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Natural Product Research: Formerly Natural Product Letters Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/gnpl20
A new sesquiterpene from Ixeris chinensis a
a
a
a
Qinghu Wang , Nayintai Dai , Narenchaoketu Han , Rongjun Wu & a
Jiesi Wu a
College of Traditional Mongolian Medicine, Inner Mongolia University for Nationalities, Tongliao 028000 Inner Mongolia, P.R. China Published online: 30 Jun 2014.
To cite this article: Qinghu Wang, Nayintai Dai, Narenchaoketu Han, Rongjun Wu & Jiesi Wu (2014) A new sesquiterpene from Ixeris chinensis, Natural Product Research: Formerly Natural Product Letters, 28:19, 1579-1582, DOI: 10.1080/14786419.2014.927467 To link to this article: http://dx.doi.org/10.1080/14786419.2014.927467
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Natural Product Research, 2014 Vol. 28, No. 19, 1579–1582, http://dx.doi.org/10.1080/14786419.2014.927467
A new sesquiterpene from Ixeris chinensis Qinghu Wang*, Nayintai Dai, Narenchaoketu Han, Rongjun Wu and Jiesi Wu College of Traditional Mongolian Medicine, Inner Mongolia University for Nationalities, Tongliao 028000, Inner Mongolia, P.R. China
Downloaded by [University of York] at 08:22 02 November 2014
(Received 28 March 2014; final version received 20 May 2014) The petroleum ether (PE) extract from Ixeris chinensis was submitted to chromatographic separation. A new sesquiterpene, namely 14-noreudesma-3hydroxy-3-en-2,9-dione, was isolated from the PE extract. The structures of the sesquiterpene was elucidated by using spectroscopic methods, including UV, IR, HRESI-MS and extensive 1D and 2D NMR techniques. Keywords: Ixeris chinensis; spectroscopic methods; sesquiterpene
1. Introduction Ixeris chinensis Nakai (I. chinensis), which belongs to the Compositae family, is a perennial plant found in various areas in China. The aerial parts of I. chinensis are used as a folk medicine for the treatment of bronchitis, pneumonia, pharyngitis, dysentery and poisonous indigestion on the basis of its anti-febrile, antidotal and analgesic effects (Jiangsu New Medical College 1986; Bu 1995). The known constituents of this plant include terpenoids (Zhang et al. 2002; Zhang, Wang, et al. 2006; Zhang, Zhao, et al. 2006) and flavonoids (Zhou & Yuan 1996; Wang & Wang 2007). The terpenoids (Seto et al. 1988; Chen et al. 2006) exhibited significant pharmacological activities including anti-inflammatory, cytotoxicity against A 549 lung carcinoma, WI-38 lung fibroblast, VA-13 lung malignant tumour and HepG2 human liver tumour cells, which are consistent with the clinic use of I. chinensis in Mongolian clinic. In our phytochemical investigation (Wang et al. 2012; Wu et al. 2012), several sesquiterpene lactones and flavonoids were isolated. In continuation of our investigation of the plant, we report herein the isolation and characterisation of a new compound, 14-noreudesma-3-hydroxy-3-en-2,9-dione (1). 2. Results and discussion Chromatographic fractionation of the PE extract from I. chinensis has led to the isolation of a new sesquiterpene (1). Compound 1 was obtained as a colourless crystal. The IR spectrum revealed absorption bands characteristic of a hydroxyl (3400 cm21), ketone (1708 and 1668 cm21) and double bond(s) (1637 cm21). The molecular formula was determined to be C15H21O3 by using HR-ESI-MS at m/z 249.1485 [M þ H]2 (calcd for 249.1491), and the 13C NMR spectrum displayed 15 signals suggesting the structure of a sesquiterpene. The 13C NMR spectral data (Table S1) indicated the presence of three methyls, three methylenes, two methines, one quaternary carbon, two carbonyls as well as one tetrasubstituted double bond and one terminal double bond in the molecule of 1. The 1H NMR spectrum of 1 revealed two olefinic hydrogens dH 4.81 (1H, d, J ¼ 1.5 Hz) and 4.76 (1H, d, J ¼ 1.5 Hz), and the correlations of dH *Corresponding author. Email: [email protected] q 2014 Taylor & Francis
Downloaded by [University of York] at 08:22 02 November 2014
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Q. Wang et al.
