Antihypertensive effects of DL-tetrahydropalmatine: an active principle isolated from Corydalis

NMDA Receptor Modulation in COVID-19-Associated Acute Respiratory Syndrome in both In Silico and In Vitro Approach

The normal function of the N-methyl D-aspartate receptors (NMDAR) in human lungs depends on precisely regulated synaptic glutamate levels. Pathophysiology of the lungs is brought on by the changes in homeostasis of glutamate in the synapsis that leads to abnormal NMDAR activity. Severe acute respiratory syndrome (SARS) primarily results in lung infections, particularly lung muscle stiffening, and NMDA receptor potentiation may increase calcium ion influx and support downstream signaling mechanisms. Hence, NMDAR modulators that depend on glutamate levels could be therapeutically useful medications with fewer unintended side effects. A compound called THP (tetrahydropalmatine) that amplifies Ca2+ influx and potentiates NMDA receptors has been identified in the current study. In asthmatic human airway smooth muscle (HASM) cells, THP regulates the NMDA receptor and helps in asthmatic ASM contraction, and the pharmacological stimulation of ASM depends on both brain and respiratory NMDA receptors. Glutamate potency is altered by this substance without any voltage-dependent side effects. Additionally, a GGPP (geranylgeranyl pyrophosphate)-dependent mechanism of THP reduced the production of pro-inflammatory cytokines in ASM. THP is distinctive in terms of its chemical makeup, functioning, and agonist concentration-dependent and allosteric modulatory activity. To treat COVID-19-related SARS, THP, or any future-related compounds will make good drug-like molecule candidates.

Antihypertensive Effects of Aqueous Extract of Ricinodendron heudelotii (Baill.) Pierre (Euphorbiaceae) in Wistar Rat

Ricinodendron heudelotii stem bark is commonly used in Cameroonian traditional medicine to treat cardiovascular diseases such as hypertension. The present study was designed to investigate the antihypertensive and antioxidant properties of the aqueous extract of Ricinodendron heudelotii in salt-induced hypertensive rats. Analysis by HPLC-ESI-Q-TOF-MS was used to identify various chemical components of the extract. A total of thirty rats were used for each test. High-salt hypertension was induced in rats by oral administration of NaCl for 12 weeks. Mean blood pressure (MBP) and heart rate (HR) were monitored by noninvasive methods. Oral administration of Ricinodendron heudelotii significantly ( $p<0.01$ ) reduced the increase of mean blood pressure (23.12%, 26.14%, and 24.34%) and heart rate (31.19%, 31.09%, and 26.98%), respectively, at the doses of 40, 20, and 6 mg/kg, compared to the hypertensive group. All the doses tested significantly reduced or/and ameliorated biochemical and oxidative stress parameters. Histological analysis showed that Ricinodendron heudelotii restored renal disorders induced by the administration of salt. The aqueous extract of Ricinodendron heudelotii exerts a cardioprotective effect, and the antihypertensive activity seems associated with an improvement in antioxidant status. Overall, the results justify and support the traditional use of Ricinodendron heudelotii.

A computational workflow for the expansion of heterologous biosynthetic pathways to natural product derivatives

Plant natural products (PNPs) and their derivatives are important but underexplored sources of pharmaceutical molecules. To access this untapped potential, the reconstitution of heterologous PNP biosynthesis pathways in engineered microbes provides a valuable starting point to explore and produce novel PNP derivatives. Here, we introduce a computational workflow to systematically screen the biochemical vicinity of a biosynthetic pathway for pharmaceutical compounds that could be produced by derivatizing pathway intermediates. We apply our workflow to the biosynthetic pathway of noscapine, a benzylisoquinoline alkaloid (BIA) with a long history of medicinal use. Our workflow identifies pathways and enzyme candidates for the production of (S)-tetrahydropalmatine, a known analgesic and anxiolytic, and three additional derivatives. We then construct pathways for these compounds in yeast, resulting in platforms for de novo biosynthesis of BIA derivatives and demonstrating the value of cheminformatic tools to predict reactions, pathways, and enzymes in synthetic biology and metabolic engineering.

A Comparative Pharmacokinetic Profile of Trahydropalmatine After Oral Administration of its Monomer, Rhizoma Corydalis Alkaloid Extracts and Tong-Bi-Si-Wei-Fang to Rats

Background:

Tong-Bi-Si-Wei-Fang (TBSWF) is a candidate formula of Traditional Chinese Medicine (TCM) for treating rheumatoid bone diseases, which is composed of rhizoma corydalis alkaloids, saponins of glycyrrhiza uralensis and panax notoginseng, flavonoids of rhizoma drynariae and glycyrrhiza uralensis. </P><P> Objective: Trahydropalmatine (THP), the main active ingredient of rhizoma corydalis alkaloids, was selected to study in vivo pharmacokinetics and druggability of TBSWF.

