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Prenyltransfer is an early-stage carbon-hydrogen bond (C-H) functionalization prevalent in the biosynthesis of a diverse array of biologically active bacterial, fungal, plant, and metazoan diketopiperazine (DKP) alkaloids. Toward the development of a unified strategy for biocatalytic construction of prenylated DKP indole alkaloids, we sought to identify and characterize a substrate-permissive C2 reverse prenyltransferase (PT). As the first tailoring event within the biosynthesis of cytotoxic notoamide metabolites, PT NotF catalyzes C2 reverse prenyltransfer of brevianamide F. Solving a crystal structure of NotF (in complex with native substrate and prenyl donor mimic dimethylallyl S-thiolodiphosphate (DMSPP)) revealed a large, solvent-exposed active site, intimating NotF may possess a significantly broad substrate scope. To assess the substrate selectivity of NotF, we synthesized a panel of 30 sterically and electronically differentiated tryptophanyl DKPs, the majority of which were selectively prenylated by NotF in synthetically useful conversions (2 to >99%). Quantitative representation of this substrate library and development of a descriptive statistical model provided insight into the molecular origins of NotF's substrate promiscuity. This approach enabled the identification of key substrate descriptors (electrophilicity, size, and flexibility) that govern the rate of NotF-catalyzed prenyltransfer, and the development of an "induced fit docking (IFD)-guided" engineering strategy for improved turnover of our largest substrates. We further demonstrated the utility of NotF in tandem with oxidative cyclization using flavin monooxygenase, BvnB. This one-pot, in vitro biocatalytic cascade enabled the first chemoenzymatic synthesis of the marine fungal natural product, (-)-eurotiumin A, in three steps and 60% overall yield.

Indigo is a bis-indolic alkaloid that has antioxidant and anti-inflammatory effects reported in literature and is a promissory compound for treating chronic inflammatory diseases. This fact prompted to investigate the effects of this alkaloid in the experimental model of Duchenne muscular dystrophy. The main aim of this study was to evaluate the potential role of the indigo on oxidative stress and related signaling pathways in primary skeletal muscle cell cultures and in the diaphragm muscle from mdx mice. The MTT and Neutral Red assays showed no indigo dose-dependent toxicities in mdx muscle cells at concentrations analyzed (3.12, 6.25, 12.50, and 25.00 μg/mL). Antioxidant effect of indigo, in mdx muscle cells and diaphragm muscle, was demonstrated by reduction in 4-HNE content, H(2)O(2) levels, DHE reaction, and lipofuscin granules. A significant decrease in the inflammatory process was identified by a reduction on TNF and NF-κB levels, on inflammatory area, and on macrophage infiltration in the dystrophic sample, after indigo treatment. Upregulation of PGC-1α and SIRT1 in dystrophic muscle cells treated with indigo was also observed. These results suggest the potential of indigo as a therapeutic agent for muscular dystrophy, through their action anti-inflammatory, antioxidant, and modulator of SIRT1/PGC-1α pathway. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12192-022-01282-0.

Uncaria species (Rubiaceae) are used as traditional Chinese medicines (TCMs) to treat central nervous system (CNS) diseases, and monoterpene indole alkaloids are the main bioactive constituents. Localization and quantification of CNS drugs in fine brain regions are important to provide insights into their pharmacodynamics, for which quantitative mass spectrometry imaging (MSI) has emerged as a powerful technique. A systematic study of the quantitative imaging of seven Uncaria alkaloids in rat brains using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was presented. The distribution of the alkaloids in thirteen brain regions was quantified successfully using the calibration curves generated by a modified on-tissue approach. The distribution trend of different Uncaria alkaloids in the rat brain was listed as monoterpene indole alkaloids monoterpene oxindole alkaloids, R-configuration epimers S-configuration epimers. Particularly, Uncaria alkaloids were detected directly in the pineal gland for the first time and their enrichment phenomenon in this region had an instructive significance in future pharmacodynamic studies.

Calothrixin A (

Gelsenicine, mainly isolated from Gelsemium elegans Benth., is one of the most toxic alkaloids. The lack of information on gelsenicine leads to inaccurate risk and poisoning evaluation. In this study, the metabolic profiling and toxicokinetics of gelsenicine was studied by ultra-high performance liquid chromatography (UPLC) with quadrupole time-of-flight (Q-ToF) and tandem mass spectrometry in rats after intraperitoneal (i.p., 40 μg/kg) and intragastric (i.g., 60 μg/kg) administration. After i.p. administration, the area under the curve (AUC), the apparent volume of distribution (V), and the total body clearance (CL/F) of gelsenicine in plasma were 3.79 μg/L h, 38.47 L/kg, and 11.87 mL/h kg, respectively. After i.g. administration, the corresponding values were slightly increased (5.49 μg/L h; 53.10 mL/kg, and 12.66 mL/h kg). The toxicokinetic results indicated that the hepatic first-pass effect was predominant after i.p. administration. The UPLC-Q-ToF-MS data revealed nine metabolites in plasma, urine, and bile which were largely obtained by demethylation, hydroxylation, acetylation and glycine conjugation. Metabolites were mainly excreted through urine and bile, most of which in urine was basically eliminated in 24 h. Molecular docking and liver microsome experiments further showed that gelsenicine was metabolized by cytochrome P450 3A4 and 3A5. Summarizing, the present study provides metabolic and toxicokinetic information on gelsenicine which in turn may help in future risk assessment and forensic identification after poisonings.

Insect group h chitinase is a promising target for designing non-target safe pesticides in that it is exclusively distributed in lepidopteran insects, over 80% of which are agricultural pests. In this work, lynamicin B was discovered to be an inhibitor of OfChi-h, the group h chitinase from the lepidopteran pest Ostrinia furnacalis. Lynamicin B was revealed to competitively inhibit OfChi-h with a Ki value of 8.76 μM and does not significantly inhibit other chitinases. The co-crystal structure of lynamicin B and OfChi-h revealed that the dichloroindolyl group of lynamicin B occupies an unexplored pocket below subsites +1 and +2 of the substrate-binding cleft, which is vital for its selectivity. Feeding experiments demonstrated that lynamicin B exhibited high insecticidal activities against other lepidopteran pests Mythimna separata and Spodoptera frugiperda besides O. furnacalis. Moreover, lynamicin B did not affect Trichogramma ostriniae, a natural enemy of O. furnacalis. This study provides a natural-derived potent pesticide for the control of lepidopteran pests, leaving its natural enemy unaffected.

