(+)-fenchol and (-)-isopinocampheol derivatives targeting the entry process of filoviruses.

The increasing frequency of filovirus outbreaks in African countries has led to a pressing need for the development of effective antifilovirus agents. In continuation of our previous research on the antifilovirus activity of monoterpenoid derivatives, we synthesized a series of (+)-fenchol and (-)-isopinocampheol derivatives by varying the type of heterocycle and linker length. Derivatives with an N-alkylpiperazine cycle proved to be the most potent antiviral compounds, with half-maximal inhibitory concentration (IC50) 1.4-20 µÐœ against Lenti-EboV-GP infection and 11.3-47 µÐœ against Lenti-MarV-GP infection. Mechanism-of-action experiments revealed that the compounds may exert their action by binding to surface glycoproteins (GPs). It was demonstrated that the binding of the synthesized compounds to the Marburg virus GP is less efficient as compared to the Ebola virus GP. Furthermore, it was shown that the compounds possess lysosomotropic properties. Thus, the antiviral activity may be due to dual effects. This study offers new antiviral agents that are worthy of further exploration.

Design, synthesis and antiviral evaluation of novel conjugates of the 1,7,7-trimethylbicyclo[2.2.1]heptane scaffold and saturated N-heterocycles via 1,2,3-triazole linker.

A new series of heterocyclic derivatives with a 1,7,7-trimethylbicyclo[2.2.1]heptane fragment was designed, synthesised and biologically evaluated. Synthesis of the target compounds was performed using the Cu(I) catalysed cycloaddition reaction. The key starting substances in the click reaction were an alkyne containing a 1,7,7-trimethylbicyclo[2.2.1]heptane fragment and a series of azides with saturated nitrogen-containing heterocycles. Some of the derivatives were found to exhibit strong antiviral activity against Marburg and Ebola pseudotype viruses. Lysosomal trapping assays revealed the derivatives to possess lysosomotropic properties. The molecular modelling study demonstrated the binding affinity between the compounds investigated and the possible active site to be mainly due to hydrophobic interactions. Thus, combining a natural hydrophobic structural fragment and a lysosome-targetable heterocycle may be an effective strategy for designing antiviral agents.

Aerosol Inhalation Delivery of Ag Nanoparticles in Mice: Pharmacokinetics and Antibacterial Action.

The aerosol inhalation delivery of composite particles consisting of Ag nanoparticles enveloped by polyvinylpyrrolidone was investigated in experiments with mice. An ultrasonic nebulizing system was created for the generation of aerosols with a mean diameter and mass concentration of 700 ± 50 nm and 65 ± 5 mg/m3, respectively. The mass fraction of Ag in the composite particles was α = 0.061. The aerosol delivery was performed in a whole-body chamber with an exposition time of 20 min. Pharmacokinetic measurements were taken and the silver concentrations in the blood and lungs of the mice were measured as a function of time after exposition by means of electrothermal (graphite furnace) atomic absorption spectrometry. The inhalation dose and other pharmacokinetic parameters were determined. The antibacterial effect of aerosolized silver was assessed for mice infected with Klebsiella pneumoniae 82 and Staphylococcus aureus ATCC 25953. The survival rate of the infected mice after the aerosol exposure demonstrated the high antibacterial efficiency of Ag nanoparticles after inhalation delivery.

Effect of the Composition of Leuzea and Cranberry Meal Extracts on Metabolic Processes in Norm and Pathology.

This study was conducted to evaluate the effects of long-term administration of a new herbal composition of leuzea and cranberry meal extracts at a dose of 70:500 mg/kg in healthy and pathological mice. After 4 weeks of daily composition administration to healthy CD-1 mice and C57BL/6 mice with diet-induced metabolic syndrome, oral glucose tolerance test (OGTT), serum biochemical examination and histology of internal organs were performed. Additionally, histological examination of white and brown adipose tissue was performed to evaluate the ability of the composition to prevent abdominal obesity in C57BL/6Ay (agouti yellow) mice. The results showed that the composition increased tissue sensitivity to glucose in healthy CD-1 mice; at the same time, it did not worsen the course of pathological processes in pathological mice. In both cases, the application of the developed composition was safe and contributed to the restoration of metabolic parameters.

Synthesis, Pharmacological Evaluation, and Molecular Modeling of Lappaconitine-1,5-Benzodiazepine Hybrids.