Methods:

The plasma concentration-time (C-T) profiles of THP and the pharmacokinetic property parameters after oral administration of THP monomer, extract of corydalis alkaloids (ECA) and TBSWF to rats, respectively were compared by a fully-validated HPLC method.

Results:

Compared to the THP monomer, the THP in TBSWF is absorbed faster, resides in the plasma longer and has a similar apparent volume of distribution Vz/F (10~20 L/kg). Compared to THP monomer and THP in TBSWF, the area under the concentration-time curve AUC 0-t of THP in ECA decreases two-third; Vz/F of THP in ECA (85.02 L/kg) is significantly higher than that of THP in TBSWF(p <0.05). Unlike THP monomer and THP in ECA, double peaks are observed in the C-T profile of THP after oral administration of TBSWF. THP in TBSWF exhibits slow release to a certain degree.

Conclusion:

The interactions among the ingredients of TBSWF promote the adsorption and prolong the residence time of THP in vivo, and provide an explanation for the advantages of TBSWF from the point of pharmacokinetics.

A Randomized, Double-Blind, Multicenter, Placebo-Controlled Trial of Qi-Zhi-Wei-Tong Granules on Postprandial Distress Syndrome-Predominant Functional Dyspepsia

Background:

Functional dyspepsia (FD) is a common upper gastrointestinal disorder worldwide, but the current treatments for FD are still unsatisfactory. The aims of this study were to investigate the efficacy and safety of Qi-Zhi-Wei-Tong granules in patients with postprandial distress syndrome (PDS)-predominant FD.

Methods:

The study was conducted as a randomized, double-blinded, multicenter, placebo-controlled design in 197 patients with PDS. All participants received placebo treatment for 1 week. Patients whose total symptom score decreased by <50% after the placebo treatment were recruited into the 4-week treatment period, in which they were randomly assigned to be treated with either Qi-Zhi-Wei-Tong granules or placebo. The patients were then followed for 2 weeks without any treatment. Dyspeptic symptoms were scored at weeks 2 and 4 during the random treatment period and 2 weeks after the treatment. Anxiety and depression symptoms were also scored and compared.

Results:

(1) The total effective rates in the Qi-Zhi-Wei-Tong granules group at weeks 2 and 4 during the random treatment period and 2 weeks after treatment were all significantly higher than those in the placebo group (38.82% vs. 8.75%, P < 0.001; 69.14% vs. 16.25%, P < 0.001; 77.65% vs. 21.25%, P < 0.001). (2) The total dyspeptic symptoms scores in the Qi-Zhi-Wei-Tong granules group at weeks 2 and 4 and 2 weeks after treatment were significantly lower than those in the placebo group. (3) The severity and frequency of each dyspeptic symptom at weeks 2 and 4 and the follow-up period were all significantly lower than those in the placebo group. (4) The anxiety scores in the Qi-Zhi-Wei-Tong granules group were significantly lower than those in the placebo group. (5) Qi-Zhi-Wei-Tong granules did not have more adverse effects than the placebo.

Conclusion:

Qi-Zhi-Wei-Tong granules offer significant symptomatic improvement in PDS with no more adverse effects than placebo.

Trial Registration:

https://clinicaltrials.gov/, NCT02460601.

Development and Validation of a HPLC-ESI-MS/MS Method for Simultaneous Quantification of Fourteen Alkaloids in Mouse Plasma after Oral Administration of the Extract of Corydalis yanhusuo Tuber: Application to Pharmacokinetic Study