4.81 (1H, d, J ¼ 1.5 Hz) and 4.76 (1H, d, J ¼ 1.5 Hz) with dC 110.3 were observed in the HSQC spectrum. This indicated the presence of three methyl groups linked to three quaternary carbons in the 1H NMR spectrum and the correlations of dH 1.80 (3H, s), 1.77 (3H, s) and 1.41 (3H, s) with dC 10.7, 20.4 and 27.0 observed in the HSQC spectrum, respectively. The correlations observed in the HMBC spectrum (Figure 1) confirmed the planar structure of 2, in which the correlation of OH (dH 6.21, s) with C-2 (dC 191.6), C-3 (dC 144.5) and C-4 (dC 129.5) indicated the hydroxyl group located at C-3, and CH3-14 (dH 1.41, s) with C-4 (dC 129.5), C-5 (dC 42.8), C-6 (dC 42.0) and C-10 (dC 54.2), CH3-15 (dH 1.80, s) with C-3 (dC 144.5), C-4 (dC 129.5), C-5 (dC 42.8) and C-14 (dC 27.0) as well as CH3-13 (dH 1.77, s) with C-7 (dC 41.1), C-11 (dC 146.6) and C-12 (dC 110.3) indicated the three methyl groups located at C-4, C-5 and C-11, and 3-OH (dH 6.21, s) with C-2 (dC 191.6), C-3 (dC 144.5) and C-4 (dC 129.5), together with H-1 (dH 2.62, 306) with C-1 (dC 31.9), C-2 (dC 191.6), C-8 (dC 45.9) and C-9 (dC 208.9) indicated that the two carbonyls were attached to C-2 and C-9, respectively. This indicated the mutual coupling between H-1 and H-10, H-6 and H-7, H-7 and H-8 observed in the 1H – 1H COSY spectrum and the coupling between H-1 and C-1, H-10 and C-10, H-6 and C-6, H-7 and C-7, H-8 and C-8 observed in the HMQC spectrum are in agreement with the structure of the sesquiterpene. The relative configuration to isocrotyl group at C-7 was thus confirmed by comparison of the coupling constant observed to the signal at dH 2.20 (br t, J ¼ 12.5 Hz). This value is indicative of trans-diaxial couplings (Lago et al. 2002) between this hydrogen and the adjacent H-6 and H-8, which were confirmed by the correlations observed in the 1H – 1H COSY spectrum. Nevertheless, in the NOESY spectrum, the CH3-14 (d 1.41) displayed strong correlation with the proton at d 2.70 (H-10), whereas the H-7 exhibited no correlation with H-10 and CH3-14. Thus, the structure of compound 1 was elucidated and named as 14-noreudesma-3-hydroxy-3en-2,9-dione. 3. Experimental 3.1. General experimental procedures Melting points were determined using an X-4 micro melting point apparatus and were uncorrected (Shanghai Jingke Industrial Co., China). Optical rotations were measured in CHCl3 at 258C on a Perkin-Elmer 241 polarimeter (Perkin-Elmer, USA). The UV spectra were recorded on a Shimadzu UV-2201 spectrometer (Shimadzu, Japan). The IR spectra were recorded in KBr discs on a Thermo Nicolet 200 double beam spectrophotometer (Shimadzu, Japan). The HRESI-MS spectra were measured on Bruker Daltonics MicroTOFQ (Bruker Daltonics Inc., Germany). NMR spectra were measured on a Bruker AVANCE III – 500 NMR spectrometer (Bruker, Germany) with tetramethylsilane as the internal reference, and chemical shifts are
Figure 1. Some key HMBC correlations of 1.
