A novel nano-drug delivery system of glycyrrhetinic acid-mediated intracellular breakable brucine for enhanced anti-hepatitis B efficacy.

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.

Oral acute toxicity study and in vivo antimalarial activity of Strychnos lucida R. Br. tablet.

ETHNOPHARMACOLOGICAL RELEVANCE: Malaria eradication has been a major goal of the Indonesian government since 2020. Medicinal plants, such as Strychnos lucida R. Br., are empirically used to treat malaria through traditional preparation methods. However, the safety and efficacy of these plants have not yet been confirmed. Therefore, further investigations are necessary to confirm the safety and efficacy of S. lucida as an antimalarial agent. AIMS OF THE STUDY: To quantify the concentration of brucine in the S. lucida extract, determine the acute oral toxicity of the standardized extract, and evaluate the in vivo antimalarial potency of S. lucida tablet (SLT). MATERIALS AND METHODS: Acute oral toxicity of S.lucida extract was determined using the Organization for Economic Co-operation and Development 420 procedure, and the analytical method for brucine quantification was validated using high-performance liquid chromatography. In addition, antimalarial activity was determined using the Peter's four-day suppressive method. RESULTS: Acute toxicity analysis revealed S. lucida as a low-toxicity compound with a cut-off median lethal dose of 2000-5000 mg/kg body weight [BW], which was supported by the hematological and biochemical profiles of the kidneys, liver, and pancreas (p > 0.05). Extract standardization revealed that S. lucida contained 3.91 ± 0.074% w/w brucine, adhering to the limit specified in the Indonesian Herbal Pharmacopeia. Antimalarial test revealed that SLT inhibited the growth of Plasmodium berghei by 27.74-45.27%. Moreover, SLT improved the hemoglobin and hematocrit levels. White blood cell and lymphocyte counts were lower in the SLT-treated group than in the K (+) group (p < 0.05). CONCLUSION: Histopathological and biochemical evaluations revealed that S. lucida extract was safe at a dose of 2000 mg/kg BW with low toxicity. SLT inhibited Plasmodium growth and improved the hemoglobin, hematocrit, and red blood cell profiles. Additionally, SLT reduced the lymphocyte and WBC counts and increased the monocyte and thrombocyte counts as part of the immune system response against Plasmodium infection.

Brucine alleviates fibroblast-like synoviocytes dysfunction and inflammation by regulating YY1 during rheumatoid arthritis.

Brucine is a weak alkaline indole alkaloid with wide pharmacological activities and has been identified to protect against rheumatoid arthritis (RA) process. Circular RNAs (circRNAs) are also reported to be involved in the pathogenesis of RA. Here, we aimed to probe the role and mechanism of Brucine and circ_0139658 in RA progression. The fibroblast-like synoviocytes of RA (RA-FLSs) were isolated for functional analysis. Cell proliferation, apoptosis, invasion, migration, as well as inflammatory response were evaluated by CCK-8 assay, EdU assay, flow cytometry, transwell assay, and ELISA analysis, respectively. qRT-PCR and western blotting analyses were utilized to measure the levels of genes and proteins. The binding between miR-653-5p and circ_0139658 or Yin Yang 1 (YY1), was verified using dual-luciferase reporter and RNA pull-down assays. Brucine suppressed the proliferation, migration, and invasion of RA-FLSs, and alleviated inflammation by reducing the release of pro-inflammatory factors and macrophage M1 polarization. RA-FLSs showed increased circ_0139658 and YY1 levels and decreased miR-653-5p levels. Circ_0139658 is directly bound to miR-653-5p to regulate YY1 expression. Brucine treatment suppressed circ_0139658 and YY1 expression but increased YY1 expression in RA-FLSs. Functionally, circ_0139658 overexpression reversed the suppressing effects of Brucine on RA-FLS dysfunction and inflammation. Moreover, circ_0139658 silencing alleviated the dysfunction and inflammation in RA-FLSs, which were reverted by YY1 overexpression. Brucine suppressed the proliferation, migration, invasion, and inflammation in RA-FLSs by decreasing YY1 via circ_0139658/miR-653-5p axis.

