Proanthocyanidins and phenolglycosides from Rumex acetosa L

Rumex acetosa L. (Polygonaceae), also known as “sauerampfer“ or “sorrel“, is a perennial herb, which grows abundantly in most parts of Europe and North America. It is a traditional ingredient in salad or soup due to its vitamin C content. Additionally, preparations of Rumex species were used for constipation or for treatment of chronic skin diseases [1]. This claimed therapeutic use and the close relationship to rhubarb (Rheum officinale) indicate a high content of tannins, especially proanthocyanidins. In the literature, the amount of tannins found in different related Rumex species varies from about 2 to 15% [2, 3]. However, only few investigations concerning tannin composition in Rumex have been carried out so far. In order to isolate and elucidate new proanthocyanidins from Rumex acetosa we purified an acetone/water extract via elution on Sephadex LH20, MLCCC, MCI-Gel and RP-18 material. Different proanthocyanidins, a polymer fraction and the new phenolglycoside 1-O-β-D – (2,4-Dihydroxy-6-methoxyphenyl)-6-O-(4-hydroxy-3,5-dimethoxybenzoyl)-glucopyranoside were obtained. The isolated proanthocyanidin fractions contain mono-, di-, tri-, and tetramers consisting of catechin, epicatechin and epiafzelechin as flavan-3-ol components. A- and B-type interflavan-linkage was found as well as substitution with gallic acid. The polymer fraction was characterized by NMR and MS techniques.

References: 1. Williamson, E.M. (2003), Potter's Herbal Cyclopaedia. C.W. Daniel Company Limited. Essex. 2. McGuffin M. (1997) American Herbal Products Assosiation's Botanical Safety Handbook. CRC Press. Boca Raton. 3. Demirezer, L.Ö. et al. (1997), FABAD 22: 153–158.