Isosteroidal alkaloids as potent dual-binding site inhibitors of both acetylcholinesterase and butyrylcholinesterase from the bulbs of Fritillaria walujewii

Undescribed steroidal alkaloids from the bulbs of Fritillaria ussuriensis Maxim and their anti-inflammatory activities

In total, 16 undescribed steroidal alkaloids (1-16), along with nine known ones (17-25), were isolated from the bulbs of Fritillaria ussuriensis Maxim. Among the undescribed compounds mentioned, compounds 1-6, 8 bearing an 16β-hydroxy substituent, as well as compounds 13 and 14 exhibited an unusual seven-membered skeleton. Their structures were established based on extensive spectroscopic analyses, including HRESIMS and NMR (1D and 2D), and comparison with the data reported in the literature. Furthermore, all the compounds were evaluated for their anti-inflammatory effect on the NO production of LPS-stimulated RAW264.7 cells. Compounds 1, 4, 11, 15, 22 and 24 could significantly inhibit NO production with IC50 values below 10 μM.

Cevanine-type steroidal alkaloids from the bulbs of Fritillaria cirrhosa D. Don

Eight previously undescribed cevanine-type steroidal alkaloids, cirrhosinones I-N and cirrhosinols A-B, along with five known analogs, were isolated from the bulbs of Fritillaria cirrhosa D. Don. Their structures were elucidated on the basis of comprehensive analysis of HRESIMS, 1D and 2D NMR spectroscopic data, and single-crystal X-ray diffraction analyses. All compounds revealed weak NO inhibitory activities in the LPS-stimulated NR8383 cells at the concentration of 20 μM, with inhibition ratios ranging from 5.1% to 14.3%.

Structural, computational and in silico studies of 4-bromo-3-flurobenzonitrile as anti-Alzheimer and anti-Parkinson agents

A novel dimer of the 4-bromo-3-fluorobenzonitrile was crystallized and studied using a spectroscopic method such as the scanning electron microscope method. The computational simulations substantiated the structural analysis findings. The Hirshfeld surface analysis has been performed for visualizing, exploring and quantifying the intra and inter-molecular interactions that stabilize the crystal packing of the compound. The NBO and QTAIM analyses were applied to study the nature and origin of the attractive forces involved in the crystal structure. Further, the pharmacokinetic properties of the compound were evaluated, indicating good brain-blood barrier and central nervous system penetration capability. Hence, in silico studies was carried out to explore the binding pattern of the titled compound against acetylcholinesterase and butyrylcholinesterase, and tumor necrosis factor-alpha converting enzyme proteins using molecular docking and molecular dynamics simulations approach. Further, the titled compound is compared with standard drugs through molecular docking studies. The in silico studies finally predicts that the compound under investigation may act as a good inhibitor for treating Alzheimer's disease and further in vitro and in vivo studies may provide its therapeutic potential.Communicated by Ramaswamy H. Sarma.

Synthesis and anti-liver fibrosis activity of imidazole and thiazole compounds containing amino acids

Four series of imidazoles (15a-g, 20c, and 20d) and thiazoles (18a-g, 22a, and 22b) possessing various amino acids were synthesized and evaluated for activin receptor-like kinase 5 (ALK5) inhibitory activities in an enzymatic assay. Among them, compounds 15g and 18c showed the highest inhibitory activity against ALK5, with IC50 values of 0.017 and 0.025 μM, respectively. Compounds 15g and 18c efficiently inhibited extracellular matrix (ECM) deposition in TGF-β-induced hepatic stellate cells (HSCs), and eventually suppressed HSC activation. Moreover, compound 15g showed a good pharmacokinetic (PK) profile with a favorable half-life (t1/2 = 9.14 h). The results indicated that these compounds exhibited activity targeting ALK5 and may have potential in the treatment of liver fibrosis; thus they are worthy of further study.