Diterpenoid alkaloids, originating from the amination of natural tetracyclic diterpenes, have long interested scientists due to their medicinal uses and infamous toxicity which has limited the clinical application of the native compound. Alkaloid lappaconitine extracted from various Aconitum and Delphinium species has displayed extensive bioactivities and active ongoing research to reduce its adverse effects. A convenient route to construct hybrid molecules containing diterpenoid alkaloid lappaconitine and 3H-1,5-benzodiazepine fragments was proposed. The key stage involved the formation of 5'-alkynone-lappaconitines in situ by acyl Sonogashira coupling of 5'-ethynyllappaconitine, followed by cyclocondensation with o-phenylenediamine. New hybrid compounds showed low toxicity and outstanding analgesic activity in experimental pain models, which depended on the nature of the substituent in the benzodiazepine nucleus. An analogous dependence was also shown for the antiarrhythmic activity in the epinephrine arrhythmia test in vivo. Studies on the isolated atrium have shown that the mechanism of action of the new compounds is included the blockade of beta-adrenergic receptors and potassium channels. Molecular docking analysis was conducted to determine the binding potential of target molecules with the voltage-gated sodium channel NaV1.5. All obtained results provide a basis for future rational modifications of lappaconitine, reducing side effects, while retaining its therapeutic effects.

Antiulcer Activity of Anthraquinone-Flavonoid Complex of Rumex tianschanicus Losinsk.

The composition of an ethanol extract from the roots of Rumex tianschanicus Losinsk of the Trans-Ili Alatau wild flora was studied in order to determine its antiulcer activity. The phytochemical composition of the anthraquinone-flavonoid complex from (AFC) R. tianschanicus revealed the presence of numerous polyphenolic compounds, the most abundant of which are anthraquinones (1.77%), flavonoids (6.95%), and tannins (13.39%). The use of column chromatography (CC) and thin-layer chromatography (TLC) in conjunction with UV, IR, NMR spectroscopy, and mass spectrometry data allowed the researchers to isolate and identify the major components of the anthraquinone-flavonoid complex's polyphenol fraction: physcion, chrysophanol, emodin, isorhamnetin, quercetin, and myricetin. The gastroprotective effect of the polyphenolic fraction of the anthraquinone-flavonoid complex (AFC) of R. tianschanicus roots was examined in an experimental model of rat gastric ulcer induced by indomethacin. The preventive and therapeutic effect of the anthraquinone-flavonoid complex at a dose of 100 mg/kg was analyzed using intragastric administration per day for 1 to 10 days, followed by a histological examination of stomach tissues. It has been demonstrated that prophylactic and prolonged use of the AFC R. tianschanicus in laboratory animals resulted in significantly less pronounced hemodynamic and desquamative changes in the epithelium of gastric tissues. The acquired results thus offer fresh insight into the anthraquinone and flavonoid metabolite component composition of R. tianschanicus roots, and they imply that the examined extract can be used to develop herbal medicines with antiulcer activity.

Hepatoprotective Effect of a New FFAR1 Agonist-N-Alkylated Isobornylamine.

Free fatty acid receptor-1 (FFAR1) is one of the possible therapeutic targets in the search for new hepatoprotective drugs. FFAR1 agonists were found to have hypolipidemic, antifibrotic, anti-inflammatory, antiproliferative and antioxidant effects in addition to hypoglycemic action. In this work, we conducted a study of the hepatoprotective effect of the compound QS-528 (previously discovered as an agonist of FFAR1) at doses of 60, 90, 120 and 150 mg/kg on carbon tetrachloride (CCl4)-induced liver injury. At the end of the experiment, a biochemical blood assay demonstrated that the introduction of QS-528 dose-dependently reduces the levels of liver enzymes (AST, ALT and ALKP). Histological and morphometric studies of animals' livers treated with QS-528 at doses of 120 and 150 mg/kg showed a decrease in degenerative/necrotic changes in hepatocytes and an increase in the regenerative activity of the liver. In addition, no toxicity at a single oral dose of 1000 mg/kg and an increase in HepG2 cell viability in vitro were found. Thus, the compound QS-528 was found to exhibit a hepatoprotective effect against CCl4-induced toxic liver damage.