The tuber of Corydalis yanhusuo is a famous traditional Chinese medicine and found to have potent pharmacological effects, such as antinociceptive, antitumor, antibacterial, anti-inflammatory, and anti-depressive activities. Although there are several methods to be developed for the analysis and detection of the bioactive ingredients’ alkaloids, so far, only few prominent alkaloids could be quantified, and in vitro and in vivo changes of comprehensive alkaloids after oral administration are still little known. In this study, we first developed a simple and sensitive high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method to quantify the comprehensive alkaloids of extracts of C. yanhusuo in mouse plasma, using nitidine chloride as an internal standard. As results, at least fourteen alkaloids, including an aporphine (oxoglaucine), a protopine (protopine), five tertiary alkaloids (corydaline, tetrahydroberberine, tetrahydropalmatine, tetrahydrocolumbamine, and tetrahydrocoptisine) and seven quaternary alkaloids (columbamine, palmatine, berberine, epiberberine, coptisine, jatrorrhizine, and dehydrocorydaline) could be well quantified simultaneously in mouse plasma. The lower limits of quantification were greater than, or equal to, 0.67 ng/mL, and the average matrix effects ranged from 96.4% to 114.3%. The mean extraction recoveries of quality control samples were over 71.40%, and the precision and accuracy were within the acceptable limits. All the analytes were shown to be stable under different storage conditions. Then the established method was successfully applied to investigate the pharmacokinetics of these alkaloids after oral administration of the extract of Corydalis yanhusuo in mice. To the best of our knowledge, this is the first document to report the comprehensive and simultaneous analyses of alkaloids of C. yanhusuo in mouse plasma. It was efficient and useful for comprehensive pharmacokinetic and metabolomic analyses of these complex alkaloids after drug administration.

Asymmetric synthesis of isoquinolinonaphthyridines catalyzed by a chiral Brønsted acid

A catalytic asymmetric method for the synthesis of chiral isoquinolinonaphthyridines has been developed. A chiral disulfonimide catalyzes a redox cyclization reaction between 2-methyl-3-aldehydeazaarenes and 1,2,3,4-tetrahydroisoquinolines to deliver a range of isoquinolinonaphthyridines with good to high yields (up to 91%) and up to 92 : 8 er.

Antihypertensive and cardioprotective effects of Cerebralcare granule® on spontaneously hypertensive rats from the perspective of the gaseous triumvirate NO-CO-H2S system

Cerebralcare granule(®) (CG) has been reported to have hypotensive effect. However, several pathways involved in the mechanism of hypotension are still unclear. This study was designed to verify the antihypertensive effect of CG and to characterize its mechanism of action, especially from the perspective of gasotrasmmiter NO/cGMP, CO/HO and H2S/CSE systems. By using the widely used in vitro model of rat isolated thoracic aortic rings, the vasorelaxant effect of CG were studied. Furthermore, we assessed the chronic hypotensive effect of CG on spontaneously hypertensive rats (SHRs) and further to explore the potential mechanisms of its antihypertensive activity. Data in the present study demonstrated that oral treatment with CG could induce a potent antihypertensive effect. CG could reduce the intima-media thickness (IMT) of thoracic aorta significantly and increase the serum NO and H2S levels. In addition, the present results indicated that CG played a critical protective role against pressure overload-induced cardiac hypertrophy. CG not only inhibited the development of cardiac hypertrophy but also improved ventricular function. In vitro, the results showed that CG induced relaxation in rat aortic rings through an endothelium-dependent pathway mediated by NO/cGMP, CO/HO and H2S/CSE systems. Taken together, the present study demonstrated that CG could induce a potent antihypertensive effect that was partly due to the improvement of endothelial function. Also CG played a critical protective role against pressure overload-induced cardiac hypertrophy. In addition, CG could induce relaxation in rat aortic rings.

Levo-Tetrahydropalmatine Attenuates Bone Cancer Pain by Inhibiting Microglial Cells Activation

Objective. The present study is to investigate the analgesic roles of L-THP in rats with bone cancer pain caused by tumor cell implantation (TCI). Methods. Thermal hyperalgesia and mechanical allodynia were measured at different time points before and after operation. L-THP (20, 40, and 60 mg/kg) were administrated intragastrically at early phase of postoperation (before pain appearance) and later phase of postoperation (after pain appearance), respectively. The concentrations of TNF-α, IL-1β, and IL-18 in spinal cord were measured by enzyme-linked immunosorbent assay. Western blot was used to test the activation of astrocytes and microglial cells in spinal cord after TCI treatment. Results. TCI treatment induced significant thermal hyperalgesia and mechanical allodynia. Administration of L-THP at high doses significantly prevented and/or reversed bone cancer-related pain behaviors. Besides, TCI-induced activation of microglial cells and the increased levels of TNF-α and IL-18 were inhibited by L-THP administration. However, L-THP failed to affect TCI-induced astrocytes activation and IL-1β increase. Conclusion. This study suggests the possible clinical utility of L-THP in the treatment of bone cancer pain. The analgesic effects of L-THP on bone cancer pain maybe underlying the inhibition of microglial cells activation and proinflammatory cytokines increase.