Cevanine-type alkaloids from the bulbs of Fritillaria unibracteata var. wabuensis and their antifibrotic activities in vitro

Steroidal alkaloids are the main bioactive components of the bulbs of Fritillaria, which have been used as traditional Chinese medicine, known as "Beimu", for the treatment of cough for thousands of years in China. Cough and dyspnea are the most common symptoms observed in patients with pulmonary fibrosis. However, the antifibrotic activity of steroidal alkaloids has not been reported yet. In this study, two previously unreported cevanine-type steroidal alkaloids (1 and 2), four previously undescribed cevanine-type alkaloid glycosides (3-6), and 19 known steroidal alkaloids (7-25) were isolated from the bulbs of Fritillaria unibracteata var. wabuensis. The structures of these compounds were elucidated by comprehensive HRESIMS and NMR spectroscopic data analysis, as well as DP4+ NMR calculations. The biological evaluation showed that compounds 2, 7-10, 14, 15, and 17 downregulated fibrotic markers induced by transforming growth factor-β (TGF-β) in MRC-5 cells. Moreover, compounds 14 and 17 dose dependently inhibited TGF-β-induced epithelial-mesenchymal transition in A549 cells, alleviated TGF-β-induced migration and proliferation of fibroblasts, and decreased the expression of fibrotic markers, fibronectin, and N-cadherin in TGF-β-induced MRC-5 cells. The research showed the potential of cevanine-type alkaloids as a class of natural antifibrotic agents.

Diastereomers of Steroidal Alkaloids with Cytotoxic Activities against Non-Small-Cell Lung Cancer from the Bulbs of Fritillaria sinica

Eleven new steroidal alkaloids, along with nine known related compounds, were isolated from the bulbs of Fritillaria sinica. Seven pairs of diastereomers were identified, including six and four 20-deoxy cevanine-type steroidal alkaloid diastereomers with molecular weights of 413 and 415, respectively. Structures were elucidated based on spectroscopic data analysis, chemical derivatization, and single-crystal X-ray diffraction analysis. Compounds 5, 9, 11, 12, 16, and 20 exhibited significant in vitro cytotoxic activity against non-small-cell lung cancer with CC50 values from 6.8 ± 3.9 to 12 ± 5 μM.

Naturally Occurring Cholinesterase Inhibitors from Plants, Fungi, Algae, and Animals: A Review of the Most Effective Inhibitors Reported in 2012-2022

Since the development of the "cholinergic hypothesis" as an important therapeutic approach in the treatment of Alzheimer's disease (AD), the scientific community has made a remarkable effort to discover new and effective molecules with the ability to inhibit the enzyme acetylcholinesterase (AChE). The natural function of this enzyme is to catalyze the hydrolysis of the neurotransmitter acetylcholine in the brain. Thus, its inhibition increases the levels of this neurochemical and improves the cholinergic functions in patients with AD alleviating the symptoms of this neurological disorder. In recent years, attention has also been focused on the role of another enzyme, butyrylcholinesterase (BChE), mainly in the advanced stages of AD, transforming this enzyme into another target of interest in the search for new anticholinesterase agents. Over the past decades, Nature has proven to be a rich source of bioactive compounds relevant to the discovery of new molecules with potential applications in AD therapy. Bioprospecting of new cholinesterase inhibitors among natural products has led to the discovery of an important number of new AChE and BChE inhibitors that became potential lead compounds for the development of anti-AD drugs. This review summarizes a total of 260 active compounds from 142 studies which correspond to the most relevant (IC50 ≤ 15 μM) research work published during 2012-2022 on plant-derived anticholinesterase compounds, as well as several potent inhibitors obtained from other sources like fungi, algae, and animals.

Putting the Puzzle Together To Get the Whole Picture: Molecular Basis of the Affinity of Two Steroid Derivatives to Acetylcholinesterase

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that has no cure because its etiology is still unknown, and its main treatment is the administration of acetylcholinesterase (AChE) inhibitors. The study of the mechanism of action of this family of compounds is critical for the design of new more potent and specific inhibitors. In this work, we study the molecular basis of an uncompetitive inhibitor (compound 1, 2β, 3α-dihydroxy-5α-cholestan-6-one disulfate), which we have proved to be a peripheral anionic site (PAS)-binding AChE inhibitor. The pipeline designed in this work is key to the development of other PAS inhibitors that not only inhibit the esterase action of the enzyme but could also modulate the non-cholinergic functions of AChE linked to the process of amylogenesis. Our studies showed that 1 inhibits the enzyme not simply by blocking the main gate but by an allosteric mechanism. A detailed and careful analysis of the ligand binding position and the protein dynamics, particularly regarding their secondary gates and active site, was necessary to conclude this. The same analysis was executed with an inactive analogue (compound 2, 2β, 3α-dihydroxy-5α-cholestan-6-one). Our first computational results showed no differences in affinity to AChE between both steroids, making further analysis necessary. This work highlights the variables to be considered and develops a refined methodology, for the successful design of new potent dual-action drugs for AD, particularly PAS inhibitors, an attractive strategy to combat AD.