Brucine Inhibits Proliferation of Pancreatic Ductal Adenocarcinoma through PI3K/AKT Pathway-induced Mitochondrial Apoptosis.

INTRODUCTION: The purpose of this research was to settle the role of brucine in pancreatic ductal adenocarcinoma (PDAC) and the mechanisms involved. METHODS: The findings of this study suggest that brucine exerts inhibitory effects on cell growth, clonogenicity, and invasive potential of Panc02 and Mia Paca-2 cells. These effects may be linked to an increase in apoptotic-prone cell population. RESULTS: Gene sequencing data suggests that these effects are mediated through the induction of apoptosis. Experimental evidence further supports the notion that brucine reduces mitochondrial membrane potential and upregulates Bax expression while downregulating Bcl-2 expression. These effects are believed to be a result of brucine-mediated suppression of PI3K/Akt activity, which serves as a regulatory factor of mTOR, Bax, and Bcl-2. Suppression of PI3K activity enhances the tumor-suppressing effects of brucine. CONCLUSION: Overall, these findings suggest that brucine has therapeutic potential as a remedy option for PDAC.

Ultra-sensitive fluorescent detection of strychnine based on carbon dot self-assembled gold nanocage sensing probe.

The ultra-sensitive detection of strychnine is crucial to provide powerful evidence in strychnine poisoning cases. In this study, a novel fluorescent carbon dots (CDs) self-assembled gold nanocage (AuNCs) composite is synthesized for the ultra-sensitive detection of strychnine using molecularly imprinted polymer sensing technology (MIPs-CDs@AuNCs). With strong loading and delivery capability of AuNCs, the CDs could be loaded into AuNCs, where the anisotropy of CDs could significantly decrease and the fluorescence of the MIPs-CDs@AuNCs probe gained lower relative standard deviation (RSD). Moreover, the fluorescence response of MIPs-CDs@AuNCs to target strychnine was observed to be more significant than MIPs-CDs without gold nanocages. Under optimal conditions, the developed MIPs-CDs@AuNCs fluorescence strategy showed good linear relationship at the concentration of strychnine from 3 ng mL-1 to 200 ng mL-1 with the limit of detection as low as 1 ng mL-1. Besides, real blood samples were analyzed without complex pre-preparation procedure to investigate the performance of the proposed molecularly imprinted fluorescence probe, and satisfactory results were obtained with absolute deviations between -1.16 ng mL-1 and 1.28 ng mL-1, which exhibited a great potential for the detection of strychnine in health care work.

Synthesis and Characterization of Graphene Oxide/Polyethylene Glycol/Folic Acid/Brucine Nanocomposites and Their Anticancer Activity on HepG2 Cells.