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expressed in d (ppm). Column chromatography was performed by using silica gel (200 – 300 mesh, Marine Chemical Factory, Qingdao, China). Fractions were monitored by using TLC (silica gel GF25410 –40 mm, Marine Chemical Factory), and spots were visualised by heating silica gel plates sprayed with 10% H2SO4 in EtOH. 3.2. Plant material The whole plants of I. chinensis Nakai, used as experimental material, were collected in Tongliao, Inner Mongolia of China, in June 2012, and identified by Prof. Buhebateer (Inner Mongolia University for Nationalities). A voucher (No. 20120602) has been deposited in the School of Traditional Mongolian Medicine of Inner Mongolia University for Nationalities.
Downloaded by [University of York] at 08:22 02 November 2014
3.3. Extraction and isolation The air-dried whole plant of I. chinensis Nakai (2.0 kg) was powdered and extracted twice under reflux petroleum ether (PE) (30 L). Evaporation of the solvent under reduced pressure delivered the PE extract. The PE extract (50.0 g) was isolated by column chromatography on silica gel and gradiently eluted with PE –EtOAc (100:1 to 20:1) to give 10 fractions (Fractions 1 – 10). Fraction 3 [300 mg, PE – EtOAc (80:1) elute] was subjected to silica gel column chromatography using PE – EtOAc with increasing polarity (90:1 to 70:1) to give 1 (26 mg). 3.3.1. 14-Noreudesma-3-hydroxy-3-en-2,9-dione Colourless crystal; ½a25 D ¼ þ23 (CHCl3, c ¼ 0.12); UV (hexane) lmax (nm) (log 1): 271 (2.04); IR (KBr) y max: 3400, 2970, 2935, 2873, 1708, 1668, 1637 cm21. 1H NMR (500 MHz, DMSO-d6) dH: 3.06 (1H, dd, J ¼ 17.0, 2.0 Hz, H-1a), 2.62 (1H, dd, J ¼ 17.0, 4.5 Hz, H-1b), 2.26 (1H, dd, J ¼ 14.0, 2.5 Hz, H-6a), 1.64 (1H, dd, J ¼ 14.0, 12.5 Hz, H-6b), 2.20 (1H, tt, J ¼ 12.5, 2.5 Hz, H-7), 2.48 (1H, dd, J ¼ 13.0, 2.5 Hz, H-8a), 2.32 (1H, dd, J ¼ 13.0, 12.5 Hz, H-8b), 2.70 (1H, dd, J ¼ 4.5, 2.0 Hz, H-10), 4.81 (1H, d, J ¼ 1.5 Hz, H-12a), 4.76 (1H, d, J ¼ 1.5 Hz, H-12b), 1.77 (3H, s, H-13), 1.41 (3H, s, H-14), 1.80 (3H, s, H-15), 6.21 (1H, s, 3-OH). 13C NMR (125 MHz, DMSO-d6) dC: 31.9 (C-1), 191.6 (C-2), 144.5 (C-3), 129.5 (C-4), 42.8 (C-5), 42.0 (C6), 41.1 (C-7), 45.9 (C-8), 208.9 (C-9), 54.2 (C-10), 146.6 (C-11), 110.3 (C-12), 20.4 (C-13), 27.0 (C-14), 10.7 (C-15). HMBC correlations were shown in Figure 1. HR-ESI-MS: m/z 249.1485 [M þ H]2 (calcd for 249.1491). 4. Conclusion A new sesquiterpene, namely 14-noreudesma-3-hydroxy-3-en-2,9-dione, were isolated from the PE extract of I. chinensis Nakai. Supplementary material Supplementary material relating to this article is available online, alongside Table S1 and Figures S1 –S17. Acknowledgements The authors thank Ning Xu and Narenchaoketu for the measurements of NMR spectra.
References Bu HBTE. 1995. Mengyaoshouce. Vol. 1. China: Liaoning Nationalities Publishing House; p. 125–126. Chen WL, Liu QF, Wang J. 2006. New guaiane, megastigmane and eudesmane-type sesquiterpenoids and antiinflammatory constituents from Yaoungia japonica. Planta Med. 72:143–150. Jiangsu New Medical College. 1986. Dictionary of Chinese herbal medicine. Vol. 2. China: Shanghai People’s Publishing House; p. 1285–1288.
