LAUSR

Cirsium setosum (Willd.) M. Bieb. (Asteraceae) is a perennial herbaceous thistle indigenous to Europe, Western and Eastern Siberia, the Far East, Mongolia, China, Japan, Caucasus, Sakhalin, Central Asia, and the Arctic [1–4]. Decoction of the herb is used in folk medicine for colic and topically for diatheses, eczema, and various types of dermatitis. Juice of leaves and young plants possesses wound-healing and anti-inflammatory activity. Tincture and decoction of all plant parts are used for nervous disorders [4]. Preparations of the aerial part of the plant were used experimentally for neoplasms of the stomach and lungs [4, 5]. The charred dried aerial part is used in Chinese medicine [6]. The lipid composition of the plant has not been previously studied. The aerial part of C. setosum collected during flowering (July 2018) and subterranean plant organs collected during wilting (September, 2018) in Ivolginsky District, Republic of Buryatia, were studied. The lipid contents of samples were quantified gravimetrically beforehand [7]. The lipid fraction was isolated by a modified Bligh–Dyer method [8] followed by acid methanolysis to produce fatty acid methyl esters (FAMEs). The products were extracted with hexane. The extract was evaporated and treated with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) to produce volatile sterol and hydroxyacid derivatives (45 min, 80°C). The resulting reaction mixture was dissolved in hexane. FAMEs were analyzed by GC-MS on an Agilent Packard HP 6890 gas chromatograph with an HP MSD 5973N quadrupole mass spectrometer as the detector. Chromatography used an HP-5ms column (30 m × 0.25 mm × 0.25 μm; copolymer of 5% diphenyl, 95% dimethylsiloxane), He carrier gas (constant 1.5 mL/min flow rate), column temperature 125°C (isothermal for 0.5 min) and 125–320°C (7°C/min, isothermal for 0.5 min), vaporizer temperature 280°C, and ion source 230°C. The sample volume was 1 μL of solution with flow division 40:1. The percent composition of the mixture was calculated from GC peak areas without correction factors. Qualitative analysis was based on comparing retention times and total mass spectra of the corresponding pure compounds using NIST11.L library data and standard mixtures [Bacterial Acid Methyl Esters (CP Mix, Supelco, Bellefonte, PA, USA) and a FAME mixture (Supelco 37 comp. FAME Mix 10 mg/mL in CH2Cl2)]. The lipid fraction content in the aerial plant part was 1.63%; in subterranean organs, 0.49% of the air-dried raw material mass (average of three determinations). Table 1 presents the GC-MS results for constituents with contents ≥0.1%. Greater than 30 compounds were detected in the studied samples, of which 19 were identified. The qualitative composition and quantitative contents of the lipid constituents in the samples differed. The aerial part contained 17 identified compounds; subterranean organs, 13. The contents of saturated fatty acids (SFAs) in the aerial part reached 31.65%; in subterranean organs, 32.55% of the total lipid fraction. The contents of polyunsaturated fatty acids (PUFAs) in the aerial part and subterranean organs were 36.49 and 42.40%, respectively. The contents of monoenoic fatty acids (MFAs) were 4.60 and 1.24%, respectively. The dominant SFA in both samples was palmitic acid (16:0) at 22.46 and 26.79%. Two PUFAs, linoleic (18:2n6) with contents of 9.24 and 30.00%, and the linolenic acid isomer (18:3n6) with contents of 27.25 and 12.40%, respectively, of the total lipid fraction were identified in the aerial part and subterranean organs of C. setosum.