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1.
J Biomater Appl ; 39(2): 150-161, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38748570

ABSTRACT

Background: Glycyrrhetinic acid-mediated brucine self-assembled nanomicelles enhance the anti-hepatitis B properties of brucine by improving its water solubility, short half-life, toxicity, and side effects. Brucine (B) is an indole alkaloid extracted from the seeds of Strychnos nux-vomica (Loganiaceae). Purpose: To assess the efficacy of the Brucine-Glycyrrhetnic acid-Polyethylene glycol-3,3'-dithiodipropionic acid-Glycerin monostearate (B-GPSG) in treating hepatitis B, its potential to protect against acute liver injury caused by d-galactosamine and its anti-hepatoma activities were studied. Research Design: The concentration of B-GPSG used in the in vivo and in vitro experiments was 0.63 mg/mL. The rats injected with d-GalN (450 mg/kg) were used as liver injury models. The rats were separated into normal, model, positive, positive control, B-PSG and B-GPSG groups. Hepatoma cells expressing HBV HepG2.2.15 were used for in vitro experiments. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, plate cloning, Hoechst staining and flow cytometry were conducted to explore the mechanism of B-GPSG against hepatitis B. Results: Compared with the model group, the liver coefficient of B-GPSG group decreased (4.59 ± 0.17 vs 5.88 ± 0.42), the content of MDA in rat liver homogenate decreased (12.54 ± 1.81 vs 23.05 ± 2.98), the activity of SOD increased, the activity of ALT and AST in rat serum decreased. In vitro, the IC50 values of B-GPSG group decreased. B-GPSG group effectively inhibited the proliferation and migration of HepG2.2.15 cells. Conclusions: The hepatoprotective effects of B-GPSG nanomicelles, which are attributed to their GA-mediated liver targeting and synergistic actions with brucine, suggest their therapeutic potential against hepatitis B. This development opens up new possibilities for the application of traditional Chinese medicine and nanomedicine in anti-hepatitis B.


Subject(s)
Glycyrrhetinic Acid , Hepatitis B , Strychnine , Animals , Glycyrrhetinic Acid/analogs & derivatives , Glycyrrhetinic Acid/chemistry , Glycyrrhetinic Acid/pharmacology , Humans , Hep G2 Cells , Hepatitis B/drug therapy , Strychnine/analogs & derivatives , Strychnine/pharmacology , Strychnine/administration & dosage , Strychnine/chemistry , Rats , Male , Rats, Sprague-Dawley , Antiviral Agents/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/administration & dosage , Liver/metabolism , Liver/drug effects , Nanoparticle Drug Delivery System/chemistry
2.
Molecules ; 27(19)2022 Sep 21.
Article in English | MEDLINE | ID: mdl-36234720

ABSTRACT

The decoction turns into a complex multiphase system following exposure to high temperature and a complex chemical environment. However, the differences in the concentration of key active ingredients in different phase states and the release of drugs in sedimentary phase have yet to be elucidated. A simple ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous quantitative determination of brucine, strychnine, liquiritin, isoliquiritin, isoliquiritigenin and glycyrrhizic acid concentrations and it was applied to compare the content of different phases and measure the release characteristics of the sedimentary phase in "Glycyrrhiza glabra-Nux vomica" decoction (NGD). The results show that the method's selectivity, precision (intraday and interday ≤ 2%), matrix effect (101-108%), recovery and stability results were acceptable according to the guidelines. The method is sensitive and reliable. The content determination results show that the most toxic strychnine in the sedimentary phase accounted for 75.70% of the total components. The different components exhibited differential release in different media, and its components were released in the artificial intestinal fluid up to 81.02% in 12 h. Several components conformed to the primary kinetic model and the Ritger-Peppas model, and the most toxic compound exhibited slow release, thus conforming to the Ritger-Peppas model. This study provides a standard of reference for studies investigating reduction in toxicity of the combination of Glycyrrhiza glabra (Glycyrrhiza glabra L.) and Nux vomica (Strychnos nux-vomica L.).