Undescribed steroidal alkaloids from the bulbs of Fritillaria sinica

Eight undescribed steroidal alkaloid derivatives, including three cevanine-type isosteroidal alkaloids (two N-oxide glycosides and one D-ring aromatization) (1-3), one verazine-type steroidal alkaloid derivative (4), three solanidine-type steroidal alkaloid glycosides (5-7), and one veratramine-type analogue (8), along with three known compounds (9-11) were isolated from the bulbs of Fritillaria sinica. Their structures were elucidated by comprehensive analysis of spectroscopic data, acidic hydrolysis, and X-ray crystal diffractions. In the in vitro bioassay, the anti-cancer effect, anti-oxidation and anti-inflammatory activities for the isolates were evaluated at a concentration of 10 μM.

Steroidal alkaloids from the bulbs of Fritillaria unibracteata var. wabuensis and their anti-inflammatory activities

Fourteen previously undescribed steroidal alkaloids, including six jervine-type, wabujervine A-E and wabujerside A, seven cevanine-type, wabucevanine A-G, and one secolanidin-type, wabusesolanine A, along with thirteen known steroidal alkaloids, were isolated from the bulbs of Fritillaria unibracteata var. wabuensis. On the basis of comprehensive analysis of IR, HRESIMS, 1D and 2D NMR spectroscopic data, and single-crystal X-ray diffraction analyses, their structures were elucidated. In the zebrafish acute inflammatory models, nine compounds showed anti-inflammatory activity.

Synthesis and Evaluation of NF-κB Inhibitory Activity of Mollugin Derivatives

(1) Background: Nuclear factor κB (NF-κB) is an important transcriptional regulator that regulates the inflammatory pathway and plays a key role in cellular inflammatory and immune responses. The presence of a high concentration of NF-κB is positively correlated with the severity of inflammation. Therefore, the inhibition of this pathway is an important therapeutic target for the treatment of various types of inflammation; (2) Methods: we designed and synthesized 23 mollugin derivatives and evaluated their inhibitory activity against NF-κB transcription; (3) Results: Compound 6d exhibited the most promising inhibitory activity (IC₅₀ = 3.81 µM) and did not show any significant cytotoxicity against the tested cell lines. Investigation of the mechanism of action indicated that 6d down-regulated NF-κB expression, possibly by suppressing TNF-α-induced expression of the p65 protein. Most of the compounds exhibited potent anti-inflammatory activity. Compound 4f was the most potent compound with 83.08% inhibition of inflammation after intraperitoneal administration, which was more potent than mollugin and the reference drugs (ibuprofen and mesalazine). ADMET prediction analysis indicated that compounds 6d and 4f had good pharmacokinetics and drug-like behavior; (4) Conclusions: Several series of mollugin derivatives were designed, synthesized, and evaluated for NF-κB inhibitory activity and toxicity. These results provide an initial basis for the development of 4f and 6d as potential anti-inflammatory agents.

Novel Morpholine-Bearing Quinoline Derivatives as Potential Cholinesterase Inhibitors: The Influence of Amine, Carbon Linkers and Phenylamino Groups

A series of novel 4-N-phenylaminoquinoline derivatives containing a morpholine group were designed and synthesized, and their anti-cholinesterase activities and ABTS radical-scavenging activities were tested. Among them, compounds 11a, 11g, 11h, 11j, 11l, and 12a had comparable inhibition activities to reference galantamine in AChE. Especially, compound 11g revealed the most potent inhibition on AChE and BChE with IC₅₀ values of 1.94 ± 0.13 μM and 28.37 ± 1.85 μM, respectively. The kinetic analysis demonstrated that both the compounds 11a and 11g acted as mixed-type AChE inhibitors. A further docking comparison between the 11a- and 12a-AChE complexes agreed with the different inhibitory potency observed in experiments. Besides, compounds 11f and 11l showed excellent ABTS radical-scavenging activities, with IC₅₀ values of 9.07 ± 1.34 μM and 6.05 ± 1.17 μM, respectively, which were superior to the control, Trolox (IC₅₀ = 11.03 ± 0.76 μM). It is worth noting that 3-aminoquinoline derivatives 12a–12d exhibited better drug-like properties.

