Gastric-mucous membrane protection activity of coptisine derivatives

Trifluoromethylation of dihydrocoptisines and the effect on structural stability and XBP1-activating activity

In order to obtain new dihydrocoptisine-type compounds with stable structure and activating XBP1 transcriptional activity, (±)-8-trifluoromethyldihydrocoptisine derivatives as target compounds were synthesized from quaternary ammonium chlorides of coptisine alkaloids as starting materials by a one-step reaction. The structures of the synthesized compounds were confirmed by ¹H-, ¹³C-, and ¹⁹F-NMR as well as HRESIMS methods. These compounds showed more significant structural stability and activating XBP1 transcription activity in vitro than dihydrocoptisine as positive control. No obvious cytotoxicity on normal cell in vitro was observed with (±)-8-trifluoromethyldihydrocoptisines. Trifluoromethylation can be used as one of the fluorine modification strategies for dihydrocoptisines to guide follow-up studies on structural modification of coptisine-type alkaloids and on anti-Ulcerative colitis drugs with coptisines.

Blood-Glucose-Lowering Effect of Coptidis Rhizoma Extracts From Different Origins via Gut Microbiota Modulation in db/db Mice

Background:Coptidis rhizoma extracts (CREs) have been used widely for their anti-diabetic and anti-microbial activities, and berberine/jatrorrhizine/coptisine/palmatine are the primary bioactive components. Although guidelines have adopted content analyses of these components as a quality control method for CREs, it is difficult to differentiate the CREs from different sources using this method because of the lack of indications for their related pharmacological activities.

Purpose: To explore the effect of CREs (CREA/CREB/CREC) with different compositions of major components on the gut microbiota and blood glucose levels in db/db mice.

Methods: Degradation of berberine/jatrorrhizine/coptisine/palmatine from CREA/CREB/CREC in rat/mouse intestinal contents and their impact on nine common gastrointestinal bacteria were investigated. In addition, the effects of oral administration of CREA/CREB/CREC for 2 weeks on the gut microbiota and blood glucose levels in db/db mice were monitored via insulin/glucose tolerance test (ITT/GTT), insulin concentration, homeostatic model assessment of insulin resistance and fecal 16S rRNA sequencing.

Results and Conclusion: The total amount of berberine/jatrorrhizine/coptisine/palmatine was highest in CREA. Clostridium perfringens was strongly inhibited by all three CREs, with CREA demonstrating the most significant inhibitory effects on minimum inhibitory concentration, time-kill kinetics, and ATP production. In db/db mice, CREA resulted in the most significant decrease in ITT/GTT and depicted different changes in the microbiota from CREB/CREC. Thus, CREs with different compositions of berberine/jatrorrhizine/coptisine/palmatine differed in terms of time-kill kinetics and ATP production assays on C. perfringens. CREA revealed the potent bacterial inhibitory effects and glucose-lowering activity.

Gut Microbiota-Mediated Transformation of Coptisine Into a Novel Metabolite 8-Oxocoptisine: Insight Into Its Superior Anti-Colitis Effect

Coptisine (COP) is a bioactive isoquinoline alkaloid derived from Coptis Chinemsis Franch, which is traditionally applied for the management of colitis. However, the blood concentration of COP was extremely low, and its gut microbiota-mediated metabolites were thought to contribute to its prominent bioactivities. To comparatively elucidate the protective effect and underlying mechanism of COP and its novel gut microbiota metabolite (8-oxocoptisine, OCOP) against colitis, we used dextran sulfate sodium (DSS) to induce colitis in mice. Clinical symptoms, microscopic alternation, immune-inflammatory parameters for colitis were estimated. The results indicated that OCOP dramatically ameliorated disease activity index (DAI), the shortening of colon length and colonic histopathological deteriorations. OCOP treatment also suppressed the mRNA expression and release of inflammatory mediators (TGF-β, TNF-α, IL-6, IL-18, IL-1β and IFN-γ) and elevated the transcriptional and translational levels of anti-inflammatory cytokine (IL-10) as well as the mRNA expression levels of adhesion molecules (ICAM-1 and VCAM-1). Besides, the activation of NF-κB pathway and NLRP3 inflammasome was markedly inhibited by OCOP. Furthermore, OCOP displayed superior anti-colitis effect to COP, and was similar to MSZ with much smaller dosage. Taken together, the protective effect of OCOP against DSS-induced colitis might be intimately related to inhibition of NF-κB pathway and NLRP3 inflammasome. And the findings indicated that OCOP might have greater potential than COP to be further exploited as a promising candidate in the treatment of colitis.

