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A new glycoside from Polygala tenuifolia Willd
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Chinese Chemical Letters 19 (2008) 817–820 www.elsevier.com/locate/cclet
A new glycoside from Polygala tenuifolia Willd Tun Hai Xu a,c, Gang Lv b, Tong Hua Liu a, Ya Juan Xu b,*, Yun Shan Si b, Sheng Xu Xie b, Hong Feng Zhao b, Dong Han b, Dong Ming Xu b b
a School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100102, China Academy of Traditional Chinese Medicine and Material Medica of Jilin Province, Changchun 130021, China c School of Traditional Chinese Medicine, Xinjiang University of Medicine, Urumchi 830054, China
Received 3 December 2007
Abstract A new triterpenoid glycoside, 3-b-O-b-D-glucopyranosyl presenegenin 28-O-a-L-arabipyranosyl(1 ! 3)-b-Dxylopyranosyl(1 ! 4)-[b-D-apiofuranosyl(1 ! 3)]-a-L-rhamnopyranosyl(1 ! 2)-[a-L-rhamnopyranosyl(1 ! 3)]-b-D-fucopyranosyl ester (1) was isolated from the Polygala tenuifolia Willd., together with two known saponins, including polygalasaponinXXIV (2) and polygalasaponinXXVIII (3). The structure of new compound was elucidated by spectroscopic methods. # 2008 Ya Juan Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Polygala tenuifolia Willd.; Triterpenoid saponin; Polygalaceae
Polygala tenuifolia Willd. is distributed in northeast China. Its root is a well-known Chinese traditional medicine used as a sedative expectorant and tonic. In previous studies on the constituents of the roots of P. tenuifolia Willd., several triterpenoid glycosides were isolated [1]. In the present paper, we report the isolation and structure elucidation of a new triterpenoid saponin by using spectroscopic methods. The roots of P. tenuifolia Willd. were purchased from Changchun, in September 2004. A voucher specimen (No.0400908), identified by Professor Minglu Deng. The dried roots of P. tenuifolia (7.5 kg), were extracted three times with H2O. The extract (215 g) was chromatographed over a D101 macroporous resin column (10 cm 80 cm) and the 60% EtOH eluate was separated by silica gel column (solvent, n-BuOH) and then purified by semipreparative HPLC (MeOH–H2O/8:27:3, 3.0 mL/min, 210 nm) to give compound 1 (55 mg), 2 (67 mg), and 3 (53 mg). Compound 1 amorphous powder, the IR spectrum (KBr, n) showed absorptions at 3418 (O–H), 1722 (C O), 1637 (C C) cm1. Its HR TOF MS showed [M+Na]+ at m/z 1537.6646 (calcd. 1537.6674) corresponding to the formula C69H110O36. Its 1H NMR spectrum showed an olefinic proton at dH 5.63 (br s, 1H,), two oxygenated methine proton signals at dH 4.12 (br s, 1H,), 3.28 (br s, 1H,), an oxygenated methylene [dH 3.89, 4.50 (d, each 1H, J = 12 Hz)] and five tertiary methyl proton signals at dH 0.66, 0.69, 0.96, 1.51, 1.83. The 13C NMR spectrum revealed 30 carbons, including two caboxylic carbons, a double bond, two oxygenated methines, one oxygenated methylene and five tertiary methyls. The signals of seven anomeric protons [dH 4.95 (d, 1H, J = 7.8 Hz, Hglc-1), 5.85 (d, 1H, J = 8.0 Hz, H-fuc-1), 6.10 (br
* Corresponding author. E-mail address: [email protected] (Y.J. Xu). 1001-8417/$ – see front matter # 2008 Ya Juan Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2008.04.030