Studies have discovered that different extracts of Evodia rutaecarpa and its phytochemicals show a variety of biological activities associated with inflammation. Although rutaecarpine, an alkaloid isolated from the unripe fruit of E. rutaecarpa, has been exposed to have anti-inflammatory properties, the mechanism of action has not been well studied. Thus, this study investigated the molecular mechanisms of rutaecarpine (RUT) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. RUT reserved the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukin (IL)-1β in the LPS-induced macrophages. RUT showed an inhibitory effect on the mitogen-activated protein kinases (MAPKs), and it also inhibited nuclear transcription factor kappa-B (NF-κB) by hindering IκBα and NF-κB p65 phosphorylation and p65 nuclear translocation. The phospho-PI3K and Akt was concentration-dependently suppressed by RUT. However, RUT not only suggestively reduced the migratory ability of macrophages and their numbers induced by LPS but also inhibited the phospho-Src, and FAK. Taken together, these results indicate that RUT participates a vital role in the inhibition of LPS-induced inflammatory processes in RAW 264.7 macrophages and that the mechanisms involve PI3K/Akt and MAPK-mediated downregulation of NF-κB signaling pathways. Notably, reducing the migration and number of cells induced by LPS via inhibiting of Src/FAK pathway was also included to the anti-inflammatory mechanism of RUT. Therefore, RUT may have potential benefits as a therapeutic agent against chronic inflammatory diseases.

Acute pancreatitis (AP) is an acute inflammatory condition of the pancreas. Previous studies have shown that rutaecarpine (RUT), an important alkaloid component of Evodia rutaecarpa, exhibits certain protective effects against AP in rats by upregulating calcitonin gene-related peptide (CGRP). However, the molecular mechanism of RUT in AP remains unknown. This study aimed to investigate the effects of RUT on cerulein-induced AP in vivo and in vitro, and to explore the underlying molecular mechanisms. In cerulein/LPS-treated wild-type mice, but not CGRP gene knock-out mice, RUT significantly ameliorated pancreatic inflammation by alleviating histopathological changes, reducing IL-6 and TNF-α levels, and increasing in IL-10 levels. Moreover, RUT improved AP by suppressing the MAPK and NF-κB signaling pathways. These effects were mostly mediated through CGRP. Cell-based studies revealed that RUT significantly improved cell viability while suppressing the apoptosis of AR42J cells with cerulein-induced AP, downregulating IL-6 and TNF-α, stimulating IL-10 release, and inhibiting MAPK, NF-κB, and STAT3 signaling activation, all in a CGRP-dependent manner. RUT ameliorated cerulein/LPS-induced AP inflammatory responses in mice and AR42J cells in a CGRP-dependent manner and thus may represent a potential therapeutic option for AP patients. Our study provides valuable insights for AP drug development.

Previous studies have demonstrated that brain-derived neurotrophic factor (BDNF) is one of the diffusible messengers for enhancing synaptic transmission in the hippocampus. Less information is available about the possible roles of BDNF in the anterior cingulate cortex (ACC). In the present study, we used 64-electrode array field recording system to investigate the effect of BDNF on ACC excitatory transmission. We found that BDNF enhanced synaptic responses in a dose-dependent manner in the ACC in C57/BL6 mice. The enhancement was long-lasting, and persisted for at least 3 h. In addition to the enhancement, BDNF also recruited inactive synaptic responses in the ACC. Bath application of the tropomyosin receptor kinase B (TrkB) receptor antagonist K252a blocked BDNF-induced enhancement. L-type voltage-gated calcium channels (L-VGCC), metabotropic glutamate receptors (mGluRs), but not NMDA receptors were required for BDNF-produced enhancement. Moreover, calcium-stimulated adenylyl cyclase subtype 1 (AC1) but not AC8 was essential for the enhancement. A selective AC1 inhibitor NB001 completely blocked the enhancement. Furthermore, BDNF-produced enhancement occluded theta burst stimulation (TBS) induced long-term potentiation (LTP), suggesting that they may share similar signaling mechanisms. Finally, the expression of BDNF-induced enhancement depends on postsynaptic incorporation of calcium-permeable AMPA receptors (CP-AMPARs) and protein kinase Mζ (PKMζ). Our results demonstrate that cortical BDNF may contribute to synaptic potentiation in the ACC.

Background In recent years, an increase in the occurrence of illnesses caused by two clinically- important arboviruses has been reported: Zika virus (ZIKV) and Chikungunya virus (CHIKV). There is no licensed antiviral treatment for either of the two abovementioned viruses. Bearing in mind that the antiviral effect of indole alkaloids has been reported for other arboviral models, the present study proposed to evaluate the antiviral in vitro and in silico effects of four indole alkaloids on infections by these two viruses in different cell lines. Methods The antiviral effects of voacangine (VOAC), voacangine-7-hydroxyindolenine (VOAC-OH), rupicoline and 3-oxo voacangine (OXO-VOAC) were evaluated in Vero, U937 and A549 cells using different experimental strategies (Pre, Trans, Post and combined treatment). Viral infection was quantified by different methodologies, including infectious viral particles by plating, viral genome by RT-qPCR, and viral protein by cell ELISA. Moreover, molecular docking was used to evaluate the possible interactions between structural and nonstructural viral proteins and the compounds. The results obtained from the antiviral strategies for each experimental condition were compared in all cases with the untreated controls. Statistically significant differences were identified using a parametric Student’s t-test. In all cases, p values below 0.05 (p Results In the pre-treatment strategy in Vero cells, VOAC and VOAC-OH inhibited both viral models and OXO-VOAC inhibited only ZIKV; in U937 cells infected with CHIKV/Col, only VOAC-OH inhibited infection, but none of the compounds had activity in A549 cells; in U937 cells and A549 cells infected with ZIKV/Col, the three compounds that were effective in Vero cells also had antiviral activity. In the trans-treatment strategy, only VOAC-OH was virucidal against ZIKV/Col. In the post-treatment strategy, only rupicoline was effective in the CHIKV/Col model in Vero and A549 cells, whereas VOAC and VOAC-OH inhibited ZIKV infection in all three cell lines. In the combined strategy, VOAC, VOAC-OH and rupicoline inhibited CHIKV/Col and ZIKV/Col, but only rupicoline improved the antiviral effect of ZIKV/Col-infected cultures with respect to the individual strategies. Molecular docking showed that all the compounds had favorable binding energies with the structural proteins E2 and NSP2 (CHIKV) and E and NS5 (ZIKV). Conclusions The present study demonstrates that indole alkaloids are promising antiviral drugs in the process of ZIKV and CHIKV infection; however, the mechanisms of action evaluated in this study would indicate that the effect is different in each viral model and, in turn, dependent on the cell line.

