Next Article in Journal
Efficient TCT-catalyzed Synthesis of 1,5-Benzodiazepine Derivatives under Mild Conditions
Previous Article in Journal
Useful Spectrokinetic Methods for the Investigation of Photochromic and Thermo-Photochromic Spiropyrans
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Isoquinoline Alkaloids Isolated from Corydalis yanhusuo and Their Binding Affinities at the Dopamine D1 Receptor

Bio-Organic and Natural Products Laboratory, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA
Department of Pharmacology and Center for Substance Abuse Research, School of Medicine, Temple University, 3420 N. Broad St, Philadelphia, PA 19140, USA
Department of Pharmacology, University of North Carolina Medical School, Chapel Hill, NC 27599, USA
Center for Neurobiology Division of Medicinal Chemistry and Natural Products, and NIMH Psychoactive Drug Screening Program, University of North Carolina Medical School, Chapel Hill, NC 27599, USA
Author to whom correspondence should be addressed.
Molecules 2008, 13(9), 2303-2312;
Submission received: 29 August 2008 / Revised: 15 September 2008 / Accepted: 16 September 2008 / Published: 25 September 2008


Bioactivity-guided fractionation of Corydalis yanhusuo has resulted in the isolation of eight known isoquinoline alkaloids - tetrahydropalmatine, isocorypalmine, stylopine, corydaline, columbamine, coptisin, 13-methylpalmatine, and dehydro-corybulbine. The tertiary alkaloids were further analyzed by chiral HPLC to determine the ratios of d-and l-isomers. The isolated compounds were screened for their binding affinities at the dopamine D1 receptor. Isocorypalmine had the highest affinity (Ki = 83 nM). The structure-affinity relationships of these alkaloids are discussed.


Alcohol and drug abuse are major social and medical problems that impose a significant burden on society [1,2]. Because of the complexity of drug dependence and the lack of effective remedy, especially for relapse, the development of pharmacotherapy for its treatment has been a serious challenge [3]. Despite a great deal of effort in developing effective therapies, only few medications have been approved by the U.S. Food and Drug Administration [2, 4]. These medications have shown only limited efficacy, serious side effects and poor compliance in patients [5,6,7,8], therefore, an alternative approach, the systematic evaluation of traditional herbal medicines, may provide new drug candidates for the treatment of alcohol and drug abuse. Chinese herbal medicines have been used historically in the treatment of alcohol and drug abuse [4, 9]. Many are still prescribed in China and Southeast Asia for this purpose, and their clinical efficacy of some medications has recently been documented [10]. NPI-025 [11] is a herbal formula used clinically to treat opioid addiction in Hong Kong. It is composed of five Chinese herbs, including Rhizoma Corydalis (Yan Hu Suo), Rhizoma Et Radix Notopterygh (Qiang Huo), Ramulus Uncariae Cum Uncis (Gou Teng), Rhizoma Chuanxiong (Chuan Xiong) and Radix Aconiti Lateralis Preparata (Fu Zi, treated with hot strong base to reduce toxicity) [12,13].
The dried tuber of Corydalis yanhusuo (Papaveraceae) is one of key ingredients in NPI-025. C. yanhusuo has been used traditionally to promote blood circulation, reinforce vital energy, and alleviate pain such as headache, chest pain, epigastric pain, abdominal pain, backache, arthralgia, dysmenorrheal pain, or trauma, and is officially listed in the Chinese Pharmacopoeia [14,15,16]. Previous phytochemical and pharmacological studies have identified several alkaloids as the active secondary metabolites of the plant [16]. dl-Tetrahydropalmatine (dl-THP), one of the major active alkaloids, has been found to be a neuroactive alkaloid [17,18,19]. It has been listed in the Chinese Pharmacopoeia since 1977 as an analgesic with sedative and hypnotic effects. Recent studies have demonstrated that l-THP inhibits opiate tolerance and withdrawal syndromes in rats [20,21]. It was also reported that l-THP significantly inhibits cocaine- or methamphetamine-induced conditioned place preference [22,23]. In addition, l-THP inhibited cocaine-triggered reinstatement [24] and the rewarding effects of cocaine in rats as measured by cocaine self-administration [24,25] and intracranial self-stimulation [25]. In a recent double-blind clinical trial in China, Yang et al. [10] found that treatment of 119 heroin-only dependent in-patients with l-THP (60 mg orally twice a day) for one month significantly reduced heroin craving and withdrawal symptoms. These findings suggest that l-THP could be an excellent drug candidate for treatment of drug addition.
As part of our ongoing investigation of alternative therapies for substance addiction [11, 26], we initiated a comprehensive fractionation study guided by dopamine receptor binding assays in an attempt to find new dopamine receptor agonists or antagonists from C. yanhusuo. Herein we report the isolation of eight isoquinoline alkaloids, their D1 receptor binding activities and their stereochemistry by chiral HPLC method.

