Chinese Chemical Letters 24 (2013) 512–514 Contents lists available at SciVerse ScienceDirect Chinese Chemical Letters journal homepage: www.elsevier.com/locate/cclet Original article Two new cyclic diarylheptanoids from the stems of Ostryopsis nobilis Yan-Xia Zhang, Bing Xia, Yan Zhou, Li-Sheng Ding, Shu-Lin Peng * Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China ARTICLE INFO ABSTRACT Article history: Two new cyclic diarylheptanoids named ostryopsitrienol (1) and ostryopsitriol (2), together with six Received 27 November 2012 known compounds, were isolated from the stems of endemic medicinal plant of Ostryopsis nobilis Received in revised form 4 February 2013 (Betulaceae). The structures of the new compounds were elucidated by means of HRMS, 1D NMR, 2DNMR Accepted 28 February 2013 and X-ray crystallography analysis. Available online 10 May 2013 ß 2013 Shu-Lin Peng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Ostryopsis nobilis Cyclic diarylheptanoid Ostryopsitrienol Ostryopsitriol 1. Introduction 2.2. Extraction and isolation Ostryopsis nobilis I.B. Balfour & W.W. Smith (Betulaceae), as an The dried stems (15 kg) were extracted with methanol at room endemic plant is mainly distributed in the Yunnan and Sichuan temperature. After concentration in vacuo, the gummy residue was provinces of China [1]. The bark of O. nobilis is used as Chinese suspended in H2O, and then extracted with petroleum ether and ethnomedicinal medicines for bone-knitting and hemostatic EtOAc, successively, to give petroleum ether and EtOAc fractions. therapeutic properties. So far there is only one report on the The petroleum ether fraction was submitted to silica gel column chemical constituents of O. nobilis [2]. In our study, two new cyclic chromatography to yield (8) (800 mg). The EtOAc fraction was diarylheptenoids, a diphenyl ether-type cyclic diarylheptenoid subjected to CC on silica gel eluting with a mixture of CHCl3–MeOH named ostryopsitrienol (1) and a diphenyl-type cyclic diarylhep- with increasing polarity to give five fractions (A–E). Fr.B was tenoid named ostryopsitriol (2), together with betulatetraol (3) [3], subjected to reversed-phase CC with MeOH–H2O (20% ! 80%) as 3,5-dihydroxy-1,7-bis(4-hydroxyphenyl)heptane (4) [4], dammar- the solvent system to yield compound 1 (9 mg). Fr.C was enediol II 3-caffeate (5) [5],3b-(3,4-dihydroxycinnamoyl)-ery- repeatedly chromatographed over silica gel CC eluting with throdiol (6) [6], daucosterol (7) and b-sitosterol (8), were isolated CHCl3–MeOH with increasing polarity to afford compound 5 from the stems of O. nobilis. These compounds were isolated from (25 mg) and 6 (30 mg). Fr.D was subjected to reversed-phase CC this endemic plant for the first time. with MeOH–H2O (15% ! 80%) as the solvent system to yield compound 4 (30 mg) and five sub-fractions (D1–D5). The sub- fraction D4 was further purified by silica gel CC eluting with 2. Experimental CHCl3–MeOH with increasing polarity to yield compound 2 (6 mg) and 7 (500 mg). Fr.E was subjected to a series of purification steps 2.1. Plant material using silica gel CC, and RP-18 and Sephadex LH-20 to obtain compound 3 (30 mg). The stems of O. nobilis were collected from Sichuan Province of China in July 2010, and authenticated by Prof. Xiaohong Hu. A 3. Results and discussion voucher specimen was deposited in the Herbarium of Chengdu Institute of Biology, Chinese Academy of Sciences. Ostryopsitrienol (1) was obtained as a white crystal (in 20 methanol). ½aD À 595 (c 0.02, MeOH). Its molecular formula, C20H18O4 which indicated 12 degrees of unsaturation, was established from the quasi-molecular ion peak at m/z 345.1096 + * Corresponding author. [M+Na] (calcd. for C20H18O4Na: 345.1097) in the HRESIMS. The IR E-mail address: [email protected] (S.-L. Peng). (KBr) absorption bands at 3391, 2920, 1570, 1500, 1430, 1001-8417/$ – see front matter ß 2013 Shu-Lin Peng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. http://dx.doi.org/10.1016/j.cclet.2013.03.035 [(Fig._1)TD$IG] Y.