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Article

Protoberberine Isoquinoline Alkaloids from Arcangelisia gusanlung

1
Institute of Medicinal Plant Development, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100193, China
2
School of Medicine, China Three Gorges University, Yichang 443002, China
3
Hainan Branch of the Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Wanning 571533, China
4
China Hubei Key Laboratory of Natural Products Research and Development, College of Chemistry and Life Science, China Three Gorges University, Yichang 443002, China
*
Author to whom correspondence should be addressed.
Molecules 2014, 19(9), 13332-13341; https://doi.org/10.3390/molecules190913332
Submission received: 25 July 2014 / Revised: 20 August 2014 / Accepted: 21 August 2014 / Published: 29 August 2014
(This article belongs to the Section Natural Products Chemistry)

Abstract

:
HPLC-DAD-directed isolation and purification of the methanol extract of stems of Arcangelisia gusanlung H. S. Lo. led to the isolation of a new protoberberine alkaloid, gusanlung E (1), along with fourteen known derivatives 215, seven of which were obtained from the genus Arcangelisia for the first time. The structures and absolute stereochemistry of these compounds were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR, mass spectrometry, and CD analyses. Gusanlung E (1) expressed weak cytotoxic activity against the SGC 7901 cell line with an IC50 value of 85.1 µM.

Graphical Abstract

1. Introduction

Arcangelisia gusanlung H. S. Lo (Menispermaceae) is a small shrub widely distributed in the south of China including the provinces of Guangdong, Guangxi, and Hainan. The stems of A. gusanlung have been clinically used in Chinese folk medicine as an anti-inflammatory, antipyretic, and detoxication reagent [1]. Previous phytochemical investigations of the plant revealed the presence of a series of protoberberine alkaloids [2,3,4] and megastigane glycosides [5] in its stems. Protoberberine alkaloids, which belongs to a isoquinoline alkaloid class, are widely distributed in many species of the Berberidaceae, Annonaceae, Fumariaceae, Papaveraceae, Ranunculaceae, Rutaceae, and other plant families, encompassing a diverse class of secondary metabolites with many pharmacologically active members, such as berberine and palmatine [6,7]. Over the last decade, these alkaloids have attracted considerable attention due to their wide range of biochemical and pharmacological actions, which have applications in various therapeutic areas such as cancer, inflammation, diabetes, depression, hypertension, and various infectious areas [8].
In order to further investigate the active components of A. gusanlung, HPLC-DAD-directed isolation was carried out on the CH3OH extract of the stems of A. gusanlung. As a result, 15 protoberberine alkaloids including a new one, gusanlung E (1), together with fourteen known derivatives 215, seven of which were obtained from the genus Arcangelisia for the first time (Figure 1). Herein, we report the detailed isolation and structural characterization of these compounds, as well as cytotoxic activity of gusanlung E (1).
Figure 1. Structures of compounds 115.
Figure 1. Structures of compounds 115.
Molecules 19 13332 g001