Background: Liver cancer is the sixth most prevalent form of cancer and the second major cause of cancer-associated mortalities worldwide. Cancer nanotechnology has the ability to fundamentally alter cancer treatment, diagnosis, and detection. Objective: In this study, we explained the development of graphene oxide/polyethylene glycol/folic acid/brucine nanocomposites (GO/PEG/Bru-FA NCs) and evaluated their antimicrobial and anticancer effect on the liver cancer HepG2 cells. Methodology: The GO/PEG/Bru-FA NCs were prepared using the co-precipitation technique and characterized using various techniques. The cytotoxicity of the GO/PEG/Bru-FA NCs was tested against both liver cancer HepG2 and non-malignant Vero cells using an MTT assay. The antimicrobial activity of the GO/PEG/Bru-FA NCs was tested against several pathogens using the well diffusion technique. The effects of GO/PEG/Bru-FA NCs on endogenous ROS accumulation, apoptosis, and MMP levels were examined using corresponding fluorescent staining assays, respectively. The apoptotic protein expressions, such as Bax, Bcl-2, and caspases, were studied using the corresponding kits. Results: The findings of various characterization assays revealed the development of GO/PEG/Bru-FA NCs with face-centered spherical morphology and an agglomerated appearance with an average size of 197.40 nm. The GO/PEG/Bru-FA NCs treatment remarkably inhibited the growth of the tested pathogens. The findings of the MTT assay evidenced that the GO/PEG/Bru-FA NCs effectively reduced the HepG2 cell growth while not showing toxicity to the Vero cells. The findings of the fluorescent assay proved that the GO/PEG/Bru-FA NCs increased ROS generation, reduced MMP levels, and promoted apoptosis in the HepG2 cells. The levels of Bax, caspase-9, and -3 were increased, and Bcl-2 was reduced in the GO/PEG/Bru-FA NCs-treated HepG2 cells. Conclusion: The results of this work demonstrate that GO/PEG/Bru-FA NCs suppress viability and induce apoptosis in HepG2 cells, indicating their potential as an anticancer candidate.

Disinhibition does not play a role in endomorphin-2-induced changes in inspiratory motoneuron output produced by in vitro neonatal rat preparations.

Low level activation of mu-opioid receptors (MORs) in neonatal rat brainstem-spinal cord preparations increases inspiratory burst amplitude recorded on cervical spinal roots. We tested whether: (1) MOR activation with an endogenous ligand, such as endomorphin-2, increases inspiratory burst amplitude, (2) disinhibition of GABAergic or glycinergic inhibitory synaptic transmission is involved, and (3) inflammation alters endomorphin-2 effects. Using neonatal rat (P0-P3) brainstem-spinal cord preparations, bath-applied endomorphin-2 (10-200 nM) increased inspiratory burst amplitude and decreased burst frequency. Blockade of GABAA receptors (picrotoxin), glycine receptors (strychnine), or both (picrotoxin and strychnine) did not abolish endomorphin-2-induced effects. In preparations isolated from neonatal rats injected 3 h previously with lipopolysaccharide (LPS, 0.1 mg/kg), endomorphin-2 continued to decrease burst frequency but abolished the burst amplitude increase. Collectively, these data indicate that disinhibition of inhibitory synaptic transmission is unlikely to play a role in endomorphin-2-induced changes in inspiratory motor output, and that different mechanisms underlie the endomorphin-2-induced increases in inspiratory burst amplitude and decreases in burst frequency.

Brucine D restrains colorectal cancer tumorigenesis and autophagy by downregulating circ_0068464.

Bruceine D (BD) from Brucea javanica (L) exerts an antitumor effect in several human cancers. At present, it has not been reported whether BD inhibits the malignancy of colorectal cancer (CRC) cells. Therefore, investigating the role and regulatory mechanisms of BD in CRC is the main thrust of this study. Effect of BD on CRC cell viability, proliferation, apoptosis, invasion, and autophagy was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide, 5-ethynyl-2'-deoxyuridine, flow cytometry, transwell invasion, and western blotting assays. Expression changes of has_circ_0068464 (circ_0068464) were detected using real time quantitative polymerase chain reaction. The molecular mechanisms related to circ_0068464 were predicted through online prediction websites Starbase 2.0, circinteractome, and CircBank and validated using dual-luciferase reporter and RNA pull-down assays. The tumorigenic ability of BD and circ_0068464 on CRC was confirmed by xenograft experiments. The results showed that BD lessened CRC cell proliferation, invasion, autophagy, and prompted cell apoptosis. Circ_0068464 was overexpressed in CRC samples and cells. BD led to a significant reduction in circ_0068464 levels in cells of this carcinoma, but circ_0068464 overexpression partially rescued these effects urged by BD. Also, the combination of BD and circ_0068464 silencing decreased xenograft tumor growth compared to BD alone. Importantly, circ_0068464 could regulate ATG5 expression by functioning as a miR-520h molecular sponge. In conclusion, BD might suppress CRC growth by inhibiting the circ_0068464/miR-520h/ATG5 axis, providing a new perspective for the molecular pathogenesis of CRC and preliminarily indicating that BD may be a promising drug for CRC treatment.