Subject(s)
Strychnos nux-vomica , Chromatography, High Pressure Liquid , Chromatography, Liquid , Glycyrrhizic Acid/analysis , Seeds/chemistry , Strychnine/chemistry , Strychnos nux-vomica/chemistry , Tandem Mass Spectrometry
3.
Nature ; 607(7919): 617-622, 2022 07.
Article in English | MEDLINE | ID: mdl-35794473

ABSTRACT

Strychnine is a natural product that, through isolation, structural elucidation and synthetic efforts, shaped the field of organic chemistry. Currently, strychnine is used as a pesticide to control rodents1 because of its potent neurotoxicity2,3. The polycyclic architecture of strychnine has inspired chemists to develop new synthetic transformations and strategies to access this molecular scaffold4, yet it is still unknown how plants create this complex structure. Here we report the biosynthetic pathway of strychnine, along with the related molecules brucine and diaboline. Moreover, we successfully recapitulate strychnine, brucine and diaboline biosynthesis in Nicotiana benthamiana from an upstream intermediate, thus demonstrating that this complex, pharmacologically active class of compounds can now be harnessed through metabolic engineering approaches.


Subject(s)
Biosynthetic Pathways , Metabolic Engineering , Strychnine , Biosynthetic Pathways/genetics , Strychnine/analogs & derivatives , Strychnine/biosynthesis , Strychnine/chemistry , Nicotiana/chemistry , Nicotiana/genetics , Nicotiana/metabolism
4.
Toxicon ; 215: 57-68, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35690276

ABSTRACT

INTRODUCTION: Plants of the Strychnos genus, which include about 200 species, are used for multiple traditional purposes as hunting poison, for example, and have shown interesting pharmacological properties, especially curarizing and tetanizing, but also against malaria. Many monoterpene indole alkaloids have already been isolated and identified. Among them, there is strychnine, a famous alkaloid that can cause death by asphyxiation. OBJECTIVE: Investigate alkaloidic molecular diversity from Strychnos genus using molecular networking technique and study the Strychnos genus from a chemotaxonomic point of view. MATERIAL AND METHODS: Twenty-eight different species and different plant parts were ground into powder using a grinder. The methanolic extracts were carried out using a pressurized solvent extraction and the alkaloid extract was performed manually with a separating funnel. The extracts were analyzed by HPLC-ESI(+)-Q/TOF. The data were processed using MZmine 2 software and the molecular network was generated on the GNPS platform. The study of the generated molecular network allowed the detection of various alkaloids. Among these is the famous strychnine which has been detected in 7 new Strychnos species not yet described as strychnine producers. This identification was investigated using orthogonal approaches, namely TLC, NMR, HPLC-UV and UHPLC-ESI(+)-Q/TOF analyses. The LOD by HPLC-UV of strychnine was also determined. RESULTS: Further analyses allowed to confirm the presence of strychnine in S. densiflora trunk barks but also to show the presence of strychnine with high probability in the trunk barks of S. camptoneura, S. congolana, S. boonei, and S. tchibangensis, and in the leaves of S. usambarensis. About the trunk barks of S. tricalyisoides, the probability of a strychnine content remains low. CONCLUSION: This work exemplified the efficiency of molecular networking in identifying known metabolites (major and minor alkaloids) involved in the chemotaxonomic study of plants from Strychnos genus.


Subject(s)
Alkaloids , Strychnos , Alkaloids/chemistry , Indole Alkaloids , Plant Leaves , Strychnine/chemistry , Strychnine/pharmacology , Strychnos/chemistry
5.
J Org Chem ; 87(8): 5199-5212, 2022 04 15.
Article in English | MEDLINE | ID: mdl-35275636

ABSTRACT

The complex structures and important biological functions of Strychnos alkaloids have attracted a great deal of attention from synthetic chemists. Herein, we describe the concise asymmetric total syntheses of the Strychnos alkaloids, (-)-dehydrotubifoline, (-)-tubifoline, and (-)-tubifolidine, as well as the formal total synthesis of (-)-strychnine. Our strategy features the construction of the common tetracyclic pyrrolo[2,3-d]carbazole structure using regioselective Fischer indolization on unsymmetrical cyclic ketones and late-stage functionalization for divergent synthesis. We developed a stepwise Fischer indolization featuring selective formation of enol triflate to solve the challenging regioselectivity problem, leading to the common tetracyclic ring skeleton in these Strychnos alkaloids. The regioselectivity of Fischer indolization on unsymmetrical cyclic ketones was studied on the basis of different types of ring systems and supported by density functional theory calculations. Overall, our success in the construction of this tetracyclic ring secured the syntheses of Strychnos alkaloids and may provide a general method for the total syntheses of various alkaloids containing this skeleton.