2. Results and Discussion

2.1. Structural Characterization

Gusanlung E (1) was obtained as yellow crystals, and its molecular formula was determined as C19H22NO4 by HR-ESI-MS at m/z 328.1581 [M]+ (calcd. for C19H22NO4: 328.1549), indicating ten degrees of unsaturation. The 1H-, 13C-NMR and HSQC spectroscopic data suggested the presence of 19 carbons. The 1H-NMR spectrum showed four aromatic protons at δ 6.86, 6.71, 6.62 and 6.61, one aromatic methoxyl group at δ 3.87 (3H, s) and an N-methyl signal at δ 3.20 (3H, s). The signal at δ 3.26 (2H, m) was assigned as H-5, whereas the signals at 3.49 (1H) and 3.82 (1H) were assigned as germinal protons to H-6. Moreover, signals of a pair of methylene protons and an isolated -CH-CH2- moiety were found in the aliphatic region. The large coupling constant (15.0 Hz) of a pair of doublets at δ 4.71 and δ 4.52 suggested the existence of germinal protons, which was confirmed by HSQC. This is a typical characteristic of methylene group (C-8) of the protoberberine alkaloids [9]. The signals of an isolated -CH-CH2- moiety were assigned to C-13a and C-13. In addition, there were three exchangeable protons were observed at δ 9.13 in the proton NMR spectrum of DMSO-d6. Analysis of the 1H-, 13C-, and HSQC NMR spectroscopic data (Table 1) revealed that there were twelve aromatic carbon signals: four aromatic methylene (δC:115.8, 114.5, 114.1, 113.3), eight aromatic quaternary (four oxygenated); four methylene; one methane; one aromatic methoxyl (δC 57.6) and one N-methyl carbon (δC 50.7). According to the above information, the structure of 1 was closely related to the 2,3,10,11-tetrasubstituted-N-methyltetrahydroprotoberberine skeleton [10,11]. The complete assignments were accomplished using 1H-1H COSY, HSQC, HMBC and NOESY spectra.
Table 1. 1H- (600 MHz, δ ppm, J in Hz), 13C-NMR (150 MHz, δ ppm), COSY and HMBC spectroscopic data for compound 1 in methanol-d4.
Table 1. 1H- (600 MHz, δ ppm, J in Hz), 13C-NMR (150 MHz, δ ppm), COSY and HMBC spectroscopic data for compound 1 in methanol-d4.
PositionδCδH (J Hz)COSYHMBC
1114.5, CH6.71 s C-3, C-4a, C-13a
1a125.8, C
2147.5, C
3150.1, C
4113.3, CH6.83 s C-2, C-3, C-1a, C-4a, C-5
4a120.3, C
524.3, CH23.28, 3.23 mH-6C-1a, C-4a, C-4
653.3, CH23.82, 3.49 mH-5C-4a, C-13a, N-CH3, C-8, C-5
865.1, CH24.71, 4.52 d (15) C-12a, C-8a, C-6, C-9, C-13a, N-CH3, C-12a
8a118.0, C
9114.1, CH6.60 s C-11, C-12a, C-10, C-8a, C-8
10146.7, C
11147.8, C
12115.8, CH6.83 s C-11, C-10, C-9, C-8a, C-13
12a122.0, C
1335.4, CH23.35 dd (4.8, 19.6) 3.02 dd (10.2, 18.0)H-13aC-8a, C-1a, C-12,
13a67.6, CH4.66 dd (6.6, 10.2)H-13C-12a, C-4a, C-1, C-8, C-13
3-OCH356.7, CH33.87 s C-3, C-4, C-2
N-CH350.7, CH33.20 s C-13a, C-6, C-8
Interpretation of the 1H-1H COSY NMR data of 1 confirmed that two isolated proton spin-systems belong to C-5-C-5a and C-13-C-13a units, and the remaining connections were established by analysis of HMBC correlations. The HMBC correlations from -OCH3 to C-1, C-3, and C-4, whereas correlations from H-1 to C-3, C-13a and C-4a, and from H-4 to C-1a, C-2 and C-5, indicated that A ring possessed 2-OH and 3-OCH3 substitutions (Figure 2). The result was further confirmed by NOESY spectrum, in which the NOE correlations between 3-OCH3 and H-4, H-4 and H-5, H-1 and H-13a were observed. In the same way, the cross peaks of H-9 with C-8, C-12a, C-11 and H-12 with C-10, C-8a, C-13 in the HMBC spectrum suggested dihydroxyl substitutions at C-10 and C-11 in D ring. Moreover, H-9 was correlated with H-8 and H-12 with H-13 in the NOESY spectrum (Figure 3). Therefore, the planar structure of 1 was characterized as 2,10,11-trihydroxy-3-methoxy-N-methyltetrahydro-protoberberine.
The relative configuration was determined by a NOESY experiment. The N-methyl protons showed a NOE correlation with H-13a (Figure 3). Moreover, the NOE correlation between H-6 and N-methyl protons suggested the axial position of H-6. The H-13 signal showed a large coupling constant (12.0 Hz) with the signal of H-13a, indicating that H-13 was at axial position [11]. Meanwhile, the 1H- and 13C-NMR chemical shifts of N-methyl group (δH 3.20, δc 50.7) as well as a NOESY cross peak between the N-methyl group and H-13a suggested a B/C-cis fused form [12]. Furthermore, the negative value of specific optical rotation and circular dichroism (CD) curve indicated the 7S, 13aS configurations [13]. Accordingly, the structure of the new compound was elucidated as shown in Figure 1.
Figure 2. 1H-1H COSY and key HMBC correlations of compound 1.
Figure 2. 1H-1H COSY and key HMBC correlations of compound 1.
Molecules 19 13332 g002
Figure 3. Key NOE of compound 1.
Figure 3. Key NOE of compound 1.
Molecules 19 13332 g003
Compounds 215 were identified as berberine (2) [14], thalifendine (3) [15], palmatine (4) [16], stephabine (5) [17], 8-oxyberbeine (6) [18], tetrahydropalmatine (7) [19], 8-oxotetrahydroplamatine (8) [20], gusanlung C (9) [7], gusanlung B (10) [6], jatrorrhizine (11) [21], 8,13-dioxo-14-hydroxycanadine (12) [22], 8,13-dioxo-14-methoxycanadine (13) [23,24], corydaline (14) [24] and tetrahydrothalifendine (15) [25], respectively, by comparison of the 1H- and 13C-NMR data with reported spectroscopic data. Among them, 5, 7, 8, and 1215 were isolated from this plant for the first time.

2.2. Cytotoxic Activities

Gusanlung E (1) exhibited weak cytotoxic activity against cell line SGC 7901 with IC50 value of 85.1 µM.

3. Experimental Section

3.1. General Experimental Procedures

Optical rotations were recorded on a JASCO DIP-1000 polarimeter (JASCO, Kyoto, Japan). IR spectra were recorded on a Shimadzu FTIR-8400s (Shimadzu, Kyoto, Japan). UV spectra were run on a Shimadzu UV-2550 UV-VIS spectrophotometer (Shimadzu, Kyoto, Japan). CD spectra were measured on a JASCO J-810 spectrometer (JASCO, Kyoto, Japan). 1D and 2 D NMR spectra were measured in methanol-d4H 3.30/δC 49.5) on a Bruker Avance Ш 600 spectrometer (1H: 600 MHz, 13C: 150 MHz) (Munich, Ettlingen, Germany). HRESIMS were obtained using a LTQ Orbitrap XL spectrometer (Thermo Fisher, Bremen, Germany). Analytical HPLC was performed on a Waters 600 with a Waters 2996 photodiode array detector (Waters, Milford, MA, USA). Semipreparative HPLC was performed on a Shimadzu LC-6AD with a Shimadzu SPD-6AD spectrophotometric detector (Shimadzu, Kyoto, Japan).