Schisandrin B, a dual positive allosteric modulator of GABAA and glycine receptors, alleviates seizures in multiple mouse models.

Epilepsy is a prevalent and severe neurological disorder and approximately 30% of patients are resistant to existing medications. It is of utmost importance to develop alternative therapies to treat epilepsy. Schisandrin B (SchB) is a major bioactive constituent of Schisandra chinensis (Turcz.) Baill and has multiple neuroprotective effects, sedative and hypnotic activities. In this study, we investigated the antiseizure effect of SchB in various mouse models of seizure and explored the underlying mechanisms. Pentylenetetrazole (PTZ), strychnine (STR), and pilocarpine-induced mouse seizure models were established. We showed that injection of SchB (10, 30, 60 mg/kg, i.p.) dose-dependently delayed the onset of generalized tonic-clonic seizures (GTCS), reduced the incidence of GTCS and mortality in PTZ and STR models. Meanwhile, injection of SchB (30 mg/kg, i.p.) exhibited therapeutic potential in pilocarpine-induced status epilepticus model, which was considered as a drug-resistant model. In whole-cell recording from CHO/HEK-239 cells stably expressing recombinant human GABAA receptors (GABAARs) and glycine receptors (GlyRs) and cultured hippocampal neurons, co-application of SchB dose-dependently enhanced GABA or glycine-induced current with EC50 values at around 5 µM, and application of SchB (10 µM) alone did not activate the channels in the absence of GABA or glycine. Furthermore, SchB (10 µM) eliminated both PTZ-induced inhibition on GABA-induced current (IGABA) and strychnine (STR)-induced inhibition on glycine-induced current (Iglycine). Moreover, SchB (10 µM) efficiently rescued the impaired GABAARs associated with genetic epilepsies. In addition, the homologous mutants in both GlyRs-α1(S267Q) and GABAARs-α1(S297Q)ß2(N289S)γ2L receptors by site-directed mutagenesis tests abolished SchB-induced potentiation of IGABA and Iglycine. In conclusion, we have identified SchB as a natural positive allosteric modulator of GABAARs and GlyRs, supporting its potential as alternative therapies for epilepsy.

[Strychnine, in The Mysterious Affair at Styles: Blocking Glycinergic Synaptic Transmission].

Strychnine is a poison that often appears in classical mysteries and has been used for medicine and various purposes. Clearly, its point of action is glycine receptors, and it inhibits glycinergic synaptic transmission. Because of its powerful stimulant effect on the nervous system, if taken orally, characteristic symptoms that are intense and agonizing, such as tonic convulsions, opisthotonus or posterior arch tension, and convulsive laughter, appear. These symptoms are linked to the pathological basis of tetanus, and the drug is an important topic ranging from neuroscience to medical care.

Regulation of ethanol-mediated dopamine elevation by glycine receptors located on cholinergic interneurons in the nucleus accumbens.