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T.H. Xu et al. / Chinese Chemical Letters 19 (2008) 817–820
s, 1H, H-rha-1), 5.50 (br s, 1H, H-rha’-1’), 5.05 (d, 1H, J = 7.5 Hz, H-xyl-1), 5.16 (d, 1H, J = 7.0 Hz, H-ara-1), 5.94 (d, 1H, J = 3 Hz, H-api-1)], and three secondary methyl signals ascribable to 6-deoxyhexose [d = 1.35 (d, 3H, J = 5.6 Hz, H-fuc-6), 1.42(d, 3H, J = 5.7 Hz, H-rha-6), 1.44(d, 3H, J = 5.7 Hz, H-rha0 -60 ), indicated that 1 had seven sugars including three 6-deoxyhexose. These coupling constants indicated that the glycosidic linkage of rhamnose and arabinose were a-configuration, and those of fucose, xylose, glucose and apiose were b-configuration [2,3]. Upon acidic hydrolysis of compound with 1 mol/L HCl, 1 gave fucose, rhamnose, glucose, xylose, arabinose and apiose as the sugar components. These observations suggested that 1 was triterpenoidal saponin with seven sugars. In a comparison of the 13C NMR for aglycone of 1 (Table 1) with those of known presenegenin (compound 26) [4], all signals due to the aglycone of 1 were almost superimposable with those of presenegenin, except that C-3 (d 86.2) as shifted 10.4 ppm downfield, while C-2 (d 70.7) and C-28 (d 176.4) were respectively shifted 0.9 and 4.4 ppm upfield, indicating the aglycone of 1 was the same as that of presenegenin, and its 3-hydroxy groups and 28-carbonyl group carried a sugar moiety, respectively. The positions of the sugar residues in 1 were defined unambiguously by the HMBC experiment (Fig. 1). In the HMBC spectrum, long range correlation signals were found between H-1 (d 5.85) of fucose and C-28 (d 176.4) of the aglycon, H-1 (d 6.10) of rhamnose and C-2 (d 75.6) of fucose, H-I0 (d 5.50) of rhamnose0 and C-3 (d 79.3) of fucose, H-1 (d 5.94) of apiose and C-3 (d 81.8) of rhamnose, H-1 (d 5.05) of xylose and C-4 (d 78.3) of rhamnose, Table 1 13 C NMR and 1H NMR data of compound 1 in C5D5N No.
dc
dH (J, Hz)
No.
dc
dH(J, Hz)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 C-3 C-3 C-3 C-3 C-3 C-3
45.0 70.7 86.2 53.6 52.9 21.4 33.1 41.0 49.7 37.2 23.0 127.7 139.9 48.1 24.1 23.9 47.1 41.5 45.7 30.8 33.9 32.3 180.4 15.1 17.5 19.5 64.8 176.4 33.9 23.9 105.0 74.7 79.3 70.7 78.3 62.4
1.26, 2.22 3.28(m) 4.12(m)
C-28 Fuc-1 2 3 4 5 6 Rha-1 2 3 4 5 6 Rha-10 20 30 40 50 60 Xyl-1 2 3 4 5 Ara-1 2 3 4 5
95.1 75.6 79.3 72.7 70.7 17.1 101.8 71.4 81.8 78.3 69.4 18.7 104.7 72.2 72.7 73.9 70.5 18.7 104.5 74.7 86.2 69.5 66.6 105.0 72.5 73.9 69.4 67.8
Api-1 2 3 4
111.5 77.7 80.4 74.2
5.85 4.68 4.45 5.76 4.30 1.35 6.10 4.78 4.42 4.45 4.28 1.42 5.50 4.79 4.41 4.47 4.30 1.44 5.05 4.00 4.15 4.05 3.43 5.16 4.46 4.08 4.22 3.60 4.26 5.94 4.79
(d, 8) (m) (m) (m) (m) (d, 5.6) (br s) (m) (m) (m) (m) (3H, d, 5.7) (br s) (m) (m) (m) (m) (3H, d, 5.7) (d, 7.5) (m) (m) (m) (m) (d, 7) (m) (m) (m) (m) (m) (d, 3) (m)
4.30 4.51 4.05 4.05
(m) (m) (m) (m)
1
Glc-1 Glc-2 Glc-3 Glc-4 Glc-5 Glc-6
H NMR and
13
2.21 1.75, 2.10 1.72, 1.95 2.30(m) 1.88, 2.12 5.63 (m)
2.03, 2.15 1.72, 2.00 3.18 (m) 1.28, 2.62 1.10, 1.26 1.21, 1.25 1.83 (s) 1.51 (s) 0.96 (s) 3.89, 4.50 0.66 0.69 4.95 3.90 4.13 4.16 3.89 4.20
(s) (s) (d, 8) (m) (m) (m) (m) (m), 4.45(m)
5
65.7
C NMR were obtained at 400 MHz, respectively, and assigned by the DEPT, 1H- 1HCOSY, HMQC and HMBC experiments.
