A Method for Isolating Condensed Tannins from Crude Plant Extracts with Trivalent Ytterbium

Giner‐Chavez, B I; Soest, P.J. Van; Robertson, James B.; Lascano, Carlos E.; Reed, Jess D.; Pell, Alice N.

doi:10.1002/(sici)1097-0010(199707)74:3<359::aid-jsfa811>3.0.co;2-c

Cited by 87 publications

(58 citation statements)

References 18 publications

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“…However, the extinction coefficients for the chromophores produced in the reaction with these standards usually are different than the compounds from the plant extracts. This difference can lead to large under and over estimations of the content of PA and is probably the single largest cause for the great deviation in concentrations that are reported in the literature (Giner-Chavez et al 1997). Another problem is that the mechanism that leads to the reaction of PA with the analytical reagent is unrelated to the mechanism underlying their nutritional effects (Reed 1995).…”

Section: Methodsmentioning

confidence: 99%

“…The most suitable method is to use the butanol-HCl assay and isolate the PA from the plant species under investigation for use as a standard. Reversible adsorption of PA from plant extracts onto Sephadex LH-20 is a commonly used method for isolating PA from plants (Hagerman 1991, Giner-Chavez et al 1997. Reed et al (1985) developed a gravimetric method based on the ability of trivalent ytterbium to selectively precipitate PA from plant extracts.…”

Section: Methodsmentioning

confidence: 99%

“…The advantage of Yb precipitation is that the precipitate can be easily dissolved to yield a solution of the PA. These solutions are used for colorimetric analysis (Giner-Chavez et al 1997), chromatography, enzyme inhibition studies and in vitro and in vivo assays for inhibition (Reed et al 1985). The results from the assays on the dissolved PA also relate to an equivalent weight of PA precipitate.…”

Section: Methodsmentioning

confidence: 99%

“…Stewd., the insoluble fraction represents the greatest amount (Bate- Smith 1973, Giner-Chavez et al 1997, Jackson et al 1996.…”

Section: Chemistry and Nomenclature Of Proanthocyanidinsmentioning

confidence: 99%

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Journal of Range Management, Volume 54, Number 4 (July 2001)

2001

REM

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The objectives of this Colorado study were to assess primary reasons ranchers choose to stay or sell the ranch, compare the motivations for ranching between a traditional agriculturally based county and a rapidly developing county, and assess whether factors such as length of tenure, fiscal dependency on ranching, and dependency on public lands play roles in decisions to sell. Personal interviews were conducted with 37 ranchers. While land use conversion occurs for a wide variety of reasons, lack of heirs and detrimental public policy were important reasons given for selling ranches. Responses showed Routt County (a rapidly developing county) ranchers were more likely to sell due to land use conversion related issues than Moffat County ranchers (p = 0.056). Ranchers with a longer legacy on their land reported that profitability, having likely heirs, and continuing tradition enhanced their reasons to stay. Groups more "at risk" of selling were non-homesteading ranchers close to retirement, larger ranches, and ranchers dependent on ranching for income with declining profits. Large ranch owners experiencing land use conflicts with non-ranchers and ranchers modestly dependent on public forage experiencing changes in public policy regulations and land use conflicts also indicated a higher proclivity to sell. Noting how groups of ranchers are impacted by different changes can help refine community efforts related to land use conversion and create more thoughtful policy measures.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…Stewd., the insoluble fraction represents the greatest amount (Bate- Smith 1973, Giner-Chavez et al 1997, Jackson et al 1996.…”

Section: Chemistry and Nomenclature Of Proanthocyanidinsmentioning

confidence: 99%

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Journal of Range Management, Volume 54, Number 4 (July 2001)

2001

REM

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“…CT have the ability to bind proteins, metal ions and polysaccharides to render them unavailable to ruminal microbes (MuellerHarvey and Mcallan, 1992;Hedqvist et al, 2000;Tedeschi et al, 2011b). Methods have been developed that attempted to quantify and fractionate plant CT (Hagerman and Butler, 1978;Terrill et al, 1992;Giner-Chavez et al, 1997). However, these purely chemical, quantitative methods have a limited ability to predict the biological activity of specific CT from a given species (Martin and Martin, 1982;Makkar et al, 1999) and biological assays are needed for this purpose (Ammar et al, 2004;del Pino et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Developing a conceptual model of possible benefits of condensed tannins for ruminant production

Tedeschi

Ramírez-Restrepo

Muir

2014

animal

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Enteric methane (CH 4 ) emissions from ruminants have compelled a wide range of research initiatives to identify environmental abatement opportunities. However, although such mitigations can theoretically be attained with feed additives and feeding strategies, the limited empirical evidence on plant extracts used as feed additives does not support extensive or long-term reductions. Nevertheless, their strategic use (i.e. alone or combined in a simultaneous or consecutive use) may provide not only acceptable CH 4 abatement levels, but also relevant effects on animal physiology and productivity. Condensed tannins (CT) represent a range of polyphenolic compounds of flavan-3-ol units present in some forage species that can also be added to prepared diets. Methods to determine CT, or their conjugated metabolites, are not simple. Although there are limitations and uncertainties about the methods to be applied, CT are thought to reduce CH 4 production (1) indirectly by binding to the dietary fibre and/or reducing the rumen digestion and digestibility of the fibre and (2) directly by inhibiting the growth of rumen methanogens. On the basis of their role in livestock nutrition, CT influence the digestion of protein in the rumen because of their affinity for proteins (e.g. oxidative coupling and H bonding at neutral pH) that causes the CT-protein complex to be insoluble in the rumen; and dissociate in the abomasum at pH 2.5 to 3.0 for proteolysis and absorption in the small intestine. CT may also reduce gastro-intestinal parasite burdens and improve reproductive performance, foetal development, immune system response, hormone serum concentrations, wool production and lactation. The objectives of this paper are to discuss some of the beneficial and detrimental effects of CT on ruminant production systems and to develop a conceptual model to illustrate these metabolic relationships in terms of systemic physiology using earlier investigations with the CT-containing legume Lotus corniculatus. Our conceptual model indicated four complex and long-lasting relationships (digestive, toxicological, physiological and morphological) that can alter the normal biology of the animal. These relationships are interdependent, integrative, and sometimes, complementary to each other. This conceptual model can be used to develop mechanistic models to improve the understanding of the interaction between CT and the ruminants as well as to guide research initiatives of the impact of polyphenol-rich foods on human health.Keywords: condensed tannins, methane, modelling, physiology, ruminant ImplicationsThis paper reviews potential benefits of condensed tannins (CT), including mitigation of methane emission (a potent greenhouse gas), reduction of ruminal degradation of amino acids and reduction of gastro-intestinal parasitic infestation among many other benefits to cattle, sheep and goats; and proposes a conceptual model to understand the interrelationships of the mechanisms of action of these benefits within the animal. Our conceptual model lays t...

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