Alcohol use disorder is one of the major psychiatric disorders worldwide, and there are many factors and effects contributing to the disorder, for example, the experience of ethanol reward. The rewarding and reinforcing properties of ethanol have been linked to activation of the mesolimbic dopamine system, an effect that appears to involve glycine receptors (GlyRs) in the nucleus accumbens. On which neuronal subtypes these receptors are located is, however, not known. The aim of this study was to explore the role of GlyRs on cholinergic interneurons (CIN) in sustaining extracellular dopamine levels and in ethanol-induced dopamine release. To this end, CIN were ablated by anti-choline acetyltransferase-saporin administered locally in the nucleus accumbens of male Wistar rats. Changes in dopamine levels induced by ablation, ethanol and/or a GlyR antagonist were monitored using in vivo microdialysis. The GlyRs antagonist strychnine depressed extracellular dopamine in a similar manner independent on local ablation, suggesting that GlyRs on CIN are not important for sustaining the extracellular dopamine tone. However, a low concentration of strychnine hampered ethanol-induced dopamine release in sham-treated animals, whilst no reduction was seen in ablated animals, suggesting that GlyRs located on CIN are involved in ethanol-induced dopamine release. Further, in ablated rats, ethanol-induced increases of the extracellular levels of the GlyR agonists glycine and taurine were attenuated. In conclusion, this study suggests that CIN are not important for GlyR-mediated regulation of basal dopamine output, but that CIN ablation blunts the ethanol-induced dopamine release, putatively by reducing the release of GlyR agonists.

Taking the bait: Strychnine poisoning.

A 48-year-old male intentionally ingested "gopher killer" containing strychnine as a, suicide attempt. He rapidly developed generalized muscle spasms with opisthotonos followed by cardiovascular collapse. He was resuscitated, treated with 24 h of, neuromuscular paralysis, and was discharged on hospital day 10 without sequelae. A blood strychnine concentration obtained five hours post ingestion was 2.2 mg/L. Strychnine poisoning is exceedingly rare in the modern United States and this report contains a video recording of the classic exam findings.

A cluster of acute thebaine poisonings from non-food grade poppy seeds in the Australian food supply.

INTRODUCTION: Poppy seed tea is used for its opioid effects and contains multiple opium alkaloids, including morphine, codeine, papaverine, and thebaine. Animal studies indicate thebaine has strychnine-like properties, but there is limited literature describing human thebaine poisoning. We describe a cluster of acute thebaine poisoning in people ingesting tea made using poppy seeds with high thebaine content that entered the Australian food supply chain. METHODS: This is an observational study of patients poisoned after drinking poppy seed tea. Cases were identified by three prospective toxicovigilance systems: the Emerging Drug Network of Australia collaboration, the New South Wales Prescription, Recreational and Illicit Substance Evaluation program, and the Emerging Drugs Network of Australia Victoria study. We report characteristics of clinical toxicity in cases with reported ingestion of poppy seed tea and analytical confirmation of thebaine exposure. RESULTS: Forty cases presenting with multi-system toxicity following poppy seed tea ingestion were identified across seven Australian states/territories from November 2022 to January 2023. Blood testing in 23 cases confirmed high thebaine concentrations. All 23 were male (median age 35, range 16-71 years). All patients experienced muscle spasms. Rigidity was described in nine, convulsions in six, while rhabdomyolysis, acute kidney injury, and metabolic acidosis occurred in five patients. There were two cardiac arrests. The thebaine median admission blood concentration was 1.6 mg/L, with a range of 0.1-5.6 mg/L, and was the dominant opium alkaloid in all samples. Convulsions, acute kidney injury, metabolic acidosis, and cardiac arrest were associated with increasing median thebaine concentrations. Four patients were managed in the Intensive Care Unit, with two receiving continuous kidney replacement therapy (one also received intermittent haemodialysis) for kidney injury. There was one death. CONCLUSIONS: Thebaine toxicity, like strychnine poisoning, resulted in neuromuscular excitation characterized by muscle spasm, rigidity, and convulsions. Severe toxicity, including acute kidney injury, metabolic acidosis, and cardiac arrest, appears dose-dependent.

