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

Natalia Kłeczek,Anna K Kiss,Janusz Malarz,Anna Stojakowska,Barbara Gierlikowska

doi:10.3390/molecules25214913

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.

Highlights

Introduction(synonyms: Buphthalmum speciosissimum Ard., Telekia speciosissima (L.) Less.), a species which belongs to the newly created Xerolekia genus [1] is considered a member of the tribe Inuleae, subtribe Inulinae, of the family Compositae (Asteraceae) [2]
Total phenolic contents in leaves and roots of X. speciosissima were estimated as 61.66 ± 2.14 mg g−1
UHPLC-DAD-MSn analysis of hydroalcoholic extracts from roots and aerial parts of the plant revealed the presence of 17 compounds with absorption maxima at 324–328 nm

Summary

Introduction

(synonyms: Buphthalmum speciosissimum Ard., Telekia speciosissima (L.) Less.), a species which belongs to the newly created Xerolekia genus [1] is considered a member of the tribe Inuleae, subtribe Inulinae, of the family Compositae (Asteraceae) [2]. X. speciosissima is a perennial herb, 20–60 cm tall, with a stem having resin canals. Leaves of the plant are up to 25 cm long and are broadly lanceolate; inflorescences are solitary, terminal, heterogamous and have yellow flowers. The species, growing in nature, is a pre-Alpine endemite, listed in Italian and regional (Lombardy) red lists, that naturally inhabits crevices on limestone or dolomite rocks, between 1000 and 1900 m.a.s.l. Its distribution is limited to the area from Lake Como to Lake Garda and to the Ledro Valley [1,3]

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