3.2. Plant Material

The stems of A. gusanlung were collected from Wanning City in Hainan Province of The People’s Republic of China in August 2008. The sample was identified by Prof. Guobiao Chen from the Institute for Drug Control of Hainan Province. A voucher specimen (No. 200808) was deposited in the herbarium of the Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Beijing.

3.3. Extraction and Isolation

The air-dried and smashed stems of A. gusanlung (18 kg) were extracted with MeOH (3 × 80 L) and afforded a crude extract of 880 g after evaporation of the solvent under vacuum. The extract was suspended in H2O (2.0 L) and partitioned sequentially with petroleum ether (3 × 3.0 L), EtOAc (3 × 3.0 L), and n-BuOH (3 × 3.0 L). The EtOAc extract (40 g) was subjected to chromatography over silica gel (800 g, 100–200 mesh) and eluted with CH2Cl2–MeOH to yield six fractions (E1 to E6) on the basis of TLC and HPLC-DAD analyses. Repeated crystallization of fraction E5 (CH2Cl2–MeOH) yielded compounds 2 (10 g), 3 (3 g) and 4 (2 g). The n-BuOH extract (630 g) was subjected to column chromatography over macroporous resin D101 and eluted successively with EtOH–H2O (1:9, 3:7, 6:4, and 1:0) to yield four fractions (B1 to B4). Fraction B1 (10 g) was further subjected to column chromatography over macroporous resin AB-8 and eluted successively with EtOH–H2O (1:9, 2:8, 3:7 and 1:0) to yield five fractions (B1-1 to B1-5). Subfraction B1-3 (1.5 g) was subjected to chromatography over silica gel C18 (45 g) and eluted with MeOH-Water to yield 1 (50 mg), 14 (7 mg) and 15 (11 mg). Fraction B2 (40 g) was subjected to chromatography over silica gel (400 g, 100–200 mesh) and eluted with CH2Cl2–MeOH to yield 12 fractions (B2-1 to B2-12) on the basis of TLC and HPLC-DAD analyses. Fraction B2-3 (1.0 g) was subjected to chromatography over silica gel (30 g, 200–300 mesh) and eluted with CH2Cl2-MeOH to yield 10 subfractions (B2-3-1 to B2-3-10). Subfractions were further separated on Sephadex LH-20 (MeOH) followed by semipreparative HPLC (35% aq. MeOH) to give compounds 5 (8 mg), 6 (23 mg), 7 (20 mg), 8 (12 mg), 9 (10 mg), 10 (27 mg), 11 (12 mg), 12 (120 mg) and 13 (17 mg).
Gusanlung E (1): yellow crystals; [α] D20 −20 (c 0.03, MeOH); UVλmax (MeOH) nm 210.0, 287.0; IRνmax (KBr): 3179 (OH), 3042, 2361, 1617 (C=O), 1532 cm−1; CD (MeOH) Δε (nm): −9.35 (239), −1.34 (290); 1H- and 13C-NMR data, see Table 1; HRESIMS m/z 328.1581 [M]+ (calcd for C19H22NO4+, 328.1577).
Berberine (2): yellow crystals; HRESIMS m/z 336.1205 [M]+ (calcd for C20H18NO4+ 336.1236); 1H-NMR δ: 3.27 (2H, t, J = 6.0 Hz, H-5), 4.11 (3H, s, 10-OCH3), 4.21 (3H, s, 9-OCH3), 4.94 (2H, t, J = 6.0 Hz, H-6), 6.11 (2H, s, -OCH2O-), 6.97 (1H, s, H-4), 7.67 (1H, s, H-1), 8.01(1H, d, J = 9.0 Hz, H-12), 8.12 (1H, d, J = 9.0 Hz, H-11), 8.71 (1H, s, H-13), 9.77 (1H, s, H-8); 13C-NMR δ: 26.4 (C-5), 55.2 (C-6), 57.1 (10-OCH3), 62.0 (9-OCH3), 102.1 (-OCH2O-), 105.4 (C-1), 108.4 (C-4), 120.2 (C-13), 120.4 (C-1a), 121.4 (C-8a), 123.5 (C-12), 126.7 (C-11), 130.6 (C-4a), 132.9 (C-12a), 137.4 (C-13a), 143.6 (C-9), 145.4 (C-8), 147.6 (C-2), 149.7 (C-3), 150.4 (C-10).
