Water infusions from Filipendula ulmaria (L.) Maxim. flowers are used in the treatment of fever, rheumatism and traditionally in the urinary tract diseases. Active constituents of meadowsweet water extracts belong to groups of phenolic glycosides, ellagitannins and flavonoid derivatives. The presented research is focused on flavonoid-rich fraction, responsible for the diuretic activity.
Gut microbiota metabolism of xenobiotics, including natural products, is paid a lot of attention lately. For instance, researchers described gut microbial biotransformation of ellagitannins to urolithins, which are linked to health beneficial activity of ellagitannin-rich products.
Preliminary studies, based on UPLC-DAD/MSn meadowsweet infusion analysis, showed that among other flavonoid glycosides, the infusion contains two galloyl derivatives of quercetin and one galloyl derivative of kaempferol glycoside. Incubation of an infusion with human gut microbiota cultures in a small scale and chromatographic analysis were performed to examine changes over the time in a post-growth medium. Differences in dynamics of biodecomposition of mentioned galloyl derivatives in the comparison to other flavonoid metabolism were noticed. Scaled up incubation was performed in order to isolate galloyl derivatives. The process was controlled using chromatographic analysis of test samples, collected in several time points and the incubation was terminated when post-growth medium composition was proper for isolation. The medium was extracted using diethyl ether and ethyl acetate. Galloyl derivatives were isolated form ethyl acetate fraction using preparative HPLC in average yield of 10 mg and characterized using 1D and 2D NMR techniques.
The obtained results showed for the first time that galloyl derivatives of flavonoids are transformed more slowly than simple glycosides. This feature was used for the gut microbiota assisted isolation of three compounds – namely quercetin 3-O- β -(2’-O-galloyl)-D-galactopyranoside, quercetin 3-O- β -(2’-O-galloyl)-D-glucopyranoside and kaempferol 3-O- β -(2’-O-galloyl)-D-glucopyranoside. The presence of all three compounds was confirmed for the first time in flowers of Filipendula ulmaria.