A Newly Identified Monoterpenoid-Based Small Molecule Able to Support the Survival of Primary Cultured Dopamine Neurons and Alleviate MPTP-Induced Toxicity In Vivo.

Parkinson's disease (PD) is the most common age-related movement disorder characterized by the progressive loss of nigrostriatal dopaminergic neurons. To date, PD treatment strategies are mostly based on dopamine replacement medicines, which can alleviate motor symptoms but do not slow down the progression of neurodegeneration. Thus, there is a need for disease-modifying PD therapies. The aim of this work was to evaluate the neuroprotective effects of the novel compound PA96 on dopamine neurons in vivo and in vitro, assess its ability to alleviate motor deficits in MPTP- and haloperidol-based PD models, as well as PK profile and BBB penetration. PA96 was synthesized from (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl) cyclohex-3-ene-1,2-diol (Prottremin) using the original three-step stereoselective procedure. We found that PA96: (1) supported the survival of cultured näive dopamine neurons; (2) supported the survival of MPP+-challenged dopamine neurons in vitro and in vivo; (3) had chemically appropriate properties (synthesis, solubility, etc.); (4) alleviated motor deficits in MPTP- and haloperidol-based models of PD; (5) penetrated the blood-brain barrier in vivo; and (6) was eliminated from the bloodstream relative rapidly. In conclusion, the present article demonstrates the identification of PA96 as a lead compound for the future development of this compound into a clinically used drug.

The Study of Hypoglycemic Activity of 7-Terpenylcoumarins.

Natural and synthetic coumarins are often considered privileged scaffolds for obtaining pharmacological agents with hypoglycemic activity. Chemical modification of coumarins often leads to antidiabetic agents with greater efficacy. In the present work, twenty monoterpene-substituted 7-hydroxycoumarins were synthesized. A new approach using the Mitsunobu reaction was shown to be effective for the synthesis of target compounds. All of the synthesized compounds were evaluated in an oral glucose tolerance test, and two of them containing geranyl and (-)-myrtenyl substituents showed in vivo hypoglycemic action. A possible mechanism of action of these compounds may include inhibition of DPP IV, which was proved in an in vitro test.

Design, Synthesis and Assay of Novel Methylxanthine-Alkynylmethylamine Derivatives as Acetylcholinesterase Inhibitors.

Xanthine derivatives have been a great area of interest for the development of potent bioactive agents. Thirty-eight methylxanthine derivatives as acetylcholinesterase inhibitors (AChE) were designed and synthesized. Suzuki-Miyaura cross-coupling reactions of 8-chlorocaffeine with aryl(hetaryl)boronic acids, the CuAAC reaction of 8-ethynylcaffeine with several azides, and the copper(I) catalyzed one-pot three-component reaction (A3-coupling) of 8-ethynylcaffeine, 1-(prop-2-ynyl)-, or 7-(prop-2-ynyl)-dimethylxanthines with formaldehyde and secondary amines were the main approaches for the synthesis of substituted methylxanthine derivatives (yield 53-96%). The bioactivity of all new compounds was evaluated by Ellman's method, and the results showed that most of the synthesized compounds displayed good and moderate acetylcholinesterase (AChE) inhibitory activities in vitro. The structure-activity relationships were also discussed. The data revealed that compounds 53, 59, 65, 66, and 69 exhibited the most potent inhibitory activity against AChE with IC50 of 0.25, 0.552, 0.089, 0.746, and 0.121 µM, respectively. The binding conformation and simultaneous interaction modes were further clarified by molecular docking studies.

Antihypothyroid Effect of Salidroside.

In terms of prevalence, thyroid pathology, associated both with a violation of the gland function and changes in its structure, occupies one of the main places in clinical endocrinology. The problem of developing low-toxic and highly effective herbal preparations for the correction of thyroid hypofunction and its complications is urgent. Salidroside is a glucoside of tyrosol, found mostly in the roots of Rhodiola spp., and has various positive biological activities. The purpose of this study was to study the antihypothyroid potential of salidrosid-containing extract from R. semenovii roots, which was evaluated on a mercazolyl hypothyroidism model. We showed that extract containing salidroside is a safe and effective means of hypothyroidism correction, significantly reducing (p ≤ 0.001) the level of thyroid-stimulating hormone and increasing the level of thyroid hormones. The combined use of R. semenovii extract with potassium iodide enhances the therapeutic effect of the extract by 1.3-times.