Eight new cyclopiazonic acid (

The present study investigated the chemical constituents from Uncaria sessilifructus and their neuroprotective activities. The compounds were separated and purified from the 90% ethanol extract of U. sessilifructus by various chromatographic methods, including silica gel, Sephadex LH-20, and semi-preparative HPLC. Seven compounds were obtained, and their structures were identified as uncanidine J(1), uncanidine K(2), 17-O-ethylhirsutine(3), tetrahydroalstonine(4), akuammigine(5), hirsutine(6), and hirsuteine(7) by physicochemical properties and various spectral techniques, including UV, IR, MS, and NMR. Compounds 1 and 2 are two new compounds. Compound 3 is a new natural product, and compound 4 was isolated from U. sessilifructus for the first time. In addition, the isolated compounds were evaluated for their neuroprotective effects on oxygen and glucose deprivation/reoxygenation(OGD/R) injury in primary cortical neurons in rats. The results showed that compounds 1-7 had different degrees of protective effects on OGD/R injury. The EC_(50) values of compounds 2-4 were(0.17±0.03),(1.70±0.38), and(1.79±0.23) μmol·L~(-1), respectively.

Three unprecedented indole alkaloids, wincalines A-C (1-3), and four known ones (4-7), classified into six carbon skeletal types, were isolated from the leavesof Winchia calophylla. The new isolates including their absolute configurations were elucidated based on extensive spectroscopic methods, the X-ray diffraction analyses, and electronic circular dichroism (ECD) experiments, as well as comparison with literature data. Wincaline A (1) is a rare indole alkaloid zwitterion bearing a 5,5-spirocyclic moiety. A possible biosynthetic pathway for 1 was proposed. All compounds were evaluated for their anti-inflammatory effects in terms of nitric oxide (NO) production in RAW 264.7 cells stimulated by lipopolysaccharide (LPS). Nevertheless, compound 7 showed weak activity with 43% NO production inhibition rate at 100 μM.

Marine sponges continue to attract remarkable attention as one of the richest pools of bioactive metabolites in the marine environment. The genus

In recent years, a large number of studies have reported that neuroinflammation aggravates the occurrence of secondary injury after spinal cord injury. Gramine (GM), a natural indole alkaloid, possesses various pharmacological properties; however, the anti‐inflammation property remains unclear. In our study, Gramine was investigated in vitro and in vivo to explore the neuroprotection effects. In vitro experiment, our results suggest that Gramine treatment can inhibit release of pro‐inflammatory mediators. Moreover, Gramine prevented apoptosis of PC12 cells which was caused by activated HAPI microglia, and the inflammatory secretion ability of microglia was inhibited by Gramine through NF‐κB pathway. The in vivo experiment is that 80 mg/kg Gramine was injected orthotopically to rats after spinal cord injury (SCI). Behavioural and histological analyses demonstrated that Gramine treatment may alleviate microglia activation and then boost recovery of motor function after SCI. Overall, our research has demonstrated that Gramine exerts suppressed microglia activation and promotes motor functional recovery after SCI through NF‐κB pathway, which may put forward the prospect of clinical treatment of inflammation‐related central nervous diseases.

Stroke is the second leading cause of death and long-term disability worldwide, which lacks effective treatment. Perioperative stroke is associated with much higher rates of mortality and disability. The neuroprotective role of dexmedetomidine (Dex), a highly selective agonist of alpha2-adrenergic receptor, has been reported in a stroke rat model, and it was found that pretreatment of Dex before stroke could alleviate blood-brain barrier (BBB) breakdown. However, the underlying mechanisms are still unknown. As the brain endothelial cells are the main constituents of BBB and in high demand of energy, mitochondrial function of endothelial cells plays an important role in the maintenance of BBB. Given that dynamin-related protein 1 (Drp1) is a protein mediating mitochondrial fission, with mitochondrial fusion that balances mitochondrial morphology and ensures mitochondria function, the present study was designed to investigate the possible role of Drp1 in endothelial cells involved in the neuroprotective effects of Dex in ischemic stroke. Our results showed that preconditioning with Dex reduced infarction volume, alleviated brain water content and BBB damage, and improved neurological scores in middle cerebral artery occlusion rats. Meanwhile, Dex enhanced cell activity and decreased cell apoptosis in oxygen-glucose deprivation human brain microvascular endothelial cells in vitro. These protective effects of Dex were correlated with the mitochondrial morphology integrality of endothelial cells, mediated by increased phosphorylation of serine 637 in Drp1, and could be reversed by α2-adrenergic receptor antagonist Yohimbine and AMP-activated protein kinase inhibitor Compound C. These findings suggest new molecular pathways involved in the neuroprotective effects of Dex in ischemic stroke. As Dex is routinely used as a sedative drug clinically, our findings provide molecular evidence that it has perioperative neuroprotection from ischemic stroke.