Subject(s)
Alkaloids , Strychnos , Alkaloids/chemistry , Ketones , Strychnine/chemistry , Strychnos/chemistry
6.
Molecules ; 26(11)2021 Jun 07.
Article in English | MEDLINE | ID: mdl-34200144

ABSTRACT

Natural products have been extensively used for treating a wide variety of disorders. In recent times, Brucine (BRU) as one of the natural medications extracted from seeds of nux vomica, was investigated for its anticancer activity. As far as we know, this is the first study on BRU anticancer activity against skin cancer. Thus, the rational of this work was implemented to develop, optimize and characterize the anticancer activity of BRU loaded ethosomal gel. Basically, thin film hydration method was used to formulate BRU ethosomal preparations, by means of Central composite design (CCD), which were operated to construct (32) factorial design. Two independent variables were designated (phospholipid percentage and ethanol percentage) with three responses (vesicular size, encapsulation efficiency and flux). Based on the desirability function, one formula was selected and incorporated into HPMC gel base to develop BRU loaded ethosomal gel. The fabricated gel was assessed for all physical characterization. In-vitro release investigation, ex-vivo permeation and MTT calorimetric assay were performed. BRU loaded ethosomal gel exhibited acceptable values for the characterization parameters which stand proper for topical application. In-vitro release investigation was efficiently prolonged for 6 h. The flux from BRU loaded ethosome was enhanced screening optimum SSTF value. Finally, in-vitro cytotoxicity study proved that BRU loaded ethosomal gel significantly improved the anticancer activity of the drug against A375 human melanoma cell lines. Substantially, the investigation proposed a strong motivation for further study of the lately developed BRU loaded ethosomal gel as a prospective therapeutic strategy for melanoma treatment.


Subject(s)
Ethanol/chemistry , Gels/chemistry , Skin/drug effects , Strychnine/analogs & derivatives , Administration, Cutaneous , Animals , Gels/administration & dosage , Male , Phospholipids/chemistry , Rats , Rats, Wistar , Skin Absorption/drug effects , Skin Neoplasms/drug therapy , Strychnine/administration & dosage , Strychnine/chemistry
7.
J Nat Prod ; 83(10): 3141-3148, 2020 10 23.
Article in English | MEDLINE | ID: mdl-32970418

ABSTRACT

The determination of the 3D structure (configuration and preferred conformation) of complex natural and synthetic organic molecules is a long-standing but still challenging task for chemists, with various implications in pharmaceutical sciences whether or not these substances have specific bioactivities. Nuclear magnetic resonance (NMR) in aligning media, either lyotropic liquid crystals (LLCs) or polymer gels, in combination with molecular modeling is a unique framework for solving complex structural problems whose analytical wealth lies in the establishment of nonlocal structural correlations. As an alternative to the already well-established anisotropic NMR parameters, such as RDCs (residual dipolar couplings) and RCSAs (residual chemical shift anisotropies), it is shown here that deuterium residual quadrupolar couplings (2H-RQCs) can be extracted from 2H 2D-NMR spectra recorded at the natural abundance level in samples oriented in a homopolypeptide LLCs (poly-γ-benzyl-l-glutamate (PBLG)). These 2H-RQCs were successfully used to address nontrivial structural problems in organic molecules. The performance and scope of this new tool is examined for two natural chiral compounds of pharmaceutical interest (strychnine and artemisinin). This is the first report in which the 3D structure/relative configuration of complex bioactive molecules is unambiguously determined using only 2H-RQCs, which, in this case, are at 2H natural abundance.


Subject(s)
Biological Products/chemistry , Deuterium/chemistry , Anisotropy , Artemisinins/chemistry , Artemisinins/pharmacology , Liquid Crystals , Magnetic Resonance Spectroscopy , Molecular Conformation , Molecular Structure , Strychnine/chemistry , Strychnine/pharmacology
8.
Angew Chem Int Ed Engl ; 59(40): 17556-17564, 2020 09 28.
Article in English | MEDLINE | ID: mdl-32476195

ABSTRACT

We describe enantioselective syntheses of strychnos and chelidonium alkaloids. In the first case, indole acetic acid esters were established as excellent partner nucleophiles for enantioselective cooperative isothiourea/Pd catalyzed α-alkylation. This provides products containing indole-bearing stereocenters in high yield and with excellent levels of enantioinduction in a manner that is notably independent of the N-substituent. This led to concise syntheses of (-)-akuammicine and (-)-strychnine. In the second case, the poor performance of ortho-substituted cinnamyl electrophiles in the enantioselective cooperative isothiourea/Ir catalyzed α-alkylation was overcome by appropriate substituent choice, leading to enantioselective syntheses of (+)-chelidonine, (+)-norchelidonine, and (+)-chelamine.