Results and Discussion

The 70% aqueous acetone extract of C. yanhusuo were subjected to sequential extraction with hexane, ethyl acetate, butanol, methanol and water. In our initial biological study as shown in Table 1, the hexane, ethyl acetate, butanol and methanol extracts at 50 mg/mL showed moderate binding activity at rat dopamine D1 receptor (rD1R) stably expressed in CHO cells, compared with the positive control SKF82958 [27] (10 μM), while the water extract had no activity.
Table 1. Displacement of [3H]SCH 23390 binding to membranes of CHO cells stably expressing the rD1R.
Table 1. Displacement of [3H]SCH 23390 binding to membranes of CHO cells stably expressing the rD1R.
Sample I.D.ConcentrationDisplaced [3H]SCH 23390
hexane extract50 mg/mL100%
AcOEt extract50 mg/mL96%
BuOH extract50 mg/mL97%
MeOH extract50 mg/mL88%
water extract50 mg/mL-2%
SKF8295810 μM99%
The hexane, ethyl acetate, butanol and methanol extracts were chromatographed on silica gel columns to give eight known isoquinoline alkaloids (Figure 1), tetrahydropalmatine (1) [28], isocorypalmine (2) [28], stylopine (3) [29], corydaline (4) [30], columbamine (5) [31], coptisin (6) [31], 13-methylpalmatine (7) [31] and dehydrocorybulbine (8) [32]. The tertiary alkaloids 1, 2 and 3 have a chiral center at the C-14 position, and may consist of two optical isomers. Compound 4 has two chiral centers at the C-13 and C-14 positions, and the 1H-NMR spectrum of 4 displayed the H-14 methine as a doublet at δ 3.68 (J = 2.7 Hz), indicating the protons at H-13 and H-14 are cis oriented [30]. Following the reported method [17,18], compounds 1, 2, 3 and 4 were analyzed by chiral HPLC. As shown in Table 2, the ratios of d- and l-isomers of 1, 3 and 4 are 3:1, 1:10 and 10:1, respectively, while 2 gave only one peak in its chiral HPLC (Figure 2). In order to further confirm the stereochemistry of 2, l-2 was synthesized by demethylation of l-THP (l-1) with BBr3 in CH2Cl2 (Scheme 1). The reaction time is critical for a good yield. After one hour, the main product was l-2, while after 2 h the main product was found to be the l-scoulerine (9). Compounds l-2 and 9 were difficult to be separated by silica gel column chromatography. However, based on its solubility, l-2 can be readily purified by recrystalization from methanol. Following the same synthetic procedure, dl-2 was also prepared from dl-THP (dl-1). Comparison of the chiral HPLC chromatogram of 2 with those of l-2 and dl-2 (Figure 2) confirmed that compound 2 was the l-enantiomer.
Scheme 1. Synthesis of l-2 from l-1.
Scheme 1. Synthesis of l-2 from l-1.
Molecules 13 02303 g003
Figure 1. Isoquinoline alkaloids isolated from C. yanhusuo.
Figure 1. Isoquinoline alkaloids isolated from C. yanhusuo.
Molecules 13 02303 g001
Figure 2. Chromatograms obtained from chiral separation of 2 (A), synthetic l-2 (B) and dl-2 (C).
Figure 2. Chromatograms obtained from chiral separation of 2 (A), synthetic l-2 (B) and dl-2 (C).
Molecules 13 02303 g002
HPLC conditions: Waters 1525 Binary HPLC Pump; Waters 2487 Dual λ Absorbance Detector; Chiralcel OD Column (4.6 x 250 mm); 50% EtOH as mobile phase; Wavelength, 230 nm; Sample concentration, 0.5 mg/mL; Injection volume, 5 µL
The isolated alkaloids were tested for dopamine receptor binding as reported previously [11]. Compounds 1, 2, 3, 5, 7 and 8 inhibited [3H]SCH 23390 binding to human D1 receptor (hD1R) by more than 50% at 10 μM, and their binding affinities were determined (Table 2). The l-enantiomer of 1 (l-THP) has a D1 affinity of 94 nM while the 3:1 mixture of the d- and l-enantiomers 1 has a much weaker affinity of 1.3 μM. It has been reported that l-1 has analgesic activity with a more potent tranquilizing effect than the d isomer [19, 33]. Previous studies have demonstrated that l-1 acts on dopamine receptors, but d-THP does not [34, 35]. Compound l-1 is a non-subtype selective antagonist at dopamine receptors[35,36,37].
Of the isolated alkaloids, compound 2 has the highest D1 affinity with a Ki of 83 nM, comparable in potency to l-1. Jin et al. [35, 37] reported that l-THP derivatives with one hydroxyl group at C-2 and two hydroxyl groups at C-2 and C-9 or C-2 and C-10 were more potent at dopamine receptors than l-1. On the other hand, Guo et al. [38] reported that l-1 was readily metabolized to desmethylated l-THPs in rats.
Table 2. Binding affinities of the purified alkaloids for the [3H] SCH 23390 labeled the hD1R in transiently transfected HEK-T cells.
Table 2. Binding affinities of the purified alkaloids for the [3H] SCH 23390 labeled the hD1R in transiently transfected HEK-T cells.
Compoundratio of d:l-isomersKi (nM)a
13:11,293 ± 71
20:183 ± 5
31:101,043 ± 66
5-4,112 ± 274
7-3,867 ± 235
8-1,836 ± 200
l-THP0:194 ± 9
a Each value represents the mean ± SEM of three independent experiments performed in duplicate
As shown in Table 2, the quaternary alkaloids (5 and 6) exhibited weaker binding affinities than the corresponding tertiary alkaloids (2 and 3). Comparison of the binding affinities of 7 and 8 with that of 5 revealed that the methyl group at C-13 did not affect the overall binding activity at the D1 receptor.
In order to obtain enough pure alkaloids for biological and pharmacological studies, another larger batch of crude extract of C. yanhusuo was fractionated. Compounds 1, 2, 3 and 4 were isolated from the new extract. Subsequent chiral HPLC analysis showed that the ratios of d- and l-enantiomers in newly isolated 2 and 3 remained the same as those of previous isolated 2 and 3, while the ratios in both 1 and 4 were changed to 1:1. The changes of these components in different extracts of C. yanhusuo indicated that different geographical regions, seasons of harvest, storage, or extraction conditions could affect the chemical composition significantly. As evidenced in our case, quality control of the active optical isomers will be very important for future biological, pharmacological, and clinical studies of C. yanhusuo.