Aerosol Inhalation Delivery of Ceftriaxone in Mice: Generation Procedure, Pharmacokinetics, and Therapeutic Outcome.

Aerosol inhalation delivery of ceftriaxone in mice was investigated. An ultrasonic nebulizer within the ranges of mean particle diameter 0.5-1.5 µm and mass concentration 0.01-0.6 µg/cm3 was used in inhalation experiments. Pharmacokinetic measurements were carried out using a nose-only chamber. Ceftriaxone concentration in blood serum and its mass in the lungs of mice were measured as a function of time using high-performance liquid chromatography. The body-delivered dose was within the range 3-5 mg/kg. The antibacterial effect of aerosolized ceftriaxone was investigated for mice infected with Klebsiella pneumoniae 82 and Staphylococcus aureus ATCC 25 953. The survival rate for infected mice after the treatment with ceftriaxone aerosol revealed the high antibacterial efficiency of this kind of treatment.

Conjugates of Lupane Triterpenoids with Arylpyrimidines: Synthesis and Anti-inflammatory Activity.

Semisynthetic triterpenoid betulonic acid is of significant interest due to its biological activity and synthetic application. In this study, we report the synthesis of hybrid compounds, containing betulonic acid carboxamide and arylpyrimidine fragments. A total of 15 conjugates were prepared using the cyclocondensation reaction of new terpenoid alkynyl ketones with amidinium salts. The main synthetic approach to betulonic acid amide-derived alkynylketones was based on the cross-coupling reaction of N-(4-ethynylphenyl)- or N-(2-(4-ethynylphenyl)-1-(methoxycarbonyl)ethyl)- substituted betulonic acid carboxamide with aroylchlorides. Cyclocondensation of alkynones with amidine or guanidine hydrochlorides by reflux in MeCN in the presence of K2CO3 led to the formation of terpenoid pyrimidine hybrids in 52-89% isolated yield. Anti-inflammatory properties of new type of triterpenoid-pyrimidine conjugates were studied using the histamine- and concanavalin A- induced mouse paw edema models. In a model of acute inflammation betulonic acid amide-arylpyrimidines containing a 4-fluorophenyl substituent at the C-6 position of pyrimidine ring exhibited significant and selective anti-inflammatory activity. Compounds containing the 4-bromophenyl- substituent in the pyrimidine ring revealed selective anti-inflammatory activity in the model of immunogenic inflammation (concanavalin-A model). It should be noted that the methoxycarbonyl substituted ethane link between pharmacophore ligands (betulonic acid carboxamide and arylpyrimidine) has a significant effect on anti-inflammatory activity in both in vivo models of inflammation. It was shown by molecular docking that the new derivatives are incorporated into the binding site of the protein Keap1 Kelch-domain by their pyrimidine substituent with the formation of more non-covalent bonds.

Design and Evaluation of Bispidine-Based SARS-CoV-2 Main Protease Inhibitors.

For the first time, derivatives of 3,7-diazabicyclo[3.3.1]nonane (bispidine) were proposed as potential inhibitors of the SARS-CoV-2 main viral protease (3-chymotrypsin-like, 3CLpro). Based on the created pharmacophore model of the active site of the protease, a group of compounds were modeled and tested for activity against 3CLpro. The 3CLpro activity was measured using the fluorogenic substrate Dabcyl-VNSTLQSGLRK(FAM)MA; the efficiency of the proposed approach was confirmed by comparison with literature data for ebselen and disulfiram. The results of the experiments performed with bispidine compounds showed that 14 compounds exhibited activity in the concentration range 1-10 µM, and 3 samples exhibited submicromolar activity. The structure-activity relationship studies showed that the molecules containing a carbonyl group in the ninth position of the bicycle exhibited the maximum activity. Based on the experimental and theoretical results obtained, further directions for the development of this topic were proposed.

Cascade Transformations of 1-R-Ethynyl-9,10-anthraquinones with Amidines: Expanding Access to Isoaporphinoid Alkaloids.