Subject(s)
Alkaloids/chemistry , Chelidonium/chemistry , Strychnos/chemistry , Alkaloids/chemical synthesis , Alkylation , Benzophenanthridines/chemical synthesis , Benzophenanthridines/chemistry , Berberine Alkaloids/chemical synthesis , Berberine Alkaloids/chemistry , Catalysis , Chelidonium/metabolism , Humans , Indoles/chemical synthesis , Indoles/chemistry , Iridium/chemistry , Palladium/chemistry , Sirtuin 1/antagonists & inhibitors , Sirtuin 1/metabolism , Stereoisomerism , Strychnine/chemical synthesis , Strychnine/chemistry , Strychnos/metabolism , Thiourea/chemistry
9.
Angew Chem Int Ed Engl ; 59(27): 10702-10721, 2020 06 26.
Article in English | MEDLINE | ID: mdl-32037640

ABSTRACT

Between 1910 and 1947, Robert Robinson (primarily), among others, published numerous proposed structures for strychnine. Robinson published 17 of his strychnine papers with his doctoral advisor William Henry Perkin, Jr., though all but two appeared after Robinson had taken his first permanent academic position. This Essay analyzes 20 key publications leading up to Robinson's (correct, then incorrect, then correct again though not definitively) proposal and Woodward's assignment of the actual structure of strychnine. We subjected the assignment of the strychnine structure to a modern computational quantum chemistry workflow. By computing, with density functional theory, 1 H and 13 C NMR chemical shifts for the literature-proposed strychnine structures, we were able to rule out most incorrect structures. 13 C NMR predictions were better at this, but 1 H NMR chemical shifts were helpful. A comparison is made between the consequences of publishing erroneous ideas in the first half of the 20th century and doing so in the 21st century.


Subject(s)
Strychnine/chemistry , Carbon-13 Magnetic Resonance Spectroscopy , Computational Chemistry , History, 21st Century , Molecular Structure , Proton Magnetic Resonance Spectroscopy , Strychnine/history
10.
PLoS One ; 14(12): e0226680, 2019.
Article in English | MEDLINE | ID: mdl-31881046

ABSTRACT

This paper focuses on determining the structural similarity of two molecules, i.e., the similarity of the interconnection of all the elementary cycles in the corresponding molecular graphs. In this paper, we propose and analyze an algorithmic approach based on the resolution of the Maximum Common Edge Subgraph (MCES) problem with graphs representing the interaction of cycles molecules. Using the ChEBI database, we compare the effectiveness of this approach in terms of structural similarity and computation time with two calculations of similarity of molecular graphs, one based on the MCES, the other on the use of different fingerprints (Daylight, ECFP4, ECFP6, FCFP4, FCFP6) to measure Tanimoto coefficient. We also analyze the obtained structural similarity results for a selected subset of molecules.


Subject(s)
Drug Design , Pharmaceutical Preparations/chemistry , Algorithms , Antineoplastic Agents/chemistry , Computer Graphics , Convulsants/chemistry , Docetaxel/chemistry , Dopamine/chemistry , Molecular Structure , Strychnine/chemistry
11.
Phytother Res ; 33(5): 1570-1578, 2019 May.
Article in English | MEDLINE | ID: mdl-30907037

ABSTRACT

Brucine and Strychnine are alkaloids isolated from the seeds of Strychnos nux vomica L., which have long been used as a traditional medicine for the treatment of tumor. However, the effect of Brucine and Strychnine on colorectal cancer (CRC) and the underlying molecular mechanism remain unclear. In the present study, Brucine and Strychnine displayed profound inhibitory effects on the growth of human colon cancer cells. The results of flow cytometric analysis demonstrated that the two alkaloids induced cellular apoptosis. Moreover, the growth of DLD1 xenografted tumors in nude mice was significantly suppressed in the Brucine or Strychnine treated group. Mechanistically, the Wnt/ß-catenin is involved in this phenomenon, which is characterized by significantly increased expression of DKK1 and APC, whereas decreased expression of ß-catenin, c-Myc, and p-LRP6 in CRC cells as well as tumor tissues. Collectively, Brucine and Strychnine have targeted inhibition for colon cancer proliferation both in vitro and in vivo, and it is valuable for future exploitation and utilization as an antitumor agent of CRC.