Protein aggregation, such as amyloid fibril formation, is molecular hallmark of many neurodegenerative disorders including Alzheimer's, Parkinson's, and Prion disease. Indole alkaloids are well-known as the compounds having the ability to inhibit protein fibrillation. In this study, we experimentally and computationally have investigated the anti-amyloid property of a derivative of a synthesized tetracyclic indole alkaloid (TCIA), possessing capable functional groups. The fibrillation reaction of Hen White Egg Lysozyme (HEWL) was performed in absence and presence of the indole alkaloid. For quantitative analysis, we used Thioflovin T binding assay which showed ~50% reduction in fibril formation in the presence of 20 μM TCIA. Using TEM imaging, we observed a significant morphological change in our model protein in the presence of TCIA. In addition, we exploited FT-IR assay by which Amide I peak's shifting toward lower wavenumber was clearly observed. Using Molecular Docking, the interaction of the inhibitor (TCIA) with the protein's amyloidogenic region was modeled. Also, different biophysical parameters were calculated by Molecular Dynamics (MD) simulation. Various biochemical assays, conformational change, and hydrophobicity exposure of the protein during amyloid formation indicated that the compound assists HEWL to keep its native structure via destabilizing β-sheet structure.

Drug‐mediated or medical condition‐mediated disruption of hERG function accounts for the main cause of acquired long‐QT syndrome (acLQTs), which predisposes affected individuals to ventricular arrhythmias (VA) and sudden death. Many Chinese herbal medicines, especially alkaloids, have risks of arrhythmia in clinical application. The characterized mechanisms behind this adverse effect are frequently associated with inhibition of cardiac hERG channels. The present study aimed to assess the potent effect of Rutaecarpine (Rut) on hERG channels. hERG‐HEK293 cell was applied for evaluating the effect of Rut on hERG channels and the underlying mechanism. hERG current (IhERG) was measured by patch‐clamp technique. Protein levels were analysed by Western blot, and the phosphorylation of Sp1 was determined by immunoprecipitation. Optical mapping and programmed electrical stimulation were used to evaluate cardiac electrophysiological activities, such as APD, QT/QTc, occurrence of arrhythmia, phase singularities (PSs), and dominant frequency (DF). Our results demonstrated that Rut reduced the IhERG by binding to F656 and Y652 amino acid residues of hERG channel instantaneously, subsequently accelerating the channel inactivation, and being trapped in the channel. The level of hERG channels was reduced by incubating with Rut for 24 hours, and Sp1 in nucleus was inhibited simultaneously. Mechanismly, Rut reduced threonine (Thr)/ tyrosine (Tyr) phosphorylation of Sp1 through PI3K/Akt pathway to regulate hERG channels expression. Cell‐based model unables to fully reveal the pathological process of arrhythmia. In vivo study, we found that Rut prolonged QT/QTc intervals and increased induction rate of ventricular fibrillation (VF) in guinea pig heart after being dosed Rut for 2 weeks. The critical reasons led to increased incidence of arrhythmias eventually were prolonged APD90 and APD50 and the increase of DF, numbers of PSs, incidence of early after‐depolarizations (EADs). Collectively, the results of this study suggest that Rut could reduce the IhERG by binding to hERG channels through F656 and Y652 instantaneously. While, the PI3K/Akt/Sp1 axis may play an essential role in the regulation of hERG channels, from the perspective of the long‐term effects of Rut (incubating for 24 hours). Importantly, the changes of electrophysiological properties by Rut were the main cause of VA.

Triple-negative breast cancer (TNBC), representing the most aggressive form of breast cancer with currently no targeted therapy available, is characterized by an inflammatory and hypoxic tumor microenvironment. To date, a broad spectrum of anti-tumor activities has been reported for phenanthroindolizidine alkaloids (PAs), however, their mode of action in TNBC remains elusive. Thus, we investigated six naturally occurring PAs extracted from the plant

Background: The enhancement of learning and memory through food-derived ingredients is of great interest to healthy individuals as well as those with diseases. Ergothioneine (ERGO) is a hydrophilic antioxidant highly contained in edible golden oyster mushrooms (Pleurotus cornucopiae var. citrinopileatus), and systemically absorbed by its specific transporter, carnitine/organic cation transporter OCTN1/SLC22A4. Objective: This study aims to examine the possible enhancement of object recognition memory by oral administration of ERGO in normal mice. Method: Novel object recognition test, spatial recognition test, LC-MS/MS, Golgi staining, neuronal culture, western blotting, immunocytochemistry, and quantitative RT-PCR were utilized. Result: After oral administration of ERGO (at a dose of 1–50 mg/kg) three times per week for two weeks in ICR mice, the novel object recognition test revealed a longer exploration time for the novel object than for the familiar object. Oral administration of ERGO also revealed a longer exploration time for the moved object in the spatial recognition test in mice fed ERGO-free diet. The discrimination index was significantly higher in the ERGO-treated group than the control in both behavioral tests. ERGO administration led to an increase in its concentration in the plasma and hippocampus. The systemic concentration reached was relevant to those found in humans after oral ERGO administration. Golgi staining revealed that ERGO administration increased the number of matured spines in the hippocampus. Exposure of cultured hippocampal neurons to ERGO elevated the expression of the synapse formation marker, synapsin I. This elevation of synapsin I was inhibited by the tropomyosin receptor kinase inhibitor, K252a. Treatment with ERGO also increased the expression of neurotrophin-3 and -5, and phosphorylated mammalian target of rapamycin in hippocampal neurons. Conclusion: Oral intake of ERGO which provides its plasma concentration achievable in humans may enhance object recognition memory, and this enhancement effect could occur, at least in part, through the promotion of neuronal maturation in the hippocampus.

Alcohol use-associated disorders are highly comorbid with anxiety disorders; however, their mechanism remains unknown. The amygdala plays a central role in anxiety. We recently found that 7,8-dihydroxyflavone (7,8-DHF) significantly reduces withdrawal symptoms in a rat model of chronic intermittent alcohol (ethanol) exposure. This study aimed to determine the role of 7,8-DHF in regulating anxiety induced by chronic alcohol exposure and its associated underlying mechanism. Male C57BL/6J mice were exposed to chronic intermittent alcohol for 3 weeks followed by alcohol withdrawal for 12 h with or without 7,8-DHF administered intraperitoneally. All mice were tested using an open field test and elevated plus maze to assess anxiety-like behaviors. Synaptic activity and intrinsic excitability in basal and lateral amygdala (BLA) neurons were assessed using electrophysiological recordings. 7,8-DHF alleviated alcohol-induced anxiety-like behavior and attenuated alcohol-induced enhancement of activities in BLA pyramidal neurons. Furthermore, 7,8-DHF prevented alcohol withdrawal-evoked augmentation of glutamatergic transmission in the amygdala and had no effect on GABAergic transmission in the amygdala, as demonstrated by unaltered frequency and amplitude of spontaneous inhibitory postsynaptic currents. Microinjection of K252a, a tropomyosin-related kinase B (TrkB) antagonist, into the BLA blocked the effects of 7,8-DHF on anxiety-like behavior and neuronal activity in the BLA. Our findings suggest that 7,8-DHF alleviates alcohol-induced anxiety-like behavior induced by chronic alcohol exposure through regulation of glutamate transmission involving TrKB in the BLA.