The mesolimbic dopaminergic system has been shown to play an important role in drug abuse [39]. Compounds targeted to these dopamine receptors can provide a rational treatment of drug abuse [40]. The stereochemistry of l-isocorypalmine (2) and the d/l ratio of 1, 3, and 4, were established unambiguously by using a chiral HPLC method along with concise chemical synthesis. In addition, this convenient and effective synthesis for selective cleavage the methoxy group at C-2 position allows the preparation of l-isocorypalmine in a large amount from readily available l- tetrahydropalmatine for animal study. The present study demonstrates that isoquinoline alkaloids are the principal constituents for the binding activities of C. yanhusuo extracts at the dopamine D1 receptor. l-Isocorypalmine (2) showed the highest affinity and is a promising drug candidate. This study provides an important pharmacological basis to support the traditional use of C. yanhusuo in the treatment of heroin addiction in China. Its complete pharmacological characterization is under investigation and will be reported in due course.



The NMR spectra were recorded on a Varian VXR300 spectrometer with TMS as the internal standard. EI-MS spectra were obtained on a HP5972 Series Mass spectrometer. HPLC was performed on a Waters (Milford, MA, USA) system comprised of a 1525 Binary HPLC Pump equipped with a Waters 2487 Dual λ Absorbance Detector set at a wavelength of 230 nm, a model 7725i sample injector equipped with a 5 μL loop and a Waters Breeze software package for data collection. Compounds were separated on a Chiralcel OD Column (4.6 x 250 mm). The mobile phase was 50:50 (v/v) ethanol–water. All analysis was performed at a flow-rate of 0.5 mL/min with detection at 230 nm. The mobile phase was filtered through a 0.45 μm filter and degassed. Separations were performed at room temperature. Silica gel (Fisher Scientific, USA) were used for column chromatography. TLC was performed on precoated silica gel 60 F254 plates (Merck, Germany).

