Investigation of the Supercritical CO2 Extracts of Wild Ledum Palustre L. (Rhododendron Tomentosum Harmaja) and Identification of Its Metabolites by Tandem Mass Spectrometry.

The purpose of this research was to investigate and identify by tandem mass spectrometry the polyphenolic complexes and other biologically active compounds present in the leaves and stems of Ledum palustre L. Carbon dioxide, compressed to a supercritical state, was used for the most environmentally friendly extraction of polyphenolic complexes and other biologically active compounds from Ledum palustre L. The most effective extraction characteristics (pressure 350 bar, temperature 60°C, extraction time 1 h, co-solvent MeOH 3.5%) of supercritical CO2 extraction of L. palustre were determined empirically. To identify target analytes in the supercritical extracts, high performance liquid chromatography (HPLC) in combination with a BRUKER DALTONIKS ion trap was used. The results showed the presence of 61 biologically active compounds corresponding to the Rhododendron species, of which 32 were identified for the first time in L. palustre. These are flavanols dihydrokaempferol, quercetin arabinoside, myricetin galactoside; flavones diosmetin, nevadensin, cirsimaritin; flavanone naringenin; anthocyanins delphinidin, petunidin, cyanidin pentoside, delphinidin pentoside, peonidin 3-(6-O-acetyl) glucoside, peonidin-3-O-malonylglucoside, cyanidin-3-rutinoside, peonidin 3-O-glucoside; ellagic acid; lignan medioresinol; a type A procyanidin dimer; sterols fucosterol and avenasterol, etc. [ABSTRACT FROM AUTHOR]