Pharmacognosy Magazine

ORIGINAL ARTICLE
Year
: 2016  |  Volume : 12  |  Issue : 45  |  Page : 1--3

A new biphenyl neolignan from leaves of Patrinia villosa (Thunb.) Juss.


Yan Xin-Jia1, Liu Wei1, Zhao Ying1, Chen Ning1, Xu Ying1, Wu Jian1, Wang Tan2, Li Yue2, Xiang Zheng1,  
1 Harbin University of Commerce, Harbin 150076, PR China
2 Beijing Center for Physical and Chemical Analysis, Beijing 100094, PR China

Correspondence Address:
Liu Wei
Beijing Center for Physical and Chemical Analysis, Beijing 100094
PR China
Xiang Zheng
Center of Research on Life Science and Environmental Science, Harbin University of Commerce, Harbin 150076
PR China

Abstract

Results: One new stereoisomer of biphenylneolignan with four known compounds was isolated from the leaves of Patrinia villosa Juss. Methods: The structure of the new compound was elucidated as 2,6,2«SQ»,6«SQ»-tetramethoxy-4,4«SQ»-bis (1,2-trans-2,3-epoxy-1-hydroxypropyl) biphenyl (1) on the basis of spectroscopic analysis and comparison with literature data. The four known compounds were identified as 2,6,2«SQ»,6«SQ»-tetramethoxy-4,4«SQ»-bis(1,2-cis-2,3-epoxy-1-hydroxypropyl)biphenyl (2), 1H-indole-3-carbaldehyde (3), luteolin (4) and quercetin(5) by comparison of their spectral data with the reported data, respectively. Conclusions: Compound 1 is a new biphenylneolignan, compound 2 and 3 were isolated for the first time from the plant.



How to cite this article:
Xin-Jia Y, Wei L, Ying Z, Ning C, Ying X, Jian W, Tan W, Yue L, Zheng X. A new biphenyl neolignan from leaves of Patrinia villosa (Thunb.) Juss. Phcog Mag 2016;12:1-3


How to cite this URL:
Xin-Jia Y, Wei L, Ying Z, Ning C, Ying X, Jian W, Tan W, Yue L, Zheng X. A new biphenyl neolignan from leaves of Patrinia villosa (Thunb.) Juss. Phcog Mag [serial online] 2016 [cited 2021 Apr 12 ];12:1-3
Available from: http://www.phcog.com/text.asp?2016/12/45/1/175988


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Summary

One new stereoisomer of biphenylneolignan named 2,6,2',6'-tetramethoxy-4,4'-bis (1,2-trans-2,3-epoxy-1-hydroxypropyl) biphenyl with four known compounds was isolated from the leaves of Patrinia villosa Juss.

 Introduction



Patrinia, which belongs to the family of Valerianaceae, is a widely distributed plant grown in East Asia and North America. The genus included more than 20 species, 10 of which growing in China. [1] Usually, Patrinia species are used as leaves and vegetables in some areas of China, and research also revealed its leaves with pharmacological properties, especially the species of Patrinia villosa (Thunb.) Juss. The P. villosa (Thunb.) Juss., is an important ancient herbal medicine widely used for more than 2000 years from Shen Nong Ben Cao Jing, a famous ancient Chinese medicinal literary. It has been used in traditional Chinese medicine for an inflammation, wound healing, and abdominal pain. The previous research on the chemical constituents of P. villosa (Thunb.) Juss., have revealed that it contains several compound classes. Pentacyclic triterpenoids, iridoids, and flavonoids are the dominant bioactive constituents in the leaves of P. villosa Juss., which displayed potential ability of anti-tumor and anti-inflammatory. [2],[3],[4],[5] Other components, such as sterols, fatty acids, and essential oil [2],[6],[7],[8] were also confirmed in P. villosa (Thunb.) Juss.

As part of our search for new natural compounds with anti-tumor activity, we carried out phytochemical investigations on the leaves of P. villosa (Thunb.) Juss., collected in China. A new biphenyl neolignan and four known compounds [Figure 1] were isolated from the plant. The present study reports the isolation and structural elucidation of these components.{Figure 1}

 Materials and Methods



General experimental procedures

Optical rotations were measured on a Perkin-Elmer digital polarimeter (USA). nuclear magnetic resonance (NMR) spectra were recorded with tetramethylsilane as internal standard on a Bruck AVANCE 400 FT-NMR spectrometer. Electrospray ionization/mass spectrometry was measured on an Agilent 1100 LC/MSD Trap-SL spectrometer (USA). Column chromatography was performed on silica gel (200-300 mesh) (Marine Chemical Factory, Qingdao, China) and octa decylsilyl silicion (ODS) (ultimate XB-C18, 40-70 μm, Welch Materials, Inc., USA). High-performance liquid chromatography (HPLC) separation was performed with an Agilent 1100 chromatograph apparatus using an ODS column (ultimate XB-C18, 10 × 250, 5 μm, Welch Materials, Inc., USA) and detected with an ultraviolet detector.

