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

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.

LC–ESI–FT–MSn Metabolite Profiling of Symphytum officinale L. Roots Leads to Isolation of Comfreyn A, an Unusual Arylnaphthalene Lignan

“…MS/MS fragmentation patterns suggested that 10 and 17 bear a similar structural framework as that of globoidnan A (14). Indeed, interpretation of the NMR data confirmed this hypothesis establishing the structure of 10 as 3-carboxy-6,7-dihydroxy-1-(3 ,4 -dihydroxyphenyl)-naphthalene and 17 as its ethyl ester derivative ternifoliuslignan D [24].…”

“…Caffeic acid ethyl ester (16) was the most active compound inhibiting E-selectin expression by 79.6 ± 4%, at a concentration of 64 µM, followed by comfreyn A (15), which inhibited E-selectin expression by 51.5 ± 5.3% at 50 µM. Globoidnan A (14), protocatechuic aldehyde (5), and malaxinic acid (9) were significantly inhibited E-selectin expression inhibited but with less potency, while allantoin (1) and rosmarinic acid (12) As previously reported by Daquino et al, removal of a hydrogen atom from both the p-phenolic group of caffeic acid and its ethyl ester analogue originated phenoxy radicals with the unpaired electron at the β position, which might couple to each other (8-8′coupling), generating a reactive bisquinonemethide (A) [25]. Its tautomer underwent an oxidative intramolecular cyclization (6-7′) (B).…”

“…Caffeic acid ethyl ester (16) was the most active compound inhibiting E-selectin expression by 79.6 ± 4%, at a concentration of 64 µM, followed by comfreyn A (15), which inhibited E-selectin expression by 51.5 ± 5.3% at 50 µM. Globoidnan A (14), protocatechuic aldehyde (5), and malaxinic acid (9) were significantly inhibited E-selectin expression inhibited but with less potency, while allantoin (1) and rosmarinic acid (12) did not show any activity at concentrations as high as 250 µM. Table 3.…”

“…Moreover, comfrey roots have yielded a number of oleanolic and bidesmosidic triterpene saponins [ 12 , 13 ]. Recently, a phenolic profile of a hydroalcoholic extract from the roots of Symphytum officinale L. was reported to contain salvianolic acid isomers [ 2 , 14 ].…”

Potential Hepatoprotective Activity of Super Critical Carbon Dioxide Olive Leaf Extracts against CCl4-Induced Liver Damage

“…Nowadays, supercritical fluid extraction (SFE), an environmentally friendly and selective technique, has become one of the most popular green extraction techniques [ 32 ] used mainly in large-scale industrial applications. This technique has several advantages such as high efficacy, rapidity, non-toxicity, the absence of thermal degradation resulting a very high quality extracts, and the possible direct coupling to analytical instrumental technique [ 33 ] with a particular green interest due to the use of supercritical fluids such as CO 2 instead organic solvents [ 34 ].…”