Isosteroidal alkaloids of Fritillaria taipaiensis and their implication to Alzheimer's disease: Isolation, structural elucidation and biological activity

Four undescribed and five known isosteroidal alkaloids were isolated from the bulbs of Fritillaria taipaiensis and their structures were elucidated on the basis of HR-ESI-MS, 1D and 2D NMR spectroscopic data analyses. The undescribed compounds were designated taipainines A-D. Of these, taipainine D presented a unique structure having the D/E trans (H-13α/H-17β) and E/F cis (β-axial lone pair of the N atom/H-22β) ring junctions. Possible biosynthetic pathway to taipainine D is proposed. Four compounds showed significant BChE inhibitory activities similar or better than the positive control galantamine. In addition, the preliminary structure-activity relationships (SARs) of these isosteroidal alkaloids were also investigated.

Determination of Anti-Alzheimer's Disease Activity of Selected Plant Ingredients

Neurodegenerative diseases, among which one of the more common is Alzheimer’s disease, are the one of the biggest global public health challenges facing our generation because of the increasing elderly population in most countries. With the growing burden of these diseases, it is essential to discover and develop new treatment options capable of preventing and treating them. Neurodegenerative diseases, among which one of the most common is Alzheimer’s disease, are a multifactorial disease and therefore demand multiple therapeutic approaches. One of the most important therapeutic strategies is controlling the level of acetylcholine—a neurotransmitter in cholinergic synapses—by blocking the degradation of acetylcholine using acetylcholinesterase inhibitors such as tacrine, galantamine, donepezil and rivastigmine. However, these drugs can cause some adverse side effects, such as hepatotoxicity and gastrointestinal disorder. Thus, the search for new, more effective drugs is very important. In the last few years, different active constituents from plants have been tested as potential drugs in neurodegenerative disease therapy. The availability, lower price and less toxic effects of herbal medicines compared with synthetic agents make them a simple and excellent choice in the treatment of neurodegenerative diseases. The empirical approach to discovering new drugs from the systematic screening of plant extracts or plant-derived compounds is still an important strategy when it comes to finding new biologically active substances. The aim of this review is to identify new, safe and effective compounds that are potential candidates for further in vivo and clinical tests from which more effective drugs for the treatment of Alzheimer’s disease could be selected. We reviewed the methods used to determine anti-Alzheimer’s disease activity. Here, we have discussed the relevance of plant-derived compounds with in vitro activity. Various plants and phytochemical compounds have shown different activity that could be beneficial in the treatment of Alzheimer’s disorders. Most often, medicinal plants and their active components have been investigated as acetylcholinesterase and/or butyrylcholinesterase activity inhibitors, modifiers of β-amyloid processing and antioxidant agents. This study also aims to highlight species with assessed efficacy, usable plant parts and the most active plant components in order to identify species and compounds of interest for further study. Future research directions are suggested and recommendations made to expand the use of medicinal plants, their formulations and plant-derived active compounds to prevent, mitigate and treat Alzheimer’s disease.

Novel glutamic acid derivatives from the bulbs of Fritillaria verticillate Willd and their antitumor activities

Four previously undescribed glutamic acid derivatives, verticillamines A-D (1-4), together with six known compounds (5-10) were isolated from the bulbs of Fritillaria verticillate Willd. The structures of (1-10) were established on the basis of UV, IR, MS, 1D and 2D NMR, and the absolute configurations of compounds (1-4) were determined by calculated ECD methods. Among them, compounds (1-3) were rare 2-methyl-γ-lactam alkaloid derivatives. Moreover, both γ-lactam alkaloids (1-5) and pyrrolidine alkaloids (6-7) were discovered in Fritillaria for the first time. Compound 8 exhibited moderate cytotoxic activities against A2780 and HepG 2 cells, with IC₅₀ values of 11.7 ± 5.2 μM and 25.6 ± 2.8 μM.