Plant material

The dried tubers of C. yanhusuo were collected from Qianxian Town, Dongyang District, Zhejiang province, P.R. China in May, 2005. Its botanical identification was confirmed by Dr. Shilin Chen, the Institute of Medicinal Plant Development (IMPLAD), Beijing, P.R. China. A voucher specimen has been deposited in the IMPLAD, Beijing, P.R. China.

Extraction and isolation

The dried tubers of C. yanhusuo (30 kg) were powdered and extracted with 70% aqueous acetone for three times at room temperature, and the solution was evaporated under reduced pressure to give a residue (2.2 kg). The 70% aqueous acetone extract (200 g) was subjected to sequential extraction with hexane, ethyl acetate, butanol, methanol and water. The combined part (3 g) of the above hexane, ethyl acetate and butanol extracts was chromatographed over silica gel (100 g) using CH2Cl2 with increasing amounts of MeOH (10:1, 5:1, 3:1, 1:1 and 1:2) to give five fractions A-E. Fraction A was further purified by silica gel column, with a gradient of hexane and acetone to afford 1 (20 mg), 2 (15 mg), 3 (10 mg) and 4 (15 mg). Fraction B was chromatographed over silica gel column with a gradient of CH2Cl2 and MeOH to afford 5 (10 mg), 7 (250 mg) and 8 (3 mg). Fraction C was purified by silica gel column, with a gradient of CH2Cl2 and MeOH, to afford 6 (8 mg). In a similar manner, the MeOH extract (8 g) was separated by silica gel column chromatography using CH2Cl2 with increasing amounts of MeOH to give 5 (20 mg) and 7 (500 mg).

Synthesis of l-isocorypalmine (2)

To a stirred CH2Cl2 solution (10 mL) of l-tetrahydropalmatine (l-1, 355 mg, 1.0 mmol), BBr3 solution (1 mM in CH2Cl2, 5 mL) was added. The reaction was stirred at -78 ºC for 1 h, and then was warmed to room temperature. The mixture was diluted with CH2Cl2 (50 mL) and washed with excess saturated NaHCO3. The organic extract was dried (MgSO4), filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (CH2Cl2 and MeOH, 20:1), followed by recrystallization in MeOH, to give l-2 (150 mg) and l-scoulerine (9, 40 mg).

Competitive inhibition of [3H] SCH23390 binding to dopamineD1 receptor

Chinese hamster ovary cells (CHO) stably transfected with HA-tagged rat D1 dopamine receptor (rD1R) were grown in 100-mm culture dishes in Dulbecco's modified Eagle's medium F12 HAM supplemented with 10% fetal calf serum, 0.1 mg/mL hygromycin B, 100 units/mL penicillin and 100 µg/mL streptomycin in a humidified atmosphere consisting of 5% CO2 and 95% air at 37°C. Binding to membranes prepared from CHO cells stably transfected with the rD1R was conducted with [3H]SCH23390 (0.2 nM) in 50mMTris-HCl buffer containing 1 mM EGTA (pH 7.4) (TE buffer) at room temperature for 1 h in duplicate. Nonspecific binding was defined as binding in the presence of Fluphenazine (10 μM). The purified compounds showing more than 50% displacement of [3H]SCH23390 at 10 μM were further tested for the affinity (Ki) by using GRAPHPAD PRISM.


This work was supported by Center of Excellence Research Program (P01-AT-002038-04, NCCAM/NIAAA) to D.Y.L.