Chemical constituents, pharmacological action, antitumor application, and toxicity of Strychnine Semen from Strychnons pierriana A.W.Hill.: A review.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried and mature seeds of Strychnons pierriana A.W.Hill. have been called Strychnine Semen(S. Semen). It have been used in traditional Chinese medicine for nearly 400 years. In recent decades, scholars at home and abroad have widely used S. Semen in the treatment of tumor diseases, showing good anti-tumor effects. In this paper, the modern research achievements of S. Semen are reviewed, including traditional uses, phytochemistry, pharmacology, and toxicology. AIM OF THE STUDY: In recent years, the research on S. Semen has increased gradually, especially the research on its anti-tumor. This paper not only reviewed the traditional uses, chemical constituents and pharmacological activities of S. Semen, but also comprehensively listed the mechanisms of Strychnos in the treatment of different tumors, providing a review for further research and development of Strychnos resources. MATERIALS AND METHODS: A systematic review of the literature on Fuzi was performed using several resources, namely classic books on Chinese herbal medicine and various scientific databases, such as PubMed, the Web of Science, and the China Knowledge Resource Integrated databases. RESULTS: The main constituents of S. Semen include alkaloids, terpenoids, steroids, and their glycosides. Modern studies have proved that S. Semen has a wide range of pharmacological effects, including anti-inflammatory and analgesic, anti-thrombotic, myocardial cell protection, immune regulation, nerve excitation, and anti-tumor effects. Among them, the anti-tumor effect has been the focus of research in recent years. S. Semen have a certain therapeutic effect on many kinds of tumors, such as liver cancer, colon cancer, and stomach cancer in the digestive system, breast, cervical, and ovarian cancer in the reproductive system, myeloma and leukemia in the blood system, and those in the nervous system and the immune system. CONCLUSION: Strychnine has an inhibitory effect on a variety of tumors. However, modern studies of strychnine are incomplete, and more in-depth studies are needed on its stronger bioactive constituents and potential pharmacological effects. The antitumor effect of Strychnine is worth further exploration.

Pharmacognostic profiles, evaluation of analgesic, anti-inflammatory and anticonvulsant activities of Newbouldia laevis (P. Beauv.) Seem. ex Bureau leaf and root extracts in Wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Newbouldia laevis is a popular medicinal plant whose leaves and roots are used in Nigeria as ethnomedicinal prescriptions for pain, inflammation, convulsion, and epilepsy. These claims have not been scientifically verified prior to this study. AIM OF THE STUDY: To determine pharmacognostic profiles of the leaves and roots and evaluate the analgesic, anti-inflammatory, and anticonvulsant activities of methanol leaf and root extracts in Wistar rats. MATERIAL AND METHODS: The pharmacognostic profiles of the leaves and roots were determined using standard procedures to serve as fingerprints for the plant. The methanol leaf and root extracts of Newbouldia laevis were tested for acute toxicity using the OECD's up and down method at the maximum dose of 2000 mg/kg (orally) in Wistar rats. Analgesic studies were carried out in acetic acid-induced writhing in rats and tail immersion. The anti-inflammatory activity of the extracts was evaluated using carrageenan-induced rat paw-oedema and formalin-induced inflammation in rats' mode. The anticonvulsant activity was determined using strychnine-induced, pentylenetetrazol-induced, and maximal electroshock-induced rat convulsion models. For each of these studies, the extracts doses of 100, 200 and 400 mg/kg were administered to the rats following the oral route. RESULTS: The pharmacognostic profiles showed that the leaves possessed deep-sunken paracytic stomata (5-8-16 mm2; adaxial, 8-11-24 mm2; abaxial epidermis), vein islets (2-4-10 mm2; adaxial), vein terminations (10-14-18 mm2; adaxial), palisade ratio (8.3-12.5-16.4 mm2; adaxial, 2.5-6.8-12.2 mm2; adaxial), covering unicellular trichome (8-14; adaxial), spheroidal calcium oxalate crystals (3-5 µm), and oval-shaped striated starch grain with no hilum (0.5-4.3 µm). The transverse section of the leaf showed the presence of spongy and palisade parenchyma as well as a closed vascular bundle. The root powder showed the presence of brachy sclereid, fibers without lumen, and lignin. All physicochemical parameters fall within the acceptable limits, phytochemical contents showed mainly glycosides, alkaloids, and steroids while acute oral toxicity (LD50) of the parts for 14 days did not produce any toxicity signs or mortality in the rats. The extracts produced dose-dependent (100-400 mg/kg) analgesic involving opioid receptors, anti-inflammatory, and anticonvulsant activities in the rats which were significant (p ≤ 0.05) when compared to the standard drugs. The leaf extract possessed the most potent analgesic and anti-inflammatory effects in the rats, while the most anticonvulsant effects were observed in rats treated with the leaf extract. Both extracts showed elevated levels of protection against strychnine-induced, pentylenetetrazol-induced, and maximal electroshock-induced seizure in rats. CONCLUSION: Our study revealed some pharmacognostic profiles of Newbouldia laevis leaves and roots that are vital for its identification from closely related species often used for adulteration in traditional medicine. The study further showed that the leaf and root extracts of the plant possessed dose-dependent analgesics, anti-inflammatory and anti-convulsant activities in rats, thus, justifying its use for the treatment of these diseases in Nigerian traditional medicine. There is a need to further study its mechanisms of action towards drug discovery.