Synthesis of C3/C1-Substituted Tetrahydroisoquinolines

A broad biological screening of the natural alkaloid N-methylisosalsoline (2) extracted from Hammadascoparia leaves against a panel of human and parasitic proteases revealed an interesting activity profile of 2 towards human 20S proteasome. This outcome suggests that the 1,2,3,4-tetrahydroisoquinoline skeleton may be exploited as a template for the development of novel anticancer agents. In this article, we report the synthesis and chemical characterization of a new series of isosalsoline-type alkaloids (10–11) with variations at N2 and C3 positions with respect to the natural Compound 2, obtained by a synthetic strategy that involves the Bischler-Napieralski cyclization. The substrate for the condensation to the tetrahydroisoquinoline system, i.e., a functionalized β-arylethyl amine, was obtained through an original double reduction of nitroalkene. The synthetic strategy can be directed to the construction of highly substituted and functionalized 1,2,3,4-tetrahydroisoquinolines.

Efficacy and safety of Stephania glabra: an alkaloid-rich traditional medicinal plant

Stephania glabra (Roxb.) Miers (Menispermaceae) has long been used for the treatment of asthma, tuberculosis, dysentery, hyperglycaemia, cancer, fever, intestinal complaints, sleep disturbances and inflammation in many Asian countries. It mainly contains alkaloids and, until now, over 30 alkaloids such as bisbenzylisoquinolines, hasubanalactams, berberines and aporphines have been isolated from its tuber. Most of its traditional medicinal activities are scientifically approved by various in vitro and in vivo studies. It shows remarkable anti-psychotic, anti-diabetic, antipyretic, analgesic, antimicrobial and anti-hypertensive activities. This work includes comprehensive information on the ethnobotany, chemistry and pharmacology of S. glabra. This review also focuses on the future perspectives with main emphasis on the establishment of therapeutic index and safety index of the plant. This review concludes that S. glabra has a great potential to treat various diseases, and could be used as a source for novel healthcare products in the near future, which needs further studies.

Plasma pharmacokinetics and lung distribution of tetrahydropalmatine after topical application of cold asthma recipe extract: Feishu (BL 13) versus Non-Feishu acupoint

ETHNOPHARMACOLOGICAL RELEVANCE

Acupoint application of cold asthma recipe (CAR) was a traditional Chinese medicine (TCM) method, widely used as an alternative medicine for clinical prevention of the common winter diseases of asthma and bronchitis. Tetrahydropalmatine (THP) was a main active ingredient of CAR extract. The aim of this study is to compare plasma pharmacokinetics and lung distribution of THP between Feishu (FS) acupoint (BL 13) and Non-Feishu (NFS) acupoint application of CAR extract by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

MATERIALS AND METHODS

The extract of CAR was topically administrated in FS and NFS acupoint of rats for plasma pharmacokinetics, and topically administrated in FS and NFS acupoint of mice for lung distribution. The plasma and lung homogenates were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on an ACQUITY UPLC BEH C18 column with a mobile phase consisted of 0.1% formic acid in acetonitrile and 0.1% formic acid in water. The detection was accomplished by multiple-reaction monitoring (MRM) scanning in the positive electrospray ionization (ESI(+)) mode. All pharmacokinetic parameters were estimated by non-compartmental analysis.

RESULTS

A sensitive, accurate and precise UPLC-MS/MS method was successfully established for determination of THP in 100 μL plasma and lung homogenate. The lower limit of quantification (LLOQ) of THP was 0.05 ng/mL and 0.072 ng/mL, respectively. The pharmacokinetic results manifested that THP was absorbed and eliminated slowly in plasma. Additionally, it was found that there was significantly higher amount of THP absorbed into blood and lung after FS acupoint application compared to NFS acupoint application.

CONCLUSIONS

Both of the rat plasma pharmacokinetics and mice lung distribution of THP could support that FS acupoint application of CAR extract has greater advantages of absorption into the blood circulation and distribution in target tissue over NFS acupoint application. The results might be helpful in providing a rational explanation for why the TCM chose the acupoint application and elucidating the underlying mechanism of this treatment.

Comparative pharmacokinetics and bioavailability of four alkaloids in different formulations from Corydalis decumbens

ETHNOPHARMACOLOGICAL RELEVANCE

Corydalis decumbens, a Traditional Chinese Medicine listed in Chinese Pharmacopoeia, is clinically used for the treatment of paralytic stroke, headache, rheumatic arthritis and sciatica in China.

AIM OF THE STUDY

This study was aimed to compare the pharmacokinetics and bioavailability of protopine, tetrahydropalmatine, bicuculline, and egenine in three formulations prepared from the rhizomes of Corydalis decumbens.