Thalifendine (3): faint yellow powder; HRESIMS m/z 322.1058 [M]+ (calcd for C19H16NO4+ 322.1074); 1H-NMR δ: 3.24 (2H, t, J = 6.0 Hz, H-5), 4.16 (3H, s, 9-OCH3), 4.90 (2H, t, J = 6.0 Hz, H-6), 6.10 (2H, s, -OCH2O-), 6.95 (1H, s, H-4), 7.63 (1H, s, H-1), 7.88 (1H, d, J = 9.0 Hz, H-12), 7.78 (1H, d, J = 9.0 Hz, H-11), 8.64 (1H, s, H-13), 9.77 (1H, s, H-8); 13C-NMR δ: 28.3 (C-5), 57.1 (C-6), 62.4 (9-OCH3), 103.6 (-OCH2O-), 106.4 (C-1), 109.4 (C-4), 121.7 (C-13), 122.0 (C-1a), 124.4 (C-8a), 124.7 (C-12), 132.4 (C-11), 131.6 (C-4a), 135.3 (C-12a), 139.4 (C-13a), 143.2 (C-9), 145.2 (C-8), 150.0 (C-2), 152.1 (C-3), 150.8 (C-10).
Palmatine (4): a faint yellow powder; HRESIMS m/z 352.1547 [M]+ (calcd for C21H22NO4+ 352.1543); 1H-NMR δ: 3.29 (2H, t, J = 6.0 Hz, H-5), 3.79 (3H, s, 2-OCH3), 3.81 (3H, s, 3-OCH3), 3.83 (3H, s, 9-OCH3), 3.84 (3H, s, 10-OCH3), 4.97 (2H, t, J = 6.0 Hz, H-6), 7.01 (1H, s, H-4), 7.66 (1H, s, H-1), 7.97 (1H, d, J = 9.0 Hz, H-12), 8.10 (1H, d, J = 9.0 Hz, H-11), 8.80 (1H, s, H-13), 9.79 (1H, s, H-8); 13C-NMR δ: 27.3 (C-5), 56.6 (C-6), 57.2 (2-OCH3), 57.3 (3-OCH3), 57.3 (10-OCH3), 63.0 (9-OCH3), 104.7 (C-1), 110.5 (C-4), 121.5 (C-13), 121.9 (C-1a), 120.1 (C-8a), 124.4 (C-12), 126.9 (C-11), 132.6 (C-4a), 126.9 (C-12a), 138.4 (C-13a), 153.7 (C-9), 145.3 (C-8), 148.9 (C-2), 149.7 (C-3), 144.6 (C-10).
Stephabine (5): faint yellow powder; HRESIMS m/z 368.1486 [M]+ (calcd for C21H22NO5+ 368.1498); 1H-NMR δ: 3.24 (2H, t, J = 5.4 Hz, H-5), 3.95 (3H, s, 2-OCH3), 3.93 (3H, s, 3-OCH3), 3.99 (3H, s, 10-OCH3), 4.00 (3H, s, 11-OCH3), 4.76 (2H, t, J = 5.4 Hz, H-6), 6.90 (1H, s, H-4), 7.00 (1H, s, H-12) , 7.62 (1H, s, H-9), 8.84 (1H, s, H-13), 9.14 (1H, s, H-8).
8-Oxyberberine (6): faint yellow powder; HRESIMS m/z 352.1200 [M+H]+ (calcd for C20H17NO5 352.1185); 1H-NMR δ: 2.83 (2H, t, J = 6.6 Hz, H-5), 3.78 (3H, s, 10-OCH3), 3.84 (3H, s, 9-OCH3), 3.89 (2H, t, J = 6.6 Hz, H-6), 6.01 (2H, s, -OCH2O-), 6.69 (1H, s, H-4), 6.95 (1H, s, H-1), 6.53 (1H, d, J = 9.0 Hz, H-12), 7.02 (1H, d, J = 9.0 Hz, H-11), 7.35 (1H, s, H-13), 8.03 (1H, s, N-H); 13C-NMR δ: 29.8 (C-5), 38.8 (C-6), 56.2 (10-OCH3), 60.9 (9-OCH3), 102.3 (-OCH2O-), 103.6 (C-13), 104.9 (C-1), 109.6 (C-4), 109.7 (C-11), 119.7 (C-13a), 124.6 (C-12), 126.4 (C-8a), 129.8 (C-4a), 134.0 (C-12a), 135.9 (C-1a), 148.1 (C-2), 148.8 (C-3), 149.6 (C-10), 153.0 (C-9), 160.3 (C-8).
Tetrahydropalmatine (7): faint yellow powder; HRESIMS m/z 356.1862 [M+H]+ (calcd for C21H26NO4 356.1862); 1H-NMR δ: 2.68 (2H, m, H-5), 2.84 (1H, dd, J13β, 13a = 13.0 Hz, J13β, 13α = 15.0 Hz, H-13α), 3.20 (1H, dd, J13α, 13a = 3.6 Hz, J13α, 13β = 15.6 Hz, H-13β), 3.23 (2H, m, H-6), 3.53 (1H, d, J = 15.6 Hz, H-8α), 3.59 (1H, dd, J13a, 13β = 12.0 Hz, J13a, 13α = 3.6 Hz, H-13a), 3.84 (6H, s, 9-OCH3, 10-OCH3), 3.86 (3H, s, 2-OCH3), 3.88 (3H, s, 3-OCH3), 4.26 (1H, d, J = 15.6 Hz, H-8β), 6.61 (1H, s, H-4), 6.75 (1H, s, H-1), 7.70 (1H, d, J = 9.0 Hz, H-11), 7.85 (1H, d, J = 9.0 Hz, H-12 ).
