A new lignan from Gynostemma pentaphyllum
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A new lignan from Gynostemma pentaphyllum Xiao Wen Wang a, * , Hua Ping Zhang b , Feng Chen b , Xi Wang c , Wei Ye Wen d a Food Science and Engineering College, Shanxi Agricultural University, Taigu 030801, China b Department of Food Science and Human Nutrition, Clemson University, Clemson, SC 29634 USA c Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA d College of Animal Science, Shanxi Agricultural University, Taigu 030801, China Received 9 October 2008 Abstract A new lignan ligballinone 1 with the know ligballinol 2 were isolated from plant Gynostemma pentaphyllum. Their structures were determined through spectroscopic methods including ESI-MS, 1D and 2D NMR ( 1 H, 13 C, DEPT, 1 H- 1 H COSY, HMQC, HMBC) and X-ray diffraction experiment for 2. # 2009 Xiao Wen Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Lignan; Gynostemma pentaphyllum; Cucurbitaceae; Ligballinone; Ligballinol Gynostemma pentaphyllum (Cucurbitaceae) is a perennial creeping herb wildly distributed in China, Japan, Korea as well as many other countries throughout Asia [1,2]. It has been broadly used as a folk medicine for protecting kidney, reducing inflammation, and inhibiting tumor in China [3–5]. Modern pharmacological study showed its extract own abilities to decrease the serum cholesterol and triglyceride, regulate blood pressure, enhance the immune system [6,7]. Although approximately 150 chemicals (mainly saponins) have been isolated from different parts of the title plant, little is known about its chemical profile of lignans. The research reported the ethanol extract of the root of G. pentaphyllum, isolating a new lignan named as ligballinone 1 and a known ligballinol 2. Their structures and stereochemistry were subsequently determined through spectroscopic methods, including MS, 1D and 2D NMR, and X-ray diffraction experiment. Dried powder 200 g of the root extracts of G. pentaphyllum were suspended in water (1 L) followed by partition with hexane (1 L), ethyl acetate (1 L), and n-BuOH (1 L) three times. The ethyl acetate fractions (55 g), after removing the solvents, were repeatedly subjected to normal phase and RP-C18 silica gel column chromatography to yield compounds 1 (50 mg) and 2 (15 mg). Compound 1 was purified as yellow amorphous powders. The molecular formula of C 18 H 18 O 5 was determined by accurate ESI-MS and NMR experiments. Its 1 H and 13 C NMR data were very similar to those of known 2 [8] (Fig. 1), whose structure was determined by X-ray diffraction experiment (Fig. 2) in the current report. The close chemical shift values and coupling pattern showed both 1 and 2 have two identical para-substituted benzene rings. The obvious difference between 1 and 2 in 13 C NMR (DEPT) spectra were that 1 has a lowfield quaternary carbon (d 199.90, C-7 0 , www.elsevier.com/locate/cclet Available online at www.sciencedirect.com Chinese Chemical Letters 20 (2009) 589–591 * Corresponding author. E-mail address: [email protected] (X.W. Wang). 1001-8417/$ – see front matter # 2009 Xiao Wen Wang. Publishedby Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2009.01.034
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Transcript of A new lignan from Gynostemma pentaphyllum
A new lignan from Gynostemma pentaphyllum
Xiao Wen Wang a,*, Hua Ping Zhang b, Feng Chen b, Xi Wang c, Wei Ye Wen d
a Food Science and Engineering College, Shanxi Agricultural University, Taigu 030801, Chinab Department of Food Science and Human Nutrition, Clemson University, Clemson, SC 29634 USA
c Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USAd College of Animal Science, Shanxi Agricultural University, Taigu 030801, China
Received 9 October 2008
Abstract
A new lignan ligballinone 1 with the know ligballinol 2 were isolated from plant Gynostemma pentaphyllum. Their structures
were determined through spectroscopic methods including ESI-MS, 1D and 2D NMR (1H, 13C, DEPT, 1H-1H COSY, HMQC,
HMBC) and X-ray diffraction experiment for 2.
# 2009 Xiao Wen Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Keywords: Lignan; Gynostemma pentaphyllum; Cucurbitaceae; Ligballinone; Ligballinol
Gynostemma pentaphyllum (Cucurbitaceae) is a perennial creeping herb wildly distributed in China, Japan, Korea
as well as many other countries throughout Asia [1,2]. It has been broadly used as a folk medicine for protecting
kidney, reducing inflammation, and inhibiting tumor in China [3–5]. Modern pharmacological study showed its extract
own abilities to decrease the serum cholesterol and triglyceride, regulate blood pressure, enhance the immune system
[6,7]. Although approximately 150 chemicals (mainly saponins) have been isolated from different parts of the title
plant, little is known about its chemical profile of lignans. The research reported the ethanol extract of the root of G.
pentaphyllum, isolating a new lignan named as ligballinone 1 and a known ligballinol 2. Their structures and
stereochemistry were subsequently determined through spectroscopic methods, including MS, 1D and 2D NMR, and
X-ray diffraction experiment.
Dried powder 200 g of the root extracts of G. pentaphyllum were suspended in water (1 L) followed by partition
with hexane (1 L), ethyl acetate (1 L), and n-BuOH (1 L) three times. The ethyl acetate fractions (55 g), after removing
the solvents, were repeatedly subjected to normal phase and RP-C18 silica gel column chromatography to yield
compounds 1 (50 mg) and 2 (15 mg).
