lignans and ellagitannin

Phytoestrogens are plant-derived polyphenols with a structure similar to human estrogens. The three main groups of phytoestrogens, isoflavones, ellagitannins, and lignans, are transformed into equol, urolithins, and enterolignans, respectively, by bacteria. These metabolites have more estrogenic/antiestrogenic and antioxidant activities than their precursors, and they are more bioavailable. The aim of this study was to analyze the metabolism of isoflavones, lignans and ellagitannins by gut microbiota, and to study the possible correlation in the metabolism of these three groups of phytoestrogens. In vitro fermentation experiments were performed with feces samples from 14 healthy adult volunteers, and metabolite formation was measured by HPLC-PAD and HPLC-ESI/MS. Only the microbiota of one subject produced equol, while most of them showed production of O-desmethylangolensin (O-DMA). Significant inter-subject differences were observed in the metabolism of dihydrodaidzein and dihydrogenistein, while the glucoside isoflavones and their aglycones showed less variability, except for glycitin. Most subjects produced urolithins M-5 and E. Urolithin D was not detected, while uroltithin B was found in half of the individuals analyzed, and urolithins A and C were detected in two and four subjects, respectively. Enterolactone was found in all subjects, while enterodiol only appeared in five. Isoflavone metabolism could be correlated with the metabolism of lignans and ellagitannins. However, the metabolism of ellagitannins and lignans could not be correlated. This the first study where the metabolism of the three groups together of phytoestrogen, isoflavones, lignans, and ellagitannins by gut microbiota is analyzed.

Topics: Adult; Aged; Coumarins; Female; Gastrointestinal Microbiome; Humans; Hydrolyzable Tannins; Isoflavones; Lignans; Male; Middle Aged; Phytoestrogens

Two new ellagitannin oligomers, pomegraniins A (7, tetramer) and B (8, pentamer), and a new glucose ester of neolignan, pomegralignan (19), together with six known ellagitannins, were isolated from the arils and pericarps of Punica granatum L. (pomegranate). The structures of the new compounds were elucidated based on spectroscopic analyses and chemical evidence. The known ellagitannins included oligomers such as oenothein B (4), eucalbanin B (5), and eucarpanin T1 (6), in addition to the known ellagitannin monomers such as punicalagin (1), punicalin (2), and punicacortein C (3). This paper therefore represents the first report concerning the isolation of ellagitannin oligomers from pomegranate. Examination of the inhibitory activities of the polyphenolic constituents from pomegranate towards the formation of advanced glycation end products (AGEs) revealed that all ellagitannins tested were more potent inhibitors than aminoguanidine, which was used as a positive control, and pomegraniin A (7) showed the most potent effect.

Topics: Antioxidants; Fruit; Glycation End Products, Advanced; Hydrolyzable Tannins; Lignans; Lythraceae; Plant Extracts

Three new ellagitannins named balanophotannins A-C having a 1,1'-(3,3',4,4'-tetrahydroxy)dibenzofurandicarboxyl group in their molecules and four known lignan glycosides were isolated from the extracts of fresh aboveground and underground parts of a medicinal parasitic plant Balanophora japonica (Balanophoraceae). Their structures were elucidated on the basis of spectral and chemical evidence. Chemotaxonomic significance of the known lignan glycosides in Balanophora japonica was discussed.

Topics: Balanophoraceae; Glycosides; Hydrolyzable Tannins; Lignans; Magnetic Resonance Spectroscopy; Mass Spectrometry; Methanol; Plant Components, Aerial; Plant Extracts; Plant Roots; Plants, Medicinal; Solutions