MATERIALS AND METHODS

Alkaloid extract (CDAs-SFE) was prepared from the rhizomes of Corydalis decumbens by supercritical CO2 fluid extraction; CDAs-SFE/HPβCD (hydroxypropyl-β-cyclodextrin inclusion complex), and CDAs-SFE/HCl (hydrochloride freeze-dried powder) were resulted from CDAs-SFE through complexation with HPβCD and hydrochloride, respectively. An UFLC-MS/MS method was developed for quantitative analysis of protopine, tetrahydropalmatine, bicuculline and egenine simultaneously in rat plasma after oral administration. The differences of pharmacokinetics and bioavailability of the four alkaloids in three formulations were determined by pharmacokinetics analyses.

RESULTS AND CONCLUSIONS

The Cmax, AUC and bioavailability of protopine and tetrahydropalamatine (bioactive components) in CDAs-SFE/HCl were significantly higher than in CDAs-SFE and in CDAs-SFE/HPβCD. In contrast, in CDAs-SFE/HPβCD, AUC and bioavailability of tetrahydropalamatine were significantly lower, while those of bicuculline (toxic compound) appeared to be higher than both in CDAs-SFE and in CDAs-SFE/HCl. The results indicated that CDAs-SFE/HCl was the best beneficial formulation among the three formulations for the alkaloid extract prepared from the rhizomes of Corydalis decumbens, in which protopine and tetrahydropalamatine displayed higher bioavailability, but lower for bicuculline.

Phenols, Alkaloids and Terpenes from Medicinal Plants with Antihypertensive and Vasorelaxant Activities. A Review of Natural Products as Leads to Potential Therapeutic Agents

Numerous studies support the cardiovascular effects of medicinal plants. This review examines plants whose antihypertensive and vasorelaxant effects have been scientifically validated. Our study selected only chemically characterized plants whose mode of action had already been investigated. The aim of the paper is to provide a quick way to identify medicinal plants and their constituents with antihypertensive and vasorelaxant activities.

Antinociceptive effects of intragastric DL-tetrahydropalmatine on visceral and somatic persistent nociception and pain hypersensitivity in rats

Although tetrahydropalmatine (THP), an alkaloid constituent of plants from the genera Stephania and Corydalis, is known to have analgesic property, the antinociceptive effects of THP have not been well evaluated experimentally and the appropriate indications for treatment of clinical pain remain unclear. In the present study, nociceptive and inflammatory models of both somatic and visceral origins were used to assess the antinociceptive and antihyperalgesic effects of intragastric (i.g.) pretreatment of dl-THP in rats. In the bee venom (BV) test that has been well established experimentally, i.g. pretreatment of three doses of dl-THP (20, 40, 60 mg/kg, body weight) resulted in less stably antinociceptive effect on the BV-induced persistent paw flinches that are known to be processed by spinal nociceptive circuit, however the drug of the two higher doses produced distinct suppression of the BV-induced persistent nociception rated by nociceptive score that reflects both spinal and supraspinal mediation. Similarly, the antinociception of dl-THP (60 mg/kg) was only significant for phase 1 but not for phase 2 of the formalin-induced persistent paw flinches, however, the inhibition was distinct for both phase 1 and phase 2 of the formalin nociceptive score. For the antihyperalgesic effect, in contrast, pretreatment of dl-THP (60 mg/kg) produced significant inhibition of both primary hyperalgesia to either thermal or mechanical stimuli and the mirror-image thermal hyperalgesia identified in the BV test. In the acetic acid writhing test, the number of writhes was completely blocked at the first 5-min interval followed by a sustained suppression in the remaining period of the whole time course comparing to the vehicle control. These data suggest that i.g. pre-administration of dl-THP could more effectively inhibit visceral nociception as well as thermal and mechanical inflammatory pain hypersensitivity (hyperalgesia) than persistent nociception. Moreover, the drug is likely to produce more effectiveness on supraspinally processed nociceptive behaviors than spinally mediated nociceptive behaviors, implicating an action of THP at the supraspinal level.