Subject(s)
Alkaloids/chemistry , Colonic Neoplasms/drug therapy , Strychnine/analogs & derivatives , Strychnine/chemistry , Strychnos nux-vomica/chemistry , Wnt Signaling Pathway/drug effects , Animals , Colonic Neoplasms/pathology , Humans , Mice , Mice, Nude
12.
Biomed Res Int ; 2019: 6543230, 2019.
Article in English | MEDLINE | ID: mdl-30723742

ABSTRACT

Vasculogenic mimicry (VM) with the pattern of endothelial independent tubular structure formation lined by aggressive tumor cells mimics regular tumor blood vessels to ensure robust blood supply and correlates with the proliferation, invasion, metastasis, and poor prognosis of malignant tumors, which was demonstrated to be a major obstacle for resistance to antiangiogenesis therapy. Therefore, it is urgent to discover methods to abrogate the VM formation of tumors, which possesses important practical significance for improving tumor therapy. Brucine is a traditional medicinal herb extracted from seeds of Strychnos nux-vomica L. (Loganiaceae) exhibiting antitumor activity in a variety of cancer models. In the present study, the effect of brucine on vasculogenic mimicry and the related mechanism are to be investigated. We demonstrated that, in a triple-negative breast cancer cell line MDA-MB-231, brucine induced a dose-dependent inhibitory effect on cell proliferation along with apoptosis induction at higher concentrations. The further study showed that brucine inhibited cell migration and invasion with a dose-dependent manner. Our results for the first time indicated that brucine could disrupt F-actin cytoskeleton and microtubule structure, thereby impairing hallmarks of aggressive tumors, like migration, invasion, and holding a possibility of suppressing vasculogenic mimicry. Hence, the inhibitory effect of brucine on vasculogenic mimicry was further verified. The results illustrated that brucine significantly suppressed vasculogenic mimicry tube formation with a dose-dependent effect indicated by the change of the number of tubules, intersections, and mean length of tubules. The in-depth molecular mechanism of vasculogenic mimicry suppression induced by brucine was finally suggested. It was demonstrated that brucine inhibited vasculogenic mimicry which might be through the downregulation of erythropoietin-producing hepatocellular carcinoma-A2 and matrix metalloproteinase-2 and metalloproteinase-9.


Subject(s)
Neovascularization, Pathologic/drug therapy , Strychnine/analogs & derivatives , Strychnos nux-vomica/chemistry , Triple Negative Breast Neoplasms/drug therapy , Apoptosis/drug effects , Cell Line, Tumor , Cell Movement/drug effects , Cell Proliferation/drug effects , Female , Gene Expression Regulation, Neoplastic/drug effects , Humans , Matrix Metalloproteinase 2/genetics , Matrix Metalloproteinase 9/genetics , Neoplasm Invasiveness/genetics , Neoplasm Invasiveness/pathology , Neovascularization, Pathologic/genetics , Neovascularization, Pathologic/pathology , Strychnine/chemistry , Strychnine/pharmacology , Triple Negative Breast Neoplasms/genetics , Triple Negative Breast Neoplasms/pathology
13.
Cell Mol Biol (Noisy-le-grand) ; 64(13): 69-73, 2018 Oct 30.
Article in English | MEDLINE | ID: mdl-30403598

ABSTRACT

Glutathione-S-transferase also referred as GST is one of the major detoxification enzymes in parasitic helminths. The crucial role played by GST in various chronic infections has been well reported. The dependence of nematodes on detoxification enzymes to maintain their survival within the host established the crucial role of GST in filariasis and other related diseases. Hence, this well-established role of GST in filariasis along with its greater nonhomology with its human counterpart makes it an important therapeutic drug target. Here in this study, we have tried to explore the inhibitory potential of some of the well-reported natural ant-filarial compounds against the GST from Wuchereria bancrofti (W.bancrofti) and Brugia malayi (B.malayi). In silico virtual screening, approach was used to screen the selected natural compounds against GST from W.bancrofti and B.malayi. On the basis of our results, here we are reporting some of the natural compounds which were found to be very effective against GSTs. Along with we have also revealed the characteristic of the active site of BmGST and WbGST and the role of important active site residues involve in the binding of natural compounds within the active site of GSTs. This information will oped doors for using natural compounds as anti-filarial therapy and will also be helpful for future drug discovery.


