Choosing appropriate methods and standards for assaying tannin

Hagerman, Ann; Butler, Larry G.

doi:10.1007/bf01012267

Cited by 287 publications

(202 citation statements)

References 74 publications

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“…However, the relationships varied with tree species and chemical assays. Tannins are known to be chemically diverse polyphenolic compounds with variable biological activities (Hagerman & Butler, 1989). This is clearly demonstrated by D. cinerea fruits (SPh = 6.5 GAE µg/mg DM) showing higher fermentation responses to PEG compared to A. nilotica fruits (SPh = 11.5 GAE µg/mg DM).…”

Section: Discussionmentioning

confidence: 64%

In vitro biological activity of tannins from Acacia and other tree fruits: Correlations with colorimetric and gravimetric phenolic assays

Mlambo¹,

Mould²,

Smith³

et al. 2009

SA J. An. Sci.

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This study was designed to investigate impact of tannins on in vitro ruminal fermentation parameters as well as relationships between concentration and in vitro biological activity of tannins present in tree fruits. Dry and mature fruits of known phenolic content harvested from Acacia nilotica, A. erubescens, A. erioloba, A. sieberiana, Piliostigima thonningii and Dichrostachys cinerea tree species were fermented with rumen fluid in vitro with or without polyethylene glycol (PEG). Correlation between in vitro biological activity and phenolic concentration was determined. Polyethylene glycol inclusion increased cumulative gas production from all fruit substrates. The largest increase (225%) after 48 h incubation was observed in D. cinerea fruits while the least (12.7%) increase was observed in A. erubescens fruits. Organic matter degradability (48 h) was increased by PEG inclusion for all tree species except A. erubescens and P. thonningii. For D. cinerea fruits, colorimetric assays were poorly correlated to increases in gas production due to PEG treatment. Ytterbium precipitable phenolics (YbPh) were also poorly correlated with response to PEG for A. erioloba and P. thonningii fruits. However, YbPh were strongly and positively correlated to the increase in cumulative gas production due to PEG for A. erubescens and A. nilotica. Folin-Ciocalteau assayed phenolics (SPh) were not correlated to response to PEG in P. thonningii and A. sieberiana. It was concluded that the PEG effect on in vitro fermentation was closely related to some measures of phenolic concentration but the relationships varied with tree species. _______________________________________________________________________________

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Section: Discussionmentioning

confidence: 64%

In vitro biological activity of tannins from Acacia and other tree fruits: Correlations with colorimetric and gravimetric phenolic assays

Mlambo¹,

Mould²,

Smith³

et al. 2009

SA J. An. Sci.

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“…Os métodos mais apropriados para determinação de taninos são os ensaios com precipitação de proteínas 28,29 . Alguns ensaios colorimétricos são usados para quantificar grupos de taninos específicos, muito embora estes métodos sejam amplamente usados para analisar taninos de uma maneira geral, como no caso de taninos hidrolisáveis; eles detectam somente grupos galoil e hexaidroxidifenóis (HHDP).…”