8-Oxotetrahydroplamatine (8): faint yellow powder; HRESIMS m/z 370.2023 [M+H]+ (calcd for C21H24NO5 370.1654); 1H-NMR δ: 2.78 (1H, dd, J13β, 13a = 13.0 Hz, J13β, 13α = 15.0 Hz, H-13β), 2.80 (1H, dd, J13α, 13a = 3.0 Hz, J13α, 13β = 15.0 Hz, H-13α), 2.92 (2H, m, H-5), 3.02 (1H, m, H-6α), 3.90 (9H, s, 3 × OCH3), 4.02 (3H, s, OCH3), 4.70 (1H, m, H-6β), 5.05 (1H, dd, J13a, 13β = 9.0 Hz, J13a, 13α = 2.0 Hz, H-13a), 6.67 (1H, s, H-4), 6.68 (1H, s, H-1), 6.95 (1H, d, J = 9.0 Hz, H-12 ), 7.00 (1H, d, J = 9.0 Hz, H-11); 13C-NMR δ: 29.8 (C-5), 38.0 (C-13), 39.2 (C-6), 54.5 (C-13a), 56.2 (3 × OCH3), 61.5 (OCH3), 109.5 (C-1), 111.5 (C-4), 115.5 (C-11), 120.6 (C-12), 123.0 (C-8a), 127.3 (C-12a), 127.8 (C-4a), 130.7 (C-1a), 147.9 (C-3), 148.0 (C-2), 150.7 (C-10), 153.4 (C-9), 162.7 (C-8).
Gusanlung C (9): faint yellow powder; HRESIMS m/z 314.1395 [M+H]+ (calcd for C18H20NO4 314.1392); 1H-NMR δ: 2.70 (2H, t, J = 7.2 Hz, H-5), 3.44 (2H, t, J = 7.2 Hz, H-6), 3.82 (3H, s, COOCH3), 6.46 (1H, d, J = 15.6 Hz, H-13a), 6.70 (2H, d, J = 8.0 Hz, H-9, H-11), 6.79 (1H, d, J = 8.4 Hz, H-4), 6.98 (1H, dd, J = 8.4, 2.0 Hz, H-3), 7.01(2H, d, J = 8.0 Hz, H-8a, H-12), 7.10(1H, d, J = 2.0 Hz, H-1), 7.41 (1H, d, J = 15.6 Hz, H-13), 8.00 (1H, t, J = 7.2 Hz, H-7); 13C-NMR δ: 36.8 (C-5), 40.2 (C-6), 56.5 (COOCH3), 111.6 (C-13a), 116.0 (C-8a, C-12), 116.1 (C-4), 119.7 (C-1), 122.5 (C-2), 128.0 (C-1a), 130.3 (C-9, C-11), 131.0 (C-4a), 140.7 (C-13), 148.6 (C-12a), 149.0 (C-10), 156.7 (C-2), 167.0 (C-8).
Gusanlung B (10): faint yellow powder; HRESIMS m/z 353.1252 [M]+ (calcd for C20H19NO5 353.1263); 1H-NMR δ: 2.76 (1H, dd, J13β, 13a = 13.0 Hz, J13β, 13α = 15.0 Hz, H-13β), 2.68 (1H, dd, J13α, 13a = 3.0 Hz, J13α, 13β = 15.0 Hz, H-13α), 2.83 (2H, m, H-5), 2.97 (1H, m, H-6α), 3.86 (3H, s, 9-OCH3), 4.01 (3H, s, 10-OCH3), 4.65 (1H, dd, J13a, 13β = 13.0 Hz, J13a, 13α = 3.0 Hz, H-13a), 4.92 (1H, m, H-6β), 5.96 (2H, s, OCH2O), 6.65 (1H, s, H-4), 6.67 (1H, s, H-1), 6.93 (1H, d, J = 9.0 Hz, H-12), 7.02 (1H, d, J = 9.0 Hz, H-11); 13C-NMR δ: 29.0 (C-5), 38.2 (C-13), 39.2 (C-6), 55.5 (C-13a), 56.2 (9-OCH3), 61.5 (10-OCH3), 101.5 (OCH2O), 106.5 (C-1), 108.5 (C-4), 115.8 (C-11), 121.5 (C-12), 125.9 (C-8a), 128.7 (C-4a), 128.9 (C-12a), 131.0 (C-1a), 146.5 (C-2), 146.6 (C-3), 150.1 (C-10), 153.3 (C-9), 162.4 (C-8).
Jatrorrhizine (11): faint yellow powder; HRESIMS m/z 338.1396 [M]+ (calcd for C20H20NO4+ 338.1392); 1H-NMR δ: 3.23 (2H, t, J = 6.0 Hz, H-5), 4.04 (3H, s, 2-OCH3), 4.18 (3H, s, 9-OCH3), 4.15 (3H, s, 10-OCH3), 4.95 (2H, t, J = 6.0 Hz, H-6), 7.46 (1H, s, H-4), 7.80 (1H, s, H-1), 8.08 (1H, d, J = 9.0 Hz, H-12), 8.02 (1H, d, J = 9.0 Hz, H-11), 8.81 (1H, s, H-13), 9.70 (1H, s, H-8); 13C-NMR δ: 26.8 (C-5), 57.2 (C-6), 56.5 (2-OCH3), 62.2 (9-OCH3), 115.5 (C-1), 112.5 (C-4), 119.8 (C-13b), 121.5 (C-13), 122.9 (C-12a), 123.0 (C-12), 123.8 (C-11), 130.3 (C-4a), 135.0 (C-8a), 139.4 (C-13a), 144.6 (C-10), 145.3 (C-8), 148.9 (C-2), 149.9 (C-3), 151.7 (C-9).