The interaction of acetamidine and phenylamidine with peri-R-ethynyl-9,10-anthraquinones in refluxing n-butanol leads to the formation of cascade transformations products: addition/elimination/cyclization-2-R-7H-dibenzo[de,h]quinolin-7-ones and(or) 2-R-3-aroyl-7H-dibenzo[de,h]quinolin-7-ones. The anti-inflammatory and antitumor properties of the new 2-R-7H-dibenzo[de,h]quinolin-7-ones were investigated in vivo, in vitro, and in silico. The synthesized compounds exhibit high anti-inflammatory activity at dose 20 mg/kg (intraperitoneal injection) in the models of exudative (histamine-induced) and immunogenic (concanavalin A-induced) inflammation. Molecular docking data demonstrate that quinolinones can potentially intercalate into DNA similarly to the antitumor drug doxorubicin.

The Influence of Abiotic Stress Factors on the Morphophysiological and Phytochemical Aspects of the Acclimation of the Plant Rhodiola semenowii Boriss.

Plants of the Crassulaceae family are natural accumulators of many medicinal secondary metabolites (SM). This article describes the study of morphophysiological, anatomic and phytochemical responses of immature plants of Rhodiolla semenovii under water deficit and (or) cold-stress conditions. Changes in biomass production due to water content in plant tissues such as a decrease in water deficit and an increase in cold stress were revealed. A significant decrease in the efficiency of the photosynthetic apparatus under stress conditions was noted, based on the parameters quantum efficiency of Photosystem II and electron transport rate and energy dissipated in Photosystem II. The greatest decrease in efficiency was pointed out in conditions of water shortage. The anatomical modulations of root and shoot of R. semenovii under stress conditions were found. For the first time, a detailed study of the chemical composition of the ethanol extract of root and shoot of R. semenovii under stress was carried out using gas chromatography-mass spectrometry. The qualitative and quantitative composition of SM associated with acclimation to the effects of abiotic stresses was determined. Both nonspecific and specific phytochemical changes caused by the action of water deficiency and cold treatment were identified. It has been shown that the antioxidant system in plant tissues is complex, multicomponent, depending on a number of natural and climatic factors. Further research should be focused on the use of abiotic stressors for the targeted synthesis of bioactive SMs valuable for pharmaceutical use.

Solubility, Permeability, Anti-Inflammatory Action and In Vivo Pharmacokinetic Properties of Several Mechanochemically Obtained Pharmaceutical Solid Dispersions of Nimesulide.

Nimesulide (NIM, N-(4-nitro-2-phenoxyphenyl)methanesulfonamide) is a relatively new nonsteroidal anti-inflammatory analgesic drug. It is practically insoluble in water (<0.02 mg/mL). This very poor aqueous solubility of the drug may lead to low bioavailability. The objective of the present study was to investigate the possibility of improving the solubility and the bioavailability of NIM via complexation with polysaccharide arabinogalactan (AG), disodium salt of glycyrrhizic acid (Na2GA), hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and MgCO3. Solid dispersions (SD) have been prepared using a mechanochemical technique. The physical properties of nimesulide SD in solid state were characterized by differential scanning calorimetry and X-ray diffraction studies. The characteristics of the water solutions which form from the obtained solid dispersions were analyzed by reverse phase and gel permeation HPLC. It was shown that solubility increases for all complexes under investigation. These phenomena are obliged by complexation with auxiliary substances, which was shown by 1H-NMR relaxation methods. The parallel artificial membrane permeability assay (PAMPA) was used for predicting passive intestinal absorption. Results showed that mechanochemically obtained complexes with polysaccharide AG, Na2GA, and HP-ß-CD enhanced permeation of NIM across an artificial membrane compared to that of the pure NIM. The complexes were examined for anti-inflammatory activity on a model of histamine edema. The substances were administered per os to CD-1 mice. As a result, it was found that all investigated complexes dose-dependently reduce the degree of inflammation. The best results were obtained for the complexes of NIM with Na2GA and HP-ß-CD. In noted case the inflammation can be diminished up to 2-fold at equal doses of NIM.

Synthesis of Anti-Inflammatory Spirostene-Pyrazole Conjugates by a Consecutive Multicomponent Reaction of Diosgenin with Oxalyl Chloride, Arylalkynes and Hydrazines or Hydrazones.