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Lago JH, Brochini CB, Roque NF. 2002. Terpenoids from Guarea guidonia. Phytochemistry. 60:333–338. Seto M, Miyaso T, Umahara K. 1988. Sesquiterpene lactones from Cichorium endivia L. and C. intybus L. and cytotoxic activity. Chem Pharm Bull. 36:2423–2429. Wang QH, Ao WLJ, Xin Y, Meng GX, Wu XL, Tai WQ. 2012. Simultaneous determination of sesquiterpene lactones in Ixeris chinensis by HPLC. J Food Drug Anal. 20:872–878. Wang XF, Wang XJ. 2007. Study on chemical constituents from Ixeris chinensis. Chin Tradit Herb Drug. 38:1151–1153. Wu QSS, Wang QH, Dai NYT. 2012. Study on chemical constituents of Ixeris chinensis. J Chin Med Mater. 35:1945–1949. Zhang SJ, Wang JL, Deng QG, Ando M. 2006. New triterpenes from Siyekucai (Ixeris chinensis). Chin Chem Lett. 17:195–197. Zhang SJ, Wang JL, Xue HY, Deng QG, Xing FL, Ando M. 2002. Three new guaianolides from Siyekucai (Ixeris chinenseis). J Nat Prod. 65:994–997. Zhang SJ, Zhao M, Bai LM, Hasegawa T, Wang LY, Xue HY, Deng QG, Xing FL, Bai YH, Sakai JI, et al. 2006. Bioactive guaianolides from Siyekucai (Ixeris chinensis). J Nat Prod. 69:1425–1428. Zhou HL, Yuan JR. 1996. Study on chemical constituents from Ixeris chinensis. Chin Tradit Herb Drug. 27:267–269.
Natural Product Research: Formerly Natural Product Letters Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/gnpl20
A new sesquiterpene from Ixeris chinensis a
a
a
a
Qinghu Wang , Nayintai Dai , Narenchaoketu Han , Rongjun Wu & a
Jiesi Wu a
College of Traditional Mongolian Medicine, Inner Mongolia University for Nationalities, Tongliao 028000 Inner Mongolia, P.R. China Published online: 30 Jun 2014.
To cite this article: Qinghu Wang, Nayintai Dai, Narenchaoketu Han, Rongjun Wu & Jiesi Wu (2014) A new sesquiterpene from Ixeris chinensis, Natural Product Research: Formerly Natural Product Letters, 28:19, 1579-1582, DOI: 10.1080/14786419.2014.927467 To link to this article: http://dx.doi.org/10.1080/14786419.2014.927467
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Natural Product Research, 2014 Vol. 28, No. 19, 1579–1582, http://dx.doi.org/10.1080/14786419.2014.927467
A new sesquiterpene from Ixeris chinensis Qinghu Wang*, Nayintai Dai, Narenchaoketu Han, Rongjun Wu and Jiesi Wu College of Traditional Mongolian Medicine, Inner Mongolia University for Nationalities, Tongliao 028000, Inner Mongolia, P.R. China
Downloaded by [University of York] at 08:22 02 November 2014
(Received 28 March 2014; final version received 20 May 2014) The petroleum ether (PE) extract from Ixeris chinensis was submitted to chromatographic separation. A new sesquiterpene, namely 14-noreudesma-3hydroxy-3-en-2,9-dione, was isolated from the PE extract. The structures of the sesquiterpene was elucidated by using spectroscopic methods, including UV, IR, HRESI-MS and extensive 1D and 2D NMR techniques. Keywords: Ixeris chinensis; spectroscopic methods; sesquiterpene
