LAUSR

The genus Zanthoxylum, belonging to the Rutaceae family, is widely distributed in India, Japan, Korea and Vietnam and lives in low mountain forests or thickets. Zanthoxylum armatum DC. is an important herb in China, and it was extensively used to treat cold and cough, fever, abdominal pain, altitude sickness, etc. Modern chemical investigations of Z. armatum have reported that it contains alkaloid, lignan, triterpene, flavonoids, amide, and steroid. The phytochemical investigation of stems of Z. armatum led to the isolation of 40 compounds [1, 2]. The present study led to the isolation of nine phenolic glycosides, among which eight compounds, including 1–6, 8, and 9, were obtained from Rutaceae for the first time. Compound 7 was isolated from Z. armatum for the first time. Plant Material. The root and stem of Z. armatum were collected from Nanning, Guangxi Province of China in 2014 and identified by Prof. Ze-Hao Huang (Fujian University of Traditional Chinese Medicine). A voucher specimen of the plant (#1409-21) was deposited in the Herbarium of School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, China. Extraction and Isolation. Dried stems of Z. armatum (20 kg) were extracted with 95% ethanol (50 L × 3) at room temperature. The combined EtOH solvent was filtered and concentrated under reduced pressure to give 680 g of residue. The residue was then suspended in water and partitioned successively with petroleum ether, EtOAc, and n-BuOH. The water-soluble extract (83 g) was subjected to MCI gel CHP 20P (8 × 60 cm) and eluted with a mixture of MeOH and H2O (0:10; 1:9; 3:7; 5:5; 7:3; 10:0, 600 mL for each step) to yield six fractions (Frs.1–6) [6]. Fraction 2 was further chromatographed on Toyopearl HW-40F (6 × 60 cm) with H2O to give five subfractions (Subfrs. 2A–2E). Subfraction 2A was subsequently purified by Cosmosil 75 C18-OPN (4 × 30 cm, eluted with H2O→20% MeOH) and Toyopearl HW-40F (6 × 60 cm, eluted with H2O) to yield compounds 1 (92.6 mg), 2 (63.0 mg), and 3 (46.2 mg). Fraction 3 was subjected to Toyopearl HW-40F (6 × 60 cm) with H2O to give four subfractions (Subfrs. 3A–3D). Subfraction 3B was chromatographed on MCI gel CHP 20P (5 × 40 cm, eluted with 30→50% MeOH) and Toyopearl HW-40F (6 × 60 cm, eluted with H2O) to afford compounds 4 (160.6 mg), 5 (16.6 mg), 6 (54.2 mg), and 7 (118.8 mg). Fraction 5 was subjected to Toyopearl HW-40F (6 × 60 cm) with H2O to give three subfractions (Subfrs. Fr.5A–5C). Subfraction 5A was chromatographed on MCI gel CHP 20P (5 × 40 cm, eluted with 40→70% MeOH), Toyopearl HW-40F (6 × 60 cm, eluted with H2O) and Cosmosil 75 C18-OPN (4 × 30 cm, eluted with 50%→70% MeOH) to afford 8 (15.0 mg) and 9 (17.3 mg). The structures of all isolated compounds were determined by a combination of spectroscopic methods (MS, 1H NMR and 13C NMR) and comparison with literature data. 4-Hydroxy-2,6-dimethoxyphenyl-1-O-α-L-rhamnopyranosyl(1→6)-β-D-glucopyranoside (1). White powder, C20H30O13. 1H NMR (400 MHz, D2O, δ, ppm, J/Hz): 6.14 (2H, s, H-3, 5), 4.72 (1H, d, J = 7.3, H-1′), 4.68 (1H, d, J = 1.3, H-1′′), 3.89 (1H, dd, J = 11.6, 1.4, H-6′b), 3.73 (6H, s, OMe), 3.69–3.56 (3H, m, H-6′a, 2′′, 3′′), 3.51–3.36 (5H, m, H-2′, 4′, 5′, 4′′, 5′′), 3.33 (1H, t, J = 9.6, H-3′), 1.10 (3H, d, J = 6.2, H-6′′). ESI-MS m/z 501.8 [M + Na]+ (C20H30O13Na) [3].