Steroid sapogenin diosgenin is of significant interest due to its biological activity and synthetic application. A consecutive one-pot reaction of diosgenin, oxalyl chloride, arylacetylenes, and phenylhydrazine give rise to steroidal 1,3,5-trisubstituted pyrazoles (isolated yield 46-60%) when the Stephens-Castro reaction and heterocyclization steps were carried out by heating in benzene. When the cyclization step of alkyndione with phenylhydrazine was performed in 2-methoxyethanol at room temperature, steroidal α,ß-alkynyl (E)- and (Z)-hydrazones were isolated along with 1,3,5-trisubstituted pyrazole and the isomeric 2,3,5-trisubstituted pyrazole. The consecutive reaction of diosgenin, oxalyl chloride, phenylacetylene and benzoic acid hydrazides efficiently forms steroidal 1-benzoyl-5-hydroxy-3-phenylpyrazolines. The structure of new compounds was unambiguously corroborated by comprehensive NMR spectroscopy, mass-spectrometry, and X-ray structure analyses. Performing the heterocyclization step of ynedione with hydrazine monohydrate in 2-methoxyethanol allowed the synthesis of 5-phenyl substituted steroidal pyrazole, which was found to exhibit high anti-inflammatory activity, comparable to that of diclofenac sodium, a commercial pain reliever. It was shown by molecular docking that the new derivatives are incorporated into the binding site of the protein Keap1 Kelch-domain by their alkynylhydrazone or pyrazole substituent with the formation of more non-covalent bonds and have higher affinity than the initial spirostene core.

Aerosol Inhalation Delivery of Triazavirin in Mice: Outlooks for Advanced Therapy Against Novel Viral Infections.

Under pandemic-caused emergency, evaluation of the potential of existing antiviral drugs for the treatment of COVID-19 is relevant. Triazavirin, an antiviral drug developed in Russia for per-oral administration, is involved in clinical trials against SARS-CoV-2 coronavirus. This virus has affinity to epithelial cells in respiratory tract, so drug delivery directly in lungs may enhance therapeutic effect and reduce side effects for stomach, liver, kidneys. We elaborated ultrasonic method of triazavirin aerosol generation and investigated the inhalation delivery of this drug in mice. Mean particle size and number concentration of aerosol used in inhalation experiments are 560 nm and 4 × 105 cm-3, respectively. Aerosol mass concentration is 1.6 × 10-4 mg/cm3. Inhalation for 20 min in a nose-only chamber resulted in 2 mg/kg body delivered dose and 2.6 µg/mL triazavirin concentration in blood plasma. Elimination rate constant determined in aerosol administration experiments was ke = 0.077 min-1, which agrees with the value measured after intravenous delivery, but per-oral administration resulted in considerably lower apparent elimination rate constant of pseudo-first order, probably due to non-linear dependence of absorption rate on triazavirin concentration in gastrointestinal tract. The bioavailability of triazavirin aerosol is found to be 85%, which is about four times higher than for per-oral administration.

Hybrides of Alkaloid Lappaconitine with Pyrimidine Motif on the Anthranilic Acid Moiety: Design, Synthesis, and Investigation of Antinociceptive Potency.

Convenient and efficient routes to construct hybrid molecules containing diterpene alkaloid lappaconitine and pyrimidine fragments are reported. One route takes place via first converting of lappaconitine to 1-ethynyl-lappaconitine, followed by the Sonogashira cross-coupling-cyclocondensation sequences. The other involves the palladium-catalyzed carbonylative Sonogashira reaction of 5'-iodolappaconitine with aryl acetylene and Mo (CO)6 as the CO source in acetonitrile and subsequent cyclocondensation reaction of the generated alkynone with amidines. The reaction proceeded cleanly in the presence of the PdCl2-(1-Ad)2PBn∙HBr catalytic system. The protocol provides mild reaction conditions, high yields, and high atom and step-economy. Pharmacological screening of lappaconitine-pyrimidine hybrids for antinociceptive activity in vivo revealed that these compounds possessed high activity in experimental pain models, which was dependent on the nature of the substituent in the 2 and 6 positions of the pyrimidine nucleus. Docking studies were undertaken to gain insight into the possible binding mode of these compounds with the voltage-gated sodium channel 1.7. The moderate toxicity of the leading compound 12 (50% lethal dose (LD50) value was more than 600 mg/kg in vivo) and cytotoxicity to cancer cell lines in vitro encouraged the further design of therapeutically relevant analogues based on this novel type of lappaconitine-pyrimidine hybrids.