Rutaecarpine, an indolopyridoquinazoline alkaloid, attracted attentions because of possessing various biological activities. The objective of this study was to investigate the effect of rutaecarpine on glucose and lipid metabolism in high fat diet–multiple low dose streptozotocin induced type 2 diabetic (HFD-db) mice and to understand the mechanism of action. HFD-db mice showed impaired glucose metabolism and lipid profile. Oral administration of rutaecarpine reduced the blood glucose levels, decreased blood hemoglobin A1c (HbA1c) levels, improved glucose tolerance and restored insulin sensitivity in HFD-db mice. Rutaecarpine also decreased body weight gain, water intake and visceral fat gain in HFD-db mice. Total cholesterol, triglycerides, very low density lipoprotein and low density lipoprotein were reduced and high density lipoprotein level was augmented in rutaecarpine treated HFD-db mice. Rutaecarpine also reduced the elevated levels of serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, urea and creatinine in HFD-db mice. Rutaecarpine significantly promoted the rate of glucose consumption, glucose uptake and glycolysis in C2C12 myotubes. Western blotting results showed that rutaecarpine augmented p-GSK-3β and p-AMPK expression, and suppressed G6Pase expression in HepG2 cells. These results suggest that rutaecarpine might be having therapeutic importance to fight against type 2 diabetes mellitus associated with dyslipidemia.

2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside (THSG) is the major active ingredient in Plygonum multiflorum that displays a great deal of health-benefits including anti-oxidation, anti-hyperlipidemia, anti-cancer, anti-inflammation and neuroprotection. However, it is unclear whether THSG exerts neuroprotective functions by regulating neurotrophic factors and their associated signaling pathways. In this study, hippocampal neurons were challenged with staurosporine (STS) to establish a neural damage model. We found that STS-induced cytotoxicity introduced significant morphological collapse and initiating cell apoptosis, along with the down regulation of BDNF and TrkB/Akt signaling axis. In contrast, neurons pretreated with THSG showed resistance to STS-induced toxicity and maintained cell survival. THSG rescued STS induced dysfunctions of BDNF and its associated TrkB/Akt signaling, and restored the expression of Bcl-2 and Caspase-3. However, inhibition of TrkB activity by K252a or Akt signaling by LY294002 abolished the neuroprotective effects of THSG. Therefore, BDNF and TrkB/Akt signaling axis is a promise target for THSG mediated neuroprotective functions.

Tuberculosis is the main cause of death from a single infectious agent. Globally, according to the World Health Organization, in 2018, there were an estimated 1.2 million tuberculosis deaths. Moreover, there is a continuous appearance of drug-resistant strains. Thus, development of new antituberculosis medicines should receive high priority. Plant-derived natural products are promising candidates for this purpose. We therefore screened alkaloid extracts obtained from the root and stem barks of the Mexican Apocynaceae species Tabernaemontana alba and Tabernaemontana arborea, as well as the pure alkaloids ibogaine, voacangine, and voacamine, tested for activity against Mycobacterium tuberculosis H37Rv and cytotoxicity to mammalian Vero cells using the resazurin microtiter and the MTT assays, respectively. The extracts were analyzed by GC-MS and HPLC-UV. T. arborea root bark alkaloid extract showed the highest activity against M. tuberculosis (MIC100 = 7.8 µg/mL) of the four extracts tested. HPLC suggested that voacangine and voacamine were the major components. The latter was isolated by column chromatography, and its chemical structure was elucidated by 1H and 13C NMR, and MS. Unambiguous assignation was performed by HSQC, HMBC, and NOESY experiments. Voacamine is a dimeric bis-indole-type alkaloid and is 15 times more potent than the monomeric ibogan-type alkaloids ibogaine and voacangine (MIC100 = 15.6, 250.0, and 250.0 µg/mL, respectively). However, all of these compounds showed cytotoxicity to Vero cells, with a poor selectivity index of 1.00, 0.16, and 1.42, respectively. This is the first report of voacamine activity against M. tuberculosis.

Two new chlorinated bis-indole alkaloids, dionemycin (1) and 6-OMe-7',7″-dichorochromopyrrolic acid (2), along with seven known analogs 3-9, were isolated from the deep-sea derived Streptomyces sp. SCSIO 11791. Their structures were elucidated by extensive HRESIMS, and 1D and 2D NMR data analysis. In vitro antibacterial and cytotoxic assays revealed that, compound 1, shows anti-staphylococcal activity with an MIC range of 1-2 μg/mL against six clinic strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated from human and pig. Additionally, compound 1 displayed cytotoxic activity against human cancer cell lines NCI-H460, MDA-MB-231, HCT-116, HepG2, and noncancerous MCF10A with an IC50 range of 3.1-11.2 μM. Analysis of the structure-activity relationship reveals that the chlorine atom at C-6″ could be pivotal for conferring their bioactivities, thus providing hints on chemical modifications on bis-indole alkaloid scaffold in drug design.