A new alkaloid with cytotoxic activity from Fritillaria thunbergii Miq

A new alkaloid named zhebeisine (1), together with four known compounds, eduardine (2), zhebeirine (3), isoverticine (4), and verticine (5), was isolated from the bulbs of Fritillaria thunbergii Miq. The structure of the new compound was elucidated on the basis of extensive spectroscopic methods and the in vitro biological activities of it were evaluated as well. Compound 1 features a veratramine skeleton with a rare 6/6/5/6/6/6 fused-ring system, representing the first reported veratramine-type alkaloid with a new oxazinane ring (ring-F) in Fritillaria genus. The cytotoxic activities study revealed that compound 1 inhibited the cell proliferation of HT29 and DLD1 (IC₅₀ values of 25.1 and 48.8 µM, respectively) and also induced apoptosis of the above-mentioned two cancer cell lines.

Natural drug sources for respiratory diseases from Fritillaria: chemical and biological analyses

Fritillaria naturally grows in the temperate region of Northern Hemisphere and mainly distributes in Central Asia, Mediterranean region, and North America. The dried bulbs from a dozen species of this genus have been usually used as herbal medicine, named Beimu in China. Beimu had rich sources of phytochemicals and have extensively applied to respiratory diseases including coronavirus disease (COVID-19). Fritillaria species have alkaloids that act as the main active components that contribute multiple biological activities, including anti-tussive, expectorant, and anti-asthmatic effects, especially against certain respiratory diseases. Other compounds (terpenoids, steroidal saponins, and phenylpropanoids) have also been identified in species of Fritillaria. In this review, readers will discover a brief summary of traditional uses and a comprehensive description of the chemical profiles, biological properties, and analytical techniques used for quality control. In general, the detailed summary reveals 293 specialized metabolites that have been isolated and analyzed in Fritillaria species. This review may provide a scientific basis for the chemical ecology and metabolomics in which compound identification of certain species remains a limiting step.

Potential of Naturally Derived Alkaloids as Multi-Targeted Therapeutic Agents for Neurodegenerative Diseases

Alkaloids are a class of secondary metabolites that can be derived from plants, fungi and marine sponges. They are widely known as a continuous source of medicine for the management of chronic disease including cancer, diabetes and neurodegenerative diseases. For example, galanthamine and huperzine A are alkaloid derivatives currently being used for the symptomatic management of neurodegenerative disease. The etiology of neurodegenerative diseases is polygenic and multifactorial including but not limited to inflammation, oxidative stress and protein aggregation. Therefore, natural-product-based alkaloids with polypharmacology modulation properties are potentially useful for further drug development or, to a lesser extent, as nutraceuticals to manage neurodegeneration. This review aims to discuss and summarise recent developments in relation to naturally derived alkaloids for neurodegenerative diseases.

Extraction assisted by far infrared radiation and hot air circulation with deep eutectic solvent for bioactive polysaccharides from Poria cocos (Schw.) wolf

In this study, a new ternary choline chloride-deep eutectic solvent was used to efficiently extract bioactive polysaccharides from poria cocos assisted by the new tool of the far infrared radiation (FIR) together with hot air circulation (HAC).

The synthesis and cholinesterase inhibitory activities of solasodine analogues with seven-membered F ring