Syntheses and Structure-Activity Relationships in Antibacterial Activity against Clostridium difficile and XBP1 Activation Property of 13-[(N-Alkylamino)methyl]-8-oxodihydrocoptisines

13-[(N-Alkylamino)methyl]-8-oxodihydrocoptisines were synthesized to evaluate antibacterial activity against Clostridium difficile and activating x-box-binding protein 1 (XBP1) activity, biological properties both associated with ulcerative colitis. Improving structural stability and ameliorating biological activity were major concerns. Different substituents on the structural modification site were involved to explore the influence of diverse structures on the bioactivities. The target compounds exhibited the desired activities with definite structure-activity relationship. In the series of 13-[(N-n-alkylamino)methyl]-8-oxodihydrocoptisines, the length of n-alkyl groups has a definite effect on the bioactivity, elongation of the length increasing the antibacterial activity. The synthesized compounds were determined to display strong or weak XBP1-activating activity in vitro. The preliminary results of this study warrant further medicinal chemistry studies on these synthesized compounds.

Potential Antiulcer Agents From Plants: A Comprehensive Review

Background:

Peptic ulcer is a deep gastrointestinal erosion disorder that involves the entire mucosal thickness and can even penetrate the muscular mucosa. Nowadays, several plants and compounds derived from it have been screened for their antiulcer activity. In the last few years, there has been an exponential growth in the field of herbal medicine. This field has gained popularity in both developing and developed countries because of their natural origin and less side effects.

Objective:

This review aims to provide a comprehensive summary of currently available knowledge of medicinal plants and phytoconstituents reported for their anti-ulcer properties.

Methods:

The worldwide accepted database like SCOPUS, PUBMED, SCIELO, NISCAIR, ScienceDirect, Springerlink, Web of Science, Wiley, SciFinder and Google Scholar were used to retrieve available published literature.

Results:

A comprehensive review of the present paper is an attempt to list the plants with antiulcer activity. The review narrates the dire need to explore potential chemical moieties that exert an antiulcer effect, from unexploited traditional plants. Furthermore, the present study reveals the intense requirement to exploit the exact mechanism through which either the plant extracts or their active constituents exhibit their antiulcer properties.

Conclusion:

This article is the compilation of the plants and its constituents reported for the treatment of peptic ulcers. The Comprehensive data will surely attract the number of investigators to initiate further research that might lead to the drugs for the treatment of ulcers. As sufficient scientific data is not available on plants, most of the herbals cannot be recommended for the treatment of diseases. This can be achieved by research on pure chemical structures derived from plants or to prepare new lead compounds with proven beneficial preclinical in vitro and in vivo effects. However, a lot remains to be done in further investigations for the better status of medicinal plants.

Comparison of anti-inflammatory effects of berberine, and its natural oxidative and reduced derivatives from Rhizoma Coptidis in vitro and in vivo

BACKGROUND

Berberine (BBR) is the most abundant and major active constituent of Rhizoma Coptidis (RC), which has been widely used to treat inflammatory diseases in traditional oriental medicine. Despite BBR has been found to exhibit pronounced anti-inflammatory effect, the anti-inflammatory activities of its natural derivatives were sparsely dissected out.

PURPOSE

To comparatively investigate the anti-inflammatory potential of BBR, and its natural oxoderivative (oxyberberine, OBB) and reduced derivative (dihydroberberine, DHBB) in vitro and in vivo, and delineate the possible underlying mechanism.

METHODS

LC-MS/MS was used to identify the natural derivatives of BBR in RC. The potential anti-inflammatory properties of BBR and its natural derivatives were comparatively evaluated in vitro by lipopolysaccharide (LPS)-induced RAW264.7 macrophages cells, and in vivo via three typical acute inflammation murine models. Some important inflammation-related molecules were analyzed by ELISA, qRT-PCR and Western blotting.

