Chemical Composition of Achillea alpina

The genus Achillea (Compositae, Anthemideae) comprises over 100 species worldwide, which are mainly distributed in the northern hemisphere. Among them, about ten species were found in China: A. alpina, A. millefolium, A. wilsoniana, A. setacea, A. asiatica, A. impatiens, A. ledebouri, A. ptarmicoides, A. acuminate, and A. salicifolica [1]. A. alpina has been used by local people, as a traditional herbal medicine to treat acute inflammation and pharmacological studies show that it has anti-inflammatory, antipyretic, and sedative properties. Some organic acids, monoand sesquiterpenoids, flavonoids, and polyacetylene compounds have been reported from this plant [2–8]. The aerial parts of A. alpina were collected in August 2010 from Jilin Province, China, and identified by Prof. Jianhua Wang, Pharmacognosy Laborary, School of Pharmaceutical Sciences, Hebei Medical University. Dry pieces of the aerial part of A. alpina (8 kg) were extracted with 95% ethanol at room temperature. After evaporation of the solvent under reduced pressure, the residue was suspended in water and extracted with petroleum ether, CH2Cl2, EtOAc, and n-BuOH, successively. The CH2Cl2 fraction (90 g) was subjected to silica gel column chromatography and eluted with petroleum ether–CH3COCH3 (100:1 1:1). Fractions 66 to 91 and 92 to 144 afforded 1 (26.7 mg) and 2 (15.8 mg), respectively. Fractions 191 to 229 were subjected to repeated chromatography to obtain 3 (1.7 mg). Fractions 1 to 28 were chromatographed on silica gel column to afford 4 (2.1 mg). The n-BuOH fraction (182 g) was subjected to column chromatography on Diaion HP-20 and eluted with H2O, 10% EtOH, 30% EtOH, 50% EtOH, and 70% EtOH, successively. The fractions eluted with 30% EtOH and 50% EtOH were pooled and subjected to silica gel column chromatography to afford 4 (5.2 mg), 5 (8.4 mg), 6 (12.3 mg), and 7 (4.6 mg). Their chemical structures were identified by spectral analysis using NMR spectrometers and were determined as (–)-sesamin (1) [9, 10], artemitin (2) [11], eupatorin (3) [12], 2,6-dimethoxyquinone (4) [13], eleutheroside B1 (5) [14, 15], luteolin-7-O-D-glucoside (6) [16], and isoorientin (7) [17] by comparing the data with those in the literature. Among them, compounds 4 and 5 were reported for the first time in the genus Achillea; the others (1–3, 6) were all isolated from the species Alpina for the first time. In the original reported papers, due to the limitations of NMR, especially without the help of 2D NMR, some of the 1H and 13C NMR data were misassigned in compound 3. In this paper, all the 1H and 13C NMR spectral data of this compound were reassigned after interpretation of its 2D NMR spectroscopic data. (–)-Sesamin (1). White crystals (petroleum ether–CH3COCH3), mp 121–123 C. UV (MeOH, max, nm): 286, 238. IR (KBr, max, cm –1): 3078, 1500, 1439, 1367, 1250, 1138, 1091, 1029, 922. EI-MS m/z 354 [M]+. 1H NMR (500 MHz, CDCl3, , ppm, J/Hz): 6.85 (2H, d, J = 1.5, H-2, 2 ), 6.80 (2H, dd, J = 8.0, 1.5, H-6, 6 ), 6.78 (2H, d, J = 8.0, H-5, 5 ), 5.95 (4H, s, O-CH2-O), 4.71 (2H, d, J = 4.5, H-7, 7 ), 4.23 (2H, dd, J = 9.0, 7.0, H-9a, 9a ), 3.87 (2H, dd, J = 9.0, 3.5, H-9b, 9b ), 3.05 (2H, m, H-8, 8 ). 13C NMR (125 MHz, CDCl3, , ppm): 148.0 (C-4, 4 ), 147.1 (C-3, 3 ), 135.1 (C-1, 1 ), 119.4 (C-6, 6 ), 108.2 (C-5, 5 ), 106.5 (C-2, 2 ), 101.1 (O-CH2-O), 85.8 (C-7, 7 ), 71.7 (C-9, 9 ), 54.3 (C-8, 8 ). The trans-configuration of H-7 and H-7 was evidenced by their chemical shifts and coupling constants ( 4.71, J = 4.3 Hz), which were observed at 4.42 (J = 7.2 Hz) in the cis-isomers [9].