8,13-Dioxo-14-hyroxycanadine (12): faint yellow powder; HRESIMS m/z 406.0900 [M+Na]+ (calcd for C20H17NO7Na 406.0903); 1H-NMR δ: 2.97–3.01 (1H, m, H-5a), 3.51–3.55 (1H, m, H-5b), 3.42 (1H, m, H-6a), 3.87 (3H, s, 9-OCH3), 3.89 (3H, s, 10-OCH3), 4.15 (1H, m, H-6b), 5.96 (2H, s, -OCH2O-), 6.67 (1H, s, H-4), 6.81 (1H, s, H-1), 7.29 (1H, d, J = 8.4 Hz, H-12), 7.53 (1H, d, J = 8.4 Hz, H-11); 13C-NMR δ: 31.8 (C-5), 39.5 (C-6), 57.5 (10-OCH3), 62.8 (9-OCH3), 92.2 (-OCH2O-), 103.9 (C-13a), 109.6 (C-12), 110.7 (C-11), 118.8 (C-4), 121.8 (C-1), 124.5 (C-12a), 132.6 (C-8a), 135.4 (C-1a), 138.1 (C-4a), 147.9 (C-2), 148.9 (C-3), 153.4 (C-10), 156.2 (C-9), 168.6 (C-8), 203.9 (C-13).
8,13-Dioxo-14-methoxycanadine (13): faint yellow powder; HRESIMS m/z 397.1158 [M]+ (calcd for C21H19NO7 397.1162); 1H-NMR δ: 2.78–2.80 (2H, m, H-5), 3.16 (3H, s, 14-OCH3), 3.21 (1H, m, H-6α), 3.92 (3H, s, 9-OCH3), 3.98 (3H, s, 10-OCH3), 4.93 (1H, m, H-6β), 5.98 (2H, s, -OCH2O-), 6.73 (1H, s, H-4), 6.87 (1H, s, H-1), 7.37 (1H, d, J = 9.0 Hz, H-12 ), 7.74 (1H, d, J = 9.0 Hz, H-11).
Corydaline (14): faint yellow powder; HRESIMS m/z 370.2011 [M+H]+ (calcd for C22H28NO4 370.2018); 1H-NMR δ: 0.95 (3H, d, J = 7.2 Hz, CH3), 2.60 (2H, m, H-5), 3.11 (2H, m, H-6), 3.23 (1H, m, H-13), 3.52 (1H, d, J = 15.6 Hz, H-8α), 3.71 (1H, d, J = 2.4 Hz, H-13a), 3.89 (12H, m, OCH3 × 4), 4.16 (1H, d, J =15.6 Hz, H-8β), 6.62 (1H, s, H-4), 6.67 (1H, s, H-1), 6.82 (1H, d, J = 9.0 Hz, H-11), 6.90 (1H, d, J = 9.0 Hz, H-12); 13C-NMR δ: 18.2 (13-CH3), 29.2 (C-5), 38.2 (C-13), 51.3 (C-6), 54.0 (C-8), 55.5 (-OCH3), 55.6 (-OCH3), 56.0 (-OCH3), 60.0 (-OCH3), 63.0 (C-13a), 108.7 (C-1), 110.8 (C-4), 111.1 (C-11), 123.8 (C-12), 128.4 (C-4a, C-8a, C-1a), 134.8 (C-12a), 146.0 (C-10), 147.1 (C-2), 147.5 (C-3), 145.0 (C-9).
Tetrahydrothalifendine (15): faint yellow powder; HRESIMS m/z 326.1395 [M+H]+ (calcd for C19H20NO4 326.1392); 1H-NMR δ: 2.68 (2H, m, H-5), 2.84 (1H, dd, J13β, 13a = 12.6 Hz, J13β, 13α = 15.6 Hz, H-13α), 3.13 (1H, dd, J13α, 13a = 3.6 Hz, J13α, 13β = 15.6 Hz, H-13β), 3.32 (2H, m, H-6), 3.53 (1H, d, J = 15.6 Hz, H-8α), 3.57(1H, dd, J13a, 13β = 12.6 Hz, J13a, 13α = 3.6 Hz, H-13a), 3.91(3H, s, OCH3), 4.15(1H, d, J = 15.6 Hz, H-8β), 5.96 (2H, s, -OCH2O-), 6.63 (1H, s, H-4), 6.67 (1H, s, H-1), 6.62 (1H, d, J = 9.0 Hz, H-11 ), 6.90 (1H, d, J = 9.0 Hz, H-12 ); 13C-NMR δ: 29.2 (C-5), 36.2 (C-13), 51.5 (C-6), 53.0 (C-8), 59.0 (C-13a), 55.1 (-OCH3), 101.3 (-OCH2O-),106.7 (C-1), 110.8 (C-4), 111.3 (C-11), 121.7 (C-12), 125.9 (C-8a), 127.1 (C-12a), 127.8 (C-4a), 131.0 (C-1a), 143.0 (C-10), 144.1 (C-2), 144.0 (C-3), 145.0 (C-9).