Cannabinoid receptors involved in descending inhibition on spinal seizure-like activity in the phrenic output.

Seizure-like burst activities are induced by blockade of GABAA and/or glycine receptors in various spinal ventral roots of brainstem-spinal cord preparation from neonatal rodents. We found that this is not applicable to the phrenic nerve and that a new inhibitory descending pathway may suppress seizure-like activity in the phrenic nerve. Experiments were performed in brainstem-spinal cord preparation from newborn rats (age: 0-1 day). Left phrenic nerve and right C4 activities were recorded simultaneously. When GABAA and glycine receptors were blocked by 10 µM bicuculline and 10 µM strychnine (Bic+Str), seizure-like burst activities appeared in the fourth cervical ventral root (C4) but not the phrenic nerve. After making a transverse section at C1, the inspiratory burst activity disappeared from both C4 and the phrenic nerve, whereas seizure-like activity appeared in both nerves. We hypothesized that inhibitory descending pathways other than those via GABAA and/or glycine receptors (from the medulla to the spinal cord) work to avoid disturbance of regular respiratory-related diaphragm contraction by seizure-like activity. We found that cannabinoid receptor antagonist, AM251 was effective for the induction of seizure-like activity by Bic+Str in the phrenic nerve in brainstem-spinal cord preparation. Cannabinoid receptors may be involved in this descending inhibitory system.

Attenuation of Strychnine-Induced Epilepsy Employing Amaranthus viridis L. Leaves Extract in Experimental Rats.

Objective: Epilepsy is one of the most prevalent neurological illnesses defined by periodic seizures with or without loss of consciousness caused by aberrant neural activity. There are many allopathic medications available for the treatment of epilepsy such as phenytoin (PHY), but the side effects are a major concern. Therefore, the present study involved the evaluation of the pharmacological significance of Amaranthus viridis L. extract (EAV) in the management of strychnine (STR)-induced epilepsy. Method: STR (3.5 mg/kg, i.p.) was injected into male rats 30 minutes after the pre-treatment of a standard drug (PHY: 20 mg/kg) and the two doses of EAV (EAV-200 and EAV-400 mg/kg, p.o.) to the respective groups to cause the convulsions. The anti-convulsant effect of EAV-200 and EAV-400 against STR-induced convulsion in rats was investigated in terms of convulsion onset, duration of convulsions, number of convulsions, and convulsion score. Furthermore, the mitochondrial function and integrity in the brain's prefrontal cortex (PFC) were also estimated. Results: EAV-400 significantly increased the onset of convulsion from 61.67 ± 3.051 to 119.2 ± 2.738 and reduced the STR-induced duration of convulsions from 144.8 ± 3.582 to 69.17 ± 3.736, number of convulsions from 4.000 ± 0.1592 to 1.533 ± 0.1542, and convulsion score from 5.000 ± 0.3651 to 2.833 ± 0.3073 in rats. EAV-400 significantly attenuated the STR-induced decrease in the mitochondrial function and integrity of the rat PFC. In rats, EAV-400 significantly accelerated the onset of convulsions while decreasing the STR-induced duration, frequency, and score. Conclusion: Based on investigational findings, EAV-400 could be inferred to be a possible anti-epileptic option for the treatment of epilepsy of this plan in preclinical research.