RESULTS

LC-MS/MS led to the identification of BBR, OBB and DHBB in RC ethyl acetate extract. The in vitro assay indicated that BBR, OBB and DHBB (1.25, 2.5 and 5 μM) pretreatment significantly decreased the levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), prostaglandinE2 (PGE₂) and nitricoxide (NO), and inhibited the mRNA expressions of cyclooxygenase-2 (COX-2) and inducible nitricoxide synthase (iNOS) in a dose-dependent manner, with relative efficiency of OBB > BBR > DHBB. Furthermore, OBB, BBR and DHBB remarkably inhibited the phosphorylation of nuclear factor-κB (NF-κB) p65 and inhibitory kappa Bα (IκBα). In vivo, BBR (20 mg/kg) and OBB (5, 10, and 20 mg/kg) pretreatment significantly ameliorated the xylene-induced ear edema, carrageenan-stimulated paw edema, and acetic acid-elicited vascular permeability in mice in a dose-dependent manner, with OBB exhibiting superior anti-inflammatory effect at the same dose (20 mg/kg). Histopathological analysis indicated that OBB and BBR could markedly attenuate the inflammatory deterioration and decrease the cellular infiltration in paw tissues. Additionally, the carrageenan-induced increases in TNF-α, IL-6, IL-1β, PGE₂ and NO productions, and COX-2 and iNOS mRNA expressions were effectually and concentration-dependently suppressed by OBB and BBR pretreatment.

CONCLUSION

The anti-inflammatory activity of BBR and its natural derivatives was in the order of OBB > BBR > DHBB. OBB was for the first time found to be endowed with pronounced anti-inflammatory property, which was probably associated with suppressing the activation of NF-κB signaling pathway, and the subsequent gene expressions and productions of pro-inflammatory mediators. The results might contribute to illuminating the pharmacodynamic underpinnings of RC and provide evidence for developing OBB as a safe and promising natural lead compound in inflammation treatment.

Coptisine-induced inhibition of Helicobacter pylori: elucidation of specific mechanisms by probing urease active site and its maturation process

In this study, we examined the anti-Helicobactor pylori effects of the main protoberberine-type alkaloids in Rhizoma Coptidis. Coptisine exerted varying antibacterial and bactericidal effects against three standard H. pylori strains and eleven clinical isolates, including four drug-resistant strains, with minimum inhibitory concentrations ranging from 25 to 50 μg/mL and minimal bactericidal concentrations ranging from 37.5 to 125 μg/mL. Coptisine’s anti-H. pylori effects derived from specific inhibition of urease in vivo. In vitro, coptisine inactivated urease in a concentration-dependent manner through slow-binding inhibition and involved binding to the urease active site sulfhydryl group. Coptisine inhibition of H. pylori urease (HPU) was mixed type, while inhibition of jack bean urease was non-competitive. Importantly, coptisine also inhibited HPU by binding to its nickel metallocentre. Besides, coptisine interfered with urease maturation by inhibiting activity of prototypical urease accessory protein UreG and formation of UreG dimers and by promoting dissociation of nickel from UreG dimers. These findings demonstrate that coptisine inhibits urease activity by targeting its active site and inhibiting its maturation, thereby effectively inhibiting H. pylori. Coptisine may thus be an effective anti-H. pylori agent.

Small molecule induced poly(A) single strand to self-structure conformational switching: evidence for the prominent role of H-bonding interactions

All messenger RNAs (mRNAs) have a polyadenylic acid tail that is added during post transcriptional RNA processing. Investigation of the structure-function and interactions of polyadenylic acid is an important area to target for cancer and related diseases. Jatrorrhizine and coptisine are two important isoquinoline alkaloids that are structurally very similar, differing only in the substituents on the isoquinoline chromophore. Here we demonstrate that these alkaloids differentially induce a self-structure in single stranded poly(A) using absorbance, thermal melting and differential scanning calorimetry experiments. Jatrorrhizine was found to be more effective than coptisine in binding to poly(A) from spectroscopy and calorimetry data. Molecular modeling results suggested the involvement of more H-bonds in the complexation of the former with poly(A). It appears that the presence of substituents on the alkaloid that can form H-bonding interactions with the adenine nucleotides may play a critical role in the binding and structural rearrangement of poly(A) into the self-structure. The atomic force microscopy data directly visualized the poly(A) self-structured network. We propose a plausible mechanism of the small molecule induced self-structure formation in poly(A). The results presented here may help in the design of effective poly(A) targeted molecules for therapeutic use.