T.H. Xu et al. / Chinese Chemical Letters 19 (2008) 817–820
819
Fig. 1. The structure and HMBC of compounds 1.
H-1 (d 5.16) of arabinose and C-3 (d 86.2) of xylose. These assignments showed that a sixsaccharide moiety, 28-O-a-Larabinopyranosyl (1 ! 3)-b-D-xylopyranosyl(1 ! 4)-[b-D-apiofuranosyl(1 ! 3)]-a-L-rhamno- pyranosyl (1 ! 2)-[aL-rhamnopyranosyl(1 ! 3)]-b-D-fucopyranosyl ester, was linked to the at C-28. Additionally, HMBC between H-1 (d 4.95) of glucose and C-3 (d 86.2) of the aglycon definitive prove that the glucose was linked to C-3 of the aglycon. On the basis of all of these evidences, 1 was identified as 3-b-O-b-D-glucopyranosyl presenegenin 3-b-O-b-D-glucopyranosyl presenegenin 28-O-a-L-arabipyranosyl(1 ! 3)-b-D-xylopyranosyl(1 ! 4)-[b-D-apiofuranosyl(1 ! 3)]-a-L-rhamnopyranosyl(1 ! 2)-[a-L-rhamnopyranosyl(1 ! 3)]-b-D-fucopyranosyl ester. The structure was shown in Fig. 1. The data of 13C NMR and 1H NMR were thoroughly assigned on the DEPT, 1H-1HCOSY, HMQC and HMBC spectra (Table 1). 1. Acid hydrolysis of compound 1 The compound 1 (10 mg) was heated with 2 mol/L HCl–MeOH (10 mL) under reflux for 3 h. The reaction mixture was diluted with H2O and extracted with CHCl3. The water layer was neutralized with Na2CO3, concentrated, and subjected to TLC analysis with authentic samples D-glucose, D-fucose, D-xylose, L-arabinose, L-rhamnose, and Dapiose (purchased from Sigma), and developed with CH2Cl2-MeOH-H2O (15:6:1) and H2O-MeOH-AcOH-EtOAc (15:15:20:65). Detection was carried out with aniline phthalate spray. Two known compounds 2–3 were identified as poligalasaponin XXIV(2) [1], poligalasaponinXXVIII (3) [1] by comparison of their physical and spectroscopic data with those reported in the literature, respectively. Acknowledgments The authors are grateful to the National Nature Science Foundation of China (No. 30772890) and the Collaborative Education, Research and Development Project of Beijing Municipal Commission of Education and the Key Project of Chinese Ministry of Education (No. 108132).
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T.H. Xu et al. / Chinese Chemical Letters 19 (2008) 817–820
References [1] [2] [3] [4]
D.M. Zhang, T. Miyase, M. Kuroyanagi, et al. Chem. Pharm. Bull. 44 (4) (1996) 810. P.K. Agrawal, Phytochemistry 31 (10) (1992) 3307. P.K. Agrawal, D.C. Jain, R.K. Gupta, et al. Phytochemistry 24 (11) (1985) 2479. S. Sakuma, J. Shoji, Chem. Pharm. Bull. 30 (3) (1982) 810.
