Chemical study of Artemisia filatovae

Abstract

Artemisia filatovae A. Kuprijanov sp. nova is endemic to Pavlodar District of the Republic of Kazakhstan [1]. Steam distillation isolated from this Artemisia species biologically active essential oil. Its component composition has been studied [2]. We have previously isolated the sesquiterpene lactones isoepoxyestafiatin and artefin [3]. The aerial part of the plant collected during flowering near Ekibastuz of Pavlodar District was dried in air and ground to particle size 2-4 mm. Dry finely ground raw material (600 g) of A. filatovae was extracted twice with ethanol. The alcohol extract was evaporated in a rotary evaporator. The resulting total compounds were chromatographed over a column of silica gel (1:15 ratio) with elution by petroleum ether:ethylacetate to isolate colorless crystalline 1-5. Compound 1, arglabin: mp 100-103°C, C15H18O3, MW 246 g/mol, Rf 0.69 (petroleum ether:ethylacetate, 2:1), yield 6.1 g (1.0% of air-dried raw material) [4]. Compound 2, ludartin: mp 112-116°C, C15H18O3, MW 246 g/mol, Rf 0.68 (petroleum ether:ethylacetate, 2:1), yield 2.1 g (0.35% of air-dried raw material). Ludartin was previously isolated from A. carruthii as a mixture with 11,13-dihydroludartin [5]. We isolated it pure for the first time from A. filatovae and unambiguously established its structure using spectral data (PMR, 13C NMR, IR, UV, mass). Compound 3, isoepoxyestafiatin: mp 169-171°C, C15H18O4, MW 262 g/mol, Rf 0.47 (petroleum ether:ethylacetate, 2:1), yield 1.36 g (0.23% of air-dried raw material) [3]. Compound 4, hanphyllin: mp 171°C (dec.), C15H20O3, MW 248 g/mol, Rf 0.43 (petroleum ether:ethylacetate, 2:1), yield 1.0 g (0.17% of air-dried raw material) [6]. Compound 5, candirone: mp 220-223°C, C18H16O7, MW 344 g/mol, Rf 0.57 (ethylacetate), yield 0.030 g (0.005% of air-dried raw material). Based on spectral data 5 was 5,4′-dihydroxy-3,6,8-trimethoxyflavone. Compound 5 was isolated previously from Tephrosia candida and called candirone [7]. The PMR, IR, and mass spectra of 5 were analogous to those published [7]. Chloroform extraction isolated another sesquiterpene lactone (6) in addition to these. Compound 6, artefin: mp 204-206°C, C15H20O5, MW 280 g/mol, Rf 0.43 (ethylacetate), yield 0.59 g (0.059% of airdried raw material) [3]. Arglabin (1), ludartin (2), hanphyllin (4) and cadirone (5) were isolated from this Artemisia species for the first time. Thus, we isolated from A. filatovae five sesquiterpene lactones of the guaiane and germacrane types and one flavonoid. The isolated compounds are interesting as biologically active compounds and as renewable resources for chemical modification.