Subject(s)
Anthelmintics/analysis , Anthelmintics/pharmacology , Biological Products/analysis , Biological Products/pharmacology , Brugia malayi/enzymology , Drug Evaluation, Preclinical , Glutathione Transferase/antagonists & inhibitors , Wuchereria bancrofti/enzymology , Alkaloids/chemistry , Alkaloids/pharmacology , Animals , Benzodioxoles/chemistry , Benzodioxoles/pharmacology , Brugia malayi/drug effects , Capsaicin/chemistry , Capsaicin/pharmacology , Catalytic Domain , Curcumin/chemistry , Curcumin/pharmacology , Glutathione Transferase/metabolism , Molecular Docking Simulation , Piperidines/chemistry , Piperidines/pharmacology , Polyunsaturated Alkamides/chemistry , Polyunsaturated Alkamides/pharmacology , Strychnine/chemistry , Strychnine/pharmacology , Wuchereria bancrofti/drug effects
14.
Methods ; 148: 4-8, 2018 09 15.
Article in English | MEDLINE | ID: mdl-30036639

ABSTRACT

Small molecules with rotatable bonds can occupy different conformational states in solution as a consequence of their thermal fluctuations. The accurate determination of the structures of such states, as well as of their statistical weights, has been challenging because of the technical difficulties in extracting information from experimental measurements, which are normally averaged over the conformational space available. Here, to achieve this objective, we present an approach based on a recently proposed tensor-free method for incorporating NMR residual dipolar couplings as structural restraints in replica-averaged molecular dynamics simulations. This approach enables the information provided by the experimental data to be used in the spirit of the maximum entropy principle to determine the structural ensembles of small molecules. Furthermore, in order to enhance the sampling of the conformational space we incorporated the metadynamics method in the simulations. We illustrate the method in the case of strychnine, determining the three major conformational states of this small molecule and their associated occupation probabilities.


Subject(s)
Molecular Conformation , Molecular Dynamics Simulation , Nuclear Magnetic Resonance, Biomolecular/methods , Strychnine/chemistry , Strychnine/analysis
15.
Planta Med ; 84(12-13): 881-885, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29929205

ABSTRACT

Strychnogucine B is a bisindole alkaloid previously isolated from Strychnos icaja that possesses promising in vitro antiplasmodial properties. This compound was synthesized in four steps from (-)-strychnine. As no acute toxicity was observed at the highest tested cumulative dose of 60 mg/kg, its in vivo antimalarial activity was determined intraperitoneally at 30 mg/kg/d in a Plasmodium berghei murine model. In the Peters's 4-d suppressive test, this alkaloid suppressed the parasitaemia by almost 36% on day 5 and 60% on day 7 compared to vehicle-treated mice. In addition to this interesting antimalarial activity, it showed moderate in vitro antitrypanosomal activity but no in vivo activity in an acute Trypanosoma brucei model. It was also inactive in vitro on Leishmania mexicana promastigotes. This highlights its selective antimalarial efficacy and leads to further investigation to assess its potential as new antimalarial lead compound.


Subject(s)
Alkaloids/pharmacology , Antimalarials/pharmacology , Plasmodium berghei/drug effects , Strychnine/analogs & derivatives , Strychnos/chemistry , Trypanocidal Agents/pharmacology , Alkaloids/chemistry , Animals , Antimalarials/chemistry , Disease Models, Animal , Female , Leishmania mexicana/drug effects , Mice , Strychnine/chemistry , Strychnine/pharmacology , Trypanocidal Agents/chemistry , Trypanosoma brucei brucei/drug effects
16.
Article in English | MEDLINE | ID: mdl-29883892

