The aim of the present study was to compare the in vitro inhibitory effects on the salivary and pancreatic α-amylases and the in vivo hypoglycemic actions of the hydrolysable tannin from Chinese natural gall and the condensed tannin from Acacia mearnsii. The human salivary α-amylase was more strongly inhibited by the hydrolysable than by the condensed tannin, with the concentrations for 50% inh...

Larval performance of the cottonwood leaf beetle,Chrysomela scriptaF., was evaluated in relation to genetic variation in phytochemical characteristics among Þrst year micropropagated ramets of Þve aspen clones (Populus tremuloidesMichx.). Foliage from the juvenile ramets used in this experiment exhibited moderate variation in nitrogen, phenolic glycosides, and condensed tannin concentrations am...

BACKGROUND Tannins are often cited for antinutritional effects, including chelation of non-heme iron. Despite this, studies exploring non-heme iron bioavailability inhibition with long-term consumption have reported mixed results. Salivary proline-rich proteins (PRPs) may mediate tannin-antinutritional effects on non-heme iron bioavailability. AIM To review evidence regarding biochemical bind...

A method for molecular-level quantification of condensed tannin is described that uses acid depolymerization and carbocation capture by phloroglucinol. Resulting monomers and phloroglucinol adducts are trimethylsilyl derivatized, separated by capillary gas chromatography, detected by flame ionization, and quantified relative to standards. Optimal depolymerization conditions were determined for ...

The impacts of leaf litter from genetically modified hybrid poplar accumulating high levels of condensed tannins (proanthocyanidins) were examined in soil microcosms consisting of moss growing on sieved soil. Moss preferentially proliferated in microcosms with lower tannin content; DGGE (denaturing gradient gel electrophoresis) detected increased fungal diversity in microcosms with low-tannin l...

the objective of this study was to determine the effect of irradiation of pomegranate seed (ps) on chemical composition, digestibility and kinetic of gas production. pomegranate seeds were exposed to gamma ray (gr) and electron beam (eb) at doses of 5, 10, 15 and 20 kgy. three ruminally fistulated rams were used for obtaining ruminal fluid for in vitro digestibility and gas production measuremen...

Our objective was to determine if condensed tannin extract from quebracho trees (Schinopsis quebracho-colorado; red quebracho) could be used to reduce enteric methane emissions from cattle. The experiment was designed as a repeated 3 x 3 Latin square (4 squares) with 3 treatments (0, 1, and 2% of dietary DM as quebracho tannin extract) and 3 28-d periods. Six spayed Angus heifers (238 +/- 13.3 ...

The carbon/nutrient balance hypothesis suggests that leaf carbon to nitrogen ratios influence the synthesis of secondary compounds such as condensed tannins. We studied the effects of rising atmospheric carbon dioxide on carbon to nitrogen ratios and tannin production. Six genotypes of Populus tremuloides were grown under elevated and ambient CO(2) partial pressure and high- and low-fertility s...

Leaf samples of the browse shrub Calliandra calothyrsus were used to study the effect of temperature of drying (25, 45, 65, 85 and 1058C), and method of drying, either in dry air (aerobic) or in dry nitrogen (anaerobic), on estimates of ®bre, condensed tannin (CT), digestibility and PEG binding. These estimates were also made on freeze-dried samples. Correlations were made between these variabl...

Tannins are plant-derived polyphenols with antimicrobial effects. The mechanism of tannin toxicity towards Escherichia coli was determined by using an extract from Acacia mearnsii (Black wattle) as a source of condensed tannins (proanthocyanidins). E. coli growth was inhibited by tannins only when tannins were exposed to oxygen. Tannins auto-oxidize, and substantial hydrogen peroxide was genera...