Solasodine analogues containing a seven-membered F ring with a nitrogen atom placed at position 22a were prepared from diosgenin or tigogenin in a four-step synthesis comprising of the simultaneous opening of the F-ring and introduction of cyanide in position 22α, activation of the 26-hydroxyl group as mesylate, nitrile reduction, and N-cyclization. Solasodine, six obtained 22a(N)-homo analogues, as well as four 26a-homosolasodine derivatives and their open-chain precursors (13 in total) were tested as potential inhibitors of acetyl- and butyryl-cholinesterases and showed activity at micromolar concentrations. The structure-activity relationship study revealed that activities against studied esterases are affected by the structure of E/F rings and the substitution pattern of ring A. The most potent compound 8 acted as non-competitive inhibitors and exerted IC₅₀ = 8.51 μM and 7.05 μM for eeAChE and eqBChE, respectively. Molecular docking studies revealed the hydrogen bond interaction of 8 with S293 of AChE; further rings are stabilized via hydrophobic interaction (ring A) or interaction with Y341 and W286 (rings B and C). Biological experiments showed no neurotoxicity of differentiated SH-SY5Y cells. More importantly, results from neuroprotective assay based on glutamate-induced cytotoxicity revealed that most derivatives had the ability to increase the viability of differentiated SH-SY5Y cells in comparison to galantamine and lipoic acid assayed as standards. The newly synthesized solasodine analogues are able to inhibit and to bind cholinesterases in noncompetitive mode of inhibition and exhibited neuroprotection potential of differentiated neuroblastoma cells after Glu-induced toxicity.

Identification and molecular docking study of fish roe-derived peptides as potent BACE 1, AChE, and BChE inhibitors

Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and beta-secretase 1 (BACE 1) play vital roles in the development and progression of Alzheimer's disease (AD).

Phenoxyethyl Piperidine/Morpholine Derivatives as PAS and CAS Inhibitors of Cholinesterases: Insights for Future Drug Design

Acetylcholinesterase (AChE) catalyzes the conversion of Aβ peptide to its aggregated form and the peripheral anionic site (PAS) of AChE is mainly involved in this phenomenon. Also catalytic active site (CAS) of donepezil stimulates the break-down of acetylcholine (ACh) and depletion of ACh in cholinergic synapses are well established in brains of patients with AD. In this study, a set of compounds bearing phenoxyethyl amines were synthesized and their inhibitory activity toward electric eel AChE (eeAChE) and equine butyrylcholinesterase (eqBuChE) were evaluated. Molecular dynamics (MD) was employed to record the binding interactions of best compounds against human cholinesterases (hAChE and hBuChE) as well as donepezil as reference drug. In vitro results revealed that compound 5c is capable of inhibiting eeAChE activity at IC₅₀ of 0.50 µM while no inhibitory activity was found for eqBuChE for up to 100 µM concentrations. Compound 5c, also due to its facile synthesis, small structure and high selectivity for eeAChE would be very interesting candidate in forthcoming studies. The main interacting parts of compound 5c and compound 7c (most potent eeAChE and eqBuChE inhibitors respectively) with receptors which confer selectivity for AChE and BuChE inhibition were identified, discussed, and compared with donepezil’s interactions. Also during MD simulation it was discovered for the first time that binding of substrates like donepezil to dual CAS and PAS or solely CAS region might have a suppressive impact on 4-α-helical bundles near the tryptophan amphiphilic tetramerization (WAT) domain of AChE and residues which are far away from AChE active site. The results proposed that residues involved in donepezil interactions (Trp86 and Phe295) which are located in CAS and mid-gorge are the mediator of conformational changes in whole protein structure.

Untargeted metabolomics coupled with chemometric analysis reveals species-specific steroidal alkaloids for the authentication of medicinal Fritillariae Bulbus and relevant products

Authentication of original species is embedded in the quality control system of herbal medicines. In this work, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based untargeted metabolomics coupled with chemometric analysis was utilized for the precise authentication of the Fritillaria species for both raw materials and commercial products. First, a stepwise difference-enlarging chemometric analysis strategy was proposed to analyze eight medicinal Fritillaria species. Subsequently, 21 species-specific markers were discovered and the specificity was investigated under different sample preparation methods. Finally, the obtained species-specific markers were successfully utilized to identify the Fritillaria species in commercially relevant products. This work is the first to report robust and specific markers for authentication of Fritillaria products, showing promise for tracking the supply chain of herbal suppliers.