Chinese Chemical Letters 19 (2008) 817–820 www.elsevier.com/locate/cclet
A new glycoside from Polygala tenuifolia Willd Tun Hai Xu a,c, Gang Lv b, Tong Hua Liu a, Ya Juan Xu b,*, Yun Shan Si b, Sheng Xu Xie b, Hong Feng Zhao b, Dong Han b, Dong Ming Xu b b
a School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100102, China Academy of Traditional Chinese Medicine and Material Medica of Jilin Province, Changchun 130021, China c School of Traditional Chinese Medicine, Xinjiang University of Medicine, Urumchi 830054, China
Received 3 December 2007
Abstract A new triterpenoid glycoside, 3-b-O-b-D-glucopyranosyl presenegenin 28-O-a-L-arabipyranosyl(1 ! 3)-b-Dxylopyranosyl(1 ! 4)-[b-D-apiofuranosyl(1 ! 3)]-a-L-rhamnopyranosyl(1 ! 2)-[a-L-rhamnopyranosyl(1 ! 3)]-b-D-fucopyranosyl ester (1) was isolated from the Polygala tenuifolia Willd., together with two known saponins, including polygalasaponinXXIV (2) and polygalasaponinXXVIII (3). The structure of new compound was elucidated by spectroscopic methods. # 2008 Ya Juan Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Polygala tenuifolia Willd.; Triterpenoid saponin; Polygalaceae
Polygala tenuifolia Willd. is distributed in northeast China. Its root is a well-known Chinese traditional medicine used as a sedative expectorant and tonic. In previous studies on the constituents of the roots of P. tenuifolia Willd., several triterpenoid glycosides were isolated [1]. In the present paper, we report the isolation and structure elucidation of a new triterpenoid saponin by using spectroscopic methods. The roots of P. tenuifolia Willd. were purchased from Changchun, in September 2004. A voucher specimen (No.0400908), identified by Professor Minglu Deng. The dried roots of P. tenuifolia (7.5 kg), were extracted three times with H2O. The extract (215 g) was chromatographed over a D101 macroporous resin column (10 cm 80 cm) and the 60% EtOH eluate was separated by silica gel column (solvent, n-BuOH) and then purified by semipreparative HPLC (MeOH–H2O/8:27:3, 3.0 mL/min, 210 nm) to give compound 1 (55 mg), 2 (67 mg), and 3 (53 mg). Compound 1 amorphous powder, the IR spectrum (KBr, n) showed absorptions at 3418 (O–H), 1722 (C O), 1637 (C C) cm1. Its HR TOF MS showed [M+Na]+ at m/z 1537.6646 (calcd. 1537.6674) corresponding to the formula C69H110O36. Its 1H NMR spectrum showed an olefinic proton at dH 5.63 (br s, 1H,), two oxygenated methine proton signals at dH 4.12 (br s, 1H,), 3.28 (br s, 1H,), an oxygenated methylene [dH 3.89, 4.50 (d, each 1H, J = 12 Hz)] and five tertiary methyl proton signals at dH 0.66, 0.69, 0.96, 1.51, 1.83. The 13C NMR spectrum revealed 30 carbons, including two caboxylic carbons, a double bond, two oxygenated methines, one oxygenated methylene and five tertiary methyls. The signals of seven anomeric protons [dH 4.95 (d, 1H, J = 7.8 Hz, Hglc-1), 5.85 (d, 1H, J = 8.0 Hz, H-fuc-1), 6.10 (br
* Corresponding author. E-mail address: [email protected] (Y.J. Xu). 1001-8417/$ – see front matter # 2008 Ya Juan Xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2008.04.030
818
T.H. Xu et al. / Chinese Chemical Letters 19 (2008) 817–820