Rationale The α4β2 nicotinic acetylcholine receptors (α4β2-nAChRs) may represent useful targets for cognitive improvement. It has been recently proposed that a strategy based on positive allosteric modulation of α4β2-nAChRs reveals several advantages over the direct agonist approach. Nevertheless, the procognitive effects of α4β2-nAChR positive allosteric modulators (PAMs) have not been extensively characterized. Objectives The aim of the present study was to evaluate the procognitive efficacy of desformylflustrabromine (dFBr), a selective α4β2-nAChR PAM. Methods Cognitive effects were investigated in the novel object recognition task (NORT) and the attentional set-shifting task (ASST) in rats. Results The results demonstrate that dFBr attenuated the delay-induced impairment in NORT performance and facilitated cognitive flexibility in the ASST. The beneficial effects of dFBr were inhibited by dihydro-β-erythroidine, a relatively selective α4β2-nAChR antagonist, indicating the involvement of α4β2-nAChRs in cognitive processes. The tested α4β2-PAM was also effective against ketamine- and scopolamine-induced deficits of object recognition memory. Moreover, procognitive effects were also observed after combined treatment with inactive doses of dFBr and TC-2403, a selective α4β2-nAChR agonist. Conclusions These findings indicate that dFBr presents procognitive activity, supporting the strategy based on α4β2-nAChR potentiation as a plausible therapy for cognitive impairment.

Chevalinulins A (

The overall five-year survival rate for patients with esophageal cancer is low (15 to 25%) because of the poor prognosis at earlier stages. Rutaecarpine (RTP) is a bioalkaloid found in the traditional Chinese herb Evodia rutaecarpa and has been shown to exhibit anti-proliferative effect on tumor cells. However, the mechanisms by which RTP confer these effects and its importance in esophageal squamous cell carcinoma treatment remain unclear. Thus, in the present study, we first incubated human esophageal squamous cell carcinoma cell line, CE81T/VGH, with RTP to evaluate RTP’s effects on tumor cell growth and apoptosis. We also performed a xenograft study to confirm the in vitro findings. Furthermore, we determined the expression of p53, Bax, bcl-2, caspase-3, caspase-9, and PCNA in CE81T/VGH cells or the tumor tissues to investigate the possible mechanisms. All the effects of TRP were compared with that of cisplatin. The results showed that RTP significantly inhibits CE81T/VGH cell growth, promotes arrest of cells in the G2/M phase, and induces apoptosis. Consistently, the in vivo study showed that tumor size, tumor weight, and proliferating cell nuclear antigen protein expression in tumor tissue are significantly reduced in the high-dose RTP treatment group. Furthermore, the in vitro and in vivo studies showed that RTP increases the expression of p53 and Bax proteins, while inhibiting the expression of Bcl-2 in cancer cells. In addition, RTP significantly increases the expression of cleaved caspase-9 and cleaved caspase-3 proteins in tumor tissues in mice. These results suggest that RTP may trigger the apoptosis and inhibit growth in CE81T/VGH cells by the mechanisms associated with the regulation of the expression of p53, Bax, Bcl-2, as well as caspase-9 and caspase-3.

Two new compounds, asperbenzophenone A (1) and versicolamide C (5), together with fifteen known compounds were isolated from a soft coral derived fungus Aspergillus sp. SCSIO 41036. Their structures were elucidated by spectroscopic methods, ECD analysis, and by a comparison with data from the literature. In bioassay, compound 8 showed significant inhibitory activity against lipopolysaccharide-inducted nitric oxide (NO) in RAW264.7 cells at the concentration of 10 μM. Additionally, the anti-acetylcholinesterase activity assay showed that 14 exhibited weak inhibition with an IC

Angiotensin II (Ang II)-induced cardiac inflammation contribute to pathological cardiac remodeling and hypertensive heart failure (HF). Tabersonine (Tab) is an indole alkaloid mainly isolated from Catharanthus roseus and exhibits anti-inflammatory activity in various systems. However, the role of Tab in hypertensive HF and its molecular targets remains unknown.We aimed to investigate potential cardioprotective effects and mechanism of Tab against Ang II-induced cardiac injuries.C57BL/6 mice were administered Ang II (at 1000 ng/kg/min) by micro-osmotic pump infusion for 30 days to develop hypertensive HF. Tab at 20 and 40 mg/kg/day was administered during the last 2 weeks to elucidate the cardioprotective properties. Cultured cardiomyocyte-like H9c2 cells and rat primary cardiomyocytes were used for mechanistic studies of Tab.We demonstrate for the first time that Tab provides protection against Ang II-induced cardiac dysfunction in mice, associated with reduced cardiac inflammation and fibrosis. Mechanistically, we show that Tab may interacts with TAK1 to inhibit Ang II-induced TAK1 ubiquitination and phosphorylation. Disruption of TAK1 activation by Tab blocked downstream NF-κB and JNK/P38 MAPK signaling activation and decreased cardiac inflammation and fibrosis both in vitro and in vivo. TAK1 knockdown also blocked Ang II-induced cardiomyocytes injuries and prevented the innately pharmacological effects of Tab.Our results indicate that Tab protects hearts against Ang II-mediated injuries through targeting TAK1 and inhibiting TAK1-mediated inflammatory cascade and response. Thus, Tab may be a potential therapeutic candidate for hypertensive HF.

Five new alkaloids have been isolated from the lipophilic extract of the Antarctic tunicate

Alcohol use disorder is a medical condition that impacts millions of individuals worldwide. Although there are a few pharmacotherapeutic options for alcohol-dependent individuals; there is a need for the development of novel and more effective therapeutic approaches. Alcohol and nicotine are commonly co-abused, and there is evidence that neuronal nicotinic acetylcholine receptors (nAChRs) play a role in both alcohol and nicotine dependence. Desformylflustrabromine (dFBr), a positive allosteric modulator of the α4β2 nAChRs has been shown to reduce nicotine intake, compulsive-like behavior and neuropathic pain in animal models. dFBr has also been previously shown to cross the blood-brain-barrier. We have recently shown that dFBr can attenuate the response to an acute, hypnotic dose of ethanol, via β2 nAchR. Here, we have investigated the effect of dFBr in modulating ethanol consumption using the intermittent access two-bottle choice (IA2BC) model of voluntary ethanol consumption in male and female Sprague Dawley rats. We show that dFBr selectively reduced ethanol but not sucrose consumption in the IA2BC model. Furthermore, dFBr decreased preference for ethanol in both male and female rats. No rebound increase in ethanol intake was observed after the washout period after dFBr treatment. The ability of dFBr to decrease ethanol consumption, along with its previously demonstrated ability to decrease nicotine self-administration in rodents, suggest that dFBr is an attractive therapeutic candidate to target both nicotine and alcohol abuse.