3.4. Cytotoxicity Testing

The cytotoxicity of the compounds was determined using the colorimetric methylthiazoletetrazolium (MTT) assay with taxol as the positive control (IC50 value 0.15 µM). The human stomach cancer cell line SGC 7901 in logarithmic phase were seeded in 96 well flat bottom microtitre plates at a density of 1 × 104 cells per well. cells were washed and maintained with different concentrations of drug, 10 µL MTT was added to the culture medium to a final concentration of 0.5 mg/mL and incubated at 37 °C for 4 h. Formazan crystals dissolved in 100 µL DMSO was added and 10 min later the absorbance of the solution was measured at a wavelength of 570 nm. All assays were carried out in triplicate.

4. Conclusions

From the chemical investigation of stems of A. gusanlung, fifteen protoberberine alkaloids including a new one, named gusanlung E (1), were isolated and identified. Gusanlung E (1) showed weak cytotoxicity against cancer cell line SGC 7901. These analogues should be studied in more advanced models to establish in vivo efficacy.

Supplementary Materials

Supplementary materials can be accessed at: https://www.mdpi.com/1420-3049/19/9/13332/s1.

Supplementary Files

Supplementary File 1

Acknowledgments

This work was supported by the Chinese National S&T Special Project on Major New Drug Innovation (2011ZX09307-002-01), Program for Innovative Research Team in IMPLAD (IT1305), Outstanding Young Talent Project of Scientific Research Plan of Education Department of Hubei Province (Q20131309) and Science Foundation of China Three Gorges University (KJ2011B050).