s, 1H, H-rha-1), 5.50 (br s, 1H, H-rha’-1’), 5.05 (d, 1H, J = 7.5 Hz, H-xyl-1), 5.16 (d, 1H, J = 7.0 Hz, H-ara-1), 5.94 (d, 1H, J = 3 Hz, H-api-1)], and three secondary methyl signals ascribable to 6-deoxyhexose [d = 1.35 (d, 3H, J = 5.6 Hz, H-fuc-6), 1.42(d, 3H, J = 5.7 Hz, H-rha-6), 1.44(d, 3H, J = 5.7 Hz, H-rha0 -60 ), indicated that 1 had seven sugars including three 6-deoxyhexose. These coupling constants indicated that the glycosidic linkage of rhamnose and arabinose were a-configuration, and those of fucose, xylose, glucose and apiose were b-configuration [2,3]. Upon acidic hydrolysis of compound with 1 mol/L HCl, 1 gave fucose, rhamnose, glucose, xylose, arabinose and apiose as the sugar components. These observations suggested that 1 was triterpenoidal saponin with seven sugars. In a comparison of the 13C NMR for aglycone of 1 (Table 1) with those of known presenegenin (compound 26) [4], all signals due to the aglycone of 1 were almost superimposable with those of presenegenin, except that C-3 (d 86.2) as shifted 10.4 ppm downfield, while C-2 (d 70.7) and C-28 (d 176.4) were respectively shifted 0.9 and 4.4 ppm upfield, indicating the aglycone of 1 was the same as that of presenegenin, and its 3-hydroxy groups and 28-carbonyl group carried a sugar moiety, respectively. The positions of the sugar residues in 1 were defined unambiguously by the HMBC experiment (Fig. 1). In the HMBC spectrum, long range correlation signals were found between H-1 (d 5.85) of fucose and C-28 (d 176.4) of the aglycon, H-1 (d 6.10) of rhamnose and C-2 (d 75.6) of fucose, H-I0 (d 5.50) of rhamnose0 and C-3 (d 79.3) of fucose, H-1 (d 5.94) of apiose and C-3 (d 81.8) of rhamnose, H-1 (d 5.05) of xylose and C-4 (d 78.3) of rhamnose, Table 1 13 C NMR and 1H NMR data of compound 1 in C5D5N No.
dc
dH (J, Hz)
No.
dc
dH(J, Hz)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 C-3 C-3 C-3 C-3 C-3 C-3
45.0 70.7 86.2 53.6 52.9 21.4 33.1 41.0 49.7 37.2 23.0 127.7 139.9 48.1 24.1 23.9 47.1 41.5 45.7 30.8 33.9 32.3 180.4 15.1 17.5 19.5 64.8 176.4 33.9 23.9 105.0 74.7 79.3 70.7 78.3 62.4
1.26, 2.22 3.28(m) 4.12(m)
C-28 Fuc-1 2 3 4 5 6 Rha-1 2 3 4 5 6 Rha-10 20 30 40 50 60 Xyl-1 2 3 4 5 Ara-1 2 3 4 5
95.1 75.6 79.3 72.7 70.7 17.1 101.8 71.4 81.8 78.3 69.4 18.7 104.7 72.2 72.7 73.9 70.5 18.7 104.5 74.7 86.2 69.5 66.6 105.0 72.5 73.9 69.4 67.8
Api-1 2 3 4
111.5 77.7 80.4 74.2
5.85 4.68 4.45 5.76 4.30 1.35 6.10 4.78 4.42 4.45 4.28 1.42 5.50 4.79 4.41 4.47 4.30 1.44 5.05 4.00 4.15 4.05 3.43 5.16 4.46 4.08 4.22 3.60 4.26 5.94 4.79
(d, 8) (m) (m) (m) (m) (d, 5.6) (br s) (m) (m) (m) (m) (3H, d, 5.7) (br s) (m) (m) (m) (m) (3H, d, 5.7) (d, 7.5) (m) (m) (m) (m) (d, 7) (m) (m) (m) (m) (m) (d, 3) (m)
4.30 4.51 4.05 4.05
(m) (m) (m) (m)
1
Glc-1 Glc-2 Glc-3 Glc-4 Glc-5 Glc-6
H NMR and
13
2.21 1.75, 2.10 1.72, 1.95 2.30(m) 1.88, 2.12 5.63 (m)
2.03, 2.15 1.72, 2.00 3.18 (m) 1.28, 2.62 1.10, 1.26 1.21, 1.25 1.83 (s) 1.51 (s) 0.96 (s) 3.89, 4.50 0.66 0.69 4.95 3.90 4.13 4.16 3.89 4.20
(s) (s) (d, 8) (m) (m) (m) (m) (m), 4.45(m)
5
65.7
C NMR were obtained at 400 MHz, respectively, and assigned by the DEPT, 1H- 1HCOSY, HMQC and HMBC experiments.