-X. Zhang et al. / Chinese Chemical Letters 24 (2013) 512–514 513 Fig. 1. Selected HMBC and NOSEY correlations of compound 1. 1038 cmÀ1 are assignable to hydroxyl, olefinic group, aromatic ring successful performance of the X-ray diffraction experiment with and ether functions. The 1H NMR and 13C NMR data (Table 1) Cu Ka radiation confirmed the proposed structure, the relative supported 1 to be a cyclic diarylheptanoid [7]. The 1H NMR position of two phenyl groups and the absolute configuration of the spectrum exhibited signals for a para-substituted benzene ring at d hydroxyl group at C-11 as shown (Fig. 2). The structure of 1 was 7.62, 7.17, 7.13 and 7.11 (dd, each 1H, J = 8.0, 2.0 Hz), and a 1,2,3,5- assigned as 3,11(R)-dihydroxy-2-methoxy-1,17-oxo-7,13-diphe- tetrasubstituted phenyl group at d 6.28 (d, 1H, J = 2.0 Hz, H-4) and nyl-7,9,12-heptanetriene, named ostryopsitrienol. 4.76 (d, 1H, J = 2.0 Hz, H-6). Due to the shielding effect, the H-6 Ostryopsitriol (2) was obtained as a white amorphous powder. 20 signal appeared abnormally up-field from other aromatic proton ½aD À 34 (c 0.18, MeOH). The molecular formula of 2 was signals, which is the distinguished characteristic of diphenyl ether- determined as C19H22O5 which indicated 8 degrees of unsatura- type cyclic diarylheptanoid [7]. In addition, three pairs of protons tion, on the basis of HRESIMS (m/z 353.1352 [M+Na]+, calcd. for 1 1 13 signals in the H NMR spectrum appeared at d 6.12 (d, 1H, C19H22O5Na: 353.1359). Analysis of the H NMR and C NMR J = 11.0 Hz, H-7) and 5.89 (t, 1H, J = 11.0 Hz, H-8), d 5.60 (dd, 1H, spectra of 2 indicated that the structure of 2 was also a diphenyl- J = 15.2, 11.0 Hz, H-9) and 5.38 (dd, 1H, J = 15.2, 9.1 Hz, H-10), and type cyclic diarylheptanoid similar to betulatetraol [3], except for 5.67 (dd, 1H, J = 11.8, 6.3 Hz, H-12) and d 6.56 (d, 1H, J = 11.8 Hz, H- less a hydroxyl group, videlicet, only three hydroxyl groups on the 13), combined with their characteristic coupling constants indicate aliphatic ring of 2. The 1H NMR spectrum, six aromatic proton olefinic functional groups were cis-, trans- and cis-configuration, signals as two ABX system were observed at dH 6.80 (m, 1H), 7.01 respectively. The cross peaks in 1H–1H COSY spectrum displayed (d, 1H, J = 8.2 Hz) and 6.78 (m, 1H), and 6.99 (d, 1H, J = 8.2 Hz), 6.80 connectives for H-7/H-8/H-9/H-10/H-11/H-12/H-13, and down- (m, 1H) and 6.88 (br.s, 1H, H-19). The 1H–1H COSY spectrum field signal at d 5.08 (br.s) suggested a hydroxyl group was linked at [(Fig._2)TD$IG] the methine carbon of C-11. The HMBC correlations between dH 3.86 (CH3) with dC 135.9 (C-2), and dH 9.31 (OH) with dC 151.5 (C-3), 135.9 (C-2) and 111.0 (C-4), indicated that a methoxyl group was located at C-2 and a hydroxyl group at C-3, respectively. The NOSEY correlations supported this proposed structure (Fig. 1). The Table 1 1 13 H NMR (600 MHz) and C NMR (150 MHz) data of compounds 1 and 2 (DMSO-d6). No. 12 dC dH (J in Hz) dC dH (J in Hz) 1 155.6 (s) 126.3 (s) 2 135.9 (s) 151.5 (s) 3 151.5 (s) 116.4 (d) 6.80, m 4 110.0 (d) 6.28, d (2.0) 129.8 (d) 7.01, d (8.2) 5 132.0 (s) 130.1 (s) 6 110.0 (d) 4.76, d (2.0) 134.4 (d) 6.78, m 7 130.0 (d) 6.12, d (11.0) 35.8 (t) 2.82, t (11.0), 2.82, t (11.0) 8 128.5 (d) 5.89, t (11.0) 69.8 (d) 4.12, m 9 126.4 (d) 5.60, dd (15.2, 11.0) 66.4 (d) 3.82, m 10 136.1 (d) 5.38, dd (15.2, 9.1) 46.7 (t) 2.20, m; 1.52, m 11 69.8 (d) 5.26, br s 65.3 (d) 3.68, m 12 137.9 (d) 5.67, dd (11.8, 6.3) 35.1 (t) 2.20, m; 1.62, m 13 128.4 (d) 6.56, d (11.8) 26.6 (t) 2.75, t (15.8), 2.75, t (15.8) 14 135.7 (s) 129.8 (s) 15 130.2 (d) 7.62, d (8.2) 129.8 (d) 6.99, d (8.2) 16 123.7 (d) 7.11, dd (8.2, 2.0) 116.3 (d) 6.80, m 17 156.4 (s) 151.7 (s) 18 124.5 (d) 7.17, dd (8.2, 2.0) 126.1 (s) 19 129.0 (d) 7.13, d (8.2) 134.4 (d) 6.88, s OCH 60.8 (q) 3.86, s 3 Fig. 2. X-ray structure of compound 1 showing relative configuration. 514[(Fig._3)TD$IG] Y.-X.