Beneficial effects of the extract from Corydalis yanhusuo in rats with heart failure following myocardial infarction

As indicated in ancient Chinese medical books, Corydalis yanhusuo has therapeutic effects on cardiovascular diseases. The analgesic effect of this plant has been fully elucidated, and I-tetrahydropalmatine has been shown to be the main active principle. The aim of this investigation was to evaluate its protective effects in a rat heart failure model. Rats were subjected to coronary artery ligation, and orally administered with ethanolic extract of Corydalis yanhusuo 50, 100, or 200 mg kg−1 daily, from the 7th day after surgery. We measured cardiac function, plasma atrial natriuretic peptide (ANP), relative heart and lung weights, infarct size and ventricular dilatation after treatment for 8 weeks. Administration with Corydalis yanhusuo led to a significant reduction in infarct size and improvement in cardiac function as demonstrated by lower left ventricular end diastolic pressure (LVEDP) and elevated ± dp/dtmax. We also found that Corydalis yanhusuo significantly reduced left ventricular (LV)/body weight ratio, lung/body weight ratio and significantly inhibited neurohormonal activation. Taken together, this study indicated that Corydalis yanhusuo exerted salutary effects on heart failure induced by myocardial infarction in rats.

Salutary effects of Corydalis yanhusuo extract on cardiac hypertrophy due to pressure overload in rats

We have evaluated the effects of an alcohol extract from the rhizome of Corydalis yanhusuo W.T. (CY), a well-known traditional Chinese medicinal herb, on pressure-overloaded cardiac hypertrophy induced by transverse abdominal aorta constriction (TAAC) in rats. Rats were given vehicle or CY extract (200 or 50 mg kg−1 per day) from the second week after induction of pressure overload, for a period of 7 weeks. Haemodynamic parameters, relative heart weight and myocyte cross-sectional area were measured in each group. We also estimated left ventricular (LV) collagen volume fraction (CVF) using Masson trichrome staining, and type I collagen expression by Western blot assay. Chronic TAAC caused notable cardiac hypertrophy and heart dysfunction. Significant collagen deposition and greater type I collagen expression were found in model control rats. These changes were not significantly reversed after treatment with 50 mgkg−1 CY, whereas 200 mgkg−1 significantly improved heart function and prevented cardiac hypertrophy, with parallel reductions in myocardial fibrosis, as evidenced by reduced LV CVF and reduced levels of type I collagen. In conclusion, chronic treatment of rats with CY extract attenuated development of cardiac hypertrophy.

Quaternary alkaloid, pseudocoptisine isolated from tubers of Corydalis turtschaninovi inhibits LPS-induced nitric oxide, PGE(2), and pro-inflammatory cytokines production via the down-regulation of NF-kappaB in RAW 264.7 murine macrophage cells

It is well known that pro-inflammatory mediators like nitric oxide (NO), prostaglandin E(2) (PGE(2)), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) contribute to the courses of many inflammatory diseases. In the present study, the authors investigated the anti-inflammatory effects of pseudocoptisine, a quaternary alkaloid with a benzylisoquinoline skeleton, which was isolated from the tubers of Corydalis turtschaninovii by examining its inhibitory effects on pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated murine macrophage RAW 264.7 cells. Pseudocoptisine caused dose-dependent reductions in the levels of inducible nitric oxide (iNOS) and cyclooxygenase-2 (COX-2) at both protein and mRNA levels and concomitant decreases in PGE(2) and NO production. In addition, it was found that pseudocoptisine suppressed the production and mRNA expressions of inflammatory cytokines, such as, TNF-alpha and IL-6. Furthermore, molecular data revealed that pseudocoptisine inhibited the LPS-stimulated DNA binding activity and the transcription activity of nuclear factor-kappa B (NF-kappaB). Moreover, this effect was accompanied by decreases in the phosphorylation of inhibitory kappaB (IkappaB)-alpha and in the subsequent blocking of p65 subunit of NF-kappaB translocation to the nucleus. In addition, pseudocoptisine dose-dependently inhibited the phosphorylations of ERK and p38. Taken together, these results suggest that pseudocoptisine reduces levels of the pro-inflammatory mediators, such as, iNOS, COX-2, TNF-alpha, and IL-6 through the inhibition of NF-kappaB activation via the suppression of ERK and p38 phosphorylation in RAW 264.7 cells. These findings reveal in part the molecular basis for the anti-inflammatory properties of pseudocoptisine.

One-step purification of palmatine and its derivative dl-tetrahydropalmatine from Enantia chlorantha using high-performance displacement chromatography

Palmatine and its reduced form, dl-tetrahydropalmatine are a group of isoquinoline alkaloids that have been reported to display a variety of biological and pharmacological activities. Both drugs are hydrophilic and are difficult to be purified by conventional purification methods of natural products. A high-performance displacement chromatography (HPDC) method successfully purified palmatine and its semi-synthetic derivative dl-tetrahydropalmatine from crude extract of the African medicinal plant Enantia chlorantha. The crude extract from the root bark of E. chlorantha was fractionated on an analytical reversed-phase C(18) column by using 0.1% trifluoroacetic acid (TFA) or acetic acid/H2O as a carrier and cetylpyridinium trifluoroacetate (or acetate) (1.9mg/mL) in 0.1% TFA (or acetic acid)/H2O as a displacer. Palmatine was quantitatively purified at >98% purity in the fully developed displacement mode. dl-Tetrahydropalmatine was semi-synthesized by NaBH4 reduction from crude palmatine and directly purified by HPDC. Both palmatine and dl-tetrahydropalmatine were identified by high-resolution electrospray tandem mass spectrometry, (1)H NMR and (13)C NMR. This is the first report of one-step HPDC purification of natural and semi-synthetic products from a complex crude extract.