Protective effect of coptisine free base on indomethacin-induced gastric ulcers in rats: Characterization of potential molecular mechanisms

AIMS

The aim of this study was to comparatively investigate the potential gastroprotective effect and underlying mechanisms of coptisine free base (CFB, 8-hydroxy-7, 8-dihydrocoptisine), berberine and lansoprazole against indomethacin-induced gastric ulcer in rats.

MATERIALS AND METHODS

CFB (10, 20 and 40mg/kg), berberine (20mg/kg) and lansoprazole (30mg/kg) were orally administrated to rats prior to indometacin ingestion, and gastric lesions were evaluated macroscopically and histologically, and further analyzed by ELISA, qRT-PCR and Western blot.

KEY FINDINGS

CFB exerted comparable or superior gastroprotective effect to berberine in protecting against indomethacin-induced gastric injury. CFB pretreatment significantly enhanced the levels of superoxide dismutase (SOD) and glutathione (GSH), and markedly decreased the malonaldehyde (MDA) content. CFB administration effectively suppressed the levels of myeloperoxidase (MPO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and angiotensin II (Ang II). Besides, CFB substantially up-regulated the mRNA expressions of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), and promoted gastric mucosal prostaglandin E₂ level (PGE₂). Furthermore, CFB pretreatment remarkably increased the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) from cytosol into the nucleus, and the expression of heme oxygenase-1 (HO-1), while significantly decreased the expression of mitogen activated protein Kinase Kinase 6 (MKK6) and translocation of p38 mitogen-activated protein kinase (p38 MAPK).

SIGNIFICANCE

This was the first investigation reporting the anti-ulcer effect of protoberberine alkaloid free base on in vivo rodent model. The gastroprotective mechanism of CFB might involve favorable regulation of antioxidant and anti-inflammatory status mediated, at least partially, by the Nrf2 signaling pathway and p38 MAPK translocation.

Banhasasim-Tang Treatment Reduces the Severity of Esophageal Mucosal Ulcer on Chronic Acid Reflux Esophagitis in Rats

The present study was conducted to evaluate both antioxidant and anti-inflammatory activity of Banhasasim-tang (BHSST) on chronic acid reflux esophagitis (CRE) model. Rat CRE model was established operatively and then treated with BHSST (1 g/kg body weight per day) for 15 days Esophageal pathological changes were analyzed using macroscopic examination and hematoxylin/eosin staining. The antioxidant and inflammatory protein levels were determined using Western blotting. The administration of BHSST significantly reduced both the overexpression of serum reactive oxygen species (ROS) and an excessive formation of thiobarbituric acid-reactive substances (TBARS) in esophagus tissue. Thus, the severity of esophageal ulcer was lower in BHSST treated rats than control rats on the gross and histological evaluation. Nuclear factor-erythroid 2-related factor 2 (Nrf2) led to the upregulation of antioxidant enzyme including SOD, GPx-1/2, and HO-1 by binding to antioxidant response element (ARE). Moreover, BHSST administration markedly reduced the expression of inflammatory proteins through mitogen-activated protein kinase- (MAPK-) related signaling pathways and decreased significantly the protein expressions of inflammatory mediators and cytokines by inhibition of nuclear factor-kappa B (NF-κB) activation. Taken together, these results support the fact that BHSST administration can suppress the development of esophageal mucosal ulcer via regulating inflammation through the activation of the antioxidant pathway.

Pharmacokinetics Studies of 12 Alkaloids in Rat Plasma after Oral Administration of Zuojin and Fan-Zuojin Formulas

