Identification of lipophilic flavones and flavonols by comparative HPLC, TLC and UV spectral analysis

Abstract

The identification of lipophilic flavones and flavonols using a combination of high performance liquid chromatography, thin layer chromatography and UV spectral analysis is discussed. Data are provided for the flavones, apigenin, luteolin and tricetin and twelve of their methyl ethers, 8-hydroxyluteolin, 6-hydroxyluteolin and scutellarein and fourteen of their methyl ethers, and some 6,8-dihydroxyapigenin and 6,8-dihydroxyluteolin derivatives. Data for some forty two flavonols with extra 6- and/or 8-hydroxylation, mostly 6-hydroxykaempferol and quercetagetin derivatives, are also presented. The remaining compounds analysed include fourteen 5-deoxyflavones, four 5-methoxyflavones and five 5-deoxyflavonols plus further 5-hydroxylated flavones and flavonols without B-ring oxidation or with 2'-, 5'- or 6'-hydroxylation.

Identification of the Key Astringent Compounds in Spinach (Spinacia oleracea) by Means of the Taste Dilution Analysis

“…HPLC coupled to a DAD revealed UV/vis absorption maxima of 356/350, 270/ 342, and 378/342 nm for subfractions I-3, I-9, and I-11, being well in line with the data reported for flavon-3-ol glycosides (Greenham et al 2003).…”

A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil

“…Importantly, a third flavone with mass-tocharge ratio 315 in positive ionization mode was formed by crude protein extracts with SCU7Me as substrate. Judging by a previous report (Greenham et al, 2003) and considering our knowledge about other dimethylated SCU derivatives, it is likely to be SCU5,7-dimethyl ether, a compound never reported to occur in basil. This product was barely detectable in assays without Mg 2+ and increased by over 700% upon addition of the cation, implying that it was formed by an Mg 2+ -dependent OMT (Fig.…”

Overproduction of valuable methoxylated flavones in induced tetraploid plants of Dracocephalum kotschyi Boiss

“…According to this table eleven compounds including luteolin-7-O-β-D-glucopyranoside, apigenin 7-O-glucoside (cosmosiin), rosmarinic acid, luteolin 3′-O-β-D-glucuronide, luteolin, apigenin, cirsimaritin, isokaempferide, penduletin, xanthomicrol and calycopterin (Additional file 1) identified by a comparison of the T R , UV λ max , and [M-H] -ions of the D. kotschyi peaks with those of known standards (compounds 3, 5, 6, 7, 8, 10 and 11) and quantified by its standard calibration curve and for the others (compounds 1, 2, 4 and 9) identification was done by comparing spectral data reported in previous work (Greenham et al 2003;Fattahi et al 2013) and quantified by xanthomicrol calibration curve.…”