Materials and chemicals

The P. villosa Juss., leaves were purchased from Hebei Qixin Traditional Chinese Medicine Pellets Co., Ltd., P.R. China, and identified by Prof. Kang Tingguo, College of Pharmacy, Liaoning University of Traditional Chinese Medicine. A voucher specimen (NO. PVJ20130821) has been deposited at the Pharmacognosy Laboratory, Harbin University of Commerce. Organic solvents (analytical grade or HPLC grade) for the experiment were purchased from Kermel Chemical Co., (Tianjin, China).

Extraction and isolation

The air-dried leaves of P. villosa Juss., (15 kg) were extracted three times with 70% EtOH under reflux. Evaporation of the solvent under reduced pressure gave a condensed extract (2.8 kg), which was suspended in H 2 O and then partitioned successively with light petroleum, dichloromethane, and n-BuOH. The dichloromethane portion (110 g) was then subjected to normal phase silica gel column chromatography and eluted with a gradient of CH 2 Cl 2 -MeOH (100:0 → 0:100, v/v) to give ten fractions. Fraction 2 (CH 2 Cl 2 -MeOH, 80:1, v/v) was subjected to further separation using ODS silica gel column chromatography eluted with 20%, 36%, 44%, 60%, and 80% MeOH in water, respectively. Subfraction 2.2 (36% methanol elution) was purified by semi-preparative HPLC (MeCN-H 2 O, wavelength 280 nm) to yield compounds 1 (16.5 mg) and 2 (21.3 mg). Subfraction 2.3 (44% methanol elution) was purified by semi-preparative HPLC (MeCN-H 2 O, wavelength 280 nm) to give compound 3 (10.4 mg).

The n-BuOH portion (280 g) was subjected to normal phase silica gel column chromatography and eluted with a gradient of CH 2 Cl 2 -MeOH (100:0 → 0:100, v/v) to give eight fractions. Fraction 4 was subjected to further separation using repeated ODS silica gel column and HPLC to give compounds 4 (25.0 mg) and 5 (18.6 mg).

 Results and Discussion



Compound 1 was obtained as a colorless needle crystal (CHCl 3 ), with the molecular formula C 22 H 26 O 8 as determined by the high-resolution electrospray ionization mass spectrometry (HRESIMS) at m/z 441.1518 (M + Na) + , indicating ten degrees of unsaturation. The 1 H-NMR spectrum of compound 1 [Table 1] displayed four aromatic proton signals at δH 6.59 (4H, s, H-3, H-3′, H-5, H-5′), which were assigned to two 1,2,4,6-tetrasubstituted benzene rings. In addition, the 1 H-NMR spectrum also revealed four oxymethine protons at δH 4.74 (2H, d, J = 4.0 Hz, H-7, H-7′) and 3.10 (2H, m, H-8, H-8′), two methylene protons at δH 4.28 (2H, m, H-9a, H-9′a) and 3.93 (2H, m, H-9b, H-9′b), four methoxyl groups at δH 3.90 (12H, s). The 13 C NMR spectrum displayed 22 carbon signals, including 12 aromatic carbons, four oxygen-substituted methine (δC 54.4, 54.4, 86.1, 86.1), two oxygen-substituted methylene (δC 71.8, 71.8), and four methoxyl carbons (δC 56.4), All of the above spectroscopic data were similar to those of 2,6,2′,6′-tetramethoxy-4,4′-bis (1,2-cis-2,3-epoxy-1-hydroxypropyl) biphenyl (2) except for difference of coupling constants at H-7, 7′ (J = 4.0 Hz). In the NOESY experiment [Figure 2] on 1, correlations between H-3/H-7 or H-5/H-7, and a strong cross-peak between H-8/H a -9 suggested the β-configuration for H-7 and H b -9 and an α-configuration for OH-7. The relative configuration could be proposed as 7,8-trans-8,9a-cis. Thus, the structure of one was determined as 2,6,2′,6′-tetramethoxy-4,4′-bis (1,2-trans-2,3-epoxy-1-hydroxypropyl) biphenyl.{Figure 2}{Table 1}

Compounds 2-5 were identified as 2,6,2′,6′-tetramethoxy-4,4′-bis (2,3-epoxy-1-hydroxypropyl) biphenyl (2), 1H-indole-3-carbaldehyde (3), luteolin (4), and quercetin (5) on the basis of its spectroscopic data. [9],[10],[11]

 Conclusion



One new stereoisomer of biphenyl neolignan (1) with four known compounds 2-5 was isolated from the leaves of P. villosa Juss. The structures of all the compounds were elucidated on the basis of spectroscopic analysis and comparison with literature data.