Author Contributions

Y.L.L. and Z.Z.M. designed the research; Y.L.L., L.R.T., A.Y.B., L.W. and D.Z.S. performed the experimental work; Y.L.L. wrote the manuscript. All authors discussed, edited and approved the final version.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Chinese Pharmacopoeia; People’s Medical Publishing House: Beijing, China, 1977; p. 521.
  2. Garcia, L.M.; Jewers, K.; Manchanda, A.H.; Martinod, P.; Nabney, J.; Robinson, F.V. The alkaloids of Arcangelisia Loureirii and Coscinium Wallichianum. Phytochemistry 1970, 9, 663–664. [Google Scholar] [CrossRef]
  3. Zhang, J.S.; Chen, Z.L. Two new 8-oxotetrahydroprotoberberine alkaloids, gusanlung A and B, from Acangelisia gusanlun. Planta Med. 1991, 57, 457–459. [Google Scholar] [CrossRef]
  4. Zhang, J.S.; Men-Olivier, L.L.; Massiot, G. Isoquinoline alkaloids from Arcangelisia Gusanlung. Phytochemistry 1995, 39, 439–442. [Google Scholar] [CrossRef]
  5. Yu, L.L.; Hu, W.C.; Ding, G.; Li, R.T.; Wei, J.H.; Zou, Z.M.; Wang, M. Gusanlungionosides A–D, potential tyrosinase inhibitors from Arcangelisia gusanlung. J. Nat. Prod. 2011, 74, 1009–1014. [Google Scholar] [CrossRef]
  6. Gao, J.M.; Kamnaing, P.; Kiyota, T.; Watchueng, J.; Kubo, T.; Jarussophon, S.; Konishi, Y. One-step purification of palmatine and its derivative dl-tetrahydropalmatine from Enantia chlorantha using high-performance displacement chromatography. J. Chromatogr. A 2008, 1208, 47–53. [Google Scholar]
  7. Gao, J.M.; Liu, W.T.; Li, M.L.; Liu, H.W.; Zhang, X.C.; Li, Z.X. Preparation and structural elucidation of (−)-tetrahydroberberine-(+)-2,3-di(p-toluyl) tartaric acid complex. J. Mol. Struct. 2008, 892, 466–469. [Google Scholar]
  8. Lenka, G.; Jiri, D.; Radek, M. Quaternary protoberberine alkaloids. Phytochemistry 2007, 68, 150–175. [Google Scholar]
  9. Blanchfield, J.T.; Sands, D.P.A.; Kennard, C.H.L.; Byriel, K.A.; Kitching, W. Characterisation of alkaloids from some Australian Stephania (Menispermaceae) species. Phytochemistry 2003, 63, 711–720. [Google Scholar] [CrossRef]
  10. Guo, Y.Y.; Lin, L.B.; Fu, X.W.; Kojima, K.; Ogihara, Y. Studies on alkaloids from Tinospora hainanensis. Acta Pharmacol. Sin. 1999, 34, 690–693. [Google Scholar]
  11. Inqkaninan, K.; Phenqpa, P.; Yuenyongsawad, S.; Khorana, N. Acetylcholinesterase inhibitors from Stephania venosa tuber. J. Pharm. Pharmacol. 2006, 58, 695–700. [Google Scholar] [CrossRef]
  12. Takao, N.; Iwasa, K.; Kamigauchi, M.; Sugiura, M. Studies on the alkaloids of papaveraceous plants. XXIX. Conformational analysis of tetrahydroprotoberberines by carbon-13 magnetic resonance spectroscopy. Chem. Pharm. Bull. 1977, 25, 1426–1435. [Google Scholar] [CrossRef]
  13. Takao, T.; Yuko, S.; Naotaka, N.; Hidekazu, N. Quaternary isoquinoline alkaloids from Stephania cepharantha. Chem. Pharm. Bull. 2000, 48, 370–373. [Google Scholar] [CrossRef]
  14. Tao, J.H.; Zhang, X.Q.; Ye, W.C.; Zhao, S.X. Chemical constituents from Corydalis humosa. J. Chin. Med. Mat. 2005, 28, 556–557. [Google Scholar]
  15. Su, Y.F.; Lan, H.Y.; Zhang, Z.X.; Guo, C.Y.; Guo, D. Chemical constituents of Semia quilegia adoxoides. Chin. Tradit. Herbal Drugs 2006, 37, 27–29. [Google Scholar]
  16. Raouf, A.; Jinwoong, K.; Christpher, W.W.; A. Douglas, K. Unambiguous carbon-13 NMR assignments of some biologically active protoberberine alkaloids. Hererocycles 1989, 29, 2257–2260. [Google Scholar] [CrossRef]
  17. Amarendra, P.; Craig, T.M.; Alan, J.F.; Hélène, G.; Maurice, S.; Bamrung, T.; Kakaya, P. The protoberberine alkaloids of Stephania suberosa. Phytochemistry 1987, 26, 547–549. [Google Scholar] [CrossRef]
  18. Min, Y.D.; Yang, M.C.; Lee, K.H.; Kim, K.R.; Choi, S.U.; Lee, K.R. Protoberberine alkaloids and their reversal activity of P-gp expressed multidrug resistance (MDM) from the rhizome of Coptis japonica Makino. Arch. Pharm. Res. 2006, 29, 757–761. [Google Scholar] [CrossRef]
  19. Qu, Y.; Liu, M.; Wu, Z.H.; Gao, H.Y.; Sun, B.H.; Su, Q.J.; Wu, L.J. 2, 3, 9, 10-Tetraoxygenated Protoberberine Alkaloids from Corydalis yanhusuo W. T. Wang. Asian J. Tradi. Med. 2007, 2, 61–65. [Google Scholar]
  20. Yu, R.; Ye, Q.; Chen, B.; Zhang, G.L. Chemical study on Mitrephora mainga yi. Nat. Prod. Res. Deve 2003, 15, 212–215. [Google Scholar]
  21. Cheng, C.M.; Dai, Y.; Huang, X.Z.; Zhu, Y.; Dai, J.H.; Liu, X.F.; Wang, J. Chemical constituents from roots of Tinospora sagittata var. yunnanensis. Chin. Tradit. Herbal Drugs 2010, 41, 689–692. [Google Scholar]
  22. Moniot, J.L.; Hindenlang, D.M.; Shamma, M. Chemistry of 8, 13-dioxoberbines. J. Org. Chem. 1979, 44, 4343–4346. [Google Scholar]
  23. Valencia, E.; Weiss, I.; Firdous, S.; Freyer, A.J.; Shamma, M. The isoindolobenzazepine alkaloids. Tetrahedron 1984, 40, 3957–3962. [Google Scholar]
  24. Xu, X.H.; Wang, Z.T.; Yu, G.D.; Ruan, B.F.; Li, J. Alkaloids from Rhizoma corydalis. J. Chin. Pharm. Univ. 2002, 33, 483–486. [Google Scholar]
  25. Li, J.C.; Dong, X.H.; Deng, J.W.; Dai, Y.; Zhang, J.S.; Li, G.P. Studies on the alkaloids from roots of Cordalis impatiens. J. Chin. Med. Mat. 2010, 33, 210–213. [Google Scholar]
  • Sample Availability: Samples of the compounds are not available from the authors because bioactivity tests of those compounds are going on.

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MDPI and ACS Style

Yu, L.-L.; Li, R.-T.; Ai, Y.-B.; Liu, W.; Deng, Z.-S.; Zou, Z.-M. Protoberberine Isoquinoline Alkaloids from Arcangelisia gusanlung. Molecules 2014, 19, 13332-13341. https://doi.org/10.3390/molecules190913332

AMA Style

Yu L-L, Li R-T, Ai Y-B, Liu W, Deng Z-S, Zou Z-M. Protoberberine Isoquinoline Alkaloids from Arcangelisia gusanlung. Molecules. 2014; 19(9):13332-13341. https://doi.org/10.3390/molecules190913332

Chicago/Turabian Style

Yu, Ling-Ling, Rong-Tao Li, Yuan-Bao Ai, Wei Liu, Zhang-Shuang Deng, and Zhong-Mei Zou. 2014. "Protoberberine Isoquinoline Alkaloids from Arcangelisia gusanlung" Molecules 19, no. 9: 13332-13341. https://doi.org/10.3390/molecules190913332

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