Antimicrobial resistance (AMR) is a global health challenge with methicillin resistant

Platelets play a critical role in arterial thrombosis. Rutaecarpine (RUT) was purified from Tetradium ruticarpum, a well-known Chinese medicine. This study examined the relative activity of RUT with NF-κB inhibitors in human platelets. BAY11-7082 (an inhibitor of IκB kinase [IKK]), Ro106-9920 (an inhibitor of proteasomes), and RUT concentration-dependently (1–6 μM) inhibited platelet aggregation and P-selectin expression. RUT was found to have a similar effect to that of BAY11-7082; however, it exhibits more effectiveness than Ro106-9920. RUT suppresses the NF-κB pathway as it inhibits IKK, IκBα, and p65 phosphorylation and reverses IκBα degradation in activated platelets. This study also investigated the role of p38 and NF-κB in cell signaling events and found that SB203580 (an inhibitor of p38) markedly reduced p38, IKK, and p65 phosphorylation and reversed IκBα degradation as well as p65 activation in a confocal microscope, whereas BAY11-7082 had no effects in p38 phosphorylation. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay shows that RUT and BAY11-7082 did not exhibit free radical scavenging activity. In the in vivo study, compared with BAY11-7082, RUT more effectively reduced mortality in adenosine diphosphate (ADP)-induced acute pulmonary thromboembolism without affecting the bleeding time. In conclusion, a distinctive pathway of p38-mediated NF-κB activation may involve RUT-mediated antiplatelet activation, and RUT could act as a strong prophylactic or therapeutic drug for cardiovascular diseases.

A pair of new diastereoisomers neolignans (1-2) and a new alkaloid (7) were isolated from the stems of Nauclea officinalis: naucleaoxyneolignoside A (1), naucleaoxyneolignoside B (2), (2S,3S)-javaniside (7), together with nine known compounds, 2S-3,3-di-(4-hydroxy-3-methoxyphenyl)-propane-1,2-diol (3), threo-1,2-bis-(4-hydroxy-3-methoxyphenyl)-propane-1,3-diol (4), nauclefine (5), angustidine (6), naucleoxoside A (8), naucleoxoside B (9), angustoline (10), (3S,19S)-3,14-dihydroangustoline (11), and (3S,19R)-3,14-dihydroangustoline (12).The structures of 1, 2 and 7 were elucidated by extensive spectroscopic methods and the known compounds were identified by comparison of their data with those reported in the literature. The absolution configurations of 1, 2, 7,11 and 12 were confirmed by the quantum chemical CD calculation method. Compounds 1-9 showed weak to moderate inhibitory activity on nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro with IC

Novel secondary metabolites from marine macroorganisms and marine-derived microorganisms have been intensively investigated in the last few decades. Several classes of compounds, especially indole alkaloids, have been a target for evaluating biological and pharmacological activities. As one of the most promising classes of compounds, indole alkaloids possess not only intriguing structural features but also a wide range of biological/pharmacological activities including antimicrobial, anti-inflammatory, anticancer, antidiabetic, and antiparasitic activities. This review reports the indole alkaloids isolated during the period of 2016–2021 and their relevant biological/pharmacological activities. The marine-derived indole alkaloids reported from 2016 to 2021 were collected from various scientific databases. A total of 186 indole alkaloids from various marine organisms including fungi, bacteria, sponges, bryozoans, mangroves, and algae, are described. Despite the described bioactivities, further evaluation including their mechanisms of action and biological targets is needed to determine which of these indole alkaloids are worth studying to obtain lead compounds for the development of new drugs.

A new alkaloid, geissospermiculatine was characterized in Geissospermum reticulatum A. H. Gentry bark (Apocynaceae). Here, following a simplified isolation protocol, the structure of the alkaloid was elucidated through GC-MS, LC-MS/MS, 1D, and 2D NMR (COSY, ROESY, HSQC, HMBC, 1H-15N HMBC). Cytotoxic properties were evaluated in vitro on malignant THP-1 cells, and the results demonstrated that the cytotoxicity of the alkaloid (30 μg/mL) was comparable with staurosporine (10 μM). Additionally, the toxicity was tested on zebrafish (Danio rerio) embryos in vivo by monitoring their development (0–72 h); toxicity was not evident at 30 μg/mL.

The well-known toxic medicine Gelsemium elegans is widely and historically used to treat bone fracture and skin ulcers by the folk people of China. Two new monoterpenoid indole alkaloids, gelselegandines D and E, together with the known analogue gelegamine A were isolated from G. elegans. Their structures were elucidated by means of spectroscopic techniques and quantum chemical calculations. All isolated compounds were tested for the effects on RANKL-induced osteoclast formation. Interestingly, gelselegandine E and gelegamine A, respectively, showed significant promoting and inhibitory activities on osteoclastogenesis, while gelselegandine D had no activity under the same concentration. This work suggested the different configurations for the carbons near the C-19/20 oxygen rings of the isolated compounds may be the key active groups on osteoclast formation and provided the evidence for the rationality as the traditional treatment for bone-related diseases of G. elegans.