Zuojin formula (ZJ) is a traditional Chinese medicine (TCM) prescription consisted of Coptidis Rhizoma (CR) and Euodiae Fructus (EF), and has been used to treat gastrointestinal (GI) disease for more than 700 years. Fan-Zuojin formula (FZJ) is a related TCM prescription also consisted of CR and EF with the opposite proportion. In recent years, ZJ was getting more attention for its antitumor potential, but the indeterminate pharmacokinetic (PK) behavior restricted its clinical applications, and the PK differences between ZJ and FZJ were also largely unknown. Consequently it is necessary to carry out a full-scale PK study to demonstrate the physiological disposition of ZJ, as well as the comparative PK study between ZJ and FZJ to illustrate the compatibility dose effects. Therefore a liquid chromatographic–tandem mass spectrometry (LC–MS/MS) method was established and validated for the determinations of coptisine, epiberberine, palmatine, berberine, 8-oxocoptisine, 8-oxoepiberberine, noroxyhydrastinine, corydaldine, dehydroevodiamine, evodiamine, wuchuyuamide-I, and evocarpine in rat plasma. PK characteristics of 12 alkaloids after oral administration of ZJ and FZJ were compared, and the result was analyzed and discussed with the help of an in silico study. Then an integrated PK study was carried out with the AUC-based weighting method and the total drug concentration method. The established method has been successfully applied to reveal the PK profiles of the 12 alkaloids in rat plasma after oral administration of ZJ and FZJ. The results showed that: (1) double peaks were observed in the plasma concentration-time (C–T) curves of the alkaloids after ZJ administration; but the C–T curves approximately matched the two-compartment model after FZJ administration; (2) There were wide variations in the absorption levels of these alkaloids; and even for a certain alkaloid, the dose modified systemic exposure levels and elimination rate also varied significantly after administration of ZJ and FZJ extracts. The results could be interpreted as follows: firstly, inhibition effect on GI motility caused by the high content CR alkaloids (especially berberine) in ZJ could delay the T_max, and increase the absorption and systemic exposure levels of the other alkaloids, and also lead to the double peak phenomenon of these alkaloids. However, for quaternary protoberberine alkaloids (QPA), double peaks were primarily caused by the different Ka value in two intestinal absorption sites; Secondly, absorption was the major obstacle to the systemic exposure level of the alkaloids from CR and EF. In silico and PK studies suggested that the absorption of these alkaloids, except QPAs, mainly depended on their solubility rather than permeability; Thirdly, EF could promote the absorption and accelerate the elimination of QPAs, and had a greater influence on the former than the latter. At last the integrated PK analysis suggested that berberine and dehydroevodiamine could be regarded as the representative components to reflect the PK behaviors of CR and EF alkaloids after administration of ZJ and FZJ. In conclusion, the absorption, elimination and systemic exposure level of these alkaloids were mainly influenced by the proportion of EF and CR, the pharmacological effect on GI motility, and the physicochemical property of these alkaloids. These findings would be helpful for a better understanding of the activities and clinical applications of ZJ, FZJ and other related TCM prescriptions.

Coptisine from Coptis chinensis inhibits production of inflammatory mediators in lipopolysaccharide-stimulated RAW 264.7 murine macrophage cells

Coptis chinensis has been used for the treatment of inflammatory diseases in China and other Asian countries for centuries. However, the chemical constituents and mechanism underlying the anti-inflammatory activity of this medicinal plant are poorly understood. Here, coptisine, the main constituent of C. chinensis, was shown to potently inhibit the production of nitric oxide (NO) by suppressing the protein and mRNA expressions of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Coptisine also inhibited the production of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-6 (IL-6) by suppressing expression of cytokine mRNA. Coptisine suppressed the degradation of inhibitor of nuclear factor κBα (IκBα) and phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and phosphoinositide 3-kinase/Akt (PI3K/Akt). Coptisine had no effect on the expression of toll-like receptor 4 (TLR-4) and myeloid differentiation factor 88 (MyD88) as well as LPS binding to TLR-4. Coptisine also inhibited carrageenan-elicited rat paw edema and reduced the release of TNF-α and NO in rat inflamed tissue. These results suggest that coptisine inhibits LPS-stimulated inflammation by blocking nuclear factor-kappa B, MAPK, and PI3K/Akt activation in macrophages, and can be used as an agent for the prevention and treatment of inflammatory diseases.

Binding modes of reverse fosmidomycin analogs toward the antimalarial target IspC

1-Deoxy-d-xylulose 5-phosphate reductoisomerase of Plasmodium falciparum (PfIspC, PfDxr), believed to be the rate-limiting enzyme of the nonmevalonate pathway of isoprenoid biosynthesis (MEP pathway), is a clinically validated antimalarial target. The enzyme is efficiently inhibited by the natural product fosmidomycin. To gain new insights into the structure activity relationships of reverse fosmidomycin analogs, several reverse analogs of fosmidomycin were synthesized and biologically evaluated. The 4-methoxyphenyl substituted derivative 2c showed potent inhibition of PfIspC as well as of P. falciparum growth and was more than one order of magnitude more active than fosmidomycin. The binding modes of three new derivatives in complex with PfIspC, reduced nicotinamide adenine dinucleotide phosphate, and Mg(2+) were determined by X-ray structure analysis. Notably, PfIspC selectively binds the S-enantiomers of the study compounds.