ABSTRACT

Bi qi capsule (BQC) is a traditional Chinese medicine prescription that is clinically used for the treatment of rheumatoid arthritis. Strychnine and brucine, as two typical kinds of alkaloids, are the primary active and neurotoxic constituents of BQC. In this study, a sensitive and reliable rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS) quantitative method was used to determine the concentrations of brucine and strychnine in rat brain and blood dialysates. The blood-brain barrier (BBB) penetration of free brucine and strychnine and their pharmacokinetic characteristics were investigated by the validated RRLC-MS/MS method coupled with in vivo microdialysis for the first time. The dialysate brain-blood AUC ratios of brucine were 0.098, 0.44 and 0.40 respectively at 0.4, 0.8 and 1.6 g kg-1 doses of BQC, and the dialysate brain-blood AUC ratios of strychnine were 0.20, 1.25 and 2.06 respectively at 0.4, 0.8 and 1.6 g kg-1 doses of BQC. The high brain-blood AUC ratios of brucine and strychnine were observed in medium and high dose groups of BQC. In addition, the effects of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) on brucine and strychnine across BBB were also studied using the above method as well as molecular docking. The results prompted that brucine was the substrate of P-gp, and strychnine might be the inhibitor of P-gp. Brucine and strychnine showed high brain penetration, so it is very important to well control the clinic dosage of BQC and manufactory quality for avoiding the side effects and obtaining good therapeutic efficacy. Our study could be further used in investigating BBB penetration for other drugs caused neurotoxicity.


Subject(s)
Drugs, Chinese Herbal , Strychnine/analogs & derivatives , Strychnine/analysis , Strychnine/pharmacokinetics , Animals , Brain Chemistry , Chromatography, Liquid/methods , Linear Models , Male , Microdialysis , Rats , Rats, Sprague-Dawley , Reproducibility of Results , Sensitivity and Specificity , Strychnine/blood , Strychnine/chemistry , Tandem Mass Spectrometry/methods
17.
Drug Test Anal ; 10(2): 262-271, 2018 Feb.
Article in English | MEDLINE | ID: mdl-28447397

ABSTRACT

Semen Strychni is known for its treatment of rheumatic arthritis with a low therapeutic index. Liquorice contributes a lot in herb detoxification according to the traditional Chinese medicine theory. A simple, rapid, and sensitive liquid chromatography-mass spectrometric method (LC-MS) was developed and validated for simultaneous determination of main bioactive ingredients in liquorice and Semen Strychni in rat plasma. Using moclobemide and cyproterone acetate as the internal standards, the analytes were pretreated via protein precipitation with methanol. An Ultimate AQ-C18 column (3.0 µm, 3.0 × 100 mm) was employed for chromatographic separation, combining with gradient elution. The mobile phase consisted of 0.07% formic acid and 0.12% ammonium acetate in aqueous phase (A) and acetonitrile in organic phase (B). The elution program was as follows: 0-0.5 min, 20% B; 0.5-1 min, 20-60% B; 1-7 min, 60-85% B; and 7-7.5 min, returned to 20% B, then continued to 12 min. Selected reaction monitoring was performed in both positive and negative ESI. Positive mode was adopted for detection of strychnine, brucine, and moclobemide, while negative mode was used for glycyrrhizic acid, glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, liquiritin, and cyproterone acetate. The method was validated for specificity, linearity, matrix effect, recovery, precision, accuracy, and stability. The results show that this method is sensitive, accurate and robust for biological matrix analysis. Moreover, the proposed method was applied to a pharmacokinetic study in Sprague-Dawley rats for investigating the mechanism of which liquorice detoxifies Semen Strychni.


Subject(s)
Chromatography, Liquid/methods , Flavanones/chemistry , Glucosides/chemistry , Glycyrrhiza/chemistry , Glycyrrhizic Acid/chemistry , Plasma/chemistry , Semen/chemistry , Strychnine/analogs & derivatives , Animals , Flavanones/metabolism , Glucosides/metabolism , Glycyrrhiza/metabolism , Rats , Reproducibility of Results , Strychnine/chemistry , Strychnine/pharmacokinetics
18.
Chin J Integr Med ; 24(1): 40-46, 2018 Jan.
Article in English | MEDLINE | ID: mdl-28795388

