Constituents of Xerolekia speciosissima (L.) Anderb. (Inuleae), and Anti-Inflammatory Activity of 7,10-Diisobutyryloxy-8,9-epoxythymyl Isobutyrate

Abstract

Xerolekia speciosissima (L.) Anderb., a rare plant from the north of Italy, is a member of the Inuleae-Inulinae subtribe of the Asteraceae. Despite its close taxonomic relationship with many species possessing medicinal properties, the chemical composition of the plant has remained unknown until now. A hydroalcoholic extract from the aerial parts of X. speciosissima was analyzed by HPLC-DAD-MSn, revealing the presence of caffeic acid derivatives and flavonoids. In all, 19 compounds, including commonly found chlorogenic acids and less frequently occurring butyryl and methylbutyryl conjugates of dicaffeoylquinic and tricaffeoylhexaric acids, plus two flavonoids, were tentatively identified. Chromatographic separation of a hydroalcoholic extract from the capitula of the plant led to the isolation of (+)-dehydrodiconiferyl alcohol 4-O-β-glucopyranoside, quercimeritrin, astragalin, isoquercitrin, 6-hydroxykaempferol-7-O-β-glucoside, quercetagitrin, methyl caffeate, caffeic acid, protocatechuic acid, chlorogenic acid and 1,5-dicaffeoylquinic acid. Composition of a nonpolar extract from the aerial parts of the plant was analyzed by chromatographic methods supported with 1H-NMR spectroscopy. The analysis revealed the presence of loliolide, reynosin, samtamarine, 2,3-dihydroaromaticin, 2-deoxy-4-epi-pulchellin and thymol derivatives as terpenoid constituents of the plant. One of the latter compounds—7,10-diisobutyryloxy-8,9-epoxythymyl isobutyrate—at concentrations 0.5, 1.0 and 2.5 μM, significantly reduced IL-8, IL-1β and CCL2 excretion by LPS-stimulated human neutrophils.

Constituents of Pulicaria inuloides and Cytotoxic Activities of Two Methoxylated Flavonols

“…Peaks 2, 4, 5, 9, and 11–13 represented compounds that showed a cleavage of two or three caffeoyl [M − H-(2–3 × 162)] − moieties resulting in the m / z 209 fragments, and were assigned to hexaric acid derivatives: di- O -caffeoylhexaric acid I (peak 2), di- O -caffeoylhexaric acid II (peak 4), di- O -caffeoylhexaric acid III (peak 5), tri- O -caffeoylhexaric acid I (peak 9), tri- O -caffeoylheharic acid II (peak 11), tri- O -caffeoylhexaric acid III (peak 12), and tri- O -caffeoylhexaric acid IV (peak 13). Tetra- O -caffeoylhexaric acid (peak 15) was identified based on its UV maximum, pseudo-molecular ion mass, and fragmentation pattern identical to those found earlier [ 28 ]. The compounds represented by peaks 14 and 18 were isobutyryl-dicaffeoylhexaric acid I and isobutyryl-tricaffeoylhexaric acid judging from the m / z values of their quasimolecular ions (603 [M − H] − and 765 [M − H] − , respectively) and fragmentation ions at m / z 441, 423, and 279 [ 28 , 29 ].…”

“…Tetra- O -caffeoylhexaric acid (peak 15) was identified based on its UV maximum, pseudo-molecular ion mass, and fragmentation pattern identical to those found earlier [ 28 ]. The compounds represented by peaks 14 and 18 were isobutyryl-dicaffeoylhexaric acid I and isobutyryl-tricaffeoylhexaric acid judging from the m / z values of their quasimolecular ions (603 [M − H] − and 765 [M − H] − , respectively) and fragmentation ions at m / z 441, 423, and 279 [ 28 , 29 ]. The compound corresponding to peak 19 demonstrated similar fragmentation patterns to that of 18 except for the fact that the masses of the quasimolecular ion (779 [M − H] − ) and fragmentation ions at m / z 617, 455, and 293 were fourteen units higher than those of the analogous ions from isobutyryl-tricaffeoylhexaric acid.…”

“…Plants of the Inuleae tribe are rich in hydroxycinnamates that are largely responsible for the antioxidant activity of the plant extracts, and possess potential health-enhancing properties [ 28 , 29 , 41 , 42 , 43 ]. To our knowledge, hydroxycinnamates of P. inuloides have not been studied before.…”

“…The aerial parts of the plant contained: 5-CQA, 3,4-DCQA, 3,5-DCQA, 4,5-DCQA, tetracaffeoylhexaric acid, and one acylated TCHA, whereas the roots additionally accumulated 1,3- and 1,5-DCQA, three isomeric DCHAs, TCHAs (four isomers), and another acylated TCHA. The caffeoylhexaric acids and their acylated deivatives seem to be typical constituents of the Inuleae plants [ 28 , 29 , 43 ].…”

Neuroprotective Properties of Kempferol Derivatives from Maesa membranacea against Oxidative Stress-Induced Cell Damage: An Association with Cathepsin D Inhibition and PI3K/Akt Activation

“…Isoquercitrin (purity > 95% by HPLC) was isolated from flowers of Xerolekia speciosissima (L.) Anderb. [ 60 ].…”