Anti-Strychnine Immunoconjugate Reduces the Effects of Strychnine-Induced Toxicity in Mice.

Strychnine poisoning induces seizures that result in loss of control of airway muscles, leading to asphyxiation and subsequent death. Current treatment options are limited, requiring hands-on medical care and isolation to low-stimulus environments. Anticonvulsants and muscle relaxants have shown limited success in cases of severe toxicity. Furthermore, nonfatal strychnine poisoning is likely to result in long-term muscular and cognitive damage. Due to its potency, accessibility, and lack of effective antidotes, strychnine poses a unique threat for mass casualty incidents. As a first step toward developing an anti-strychnine immunotherapy to reduce or prevent strychnine-induced seizures, a strychnine vaccine was synthesized using subunit keyhole limpet hemocyanin. Mice were vaccinated with the strychnine immunoconjugate and then given a 0.75 mg/kg IP challenge of strychnine and observed for seizures for 30 min. Vaccination reduced strychnine-induced events, and serum strychnine levels were increased while brain strychnine levels were decreased in vaccinated animals compared to the control. These data demonstrate that strychnine-specific antibodies can block the seizure-inducing effects of strychnine and could be used to develop a therapeutic for strychnine poisoning.

Conformational transitions and allosteric modulation in a heteromeric glycine receptor.

Glycine Receptors (GlyRs) provide inhibitory neuronal input in the spinal cord and brainstem, which is critical for muscle coordination and sensory perception. Synaptic GlyRs are a heteromeric assembly of α and ß subunits. Here we present cryo-EM structures of full-length zebrafish α1ßBGlyR in the presence of an antagonist (strychnine), agonist (glycine), or agonist with a positive allosteric modulator (glycine/ivermectin). Each structure shows a distinct pore conformation with varying degrees of asymmetry. Molecular dynamic simulations found the structures were in a closed (strychnine) and desensitized states (glycine and glycine/ivermectin). Ivermectin binds at all five interfaces, but in a distinct binding pose at the ß-α interface. Subunit-specific features were sufficient to solve structures without a fiduciary marker and to confirm the 4α:1ß stoichiometry recently observed. We also report features of the extracellular and intracellular domains. Together, our results show distinct compositional and conformational properties of α1ßGlyR and provide a framework for further study of this physiologically important channel.

A Combination of In Silico ADMET Prediction, In Vivo Toxicity Evaluation, and Potential Mechanism Exploration of Brucine and Brucine N-oxide-A Comparative Study.

Brucine (BRU) and brucine N-oxide (BNO) are prominent, bioactive, and toxic alkaloids in crude and processed Semen Strychni. Studies have demonstrated that BRU and BNO possess comprehensive pharmacological activities, such as anti-inflammatory and analgesic. In this context, a comparative study of BRU and BNO was performed by combination analysis of in silico ADMET prediction, in vivo toxicity evaluation, and potential action mechanism exploration. ADMET prediction showed that BRU and BNO might induce liver injury, and BRU may have a stronger hepatoxic effect. The prediction was experimentally verified using the zebrafish model. The BRU-induced hepatotoxicity of zebrafish larvae had a dose-response relationship. The mechanism of BRU-induced hepatotoxicity might relate to phosphorylation, kinase activity, and signal transduction. By comparison, signal transduction and gap junctions might involve BNO-induced hepatotoxicity. Our results provided a better understanding of BRU- and BNO-induced hepatotoxicity. We also built a foundation to elucidate the material base of the hepatotoxicity of traditional Chinese medicine Semen Strychni.