Chiral high-performance liquid chromatographic separation of the enantiomers of tetrahydropalmatine and tetrahydroberberine, isolated from Corydalis yanhusuo

HPLC methods have been developed for chiral resolution of the enantiomers of dl-tetrahydropalmatine (THP) and dl-tetrahydroberberine (THB), two active constituents of Corydalis yanhusuo W.T. Wang. On the analytical scale, good baseline separation of the enantiomers was achieved using cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases in both normal-phase and polar organic modes. Validation of the analytical methods, including linearity, limits of detection, recovery, and precision, and semipreparative resolution of dl-THP and dl-THB, were achieved with methanol as mobile phase, without any basic additives, in polar organic mode using cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases. On the semipreparative scale, small quantities of the individual enantiomers of THP and THB were isolated for study of the chiroptical properties of the individual enantiomers.

Suppressive Effects of JCICM-6, the Extract of an Anti-arthritic Herbal Formula, on the Experimental Inflammatory and Nociceptive Models in Rodents

JCICM-6, the extract of an anti-arthritic herbal formula composed of medicinal herbs of Sinomenium acutum, Aconitum carmichaeli DEBX., Curcuma Longa L., Paeonia lactiflora PALL., and Paeonia suffruticosa ANDR., was examined in the effectiveness and mechanism in reducing experimentally-induced inflammation and nociception using nine animal models. JCICM-6 was extracted from herbs and purified with Amberlite XAD-7HP adsorbent resin and analyzed with HPLC-fingerprint for quality consistency. In acute inflammatory models, the paw edema of rats was induced by subcutaneous injection of carrageenan or pro-inflammatory mediators, including histamine, serotonin, bradykinin, and prostaglandin E(2) (PGE(2)) into the right hind paws of animals; while the ear edema of mice was induced by applying arachidonic acid or 12-O-tetradecanoylphorbol 13-acetate (TPA) on the ear surface. In nociceptive models, the tail-flick response induced by radiant heat stimulation was measured and the numbers of abdominal writhing episodes of mice induced by intraperitoneal injection of acetic acid were recorded. JCICM-6 orally administered in a range of dosages from 0.438 g to 1.75 g/kg significantly and dose-dependently suppressed the paw edema of rats induced by carrageenan or various pro-inflammatory mediators and the ear edema of mice induced by arachidonic acid or TPA. JCICM-6 also significantly prolonged the reaction time of rats to radiant heat stimulation and reduced the numbers of writhing episodes of mice. These results indicated that JCICM-6 possesses significant anti-inflammatory and analgesic effects, which implies that it would be a potential candidate for further investigation as a new anti-arthritic botanical drug for humans.

Melatonin potentiates 5-HT(1A) receptor activation in rat hypothalamus and results in hypothermia

Effects of melatonin on both thermoregulatory responses and hypothalamic serotonin release were assessed in unanesthetized rats at three different ambient temperatures (Ta). Systemic administration of melatonin (30-120 mg/kg, i.p) caused a decrease in both colonic temperature and hypothalamic serotonin (5-HT) release in rats at both Ta 8 and 22 degrees C. The hypothermia was brought about by a decrease in metabolic rate at Ta 8 degrees C, whereas at Ta 22 degrees C the hypothermia was produced by both a decrease in metabolic rate and an increase in cutaneous temperature. However, in the heat (Ta 31 degrees C), neither thermoregulatory responses nor hypothalamic 5-HT release was affected by the same amount of administered melatonin. The melatonin-induced hypothermia and decreased 5-HT release in the hypothalamus were attenuated by selective depletion of brain 5-HT produced by intracerebroventricular injection of 5,7-dihydroxytryptamine. Furthermore, the melatonin-induced hypothermia was almost completely abolished by treatment with a 5-HT2A receptor agonist (DOI) or a 5-HT1A receptor antagonist [(-)-pindolol]. The data indicate that melatonin potentiates the 5-HT1A receptor activation in the hypothalamus and results in hypothermic effects which can be antagonized by the expected hyperthermic effect of DOI.