1. Introduction Ixeris chinensis Nakai (I. chinensis), which belongs to the Compositae family, is a perennial plant found in various areas in China. The aerial parts of I. chinensis are used as a folk medicine for the treatment of bronchitis, pneumonia, pharyngitis, dysentery and poisonous indigestion on the basis of its anti-febrile, antidotal and analgesic effects (Jiangsu New Medical College 1986; Bu 1995). The known constituents of this plant include terpenoids (Zhang et al. 2002; Zhang, Wang, et al. 2006; Zhang, Zhao, et al. 2006) and flavonoids (Zhou & Yuan 1996; Wang & Wang 2007). The terpenoids (Seto et al. 1988; Chen et al. 2006) exhibited significant pharmacological activities including anti-inflammatory, cytotoxicity against A 549 lung carcinoma, WI-38 lung fibroblast, VA-13 lung malignant tumour and HepG2 human liver tumour cells, which are consistent with the clinic use of I. chinensis in Mongolian clinic. In our phytochemical investigation (Wang et al. 2012; Wu et al. 2012), several sesquiterpene lactones and flavonoids were isolated. In continuation of our investigation of the plant, we report herein the isolation and characterisation of a new compound, 14-noreudesma-3-hydroxy-3-en-2,9-dione (1). 2. Results and discussion Chromatographic fractionation of the PE extract from I. chinensis has led to the isolation of a new sesquiterpene (1). Compound 1 was obtained as a colourless crystal. The IR spectrum revealed absorption bands characteristic of a hydroxyl (3400 cm21), ketone (1708 and 1668 cm21) and double bond(s) (1637 cm21). The molecular formula was determined to be C15H21O3 by using HR-ESI-MS at m/z 249.1485 [M þ H]2 (calcd for 249.1491), and the 13C NMR spectrum displayed 15 signals suggesting the structure of a sesquiterpene. The 13C NMR spectral data (Table S1) indicated the presence of three methyls, three methylenes, two methines, one quaternary carbon, two carbonyls as well as one tetrasubstituted double bond and one terminal double bond in the molecule of 1. The 1H NMR spectrum of 1 revealed two olefinic hydrogens dH 4.81 (1H, d, J ¼ 1.5 Hz) and 4.76 (1H, d, J ¼ 1.5 Hz), and the correlations of dH *Corresponding author. Email: [email protected] q 2014 Taylor & Francis
Downloaded by [University of York] at 08:22 02 November 2014
1580
Q. Wang et al.
4.81 (1H, d, J ¼ 1.5 Hz) and 4.76 (1H, d, J ¼ 1.5 Hz) with dC 110.3 were observed in the HSQC spectrum. This indicated the presence of three methyl groups linked to three quaternary carbons in the 1H NMR spectrum and the correlations of dH 1.80 (3H, s), 1.77 (3H, s) and 1.41 (3H, s) with dC 10.7, 20.4 and 27.0 observed in the HSQC spectrum, respectively. The correlations observed in the HMBC spectrum (Figure 1) confirmed the planar structure of 2, in which the correlation of OH (dH 6.21, s) with C-2 (dC 191.6), C-3 (dC 144.5) and C-4 (dC 129.5) indicated the hydroxyl group located at C-3, and CH3-14 (dH 1.41, s) with C-4 (dC 129.5), C-5 (dC 42.8), C-6 (dC 42.0) and C-10 (dC 54.2), CH3-15 (dH 1.80, s) with C-3 (dC 144.5), C-4 (dC 129.5), C-5 (dC 42.8) and C-14 (dC 27.0) as well as CH3-13 (dH 1.77, s) with C-7 (dC 41.1), C-11 (dC 146.6) and C-12 (dC 110.3) indicated the three methyl groups located at C-4, C-5 and C-11, and 3-OH (dH 6.21, s) with C-2 (dC 191.6), C-3 (dC 144.5) and C-4 (dC 129.5), together with H-1 (dH 2.62, 306) with C-1 (dC 31.9), C-2 (dC 191.6), C-8 (dC 45.9) and C-9 (dC 