Isolation of Individual Compounds from the Aerial Part of <i>Comarum palustre </i>L. and Their Structure Elucidation Using Spectroscopic Methods

Abstract

Introduction. Medicinal plants are a rich, almost inexhaustible source of medicinal substances, and due to their large chemical diversity of metabolites available for isolation their research is always an important task. One of the promising medicinal plants for research is marsh cinquefoil (Comarum palustre L.), widely used in folk medicine for the treatment of diseases of the musculoskeletal system.Aim. Isolation of individual secondary metabolites from the aerial part of C. palustre and their subsequent structural elucidation by NMR experiments.Materials and methods. The aerial parts of the marsh cinquefoil, were collected next to the Saint Petersburg State Chemical-Pharmaceutical University Nursery Garden of Medicinal Plants (Leningrad region, Vsevolozhsky district, Priozerskoe highway, 38 km) in July 2021. Fraction analysis was performed through analytical high-performance liquid chromatography (HPLC) using a LC-20 Prominence (Shimadzu corp., Japan) equipped with a SPD-M20A diode-array detector. The isolation of compounds was carried out by open column chromatography using sorbents with different selectivity, as well as by preparative HPLC using a Smartline system (Knauer, Germany) equipped with a spectrophotometric detector. The structures of the isolated compounds were established by 1D NMR experiments (Bruker Avance III 400 MHz, Germany).Results and discussion. Seven individual compounds (1–7) were isolated and their structures elucidated. Two compounds (1 and 2) are derivatives of ellagic acid, namely 4-O-α-L-arabinofuranoside ellagic acid (1) and 4-O-β-D-glucopyranoside ellagic acid (2), while the other five compounds are derivatives of flavonoids: kaempferol-3-O-β-D-glucuronide (3), quercetin-3-O-β-D-glucuronide (4), quercetin-3-O-β-D-(6’’-β-D-glucopyranosyl)-glucopyranoside (5), quercetin-3-O-β-D-(2’’-galloyl)-glucopyranoside (6) and (+)-catechin (7).Conclusion. As a result of the current research, seven individual compounds were isolated from the aerial part of the marsh cinquefoil and their structure were elucidated. Compounds 1, 2, 4, 5 and 6 were found and isolated from the aerial part of C. palustre L. for the first time.

Keywords

• <i>comarum palustre</i>
• marsh cinquefoil
• secondary metabolites
• polyphenols
• flavonoids