Section: Determinação Do Teor De Taninosunclassified

Taninos: uma abordagem da química à ecologia

et al. 2005

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. Prof. Nelson Chaves, s/n, 50670-901 Recife -PE Recebido em 31/3/04; aceito em 19/1/05; publicado na web em 13/4/05 TANNINS: FROM CHEMISTRY TO ECOLOGY. Tannins are compounds of great interest in chemistry and ecology. They have various effects on food digestibility and the performance of animals. In this work, the chemistry, the biological activity and the ecology of tannins are examined. A brief discussion of several analytical methods for the determination of tannins is presented.Keywords: tannins; colorimetric assay; biological activity. INTRODUÇÃOOs compostos do metabolismo secundário vegetal ou metabolismo especial apresentam um amplo valor nas interações entre a planta e seu ecossistema exercendo, por ex., o papel de fagoinibidores contra herbívoros ou como agentes antimicrobianos 1 . Como metabólitos secundários, os taninos são compostos fenólicos de grande interesse econômico e ecológico. Apresentam solubilidade em água e peso molecular compreendido entre 500 e 3000 Dalton, possuindo a habilidade de formar complexos insolúveis em água com proteínas, gelatinas e alcalóides 2 . Tais compostos são responsáveis pela adstringência de muitos frutos e produtos vegetais, devido à precipitação de glucoproteínas salivares, o que ocasiona a perda do poder lubrificante 3 .A ligação entre taninos e proteínas ocorre, provavelmente, através de pontes de hidrogênio entre os grupos fenólicos dos taninos e determinados sítios das proteínas, emprestando uma duradoura estabilidade a estas substâncias. Para a formação destas ligações é necessário que o peso molecular dos taninos esteja compreendido entre limites bem definidos; se este é demasiadamente elevado, a molécula não pode se intercalar entre os espaços interfibrilares das proteínas ou macromoléculas; se é muito baixo, a molécula fenólica se intercala, mas não forma um número suficiente de ligações que assegure a estabilidade da combinação 3 . Os taninos têm sido alvo de diversos estudos, sendo que a maioria vem abordando interações ecológicas entre vegetais e herbívoros, visto que se têm sugerido que os teores de taninos podem diminuir a taxa de predação por se tornarem impalatáveis, afastando seus predadores naturais 4-8 . Pesquisas sobre atividade biológica dos taninos evidenciaram importante ação contra determinados microrganismos 4 , como agentes carcinogênicos e causadores de toxicidade hepática 9 . Estes últi-mos efeitos, sem dúvida, dependem da dose e do tipo de tanino ingerido. A ingestão de chá verde e de dietas ricas em frutas que contêm taninos, por ex., tem sido associada com atividade anticarcinogênica 9 . Além disso, podem agir como antiinflamatórios e cicatrizantes 2 , e até como inibidores da transcriptase reversa em HIV 10 .Alguns trabalhos têm tratado do aspecto antinutricional de cultivares com altos teores de taninos e sua resistência a pragas 11,12 . Outros trabalhos têm avaliado a influência de diferentes variáveis nos teores de taninos em espécies de interesse econômico 13,14 . A sazonalidade tem sido apontada como um interessante fator para a...

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“…Condensed tannin concentrations (% dry mass) of leaves were determined following Madritch et al [60] by extracting plant material with 70 : 30 acetone : water (containing 10 mM ascorbic acid) and assaying extracts via the n-butanol method of Porter et al [72]. Aspen tannin standards were purified by the method of Hagerman & Butler [73]. Leaf lignin concentrations (% dry mass) were determined via the thioglycolic acid method [74] as modified by Suzuki et al [75] using commercial lignin standards.…”

Section: (B) Leaf Analysesmentioning

confidence: 99%

Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales

Madritch

Kingdon²,

Singh³

et al. 2014

Phil. Trans. R. Soc. B

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Fine-scale biodiversity is increasingly recognized as important to ecosystemlevel processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and widespread forest species in North America. We combine imaging spectroscopy (AVIRIS) data with genetic, phytochemical, microbial and biogeochemical data to determine how intraspecific plant genetic variation influences below-ground processes at landscape scales. We demonstrate that both canopy chemistry and below-ground processes vary over large spatial scales (continental) according to aspen genotype. Imaging spectrometer data distinguish aspen genotypes through variation in canopy spectral signature. In addition, foliar spectral variation correlates well with variation in canopy chemistry, especially condensed tannins. Variation in aspen canopy chemistry, in turn, is correlated with variation in below-ground processes. Variation in spectra also correlates well with variation in soil traits. These findings indicate that forest tree species can create spatial mosaics of ecosystem functioning across large spatial scales and that these patterns can be quantified via remote sensing techniques. Moreover, they demonstrate the utility of using optical properties as proxies for fine-scale measurements of biodiversity over large spatial scales.

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Choosing appropriate methods and standards for assaying tannin

Cited by 287 publications

References 74 publications

In vitro biological activity of tannins from Acacia and other tree fruits: Correlations with colorimetric and gravimetric phenolic assays

In vitro biological activity of tannins from Acacia and other tree fruits: Correlations with colorimetric and gravimetric phenolic assays

Taninos: uma abordagem da química à ecologia

Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales

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