208.9) indicated that the two carbonyls were attached to C-2 and C-9, respectively. This indicated the mutual coupling between H-1 and H-10, H-6 and H-7, H-7 and H-8 observed in the 1H – 1H COSY spectrum and the coupling between H-1 and C-1, H-10 and C-10, H-6 and C-6, H-7 and C-7, H-8 and C-8 observed in the HMQC spectrum are in agreement with the structure of the sesquiterpene. The relative configuration to isocrotyl group at C-7 was thus confirmed by comparison of the coupling constant observed to the signal at dH 2.20 (br t, J ¼ 12.5 Hz). This value is indicative of trans-diaxial couplings (Lago et al. 2002) between this hydrogen and the adjacent H-6 and H-8, which were confirmed by the correlations observed in the 1H – 1H COSY spectrum. Nevertheless, in the NOESY spectrum, the CH3-14 (d 1.41) displayed strong correlation with the proton at d 2.70 (H-10), whereas the H-7 exhibited no correlation with H-10 and CH3-14. Thus, the structure of compound 1 was elucidated and named as 14-noreudesma-3-hydroxy-3en-2,9-dione. 3. Experimental 3.1. General experimental procedures Melting points were determined using an X-4 micro melting point apparatus and were uncorrected (Shanghai Jingke Industrial Co., China). Optical rotations were measured in CHCl3 at 258C on a Perkin-Elmer 241 polarimeter (Perkin-Elmer, USA). The UV spectra were recorded on a Shimadzu UV-2201 spectrometer (Shimadzu, Japan). The IR spectra were recorded in KBr discs on a Thermo Nicolet 200 double beam spectrophotometer (Shimadzu, Japan). The HRESI-MS spectra were measured on Bruker Daltonics MicroTOFQ (Bruker Daltonics Inc., Germany). NMR spectra were measured on a Bruker AVANCE III – 500 NMR spectrometer (Bruker, Germany) with tetramethylsilane as the internal reference, and chemical shifts are
Figure 1. Some key HMBC correlations of 1.
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expressed in d (ppm). Column chromatography was performed by using silica gel (200 – 300 mesh, Marine Chemical Factory, Qingdao, China). Fractions were monitored by using TLC (silica gel GF25410 –40 mm, Marine Chemical Factory), and spots were visualised by heating silica gel plates sprayed with 10% H2SO4 in EtOH. 3.2. Plant material The whole plants of I. chinensis Nakai, used as experimental material, were collected in Tongliao, Inner Mongolia of China, in June 2012, and identified by Prof. Buhebateer (Inner Mongolia University for Nationalities). A voucher (No. 20120602) has been deposited in the School of Traditional Mongolian Medicine of Inner Mongolia University for Nationalities.
Downloaded by [University of York] at 08:22 02 November 2014
3.3. Extraction and isolation The air-dried whole plant of I. chinensis Nakai (2.0 kg) was powdered and extracted twice under reflux petroleum ether (PE) (30 L). Evaporation of the solvent under reduced pressure delivered the PE extract. The PE extract (50.0 g) was isolated by column chromatography on silica gel and gradiently eluted with PE –EtOAc (100:1 to 20:1) to give 10 fractions (Fractions 1 – 10). Fraction 3 [300 mg, PE – EtOAc (80:1) elute] was subjected to silica gel column chromatography using PE – EtOAc with increasing polarity (90:1 to 70:1) to give 1 (26 mg). 