References and Notes

  1. Lemonick, M.D.; Park, A. The Science of Addiction. Time 2007, 170, 42–48. [Google Scholar]
  2. Kreek, M.J.; Bart, G.; Lilly, C.; Laforge, K.S.; Nielsen, D.A. Pharmacogenetics and Human Molecular Genetics of Opiate and Cocaine Addictions and Their Treatments. Pharmacol. Rew. 2005, 57, 1–26. [Google Scholar]
  3. Bubar, M.J.; Cunningham, K.A. Serotonin 5-HT2A and 5-HT2C Receptors as Potential Targets for Modulation of Psychostimulant Use and Dependence. Curr. Topics Med. Chem. 2006, 6, 1971–1985. [Google Scholar] [CrossRef]
  4. Lukas, S.E.; Penetar, D.; Berko, J.; Vicens, L.; Palmer, C.; Mallya, G.; Macklin, E.A.; Lee, D.Y.W. An Extract of the Chinese Herbal Root Kudzu Reduces Alcohol Drinking by Heavy Drinkers in a Naturalistic Setting. Alcohol. Clin. Exp. Res. 2005, 29, 756–762. [Google Scholar] [CrossRef]
  5. Tracqui, A.; Kintz, P.; Ludes, B. Buprenorphine-related Deaths among Drug Addicts in France: A Report on 20 Fatalities. J. Anal. Toxicol. 1998, 22, 430–434. [Google Scholar] [CrossRef]
  6. Reynaud, M.; Petit, G.; Potard, D.; Courty, P. Six Deaths Linked to Concomitant Use of Buprenorphine and Benzodiazepines. Addiction 1998, 93, 1385–1392. [Google Scholar]
  7. Gaulier, J. M.; Marquet, P.; Lacassie, E.; Dupuy, J. L.; Lachatre, G. Fatal Intoxication Following Self-administration of A Massive Dose of Buprenorphine. J. Forensic Sci. 2000, 45, 226–228. [Google Scholar]
  8. Seifert, J.; Metzner, C.; Paetzold, W.; Borsutzky, M.; Ohlmeier, M.; Passie, T.; Hauser, U.; Becker, H.; Wiese, B.; Emrich, H. M.; Schneider, U. Mood and Affect During Detoxification of Opiate Addicts: A Comparison of Buprenorphine Versus Methadone. Addict. Biol. 2005, 10, 157–164. [Google Scholar] [CrossRef]
  9. Tang, Y.L.; Zhao, D.; Zhao, C.; Cubells, J.F. Opiate Addiction in China: Current Situation and Treatments. Addiction 2006, 101, 657–665. [Google Scholar] [CrossRef]
  10. Yang, Z.; Chen, H.; Hao, W.; Jin, G.; Li, S. Medication of L-tetrahydropalmatine Increased the Abstinence Rate in Heroin Addicts. In Abstracts of Papers - 68th Annual Scientific Meeting of the College on Problems of Drug Dependence, Scottsdale, AZ; The College on Problems of Drug Dependence: Arizona, USA, 2006; Abstract #109. [Google Scholar]
  11. Ma, Z.; Xu, W.; Liu-Chen, L.Y.; Lee, D.Y.W. Novel Coumarin Glycoside and Phenethyl Vanillate from Notopterygium forbesii and Their Binding Affinities for Opioid and Dopamine Receptors. Bioorg. Med. Chem. 2008, 16, 3218–3223. [Google Scholar] [CrossRef]
  12. Yang, M.M.P.; Yuen, R.C.F.; Kok, S.H. Experimental Studies on the Effects of Certain Chinese Herbs on Morphine Withdrawal Syndrome in Rats. J. Amer. Coll. Trad. Chin. Med. 1983, 2, 3–24. [Google Scholar]
  13. Yang, M.M.P.; Yuen, R.C.F.; Kok, S.H. Experimental Studies on the Effects of Certain Chinese Herbs on Drug Addiction. In Advances in Chinese Medicinal Material Research; Chang, H.M., Yeung, H.W., Tao, W., Koo, A., Eds.; World Scientific Publ. Co. Pte. Ltd.: Singapore, 1985; pp. 147–158. [Google Scholar]
  14. Ling, H.; Wu, L.; Li, L. Corydalis yanhusuo Rhizoma Extract Reduces Infarct Size and Improves Heart Function during Myocardial Ischemia/Reperfusion by Inhibiting Apoptosis in Rats. Phytother. Res. 2006, 20, 448–453. [Google Scholar] [CrossRef]
