LAUSR

Saussurea involucrata (Asteraceae) inhabits rocky sites of Xinjiang (China) and the Tian-Shan and Altai mountains at elevations 2400–3470 m above sea level [1]. S. involucrata is used as a traditional medicinal plant with anti-inflammatory, analgesic, antioxidant, and antihypoxic properties; for battling fatigue and aging; as treatment for infertility and hormonal and gynecological diseases; and for immunomodulation [2]. Previously, S. involucrata yielded phenylpropanoids, flavonoids, coumarins, lignans, sesquiterpenes, steroids, ceramides, and polysaccharides [3]. Nevertheless, the chemical composition of the plant seeds are insufficiently studied. Three new lignans including arctigenin-4-O-(6′′-O-acetyl-β-D-glucoside), arctigenin-4-O-(2′′-O-acetyl-β-D-glucoside), and arctigenin-4-O-(3′′-O-acetyl-β-D-glucoside) [4] and known sesquiterpenoidal and steroidal esters [5] were isolated in our previous research. In continuation of research on the chemical composition of the petroleum-ether fraction of S. involucrata seeds, we isolated seven known compounds and determined their structures using NMR spectroscopy and comparisons with the literature as ursa-12-sene-3β,11β-diol 3-O-palmitate (1) [6], bis(2-ethylhexyl)benzene-1,2-dicarboxylate (2) [7], ethyl linoleate (3) [8], 4-hydroxynonenal (4) [9], 6,10,14-trimethylpentadecan-2-one (5) [10], 2-hydroxy-6(Z)-hexadecenoic acid (6) [11], and (E)-7-tetradecen-1-ol (7) [12]. Triterpene 1 with an acyclic chain bonded through an ester was isolated for the first time from S. involucrata. Moreover, compounds 1–7 were isolated and identified for the first time from this plant. Seeds of S. involucrata were collected in Hejing, Xinjiang Province (China), in October 2018. Specimens were preserved at the Xinjiang Institute of Materia Medica. Dried and ground seeds of S. involucrata (10.0 kg) were extracted (3×) with EtOH (95%) at room temperature. The extract was suspended in H2O and extracted successively with petroleum ether, CHCl3, EtOAc, and n-BuOH. The petroleum ether fraction (580.0 g) was separated by column chromatography over silica gel with elution by petroleum ether–EtOAc to give 10 fractions. The third fraction C (180.0 g) was eluted by petroleum ether–EtOAc (50:1→10:1) to give six subfractions (C1–C6). Rechromatography of subfraction C3 (5.0 g) using ODS absorbent and a gradient of MeOH–H2O (45–100% MeOH) produced five fractions (C3.1–C3.5). Separation of fraction C3.1 (98.0 mg) by preparative HPLC afforded 2 (17.5 mg) and 5 (11.2 mg). Rechromatography of subfractions C3.2 (530.0 mg) and C3.3 (50.0 mg) over Sephadex LH-20 using CH2Cl2–MeOH (1:1) afforded 3 (20.0 mg) and 7 (20.0 mg), respectively. Subfractions C5.2 (84.0 mg) and C5.3 (508.0 mg) were chromatographed over columns of ODS (MeOH–H2O, 45–100% MeOH), Sephadex LH-20 (CH2Cl2–MeOH, 1:1), and silica gel (petroleum ether–EtOAc, 30:1) and separated by preparative HPLC to afford 6 (7.7 mg) and 1 (21.6 mg), respectively. Subfraction C6.1 (202.0 mg) afforded 4 (8.0 mg) in the same manner. NMR spectra were recorded with TMS internal standard on a Varian MR-400 spectrometer (Palo Alto, CA, USA) at operating frequency 400 MHz for 1H and 100 MHz for 13C. HPLC used an Agilent 1260 chromatograph equipped with a Waters XSELECT column (250 × 10 mm × 5 μm). Column chromatography used silica gel (100–200 and 200–300 mesh; Qingdao Haiyang Chemical & Special Silica Gel Co., Ltd., Qingdao, China) and Sephadex LH-20 (GE, New York, NY, USA). Ursa-12-sene-3β,11β-diol 3-O-palmitate (1). C46H80O3, colorless oil. 1Í NMR spectrum (400 MHz, CDCl3, δ, ppm, J/Hz): 5.35 (1H, d, J = 3.2, H-12), 4.53 (1H, m, H-11), 4.51 (1H, m, H-3), 2.27 (2H, t, J = 7.5, H-2′), 2.03–1.85 (2H, m, H-15), 2.03–1.85 (2H, m, H-16), 1.88 (1H, d, J = 9.3, H-9), 1.62 (2H, m, H-3′), 1.60, 1.41, 1.26 (2H, m, H-21), 1.40, 1.26 (2H, m, H-22), 1.40 (2H, m, H-2), 1.59, 1.28 (2H, m, H-7), 1.55, 1.41 (2H, m, H-6), 1.39 (1H, m, H-18), 1.28, 0.87 (2H, m, H-1),