The protective effect of dl-tetrahydropalmatine against the development of amygdala kindling seizures in rats

The influence of dl-tetrahydropalmatine (THP), an active component isolated from a Chinese herbal medicine corydalis, was tested on the development of electrically kindled amygdala. The seizure activity was quantified by a ultrasonic system for vertical motion measurements. Intraperitoneal injection of THP (20 or 30 mg kg(-1)) 30 min before applying the daily kindling stimulus prevented the development of the kindling process. The behavioral seizure score and the motion responses which normally develop during electrical kindling were reduced below their initial values. The results suggest that THP is a very effective antiepileptogenic and anticonvulsant agent when applied to electrically kindled rats.

The hypothermic effects of dl-tetrahydropalmatine in rats

Systemic administration of dl-tetrahydropalmatine (THP; 10-50 mg x kg(-1) intraperitoneally) produced a proportional decrease in both colonic temperature and release of hypothalamic serotonin (5-hydroxytryptamine (5-HT)) in rats at room temperature. The hypothermia was brought about by cutaneous vasodilation and decreased metabolism. The THP- induced hypothermia was significantly attenuated in rats with brain 5-HT depletion produced by control injection of 5,7-dihydroxytryptamine or in rats with 5-HT2A receptor activation produced by 1-(2,5-dimethoxy-4-iodophenyl) -2-aminopropane, or in rats with 5-HT1A receptor antagonist produced by (-)-pindolol. The results suggest involvement of serotoninergic antagonism in the THP-induced hypothermia in rats

DL-Tetrahydropalmatine may act through inhibition of amygdaloid release of dopamine to inhibit an epileptic attack in rats

DL-Tetrahydropalmatine (THP), an active component isolated from corydalis (a Chinese herbal medicine), possesses analgesic effects. Systemic administration of picrotoxin (3-4 mg/kg) produced increases of locomotion (including horizontal motion, vertical motion, and total distance traveled), elevations of turnings (including both clockwise and anticlockwise), and inhibition of postural freezing in freely moving rats, and increases of amygdaloidal release of dopamine in anesthetizes rats. All the afore-mentioned activity measures induced by picrotoxin were suppressed following THP pretreatment. The results indicate that THP may act through inhibition of amygdaloid dopamine release to inhibit an epileptic attack.

Heat shock protein expression protects against cerebral ischemia and monoamine overload in rat heatstroke

This study attempted to ascertain whether the ischemic damage to neurons and monoamine overload in brain that occur during rat heatstroke can be attenuated by heat shock protein (HSP) 72 induction. Effects of heatstroke on mean arterial pressure (MAP), cerebral blood flow (CBF), brain dopamine (DA) and serotonin (5-HT) release, and neural damage score were assayed in rats 0, 16, or 48 h after heat shock (42 degrees C for 15 min) or chemical stress (5 mg/kg sodium arsenite ip). Brain HSP 72 in rats after heat shock or chemical stress was detected by Western blot, and brain monoamine was determined by a microdialysis probe combined with high-performance liquid chromatography. Heatstroke was induced by exposing the animal to a high ambient temperature (43 degrees C); the moment at which MAP and CBF decreased from their peak values was taken as the time of heatstroke onset. Prior heat shock or chemical stress conferred significant protection against heatstroke-induced hyperthermia, arterial hypotension, cerebral ischemia, cerebral DA and 5-HT overload, and neural damage and correlated with expression of HSP 72 in brain at 16 h. However, at 48 h, when HSP 72 expression returned to basal values, the above responses that occurred during the onset of heatstroke were indistinguishable between the two groups (0 h vs. 48 h). These results lead to the hypothesis that the brain can be preconditioned by thermal or chemical injury, that this preconditioning will induce HSP 72, and that HSP 72 induction will correlate quite well with anatomic, histochemical, and hemodynamic protection in rat heatstroke.

The neuroprotective effect of DL-tetrahydropalmatine in rat heatstroke

After the onset of heatstroke, rats with saline injection displayed hyperthermia, decreased mean arterial pressure, decreased cerebral blood flow, increased brain monoamine release, and increased neuronal damage score compared with those of normothermia, control rats. The heatstroke-induced hyperthermia, arterial hypotension, cerebral ischemia, brain monoamine overload, and cerebral neuronal injury were attenuated by pretreatment with dl-tetrahydropalmatine. The data indicate that DL-tetrahydropalmatine pretreatment provides neuroprotective effect in heatstroke.