Compounds

2,6,2′,6′-Tetramethoxy-4,4′-bis (1,2-trans-2,3-epoxy-1- hydroxypropyl) biphenyl (1). Colorless needle crystal. HRESIMS m/z 441.1518 (M + Na) + (calculated for C 22 H 26 O 8 Na, 441.1520). 1 H-NMR (CDCl 3 , 300 MHz): δH : 3.10 (2H, m, H-8, H-8′), 4.28 (2H, m, H-9a, H-9′a), 3.90 (12H, s, OMe-2, OMe-2′, OMe-6, OMe-6′), 3.93 (2H, m, H-9b, H-9′b), 4.74 (2H, d, J = 4.0 Hz, H-7, H-7′), 5.52 (2H, brs, OH-7, OH-7′), 6.59 (4H, s, H-3, H-3′, H-5, H-5′). 13 C-NMR δC : 54.4 (2C, C-8, C-8′), 56.4 (4C, OMe-2, OMe-2′, OMe-6, OMe-6′), 71.8 (2C, C-9, C-9′), 86.1 (2C, C-7, C-7′), 102.8 (4C, C-3, C-3′, C-5, C-5′), 132.1 (2C, C-1, C-1′), 134.3 (2C, C-4, C-4′), 147.2 (4C, C-2, C-2′, C-6, C-6′).

2,6,2′,6′-Tetramethoxy-4,4′-bis (1,2-cis-2,3-epoxy-1-hydroxypropyl) biphenyl (2). Colorless needle crystal. 1 H-NMR (CDCl 3 , 300 MHz): δH : 3.09 (2H, m, H-8, H-8′), 3.89 (2H, m, H-9a, H-9′a), 3.90 (12H, s, OMe-2, OMe-2′, OMe-6, OMe-6′), 4.26 (2H, m, H-9b, H-9′b), 4.78 (2H, d, J = 7.0 Hz, H-7, H-7′), 5.54 (2H, brs, OH-7, OH-7′) 6.57 (4H, s, H-3, H-3′, H-5, H-5′). 13 C-MNR δC : 54.3 (2C, C-8, C-8′), 56.3 (4C, OMe-2, OMe-2′, OMe-6, OMe-6′), 71.8 (2C, C-9, C-9′), 86.0 (2C, C-7, C-7′), 102.7 (4C, C-3, C-3′, C-5, C-5′), 132.0 (2C, C-1, C-1′), 134.3 (2C, C-4, C-4′), 147.1 (4C, C-2, C-2′, C-6, C-6′).

1H-indole-3-carbaldehyde (3). Pale yellow needle crystal. 1 H-NMR (dimethyl sulfoxide [DMSO], 400 MHz) δH : 7.24 (2H, m, 5,6-H), 7.52 (1H, d, J = 8.0 Hz, 7-H), 8.10 (1H, s, 2-H), 8.29 (1H, d, J = 7.0 Hz, 4-H). 13 C-NMR δC : 185.4 (C-10), 138.9 (C-8), 137.5 (C-2), 124.6 (C-9), 123.9 (C-5), 122.6 (C-6), 121.3 (C-7), 118.64 (C-3), 112.6 (C-4).

Luteolin (4). Pale yellow powder. 1 H-NMR (DMSO, 400 MHz) δH : 13.02 (1H, brs, 5-OH), 7.45 (1H, dd, J = 8.5, 2.5 Hz, 6′-H), 7.40 (1H, d, J = 2.5 Hz, 2′-H), 6.91 (1H, d, J = 8.5 Hz, 5′-H), 6.71 (1H, s, 3-H), 6.47 (1H, d, J = 2.0 Hz, 6-H), 6.59 (1H, d, J = 1.6 Hz, H-8). 13 C-NMR δC : 163.8 (C-2), 103.3 (C-3), 181.4 (C-4), 161.4 (C-5), 99.0 (C-6), 164.9 (C-7), 93.9 (C-8), 157.3 (C-9), 103.9 (C-10), 118.8 (C-1′), 113.1 (C-2′), 145.9 (C-3′), 149.9 (C-4′), 116.0 (C-5′), 121.7 (C-6′).

Quercetin (5). Pale yellow powder. 1 H-NMR (DMSO, 400 MHz) δH : 6.20 (1H, d, J = 2.0 Hz, 6-H), 6.38 (1H, d, J = 2.0 Hz, 8-H), 6.86 (1H, d, J = 8.4 Hz, 5′-H), 7.56 (1H, dd, J = 8.4, 2.0 Hz, 6′-H), 7.65 (1H, d, J = 2.0 Hz, 2′-H), 9.32, 9.38, 9.62, 10.79, 12.49 (1H, s,-OH × 5). 13 C-NMR δC : 146.9 (C-2), 122.1 (C-3), 175.9 (C-4), 156.3 (C-5), 98.3 (C-6), 164.0 (C-7), 93.4 (C-8), 160.9 (C-9), 103.3 (C-10), 123.3 (C-1′), 115.8 (C-2′), 148.0 (C-3′), 145.2 (C-4′), 115.2 (C-5′), 120.2 (C-6′).

Acknowledgements

The authors wish to thank sincerely for the financial support of this work by the National Natural Science Foundation of China (81303211) and China Postdoctoral Science Foundation (2013M540301). Also, the authors gratefully acknowledge Dr. Da-Zhi Zhang, Center of Analysis and Test, Harbin Institute of Technology, for his kind help in determining the samples.

Financial support and sponsorship

Thanks for the financial support of this work by the National Natural Science Foundation of China (81303211) and China Postdoctoral Science Foundation (2013M540301).

Conflicts of interest

There are no conflicts of interest.

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