Natural phenolic compounds, e.g. ellagitannins, gallotannins, and flavonoid glycosides, from the aerial parts of
) have been isolated and identified. The structures of these compounds were determined by conventional methods of analysis and confirmed by MS and NMR spectral analysis. The distribution of tannins and flavonoids in
E. ciconium, E. cicutarium, E. manescavi
were examined by TLC on unmodified silica gel and on silica gel chemically modified with polar and nonpolar groups (HPTLC Si 60, HPTLC Si 60 LiChrospher, HPTLC diol, HPTLC CN, and HPTLC RP-18W).
The effects of polyphenols on plasmid DNA strand breaks by depleted uranium were studied using four catechins: (+)-catechin,
(−)-epicatechin, (−)-epigallocatechin (EGC), and (−)-epigallocatechin gallate (EGCG); seven tannins: Chinese gallotannin,
persimmon tannin (PST), mimosa tannin (MMT), myrobalan tannin, quebracho tannin, gambir tannin, and chestnut tannin; and gallic
acid. The plasmid DNA strand breaks by uranyl ion (UO22+) with hydrogen peroxide (H2O2) were strongly enhanced by EGC, EGCG, MMT, and PST (condenced tannins). The obtained results showed that the DNA strand breaks
are caused by UO22+ through the direct interaction between the uranyl complex and the negatively charged DNA phosphate backbone. The additional
DNA strand breaks by the addition of polyphenols occurred through an indirect process by the reduction of UO22+ to UO2+ and hydroxyl radical formation through a Fenton-type reaction with H2O2.
Authors:Renata Slaveska-Raicki, Vesna Rafajlovska, Vesna Rizova, and Ilinka Spirevska
A quantitative high-performance thin-layer chromatographic (HPTLC) method for analysis of gallic acid and tannin in extracts of
(L.) Sprengel, bearberry leaves (Ericaceae), and validation of the method, are described. Analyses were performed on cellulose F
HPTLC plates with
-butanol-acetic acid-water, 14 + 1 + 3.5 (
), as mobile phase. The chromatographic system afforded satisfactory
(0.35 for gallotannin and 0.46 for gallic acid), low
(0.1–0.44%), and effective resolution between components (
= 1.89). The
leaves examined contained approximately 14% tannin and 5% gallic acid. Special features of the thin-layer chromatographic (TLC) technique were taken into consideration in the validation process and calculation of validation data for the method. This HPTLC method was found to be simple, reliable, and convenient for routine analysis. Its analytical performance fulfilled acceptance criteria established for TLC methods in the official literature.
Authors:Y. T. Kamal, Hasan Soliman Yusufoglu, Prawez Alam, and Ahmed Ibrahim Fouda
tract such as diarrhea and dysentery [ 1 , 2 ]. Studies also proved the antioxidant and anti-atherosclerotic properties which also attributed to its high content of polyphenols in its free and bound gallotannins, anthocyanins, and other flavonoids [ 3