ABSTRACT

OBJECTIVE: To examine the effect of brucine on the migration, invasion, adhesion and expressions of epithelial-to-mesenchymal transition (EMT) markers and matrix metalloproteinases (MMPs) in the highly metastatic breast cancer cell lines MDA-MB-231 and Hs578-T. METHODS: MDA-MB-231 and Hs578-T cells were divided to 4 groups: the control group (0.1% DMSO), and 25, 50 and 100 µmol/L brucine groups. The cell viability was determined using a CellTiter-Glo® luminescent cell viability. The scratch wound healing assay and tanswell migration assay were used to determine the migration ability of these cells treated by different concentrations of brucine. The proliferation rate, invasive potential and adhesive ability were respectively performed by colony formation assay, transwell invasion assay and adhension assay. The protein and mRNA expressions of EMT biomarkers, MMP-2 and MMP-9 were investigated by real-time reverse transcription polymerase chain reaction and Western blot. RESULTS: Compared with the control group, brucine had little effect on cell viability or proliferation (P>0.05), but led to a dose-dependent decrease on migration, invasion, adhension of MDA-MB-231 and Hs578-T cells (P<0.01). Furthermore, brucine increased the protein and mRNA levels of EMT markers such as E-cadherin and ß-catenin in MDA-MB-231 and Hs578-T cells, and decreased the protein and mRNA levels of mesenychmal markers such as vimentin and fibronectin, as well as the expressions of MMP-2 and MMP-9 (all P<0.01). CONCLUSION: Brucine inhibited triple negative breast cancer cells metastasis potentially through EMT reversion and MMP-2 and MMP-9 inhibition.


Subject(s)
Breast Neoplasms/drug therapy , Breast Neoplasms/enzymology , Epithelial-Mesenchymal Transition , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/metabolism , Strychnine/analogs & derivatives , Biomarkers, Tumor/metabolism , Breast Neoplasms/pathology , Cell Adhesion/drug effects , Cell Line, Tumor , Cell Movement/drug effects , Cell Survival/drug effects , Collagen/pharmacology , Drug Combinations , Epithelial-Mesenchymal Transition/drug effects , Female , Humans , Laminin/pharmacology , Neoplasm Invasiveness , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Proteoglycans/pharmacology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Strychnine/chemistry , Strychnine/pharmacology , Strychnine/therapeutic use
19.
J Chem Theory Comput ; 13(11): 5647-5657, 2017 Nov 14.
Article in English | MEDLINE | ID: mdl-28992702

ABSTRACT

The recently proposed Hamiltonian adaptive resolution scheme (H-AdResS) allows the performance of molecular simulations in an open boundary framework. It allows changing, on the fly, the resolution of specific subsets of molecules (usually the solvent), which are free to diffuse between the atomistic region and the coarse-grained reservoir. So far, the method has been successfully applied to pure liquids. Coupling the H-AdResS methodology to hybrid models of proteins, such as the molecular mechanics/coarse-grained (MM/CG) scheme, is a promising approach for rigorous calculations of ligand binding free energies in low-resolution protein models. Toward this goal, here we apply for the first time H-AdResS to two atomistic proteins in dual-resolution solvent, proving its ability to reproduce structural and dynamic properties of both the proteins and the solvent, as obtained from atomistic simulations.


Subject(s)
Molecular Dynamics Simulation , Proteins/chemistry , Pyridones , Water/chemistry , Ciclopirox , Copper Transport Proteins , Humans , Hydrogen Bonding , Metallochaperones/chemistry , Models, Molecular , Molecular Chaperones , Pyridones/chemistry , Solvents , Strychnine/chemistry , Thermodynamics
20.
Chemistry ; 23(64): 16189-16193, 2017 Nov 16.
Article in English | MEDLINE | ID: mdl-28940620

ABSTRACT

The total synthesis of the flagship Strychnos indole alkaloid, strychnine, has been accomplished. The developed synthetic sequence features a novel vinylogous 1,4-addition, a challenging iodinium salt mediated silyl enol ether arylation, a palladium-catalyzed Heck reaction, and a streamlined late-stage conversion to strychnine. Furthermore, an application of asymmetric counterion-directed catalysis (ACDC) in the context of target-oriented organic synthesis has been rendered access to an optically active material. The synthetic sequence described herein represents the most concise entry to optically active strychnine to date.


Subject(s)
Strychnine/chemical synthesis , Alkaloids/chemical synthesis , Alkaloids/chemistry , Catalysis , Indoles/chemistry , Palladium/chemistry , Stereoisomerism , Strychnine/chemistry
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