-Ursi L. Sprengel) polyphenolics
    Food Chemistry, 2011
    Co-Authors: Marian Naczk, Ronald B. Pegg, Ryszard Amarowicz
    Abstract:

    Abstract Polyphenolics (PP) from bearberry (Arctostaphylos Uva-Ursi L. Sprengel) leaves were extracted with 70% (v/v) acetone. The lyophilised crude PP extract was then separated on a Sephadex LH-20 column using first 95% (v/v) ethanol as a mobile phase to elute fraction I low in tannins, and then 50% (v/v) acetone to elute fraction II rich in hydrolysable and condensed tannins. Bovine serum albumin (BSA) was effectively precipitated by PP in the bearberry-leaf crude extract and fraction II at pH values between 3.8 and 4.5. A statistically significant (P = 0.0001) linear relationship exists between the amount of PP-protein complex formed and the quantity of PP added to the reaction mixture. The slope values of these lines indicate that fraction II from the crude extract was a more effective precipitant of proteins than other examined preparations. Based on the quantity of gelatine, fetuin, and BSA required to inhibit 50% of dye-labelled PP–BSA complex precipitation, gelatine was 3–6 times more effective as a precipitation inhibitor than both unlabelled BSA and fetuin.

  • Free-radical scavenging capacity and antioxidant activity of selected plant species from the Canadian prairies
    Food Chemistry, 2004
    Co-Authors: Ryszard Amarowicz, Ronald B. Pegg, Branka Barl, P. Rahimi-moghaddam, J.a. Weil
    Abstract:

    Ethanolic extracts from the roots of wild licorice (Glycyrrhiza lepidota), narrow-leaved echinacea (Echinacea angustifolia), senega (Polygala senega), leaves of bearberry (Arctostaphylos Uva-Ursi) and aerial parts of two varieties of horsetail (Equisetum spp.) were prepared and evaluated for their free-radical scavenging capacity and their antioxidant activity, by a number of chemical assays. Assays employed included a b-carotene-linoleic acid (linoleate) model system, reducing power, scavenging effect on the DPPH � free radical and capacity to scavenge hydroxyl free radicals (HO � ), by use of electron paramagnetic resonance (EPR) spectroscopy. The bearberry-leaf extract consistently exhibited the highest antioxidant activity based on the tests performed, and seems to be a promising source of natural antioxidants. The polyphenolic constituents appear to be responsible, at least in part, for the extract’s radical-scavenging capacity. Research is progressing to characterize the antioxidant compounds in the bearberry-leaf extract and their mode of action in imparting antioxidant activity to various food systems. # 2003 Elsevier Ltd. All rights reserved.

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