  15. Fan, Z.C.; Xie, C.J.; Zhang, Z.Q. Simultaneous Quantitation of Tetrahydropalmatine and Protopine in Rabbit Plasma by HPLC–PAD, and Application to Pharmacokinetic Studies. Chromatographia 2006, 64, 577–581. [Google Scholar] [CrossRef]
  16. Ding, B.; Zhou, T.; Fan, G.; Hong, Z.; Wu, Y. Qualitative and Quantitative Determination of Ten Alkaloids in Traditional Chinese Medicine Corydalis yanhusuo W.T. Wang by LC–MS/MS and LC–DAD. J. Pharm. Biomed. Anal. 2007, 45, 219–226. [Google Scholar] [CrossRef]
  17. Hong, Z.; Fan, G.; Chai, Y.; Yin, X.; Wu, Y. Stereoselective Pharmacokinetics of Tetrahydropalmatine after Oral Administration of (-)-Enantiomer and the Racemate. Chirality 2005, 17, 293–296. [Google Scholar] [CrossRef]
  18. Hong, Z.Y.; Fan, G.R.; Chai, Y.F.; Yin, X.P.; Wu, Y.T. Chiral Liquid Chromatography Resolution and Stereoselective Pharmacokinetic Study of Tetrahydropalmatine Enantiomers in Dogs. J. Chromatogr. B 2005, 826, 108–113. [Google Scholar] [CrossRef]
  19. Zhai, Z.D.; Shi, Y.P.; Wu, X.M.; Luo, X.P. Chiral High-performance Liquid Chromatographic Separation of the Enantiomers of Tetrahydropalmatine and Tetrahydroberberine, Isolated from Corydalis yanhusuo. Anal. Bioanal. Chem. 2006, 384, 939–945. [Google Scholar] [CrossRef]
  20. Jin, W.Q.; Zhang, H.P.; Chen, X.J.; Chi, Z.Q. Effects of Rotundine on Morphine Tolerance and Dependence. China Acad. J. Digest. 1998, 4, 1136–1142. [Google Scholar]
  21. Ge, X.Q.; Zhang, H.Q.; Zhou, H.Z.; Xu, Z.X.; Bian, C.P. Experimental Studies with Tetrahydropalmatine Analogs in Relieving Morphine Withdrawal Syndromes. Chin. J. Drug Depend. 1999, 8, 108–112. [Google Scholar]
  22. Ren, Y.H.; Zhu, Y.; Jin, G.Z.; Zheng, J.W. Levo-tetrahydropalmatine Inhibits the Expression of Methamphetamine-induced Conditioned Place Preference in Rats. Chin. J. Drug Depend. 2000, 9, 182–186. [Google Scholar]
  23. Luo, J.Y.; Ren, Y.H.; Zhu, R.; Lin, D.Q.; Zheng, J.W. The Effect of L-tetrahydropalmatine on Cocaine Induced Conditioned Place Preference. Chin. J. Drug Depend. 2003, 12, 177–179. [Google Scholar]
  24. Mantsch, J.R.; Li, S.J.; Risinger, R.; Awad, S.; Katz, E.; Baker, D.A.; Yang, Z. Levo-tetrahydropalmatine Attenuates Cocaine Self-administration and Cocaine-Induced Reinstatement in Rats. Psychopharmacology 2007, 192, 581–591. [Google Scholar] [CrossRef]
  25. Xi, Z.X.; Yang, Z.; Li, S.J.; Li, X.; Dillon, C.; Peng, X.Q.; Spiller, K.; Gardner, E.L. Levo-tetrahydropalmatine Inhibits Cocaine’s Rewarding Effects: Experiments with Self-administration and Brain-stimulation Reward in Rats. Neuropharmacology 2007, 53, 771–782. [Google Scholar] [CrossRef]
  26. Lee, D.Y.W.; Ma, Z.; Liu-Chen, L.Y.; Wang, Y.; Chen, Y.; Carlezon, W.A.; Cohen, B. New Neoclerodane Diterpenoids Isolated from the Leaves of Salvia divinorum and Their Binding Affinities for Human κ Opioid Receptors. Bioorg. Med. Chem. 2005, 13, 5635–5639. [Google Scholar] [CrossRef]
  27. Mannoury la Cour, C.; Vidal, S.; Pasteau, V.; Cussac, D.; Millan, M.J. Dopamine D1 Receptor Coupling to Gs/olf and Gq in Rat Striatum and Cortex: A Scintillation Proximity Assay (SPA)/antibody-capture Characterization of Benzazepine Agonists. Neuropharmacology 2007, 52, 1003–1014. [Google Scholar] [CrossRef]
  28. Cutter, P.S.; Miller, R.B.; Schore, N.E. Synthesis of Protoberberines Using A Silyl-directed Pictet–Spengler Cyclization. Tetrahedron 2002, 58, 1471–1478. [Google Scholar] [CrossRef]
