Investigation of complexes tannic acid and myricetin with Fe(III)

Sungur, Mustafa; Uzar, Atike

doi:10.1016/j.saa.2007.03.038

Cited by 83 publications

(75 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3). In particular, tannins containing pyrogallol units readily form complexes with FeCl 3 (Sungur and Uzar, 2008), and condensed tannins containing pyrogallol groups have been identified in pine previously (Ku and Mun, 2007). The presence of increased levels of flavonoids or flavonoid derivatives in transgenic pine plants would not be surprising, since elevated flavonoid production is quite common when silencing genes early in the monolignol pathway Besseau et al, 2007).…”

Section: Compositional and Structural Changes In Lignin Of 4cl Transgmentioning

confidence: 99%

Suppression of 4-Coumarate-CoA Ligase in the Coniferous GymnospermPinus radiata

et al. 2008

View full text Add to dashboard Cite

Severe suppression of 4-coumarate-coenzyme A ligase (4CL) in the coniferous gymnosperm Pinus radiata substantially affected plant phenotype and resulted in dwarfed plants with a "bonsai tree-like" appearance. Microscopic analyses of stem sections from 2-year-old plants revealed substantial morphological changes in both wood and bark tissues. This included the formation of weakly lignified tracheids that displayed signs of collapse and the development of circumferential bands of axial parenchyma. Acetyl bromide-soluble lignin assays and proton nuclear magnetic resonance studies revealed lignin reductions of 36% to 50% in the most severely affected transgenic plants. Two-dimensional nuclear magnetic resonance and pyrolysis-gas chromatography-mass spectrometry studies indicated that lignin reductions were mainly due to depletion of guaiacyl but not p-hydroxyphenyl lignin. 4CL silencing also caused modifications in the lignin interunit linkage distribution, including elevated b-aryl ether (b-O-4 unit) and spirodienone (b-1) levels, accompanied by lower phenylcoumaran (b-5), resinol (b-b), and dibenzodioxocin (5-5/b-O-4) levels. A sharp depletion in the level of saturated (dihydroconiferyl alcohol) end groups was also observed. Severe suppression of 4CL also affected carbohydrate metabolism. Most obvious was an up to approximately 2-fold increase in galactose content in wood from transgenic plants due to increased compression wood formation. The molecular, anatomical, and analytical data verified that the isolated 4CL clone is associated with lignin biosynthesis and illustrated that 4CL silencing leads to complex, often surprising, physiological and morphological changes in P. radiata.

show abstract

Section: Compositional and Structural Changes In Lignin Of 4cl Transgmentioning

confidence: 99%

Suppression of 4-Coumarate-CoA Ligase in the Coniferous GymnospermPinus radiata

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The results related to Cu are consistent with findings described by Kraal et al (2006), who established that at Cu(II) ions to tannic acid molar ratios higher than 0.01 the amounts of free and labile complex ions of Cu increase much more in comparison to the stable Cutannic acid complexes. Tannic acid was lately reported to effectively complex and reduce the Fe(III) ions at neutral pH (Lopes et al, 1999), likely due to a very high value of the stability constant of such a complex, evaluated to be of the order of 10 + 17 (Sungur and Uzar, 2008). At pH 5.0 and lower, the stability constants of the Fe-tannic acid complex are decreased by about 8-12 orders of magnitude (Sungur and Uzar, 2008), and this could be the reason for relatively low sorption efficiencies assessed for Amberlite XAD-16.…”

Section: Resin Characteristicsmentioning

confidence: 99%

“…Tannic acid was lately reported to effectively complex and reduce the Fe(III) ions at neutral pH (Lopes et al, 1999), likely due to a very high value of the stability constant of such a complex, evaluated to be of the order of 10 + 17 (Sungur and Uzar, 2008). At pH 5.0 and lower, the stability constants of the Fe-tannic acid complex are decreased by about 8-12 orders of magnitude (Sungur and Uzar, 2008), and this could be the reason for relatively low sorption efficiencies assessed for Amberlite XAD-16.…”

Section: Resin Characteristicsmentioning

confidence: 99%

Chemical fractionation of Cu, Fe and Mn in canned Polish beers

Pohl

Prusisz

2010

Journal of Food Composition and Analysis

View full text Add to dashboard Cite

“…The 5-OH group is usually not involved in the chelation due to its lesser proton acidity and the steric hindrance caused by the first complexation [22]. Related studies on flavonols Gal, Kae, Que and Myr have been reported previously [20][21][22][23][24][25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%