Comparative Assessment of Phytochemical Profiles of Comfrey (Symphytum officinale L.) Root Extracts Obtained by Different Extraction Techniques.

Nataša Nastić,Isabel Borrás-Linares,Jaroslava Švarc-Gajić,Jesús Lozano-Sánchez,Antonio Segura-Carretero

doi:10.3390/molecules25040837

Nataša Nastić, Isabel Borrás-Linares + Show 3 more

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https://doi.org/10.3390/molecules25040837

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Abstract

In this work a comparative study on phytochemical profiles of comfrey root extracts obtained by different extraction approaches has been carried out. Chemical profiles of extracts obtained by supercritical fluid (SFE), pressurized liquid (PLE), and conventional solid/liquid extraction were compared and discussed. Phytochemical composition was assessed by high-performance liquid chromatography coupled with electrospray time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS) identifying 39 compounds reported for the first time in comfrey root, mainly phenolic acids and fatty acids. The influence of different extraction parameters on phytochemical profiles of S. officinale root was investigated for all applied techniques. PLE and maceration, using alcohol-based solvents (aqueous methanol or ethanol), were shown to be more efficient in the recovery of more polar compounds. Greater numbers of phenolics were best extracted by PLE using 85% EtOH at 63 °C. The use of SFE and 100% acetone for 30 min enabled good recoveries of nonpolar compounds. SFE using 15% EtOH as a cosolvent at 150 bar produced the best recoveries of a significant number of fatty acids. The main compositional differences between extracts obtained by different extraction techniques were assigned to the solvent type. Hence, these results provided comprehensive approaches for treating comfrey root enriched in different phytochemicals, thereby enhancing its bioaccessibility.

Highlights

Comfrey (Symphytum officinale L.) is a medicinal plant widely spread across Europe, but it can be found in some parts of Asia and South America
Comfrey root extracts obtained by maceration, Pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE) were analyzed by HPLC-ESIQTOF-MS (Figure 1)
Some of these compounds have been previously reported in comfrey root, the high-resolution of QTOF-MS enabled identification of 39 phytochemicals that have never been reported in this sample

Summary

Introduction

Comfrey (Symphytum officinale L.) is a medicinal plant widely spread across Europe, but it can be found in some parts of Asia and South America. Comfrey roots are used topically, mostly for the treatment of wounds, joint disorders, and musculoskeletal injuries of all kinds due to pyrrolizidine alkaloids that have been linked to hepatotoxicity and carcinogenicity [1,2]. The content of pyrrolizidine alkaloids is the highest in comfrey root [3,4]. Compounds that were identified in comfrey root as active in the treatment of sprains, arthritis, fractures, and hematoma include allantoin, Molecules 2020, 25, 837; doi:10.3390/molecules25040837 www.mdpi.com/journal/molecules. Allantoin activates metabolic processes in subcutaneous tissue and stimulates cell growth resulting in epithelization. It strongly promotes the cell growth in bones and connective tissue [7]

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