  29. Chrzanowska, M. Synthesis of Isoquinoline Alkaloids. Total Synthesis of (±)-Stylopine. J. Nat. Prod. 1995, 58, 401–407. [Google Scholar] [CrossRef]
  30. Cushman, M.; Dekow, F.W. A Total Synthesis of Corydaline. Tetrahedron 1978, 34, 1435–1439. [Google Scholar] [CrossRef]
  31. Tong, S.; Yan, J.; Lou, J. Preparative Isolation and Purification of Alkaloids from Corydalis yanhusuo W. T. Wang by High Speed Counter-Current Chromatography. J. Liq. Chromatogr. Relat. Technol. 2005, 28, 2979–2989. [Google Scholar] [CrossRef]
  32. Tani, C.; Tagahara, K.; Aratani, S. Studies on the Alkaloids of Papaveraceous Plants. XXIII. Alkaloids of Corydalis nokoensis Hayata. Yakugaku Zasshi 1976, 96, 527–532. [Google Scholar]
  33. Chin, K. C.; Cheng, H. F.; Hsu, B. The Pharmacological Activity of Corydalis. XII. The Effects of Optical Isomers of Tetrahydropalmatine (THP) on Central Nervous System. Acta Physiol. Sin. 1964, 27, 47–58. [Google Scholar]
  34. Xuan, J.C.; Lin, G.D.; Jin, G.Z.; Chen, Y. Relevance of Stereo and Quantum Chemistry of Four Tetrahydroprotoberberines to Their Effects on Dopamine Receptors. Acta Pharmacol. Sin. 1988, 9, 197–205. [Google Scholar]
  35. Jin, G.Z. (-)-Tetrahydropalmatine and Its Analogs as New Dopamine Receptor Antagonists. Trends Pharmacol. Sci. 1987, 8, 81–82. [Google Scholar] [CrossRef]
  36. Xu, S.X.; Yu, L.P.; Han, Y.P.; Chen, Y.; Jin, G.Z. Effects of Tetrahydroprotoberberines on Dopamine Receptor Subtypes in Brain. Acta Pharmacol. Sin. 1989, 10, 104–110. [Google Scholar]
  37. Guo, X.; Wang, L. M.; Liu, J.; Jin, G.Z. Characteristics of Tetrahydroprotoberberines on Dopamine D1 and D2 Receptors in Calf Striatum. Acta Pharmacol. Sin. 1997, 18, 225–230. [Google Scholar]
  38. Li, L.; Ye, M.; Bi, K.; Guo, D. Liquid Chromatography-tandem Mass Spectrometry for the Identification of L-tetrahydropalmatine Metabolites in Penicillium janthinellum and Rats. Biomed. Chromatogr. 2006, 20, 95–100. [Google Scholar] [CrossRef]
  39. Shippenberg, T.S.; Bals-Kubik, R.; Herz, A. Examination of the Neurochemical Substrates Mediating the Motivational Effects of Opioids: Role of the Mesolimbic Dopamine System and D-1 vs. D-2 Dopamine Receptors. J. Pharmacol. Exp. Ther. 1993, 265, 53–59. [Google Scholar]
  40. Zhang, A.; Neumeyer, J.L.; Baldessarini, R.J. Recent Progress in Development of Dopamine Receptor Subtype-Selective Agents: Potential Therapeutics for Neurological and Psychiatric Disorders. Chem. Rev. 2007, 107, 274–302. [Google Scholar] [CrossRef]
  • Sample Availability: Samples of are available from authors.

Share and Cite

MDPI and ACS Style

Ma, Z.-Z.; Xu, W.; Jensen, N.H.; Roth, B.L.; Liu-Chen, L.-Y.; Lee, D.Y.W. Isoquinoline Alkaloids Isolated from Corydalis yanhusuo and Their Binding Affinities at the Dopamine D1 Receptor. Molecules 2008, 13, 2303-2312.

AMA Style

Ma Z-Z, Xu W, Jensen NH, Roth BL, Liu-Chen L-Y, Lee DYW. Isoquinoline Alkaloids Isolated from Corydalis yanhusuo and Their Binding Affinities at the Dopamine D1 Receptor. Molecules. 2008; 13(9):2303-2312.

Chicago/Turabian Style

Ma, Zhong-Ze, Wei Xu, Niels H. Jensen, Bryan L. Roth, Lee-Yuan Liu-Chen, and David Y. W. Lee. 2008. "Isoquinoline Alkaloids Isolated from Corydalis yanhusuo and Their Binding Affinities at the Dopamine D1 Receptor" Molecules 13, no. 9: 2303-2312.

Article Metrics

Back to TopTop