Compound 1 was purified as yellow amorphous powders. The molecular formula of C18H18O5 was determined by
accurate ESI-MS and NMR experiments. Its 1H and 13C NMR data were very similar to those of known 2 [8] (Fig. 1),
whose structure was determined by X-ray diffraction experiment (Fig. 2) in the current report. The close chemical shift
values and coupling pattern showed both 1 and 2 have two identical para-substituted benzene rings. The obvious
difference between 1 and 2 in 13C NMR (DEPT) spectra were that 1 has a lowfield quaternary carbon (d 199.90, C-70,
www.elsevier.com/locate/cclet
Available online at www.sciencedirect.com
Chinese Chemical Letters 20 (2009) 589–591
* Corresponding author.
E-mail address: [email protected] (X.W. Wang).
1001-8417/$ – see front matter # 2009 Xiao Wen Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
doi:10.1016/j.cclet.2009.01.034
keto group conjugated with benzene ring) and a oxygenated methylene (d 60.57, C-9) while 2 has one oxygenated
methine (d 87.71, C-70) and one oxygenated methylene (d 72.79, C-9). 1H-1H COSY and HMQC of 1 showed a
fragment of CH(O)–CH(CH2O)–CH–CH2O, different from the coupling system of CH(O)–CH(CH2O)–CH(CH2O)–
CH(O) in 2. Those differences suggested 1 was a derivative of 2 with C-70 oxidation to a keto group (Fig. 3), supported
X.W. Wang et al. / Chinese Chemical Letters 20 (2009) 589–591590
Fig. 1. Structure of 1 and 2.
Fig. 2. X-ray structure of 2.
Table 11H (300 MHz) and 13C (75 MHz) NMR data of 1 and 2 in CD3OD (d ppm, J Hz).
Position 1 2
1H 13C 1H 13C
1 132.26 133.31
2 7.28, d, 1H, J = 8.6 129.09 7.07, d, 1H, J = 8.5 129.03
3 6.79, d, 1H, J = 8.6 115.83 6.63, dd, 1H, J = 8.5, 2.0 116.54
4 157.97 158.53
5 6.79, d, 1H, J = 8.6 115.83 6.63, dd, 1H, J = 8.5, 2.0 116.54
6 7.28, d, 1H, J = 8.6 129.09 7.07, d, 1H, J = 8.5 129.03
7 4.79, d, 1H, J = 4.4 87.75 4.57, d, 1H, J = 4.4 87.71
8 2.72, m, 1H 53.80 3.01, m, 1H 55.55
9 3.62, m, 2H 60.57 4.07, eq, dd, 1H, J = 7.0, 8.0 72.79
3.70, ax, dd, 1H, J = 4.0, 4.8
10 129.34
20 7.95, d, 1H, J = 8.8 131.99 7.07, d, 1H, J = 8.5 129.03
30 6.89, d, 1H, J = 8.8 116.09 6.63, dd, 1H, J = 8.5, 2.0 116.54
40 163.23 158.53
50 6.89, d, 1H, J = 8.8 116.09 6.63, dd, 1H, J = 8.5, 2.0 116.54
60 7.95, d, 1H, J = 8.8 131.99 7.07, d, 1H, J = 8.5 129.03
70 199.90 4.57, d, 1H, J = 4.4 87.71
80 4.26, m, 1H 49.78 3.01, m, 1H 55.55
90 4.21, dd, 1H, J = 6.0, 7.5 71.43 4.07, eq, dd, 1H, J = 7.0, 8.0 72.79
4.12, dd, 1H, J = 4.6, 7.5 3.70, ax, dd, 1H, J = 4.0, 4.8
by HMBC correlations between H-20, H-50 (d 7.95, d, 2H, J = 8.8 Hz) and C-70 (d 199.90), between H2-90 (d 4.21, dd,
1H, J = 6.0, 7.5 Hz and d 4.12, dd, 1H, J = 4.6, 7.5 Hz) and C-70 (d 199.90). The stereochemistry of the five-membered
ring in 1 was assigned as the same as those in 2 on the basis of biogenetic background with co-occurrence of the two
lignans and their similar chemical shift values and coupling constants. 1 will be easily transformed to 2 with
dehydration after reduction of the keto group of 1 to ethanol group (Fig. 3). Thus, the structure of 1 (designated as
ligballinone) was determined as the one presented in Fig. 1. The full assignments of NMR data of 1 and 2 were listed in
Table 1.
Chemical 1 did not show DPPH free radical scavenging activity but shows antimicrobial activity against
Staphylococcus aureus.
Acknowledgment
This work is finically supported by Shanxi Scholarship Council of China.
References
[1] Kunming Institute of Botany, t. C. A. o. S., Yunnan Flora, vol. 6. Science Press, Bejing, 1995, p. 389.
[2] M. Blumert, J.L. Liu, Jiaogulan-China’s ‘‘Immortality’’ Herb, Torchlight Publishing, Inc., Badger, CA, 1999, 13.
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X.W. Wang et al. / Chinese Chemical Letters 20 (2009) 589–591 591
Fig. 3. Proposed biogenetic relationship between 1 and 2.