Translocator protein (TSPO) is an 18-kDa transmembrane protein found primarily in the mitochondrial outer membrane, and it is implicated in inflammatory responses, such as cytokine release. Koumine (KM) is an indole alkaloid extracted from Gelsemium elegans Benth. It has been reported to be a high-affinity ligand of TSPO and to exert anti-inflammatory and immunomodulatory effects in our recent studies. However, the protective effect of KM on sepsis-associated liver injury (SALI) and its mechanisms are unknown.To explore the role of TSPO in SALI and then further explore the protective effect and mechanism of KM on SALI.The effect of KM on the survival rate of septic mice was confirmed in mouse models of caecal ligation and puncture (CLP)-induced and lipopolysaccharide (LPS)-induced sepsis. The protective effect of KM on CLP-induced SALI was comprehensively evaluated by observing the morphology of the mouse liver and measuring liver injury markers. The serum cytokine content was detected in mice by flow cytometry. Macrophage polarization in the liver was examined using western blotting. TSPO knockout mice were used to explore the role of TSPO in sepsis liver injury and verify the protective effect of KM on sepsis liver injury through TSPO.KM significantly improved the survival rate of both LPS- and CLP-induced sepsis in mice. KM has a significant liver protective effect on CLP-induced sepsis in mice. KM treatment ameliorated liver ischaemia, improved liver pathological injuries, and decreased the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and proinflammatory cytokines in serum. Western blotting results showed that KM inhibited M1 polarization of macrophages and promoted M2 polarization. In TSPO knockout mice, we found that TSPO knockout can improve the survival rate of septic mice, ameliorate liver ischaemia, improve liver pathological injuries, and decrease the levels of ALT, AST, and LDH. In addition, TSPO knockout inhibits the M1 polarization of macrophages in the liver of septic mice and promotes M2 polarization and the serum levels of proinflammatory cytokines. Interestingly, in TSPO knockout septic mice, these protective effects of KM were no longer effective.We report for the first time that TSPO plays a critical role in sepsis-associated liver injury by regulating the polarization of liver macrophages and reducing the inflammatory response. KM, a TSPO ligand, is a potentially desirable candidate for the treatment of SALI that may regulate macrophage M1/M2 polarization through TSPO in the liver.

As part of our continuous program to identify new potential candidates for controlling osteolytic bone diseases from natural products, the alkaloid fraction of barley (

Dysregulated activation of polyclonal B cells and production of pathogenic antibodies are involved in the development of rheumatoid arthritis (RA). Therefore, targeted B cell therapy is effective against RA. Gelsemium elegans (Gardn.Champ.) Benth., a toxic plant widely distributed in Southeast Asia, has been used for treating rheumatoid pain, neuropathic pain, spasticity, skin ulcers, and cancers for many years in traditional Chinese medicine. Koumine, an alkaloid monomer from Gelsemium elegans Benth., exerts therapeutic effects against RA. However, whether koumine affects B cells remains unknown. In this study, the effect of koumine on B cells under T cell-independent (TI) and T cell-dependent (TD) immune responses is investigated in vitro and in vivo. Mouse primary B cells were obtained by immunomagnetic bead sorting, and immunomodulatory effects of koumine on the activation, proliferation, and differentiation of B cells were determined in TI and TD models induced by lipopolysaccharide (LPS) and anti-CD40 antibodies in vitro, respectively. The humoral immune responses of TI and TD were established using NP-AECM-FICOLL and NP-CGG in C57BL/6J mice, respectively. We found that koumine inhibited B cell differentiation in the TI model and inhibited B cell activation and proliferation in the TD model in vitro. Koumine also inhibited antibody secretion in TI immune response, TD initial immune response, and in TD secondary immune response. Our results reveal that koumine has a direct and indirect immune regulatory effect on B cells, showing that it can directly inhibit the differentiation and secretion of autoantibodies after abnormal activation of B cells, and indirectly inhibit the activation and proliferation of TD B cells to reduce the secretion of antibodies. It may be an important mechanism for its anti-RA effect in mice, providing a rationale and laboratory data support for the application of koumine in anti-human RA therapy.

The role of activated platelets in acute and chronic cardiovascular diseases (CVDs) is well established. Therefore, antiplatelet drugs significantly reduce the risk of severe CVDs. Evodia rutaecarpa (Wu-Chu-Yu) is a well-known Chinese medicine, and rutaecarpine (Rut) is a main bioactive component with substantial beneficial properties including vasodilation. To address a research gap, we investigated the inhibitory mechanisms of Rut in washed human platelets and experimental mice. At low concentrations (1–5 μM), Rut strongly inhibited collagen-induced platelet aggregation, whereas it exerted only a slight or no effect on platelets stimulated with other agonists (e.g., thrombin). Rut markedly inhibited P-selectin expression; adenosine triphosphate release; [Ca2+]i mobilization; hydroxyl radical formation; and phospholipase C (PLC)γ2/protein kinase C (PKC), mitogen-activated protein kinase, and phosphoinositide 3-kinase (PI3K)/Akt/glycogen synthase kinase-3β (GSK3β) phosphorylation stimulated by collagen. SQ22536 (an adenylate cyclase inhibitor) or ODQ (a guanylate cyclase inhibitor) did not reverse Rut-mediated antiplatelet aggregation. Rut was not directly responding to vasodilator-stimulated phosphoprotein phosphorylation. Rut significantly increased the occlusion time of fluorescence irradiated thrombotic platelet plug formation. The findings demonstrated that Rut exerts a strong effect against platelet activation through the PLCγ2/PKC and PI3K/Akt/GSK3β pathways. Thus, Rut can be a potential therapeutic agent for thromboembolic disorders.

Gelsemium elegans (G. elegans) has been used in traditional Chinese medicine. This plant is highly toxic to humans, but can promote the growth of pigs and goats in the veterinary clinic. It is a very complex mixture containing tens or hundreds of different components. Therefore, multiple-component pharmacokinetic studies of G. elegans are a major challenge due to the lack of authentic standards of the components. The purpose of this study was to investigate the plasma pharmacokinetics of multiple components after a single oral dose of G. elegans in goat using a sensitive ultra-performance liquid chromatography coupled to tandem mass spectrometry method for the simultaneous semiquantification of multiple alkaloids without standards. The method was validated in terms of the specificity, LOD, LOQ, linearity, accuracy, precision and matrix effects. To validate the global pharmacokinetic characteristics, the results obtained from the semiquantitative analysis of three authentic compounds (gelsemine, koumine and humantenmine) were compared with the absolute quantification from our recently published method. The results showed that the two methods had similar analytical results, and the obtained values of Tmax, T1/2 and MRT0−t of the three alkaloids were similar between the two methods. In addition, the values of Cmax and AUC0−t of the three alkaloids after normalization were close to the real values, which indicated that this semiquantitative method could be used in the pharmacokinetic study of multiplecomponents. Then the pharmacokinetic parameters of 23 other G. elegans alkaloids in goats were obtained. The results suggested that the gelsedine-type alkaloids were the major active ingredients that predict and explain the efficacy and toxicity of G. elegans.