Constituents of Artemisia tschernieviana and Their Biological Activity

Abstract

Artemisia tschernieviana Besser (Asteraceae) is a plant of the Kazakhstan flora that is little studied chemically [1]. The antioxidant and antihemolytic activity of the extract of A. tschernieviana from Iran [2] and the composition and antimicrobial activity of essential oil [3–6] were studied before. Ground aerial part (leaves and stems) of the plant collected in western Kazakhstan in July 2013 was extracted by CHCl3–EtOH. The obtained extract was separated by column chromatography over silica gel using gradient elution by hexane, EtOAc, and EtOH. Elution by hexane–EtOAc (3:1) isolated a colorless crystalline compound 1, the structure of which was elucidated using spectral data and an x-ray crystal structure analysis (XSA). PMR and 13C NMR spectra were interpreted using 2D 1H–1H COSY and HSQC. Positions of individual atoms were determined using DEPT and 2D HMBC. Figure 1 shows the molecular structure of 1. The isolated compound 1 was the methyl ester of 3-(5 -hydroxyprenyl)-p-coumaric acid according to spectral data (PMR, 13C NMR, 13C DEPT, 1H–1H COSY, 1H–13C HSQC, HMBC) and an XSA. Compound 1 was isolated earlier from A. marschalliana Spreng. [7] and A. xanthochroa [8] and was also prepared synthetically [9]. Elution of the column by hexane–EtOAc (3:1) isolated compound 2, the structure of which was confirmed by an XSA, according to which 2 was identified as 6-demethoxy-4 -O-methylcapillarisin, which was isolated earlier [10]. Compounds 1 and 2 were isolated from A. tschernieviana for the first time. We investigated the cytotoxic, antimicrobial, antifungal, antimalarial, and antioxidant activity of the extracts, essential oil, and constituents of A. tschernieviana. Antiradical activity was studied using several extracts of A. tschernieviana, i.e., CHCl3 (Atsch-1), EtOAc (Atsch-2), and EtOH (Atsch-3). Essential oil (Atsch-4) was obtained by steam distillation in a Clevenger apparatus. Optical density of the obtained compounds was measured dependent of concentration on a Cary 60 UV-Vis spectrophotometer at 520 nm. Antiradical activity of the samples was compared with that of butylhydroxyanisole (BHA) [11]. Table 1 presents the results for the antiradical activity.