UHPLC‐DAD‐ESI‐MS/MS and HPTLC profiling of ash leaf samples from different commercial and natural sources and their in vitro effects on mediators of inflammation

Abstract

Introduction In European traditional medicine, common ash leaf infusion is recommended by European Medicines Agency to treat minor articular pain and to increase the amount of urine for flushing minor urinary complaints. However, a comprehensive ultra‐high‐performance liquid chromatography diode array detector electrospray ionisation tandem mass spectrometry (UHPLC‐DAD‐ESI‐MS/MS) analysis of this pharmacopeial plant material has never been performed. Moreover, the number of biological and pharmacological investigations proving the usefulness of this plant material in recommended traditional uses is surprisingly small. Objective Phytochemical profiling of ash leaf samples from different commercial and natural sources and the determination of the in vitro effects on inflammatory mediators in a model of human neutrophils. Methods Ash leaf samples were characterised by total hydroxycinnamic acid content and by high‐performance thin layer chromatography (HPTLC), UHPLC‐DAD‐ESI‐MS/MS methods. The effects of leaf infusions on reactive oxygen species (ROS), tumor necrosis factor (TNF‐α), interleukin 8 (IL‐8), interleukin 1β (IL‐1β), and monocyte chemoattractant protein 1 (MCP‐1) production by neutrophils were measured using luminol‐dependent chemiluminescence and enzyme‐linked immunosorbent assay (ELISA). Results In ash leaf samples 64 compounds were identified or partly identified together with four unknown compounds. The major compounds detected belong to different structural groups, including phenolic acid derivatives, phenylethanoids, flavonoids, iridoids, secoiridoids and lignans. The major compounds detected in ash samples were chlorogenic acid, quercetin‐3‐O‐rutinoside, verbascoside, oleuropein and ligstroside. However, one sample contained coumarin derivatives. This finding suggested adulteration with other Fraxinus species and/or plant parts. All infusions were able to inhibit ROS, cytokine and chemokine production. Conclusions The performed phytochemical and biological analyses contribute to the knowledge about this pharmacopeial plant material and supports its traditional use to treat minor inflammatory complaints.

Diversity of secoiridoid glycosides in leaves of UK and Danish ash provide new insight for ash dieback management

“…S18, S20). These could be GL5, previously been reported from F. excelsior 27,35 , or isomers jaspolyanoside, austrosomide and/or 6′-elenolylnicotiflorine 41,48,49 . The m/z 259/291 fragment ion pair is also observed in the MS2 spectra of the nuzhenide isomers 2, 18 and 20, and are absent from their isomer 3.…”

“…Of the remaining compounds, 28 and 33 have not previously been reported from F. excelsior and are assigned as jaspofoliamosides A and E, respectively, or isomers thereof 41,47 . 22 has the same formula as secoiridoids oleoacetoside and isooleoacetoside (C 46 H 58 O 25 ) 40,42 , though only oleoacetoside has previously been reported from F. excelsior 35 (Fig. 4e) whereas 32 discriminates tolerant from susceptible UK leaves sampled but not tolerant Danish leaves sampled (Fig.…”

“…Eleven of these compounds also exhibited [M-C 10 H 16 O 8 -H] − fragments corresponding to loss of 264 Da, as in nuzhenide (9) and oleuropein(10), whereas two compounds, 17 and 21, instead lose 248 Da (C 10 H 16 O 7 ). Crucially, thirteen compounds lose a neutral 386 Da (C 17 H 22 O 10 ) fragment, as observed in the MS2 spectra of nuzhenide (9) and GL3 (11), indicative of a terminal oleoside-methyl ester moiety 35 and eighteen compounds share fragment ion m/z 223.0610 (C 11 H 11 O 5 ), corresponding to the secoiridoid aglycone core ( Supplementary Fig. S17-S18 and Table S5).…”

“…Conversely, 24, eluting earlier, has a different fragmentation pattern (Supplementary Figs. S17, S19) and is predicted to be excelsioside, where the iridoid C-7 is linked to the hydroxytyrosol moiety via the phenol O rather than the ethanolic O atom 35,36 . Both have previously been identified in F. excelsior leaves 7 .…”

Inhibition of Neutrophil Functions and Antibacterial Effects of Tarragon (Artemisia dracunculus L.) Infusion—Phytochemical Characterization

“…Four compounds 20 (t r =45 min), 22 (t r = 46.1 min), 24 (t r = 47.8 min), and 26 (t r = 50.3 min) with UV and MS spectra ([M-H] − ion with m/z 515 and fragment ions with m/z 353 and 191) were assigned the structure di-O-caffeoylquinic acids (1,4-di-O-CQA, 3,4-di-O-CQA, 3,5-di-O-CQA, 1,5-di-O-CQA or 4,5-di-O-CQA) (Eisenman et al, 2011;Miron et al, 2011;Gu et al, 2012;Lin and Harnly, 2012;Olennikov et al, 2018;Olennikov et al, 2019). Further, compounds 2 (t r = 12 min), 3 (t r = 12.2 min), 4 (t r = 13.4 min), 10 (t r = 25 min) and 13 (t r = 34.9 min) gave pseudomolecular ions m/z [M−H] -477, 371, 359, 355, respectively, and were tentatively identified as protocatechuic acid dihexoside, caffeoyl hexaric acid, syringic acid hexoside, and ferulic acid hexoside, respectively (Barros et al, 2012;Mekky et al, 2019;Kiss et al, 2020). Flavonoid glycosides were assigned as derivatives of isorhamnetin (Miron et al, 2011;Lin and Harnly, 2012), apigenin (Lin and Harnly, 2012), patuletin (Vienne et al, 1989;Lin and Harnly, 2012), and quercetin (Obolskiy et al, 2011;Lin and Harnly, 2012).…”