New synthetic method of 8-oxocoptisine starting from natural quaternary coptisine as anti-ulcerative colitis agent

Quaternary coptisine (1), a natural bioactive quaternary protoberberine alkaloid (QPA), was treated with potassium ferricyanide in aqueous solution of 5 N sodium hydroxide leading to the acquisition of 8-oxocoptisine (2) with much higher yield than reported in the literature. This is the first report of the oxidation of a natural QPA by applying potassium ferricyanide as an oxidant. 8-Oxocoptisine showed significant anti-ulcerative colitis efficacy in vitro with EC50 value being 8.12 × 10(- 8) M.

Development of monoclonal antibody against isoquinoline alkaloid coptisine and its application for the screening of medicinal plants

In the development of immunoassay technique, the design of hapten containing a functional group suitable for protein conjugate is the key step for the preparation of antibodies against small molecules. Coptisine (MW 320), a bioactive constituent of Berberis and Coptis species, is small as an immunogen. In addition, coptisine has no reactive group in molecule for conjugating with a protein. To overcome this problem, 9-O-carboxymethyl-berberrubine was designed and conjugated with carrier protein. In order to confirm its immunogenicity, the ratio of hapten in the conjugate was determined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). After immunization, hybridomas secreting antibodies against coptisine were produced by fusing splenocytes with mouse myeloma cell line, P3-X63-Ag8-653. Among hybridomas, the clone 2A1 secreting anti-coptisine monoclonal antibody (MAb) 2A1-9E-1 was obtained through the limited dilution method. The MAb-based enzyme-linked immunosorbent assay (ELISA) against coptisine was developed and characterized. The linear range of the assay in this ELISA method was extended from 1.56 to 25 mug ml(-1) possessing the detection limit of 1.56 mug ml(-1). The established ELISA using MAb 2A1-9E-1 was applied for the survey of isoquinoline alkaloids in various medicinal plants.

Differential gene expression in rat vascular smooth muscle cells following treatment with coptisine exerts a selective antiproliferative effect

It is known that coptisine (1), an isoquinoline alkaloid, selectively inhibits proliferation of rat primary vascular smooth muscle cells (VSMCs). In the present study, the characteristics of its antiproliferative effect on several types of smooth muscle-like cells were investigated and compared to the effects of berberine (2) and palmatine (3). To clarify further the mechanism underlying the VSMC-selective antiproliferative effect of 1, the genes responsible were investigated by determining which mRNAs showed expression regulated by 1. Coptisine (1) showed a greater antiproliferative effect on smooth muscle cells derived from the aorta than on those derived from other organs. Analysis of the mRNA expression revealed that 1 upregulated two genes, growth arrest and DNA-damage-inducible alpha (Gadd45a) and response gene to complement32 (Rgc32). Both genes remained unchanged in 3Y1 fibroblasts and were not affected by 2 and 3. Coptisine (1) was found to induce the mRNA of the Gadd45a and Rgc32 genes, specifically in VSMC. Activation of these genes by 1 may mediate inhibition of cell-cycle progression. However, as these genes are commonly expressed in various cell types, a selective target for 1 activity is likely to exist upstream of these genes.

Selective regulation of multidrug resistance protein in vascular smooth muscle cells by the isoquinoline alkaloid coptisine

When the biological activites of hydrophobic drugs or xenobiotics are studied, it is important to clarify their effects on expression and function of multidrug resistance (MDR) protein. We therefore evaluated the effects of coptisine on MDR in comparison with the structurally related isoquinoline alkaloids berberine and palmatine. To achieve this, we investigated the effects of the three alkaloids on the expression and function of P-glycoprotein/MDR1, MDR1 gene products, in vascular smooth muscle cells (VSMCs). In A10 cells (a rat VSMC line), coptisine upregulated the mRNAs of Mdr1a and Mdr1b, rodent homologues of human MDR1, and these effects were completely abrogated by actinomycin D. Coptisine also induced Mdr1a/1b protein expression and enhanced the efflux of rhodamine 123 from A10 cells. In contrast, berberine and palmatine slightly upregulated the mRNAs of Mdr1a and Mdr1b, but failed to induce Mdr1a/1b protein expression or stimulate rhodamine 123 efflux. To clarify whether these effects occurred in other cells, the effects of the three alkaloids on Mdr1a/1b function were examined in 3Y1, dRLh-84 and B16 cells. Coptisine and berberine enhanced rhodamine 123 efflux in all three cell types, while palmatine inhibited it, based on the finding that palmatine efficiently activated the Mdr1a ATPase activity as a good substrate for Mdr1a. Therefore, the three isoquinoline alkaloids regulated MDR differently in cell type-specific manners. In particular, only coptisine induced Mdr1a/1b in A10 cells and stimulated rhodamine 123 efflux. Taken together, coptisine appears to exert VSMC-selective effects on Mdr1a/1b induction in contrast to berberine and palmatine.

