Composition of hexane extract of Artemisia lagocephala

Abstract

Artemisia lagocephala (Fisch. Ex Bess.) DC. is a semi-shrub with densely tomentose leaves and a strong spicy aroma. It grows in high-mountain regions of northeastern Asia [1][2][3]. The tincture of the herb is used in folk medicine to treat gastrointestinal diseases and as a wound-healing agent [4]. However, this plant is little studied with respect to its chemistry. Essential oils of wormwood from two habitats were studied earlier [5,6]. The aqueous extract of A. lagocephala contained the sesquiterpenoid lactone achillin [7]. The establishment of the structures of new cycloartane derivatives from A. lagocephala was reported [8]. Herein we communicate information on the composition of the hexane extract of A. lagocephala and the biological activity of its components. The presence of a compound of ozonide nature distinguishes A. lagocephala from other representatives of the genus Artemisia.A. lagocephala was collected on the south slope of Sikhote-Alin (Russian Federation, Primorskii Territory) at sites of limestone outcroppings at a height of 575 m above sea level in September 2009. Air-dried aerial part of A. lagocephala was extracted with hexane at room temperature. The extract was evaporated under vacuum and chromatographed (2u) over a column of silica gel using hexane:EtOAc (100:1, 50:1, 10:1, 2:1) to afford 3E-acetoxycycloartan-24-ozonide (1) [8] (7.2% of the mass of dry extract), 3E-acetoxycycloartan-24-al (2) [8] (6.2%), 25,26,27-trisnor-3E-acetoxycycloartan-24-ol (3) [8] (0.015%), 24,25,26,27-tetranor-3E-acetoxycycloartan-24-ol (4) [8] (0.01%), the sesquiterpene lactone achillin (5) [9] (8.3%), caryophyllene oxide (6) [10] (1.5%), (1R,4S)-p-menth-2-en-1-ol (7) [11] (0.2%), in addition to difficultly separated mixtures of unbranched paraffins (38% of the dry extract), ' 4 -3-ketosteroids (8-11) [12] (0.3%), and ' 5 -sterols [13] (0.2%).Pure compounds were identified based on PMR, 13 C NMR, and 2D spectra and a comparison of them with the literature [8][9][10][11]. Fractions of paraffins, ketosteroids, and sterols were studied using PMR and GC-MS and comparisons with authentic samples and the literature [12,13].The most notable component of the extract was the fraction of paraffins, which consisted of linear C 21 , C 23 , C 25 , C 27 , C 29 , and C 31 paraffins in the ratio 5:17:17:14:33:14. The high content of paraffins was probably a result of adaptation of the plant to the extreme high-mountain conditions. Steroidal compounds were present in minor amounts in the extract. Table 1 presents the composition of the ' 4 -3-ketosteroid fraction. According to our data, these compounds were not found earlier in plants. The ' 5 -sterol fraction consisted of campesterol, stigmasterol, E-sitosterol, and isofucosterol (3.6, 8.6, 76.4, and 3.3%, respectively). Sterols and ' 4 -3-ketosteroids of A. lagocephala had identical sets of side chains.Data on the effect of the compounds isolated by us on the activity of thymidine kinase, an enzyme that plays an important role in DNA biosynthesis, according to the previous meth...