Novel ACE inhibitors derived from soybean proteins using in silico and in vitro studies

The widespread application of soybean-derived peptides is currently limited due to the challenges in the identification of peptides. In the present work, in silico and in vitro analysis were applied to identify ACE inhibitory tri-peptides from soybean protein. The soybean protein was cleaved by PeptideCutter. Then, unknown tri-peptides were selected to solubility estimation and ADME prediction. Subsequently, Discovery Studio was applied to evaluate the interaction mechanism between ACE and tri-peptides. Finally, in vitro activity of theoretical ACE inhibitory tri-peptides was verified by RP-HPLC method. As a result, DMG was selected as a potent ACE inhibitory peptide. Cell experiment showed that DMG had no cytotoxic effects on HEK-293 cells. And molecular docking results indicated that DMG contacted well with ACE's active sites (Gln281, His353, Ala354, Glu384, Lys511, His513, and Tyr520). Furthermore, DMG could exert potent activity against ACE, with IC50 value of 3.95 ± 0.11 mM. PRACTICAL APPLICATIONS: Present research showed soybean is a potential protein resource to obtain ACE inhibitory peptides. Simultaneously, virtual screening method is a feasible way to substitute for classical method in emerging nutritional fields. What's more, present study provides a theoretical basis for industrial research on foodstuff for ACE inhibitory peptides without side effects.

Pharmacokinetics and enterohepatic circulation of jervine, an antitumor steroidal alkaloid from Veratrum nigrum in rats

Jervine, a novel steroidal alkaloid from Veratrum nigrum L., exhibits both antitumor effect and potential toxicity. The aim of study was to characterize the pharmacokinetic behaviors and enterohepatic circulation of jervine in rats. A rapid and simple ultra-high performance liquid chromatography-tandem mass spectrometric method was developed and validated for quantification of jervine and alpinetin (internal standard) in rat plasma. After extraction from rat plasma by a simple protein-precipitation method, the analyte was separated on a C₁₈ column (2.1 mm × 50 mm, 1.7 μm) using water with 0.1% formic acid and acetonitrile as the mobile phase delivered at a flow rate of 0.4 mL/min. Jervine and alpinetin were determined in the positive mode with multiple reaction monitoring (MRM) of the ion transitions at m/z 426.3 → 108.8 and m/z 271.0 → 166.9, respectively. Molecular docking method was used to investigate the binding of jervine to p-glycoprotein and dehydroepiandrosterone sulfotransferase. The method was well validated within acceptance limits including specificity, matrix effect, recovery, precision, accuracy, and stability, and was successfully applied to the pharmacokinetic study of jervine after oral and intravenous administration to rats. Jervine presented a small volume of distribution, fast absorption, high oral bioavailability, and enterohepatic circulation. The enterohepatic circulation was first observed in veratrum alkaloids, and was further investigated by molecular docking studies, which was related to the binding of jervine to p-glycoprotein and dehydroepiandrosterone sulfotransferase. The pharmacokinetic properties and enterohepatic circulation of jervine in rats provided a significant basis for the drug-drug interaction and toxicity study in the future.

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It is the first pharmacokinetic and bioavailability study of jervine in rats.

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A simple protein precipitation was used for pretreatment and the LLOQ was 0.25 ng/mL.

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The enterohepatic circulation was first observed in veratrum alkaloids.

Synthesis and Evaluation of 3-Substituted-4-(quinoxalin-6-yl) Pyrazoles as TGF-β Type I Receptor Kinase Inhibitors

The transforming growth factor-β (TGF-β), in which overexpression has been associated with various diseases, has become an attractive molecular target for the treatment of cancers. Thirty-two quinoxaline-derivatives of 3-substituted-4-(quinoxalin-6-yl) pyrazoles 14a–d, 15a–d, 16a–d, 17a–d, 18a–d, 19a–d, 25a, 25b, 25d, 26a, 26b, 26d, 27b, and 27d were synthesized and evaluated for their activin TGF-β type I receptor kinase and p38α mitogen activated protein (MAP) kinase inhibitory activity in enzymatic assays. Among these compounds, the most active compound 19b inhibited TGF-β type I receptor kinase phosphorylation with an IC₅₀ value of 0.28 µM, with 98% inhibition at 10 µM. Compound 19b also had good selectivity index of >35 against p38α MAP kinase, with 9.0-fold more selective than clinical candidate, compound 3 (LY-2157299). A molecular docking study was performed to identify the mechanism of action of the synthesized compounds and their good binding interactions were observed. ADMET prediction of good active compounds showed that these ones possess good pharmacokinetics and drug-likeness behavior.