T.H. Xu et al. / Chinese Chemical Letters 19 (2008) 817–820
819
Fig. 1. The structure and HMBC of compounds 1.
H-1 (d 5.16) of arabinose and C-3 (d 86.2) of xylose. These assignments showed that a sixsaccharide moiety, 28-O-a-Larabinopyranosyl (1 ! 3)-b-D-xylopyranosyl(1 ! 4)-[b-D-apiofuranosyl(1 ! 3)]-a-L-rhamno- pyranosyl (1 ! 2)-[aL-rhamnopyranosyl(1 ! 3)]-b-D-fucopyranosyl ester, was linked to the at C-28. Additionally, HMBC between H-1 (d 4.95) of glucose and C-3 (d 86.2) of the aglycon definitive prove that the glucose was linked to C-3 of the aglycon. On the basis of all of these evidences, 1 was identified as 3-b-O-b-D-glucopyranosyl presenegenin 3-b-O-b-D-glucopyranosyl presenegenin 28-O-a-L-arabipyranosyl(1 ! 3)-b-D-xylopyranosyl(1 ! 4)-[b-D-apiofuranosyl(1 ! 3)]-a-L-rhamnopyranosyl(1 ! 2)-[a-L-rhamnopyranosyl(1 ! 3)]-b-D-fucopyranosyl ester. The structure was shown in Fig. 1. The data of 13C NMR and 1H NMR were thoroughly assigned on the DEPT, 1H-1HCOSY, HMQC and HMBC spectra (Table 1). 1. Acid hydrolysis of compound 1 The compound 1 (10 mg) was heated with 2 mol/L HCl–MeOH (10 mL) under reflux for 3 h. The reaction mixture was diluted with H2O and extracted with CHCl3. The water layer was neutralized with Na2CO3, concentrated, and subjected to TLC analysis with authentic samples D-glucose, D-fucose, D-xylose, L-arabinose, L-rhamnose, and Dapiose (purchased from Sigma), and developed with CH2Cl2-MeOH-H2O (15:6:1) and H2O-MeOH-AcOH-EtOAc (15:15:20:65). Detection was carried out with aniline phthalate spray. Two known compounds 2–3 were identified as poligalasaponin XXIV(2) [1], poligalasaponinXXVIII (3) [1] by comparison of their physical and spectroscopic data with those reported in the literature, respectively. Acknowledgments The authors are grateful to the National Nature Science Foundation of China (No. 30772890) and the Collaborative Education, Research and Development Project of Beijing Municipal Commission of Education and the Key Project of Chinese Ministry of Education (No. 108132).
820
T.H. Xu et al. / Chinese Chemical Letters 19 (2008) 817–820
References [1] [2] [3] [4]
D.M. Zhang, T. Miyase, M. Kuroyanagi, et al. Chem. Pharm. Bull. 44 (4) (1996) 810. P.K. Agrawal, Phytochemistry 31 (10) (1992) 3307. P.K. Agrawal, D.C. Jain, R.K. Gupta, et al. Phytochemistry 24 (11) (1985) 2479. S. Sakuma, J. Shoji, Chem. Pharm. Bull. 30 (3) (1982) 810.