Gastric and duodenal antiulcer activity of alkaloids: a review

Peptic ulcer disease is a deep gastrointestinal erosion disorder that involves the entire mucosal thickness and can even penetrate the muscular mucosa. Numerous natural products have been evaluated as therapeutics for the treatment of a variety of diseases, including this one. These products usually derive from plant and animal sources that contain active constituents such as alkaloids, flavonoids, terpenoids, tannins and others. The alkaloids are natural nitrogen-containing secondary metabolites mostly derived from amino acids and found in about 20% of plants. There has been considerable pharmacological research into the antiulcer activity of these compounds. In this work we review the literature on alkaloids with antiulcer activity, which covers about sixty-one alkaloids, fifty-five of which have activity against this disease when induced in animals.

Simultaneous quantification of twelve bioactive components in San-huang-xie-xin-tang by HPLC

A simple and reliable high-performance liquid chromatographic method with ultraviolet detection (280 nm) has been developed for the simultaneous analysis of 12 bioactive components in San-huang-xie-xin-tang (SHXXT), a traditional Chinese medicine containing Rhei rhizome, Coptidis rhizome and Scutellariae radix. A relatively simple extraction procedure was employed and optimised, and separation of the components was obtained within 1 h using a reversed-phase column under gradient elution with acetonitrile and a buffer containing 0.01 M sodium 1-pentanesulphonate (pH 3). The lower limit of detection for the analytes ranged from 25 to 75 ng/mL. The correlation coefficients associated with each calibration curve were greater than 0.99. The precision and accuracy of the method ranged from 1.0 to 10.5% at low concentration levels, 0.8 to 8.7% at medium levels and 1.2 to 5.8% at high levels. In commercial products of SHXXT, baicalin and berberine were present in the highest amounts with levels up to 4.0 and 3.3%, respectively, in one sample. The HPLC method was able rapidly and efficiently to analyse constituents in crude herb and traditional Chinese medicinal preparations containing Rhei rhizome, Coptidis rhizome and Scutellariae radix.

Selective inhibition of vascular smooth muscle cell proliferation by coptisine isolated from Coptis rhizoma, one of the crude drugs composing Kampo medicines Unsei-in

Acceleration of vascular smooth muscle cell (VSMC) proliferation is closely linked to the pathogenesis of vascular diseases. We, therefore, focused on traditional Japanese herbal medicines (Kampo medicines) used to ameliorate the impairment of microcirculation or blood stasis and screened them for their ability to inhibit rat VSMC proliferation. Among them, Unsei-in was found to effectively suppress VSMC proliferation, and Coptis rhizome was the responsible constituent crude drug. The extract of Coptis rhizome inhibited VSMC proliferation with the GI(50) value of 4.4 microg/ml, which was much lower than those against the proliferation of 3Y1, dRLh-84, B16, and HeLa cells. The Coptis rhizome extract inhibited the progression of VSMC arrested at G(0)/G(1) phase from G(0)/G(1) to S phase, but not that of 3Y1 cells. Biological assay-guided fractionation revealed that an alkaloid of Coptis rhizome, coptisine, was the active ingredient in selectively preventing VSMC proliferation with GI(50) of 3.3 microM (1.2 microg/ml). When the structurally-related isoquinoline alkaloids of protoberberine class were studied for their inhibitory activities, berberine decreased the VSMC proliferation with GI(50) of 95.1 microM (35.4 microg/ml), about 30 times higher concentration than coptisine, while palmatine failed to show any activity. This study provides evidence that coptisine, an ingredient of Unsei-in, prevents VSMC proliferation selectively at lower concentrations compared with various cells or other structurally related alkaloids.