3.3.1. 14-Noreudesma-3-hydroxy-3-en-2,9-dione Colourless crystal; ½a25 D ¼ þ23 (CHCl3, c ¼ 0.12); UV (hexane) lmax (nm) (log 1): 271 (2.04); IR (KBr) y max: 3400, 2970, 2935, 2873, 1708, 1668, 1637 cm21. 1H NMR (500 MHz, DMSO-d6) dH: 3.06 (1H, dd, J ¼ 17.0, 2.0 Hz, H-1a), 2.62 (1H, dd, J ¼ 17.0, 4.5 Hz, H-1b), 2.26 (1H, dd, J ¼ 14.0, 2.5 Hz, H-6a), 1.64 (1H, dd, J ¼ 14.0, 12.5 Hz, H-6b), 2.20 (1H, tt, J ¼ 12.5, 2.5 Hz, H-7), 2.48 (1H, dd, J ¼ 13.0, 2.5 Hz, H-8a), 2.32 (1H, dd, J ¼ 13.0, 12.5 Hz, H-8b), 2.70 (1H, dd, J ¼ 4.5, 2.0 Hz, H-10), 4.81 (1H, d, J ¼ 1.5 Hz, H-12a), 4.76 (1H, d, J ¼ 1.5 Hz, H-12b), 1.77 (3H, s, H-13), 1.41 (3H, s, H-14), 1.80 (3H, s, H-15), 6.21 (1H, s, 3-OH). 13C NMR (125 MHz, DMSO-d6) dC: 31.9 (C-1), 191.6 (C-2), 144.5 (C-3), 129.5 (C-4), 42.8 (C-5), 42.0 (C6), 41.1 (C-7), 45.9 (C-8), 208.9 (C-9), 54.2 (C-10), 146.6 (C-11), 110.3 (C-12), 20.4 (C-13), 27.0 (C-14), 10.7 (C-15). HMBC correlations were shown in Figure 1. HR-ESI-MS: m/z 249.1485 [M þ H]2 (calcd for 249.1491). 4. Conclusion A new sesquiterpene, namely 14-noreudesma-3-hydroxy-3-en-2,9-dione, were isolated from the PE extract of I. chinensis Nakai. Supplementary material Supplementary material relating to this article is available online, alongside Table S1 and Figures S1 –S17. Acknowledgements The authors thank Ning Xu and Narenchaoketu for the measurements of NMR spectra.
References Bu HBTE. 1995. Mengyaoshouce. Vol. 1. China: Liaoning Nationalities Publishing House; p. 125–126. Chen WL, Liu QF, Wang J. 2006. New guaiane, megastigmane and eudesmane-type sesquiterpenoids and antiinflammatory constituents from Yaoungia japonica. Planta Med. 72:143–150. Jiangsu New Medical College. 1986. Dictionary of Chinese herbal medicine. Vol. 2. China: Shanghai People’s Publishing House; p. 1285–1288.
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Q. Wang et al.
Downloaded by [University of York] at 08:22 02 November 2014
Lago JH, Brochini CB, Roque NF. 2002. Terpenoids from Guarea guidonia. Phytochemistry. 60:333–338. Seto M, Miyaso T, Umahara K. 1988. Sesquiterpene lactones from Cichorium endivia L. and C. intybus L. and cytotoxic activity. Chem Pharm Bull. 36:2423–2429. Wang QH, Ao WLJ, Xin Y, Meng GX, Wu XL, Tai WQ. 2012. Simultaneous determination of sesquiterpene lactones in Ixeris chinensis by HPLC. J Food Drug Anal. 20:872–878. Wang XF, Wang XJ. 2007. Study on chemical constituents from Ixeris chinensis. Chin Tradit Herb Drug. 38:1151–1153. Wu QSS, Wang QH, Dai NYT. 2012. Study on chemical constituents of Ixeris chinensis. J Chin Med Mater. 35:1945–1949. Zhang SJ, Wang JL, Deng QG, Ando M. 2006. New triterpenes from Siyekucai (Ixeris chinensis). Chin Chem Lett. 17:195–197. Zhang SJ, Wang JL, Xue HY, Deng QG, Xing FL, Ando M. 2002. Three new guaianolides from Siyekucai (Ixeris chinenseis). J Nat Prod. 65:994–997. Zhang SJ, Zhao M, Bai LM, Hasegawa T, Wang LY, Xue HY, Deng QG, Xing FL, Bai YH, Sakai JI, et al. 2006. Bioactive guaianolides from Siyekucai (Ixeris chinensis). J Nat Prod. 69:1425–1428. Zhou HL, Yuan JR. 1996. Study on chemical constituents from Ixeris chinensis. Chin Tradit Herb Drug. 27:267–269.
