COSY Experiments Research Articles

Anti-inflammatory activity of a new cyclic peptide, citrusin XI, isolated from the fruits of Citrus unshiu

Ethnopharmacological relevanceCitrus unshiu (Rutaceae) is an easy-peeling citrus fruit, which has been used as a traditional Korean medicine for improving skin elasticity, relieving fatigue and cough, and preventing bronchitis, flu, and various cancers. However, its active components associated with anti-inflammation and underlying mechanisms remain unknown. In this study, we investigated the active constituents from the fruits of Citrus unshiu and evaluated the anti-inflammatory activity in order to support the traditional usage of Citrus unshiu. Material and methodsRepeated column chromatography, together with a semi-preparative HPLC purification was used to separate the bioactive constituent from the EtOAc soluble fraction of the EtOH extract of Citrus unshiu fruits. Anti-inflammatory effects of the isolated compounds on lipopolysaccharide (LPS)-induced production of pro-inflammatory mediators were examined using RAW264.7 macrophage cells. ResultsA new cyclic peptide, citrusin XI (1), was isolated and identified from the fruits of Citrus unshiu. The structure of compound 1 was elucidated by spectroscopic analysis, including 1D and 2D nuclear magnetic resonance (NMR) (1H, 13C, COSY, HMQC and HMBC experiments), and high resolution (HR)-mass spectrometry, and its absolute configurations were further confirmed by the Marfey׳s method. Compound 1 decreased NO production in LPS-stimulated RAW264.7 cells in a dose-dependent manner with an IC50 value of 70μM. Compound 1 suppressed NO production by decreasing iNOS expression but COX-2 expression was slightly associated with the reduction by compound 1 in LPS-induced RAW264.7 cells. Furthermore, compound 1 inhibited NF-κB activation by blocking IκBα degradation and NF-κB phosphorylation in LPS-stimulated RAW264.7 cells. ConclusionsThese results indicate that a new cyclic peptide, citrusin XI, from Citrus unshiu fruits has anti-inflammatory properties that inhibit the release of pro-inflammatory mediators. Compound 1 decreases NO production by decreasing iNOS expression and NF-κB activation associated with IκBα degradation and NF-κB phosphorylation in LPS-induced RAW264.7 cells. This is the first study to clarify the underlying mechanism of the anti-inflammatory effect exerted by a pure isolated compound from Citrus unshiu in LPS-stimulated RAW264.7 macrophage cells. The phytochemical, citrusin XI of Citrus unshiu may serve as lead compound in the design of new agents for preventing and treating inflammatory diseases.

Identification of cytotoxic and anti-inflammatory constituents from the bark of Toxicodendron vernicifluum (Stokes) F.A. Barkley

Ethnopharmacological relevanceToxicodendron vernicifluum (Stokes) F.A. Barkley (Anacardiaceae) has traditionally been used as a food supplement and in traditional herbal medicine to treat inflammatory diseases and cancers for centuries in Korea. This study was designed to isolate the bioactive constituents from the ethanol extract of Toxicodendron vernicifluum bark and evaluate their cytotoxic and anti-inflammatory activities. Material and methodsBioassay-guided fractionation and chemical investigation of the ethanol extract of Toxicodendron vernicifluum bark resulted in the isolation and identification of three new polyphenols (1–3) and six flavonoids (4–9). The structures of the isolated compounds were elucidated by spectroscopic analysis, including 1D and 2D nuclear magnetic resonance (NMR) (1H, 13C, COSY, HMQC and HMBC experiments), and high resolution (HR)-mass spectrometry, and their absolute configurations were further confirmed by chemical methods and circular dichroism (CD) data analysis. Compounds 1–9 were evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15), and anti-inflammatory activities by measuring nitric oxide (NO) levels in the medium of murine microglia BV-2 cells. ResultsThe isolated compounds were characterized as in the following: three new polyphenols, rhusopolyphenols G-I (1–3) and six flavonoids including two aurones, 2-benzyl-2,3′,4′,6-tetrahydroxybenzo[b]furan-3(2H)-one (4), sulfuretin (5), two dihydroflavonols, (+)-(2S,3R)-fustin (6), (+)-epitaxifolin (7), one chalcone, butein (8), and one flavonol, fisetin (9). The published NMR assignments of 4 were corrected by the detailed analysis of spectroscopic data in this study. Among the tested compounds, compounds 4–9 showed antiproliferative activity against the tested cells, with IC50 values of 4.78–28.89μM. Compounds 5 and 8 significantly inhibited NO production in lipopolysaccharide (LPS)-stimulated BV-2 cells with IC50 values of 23.37 and 11.68μM, respectively. ConclusionsPolyphenols including flavonoids were one of the main constituents of Toxicodendron vernicifluum bark, and activities demonstrated by the isolated compounds support the ethnopharmacological use of Toxicodendron vernicifluum as anti-cancer and/or anti-inflammatory agents.

Hydrolytic Degradation Study of Lansoprazole, Identification, Isolation and Characterisation of Base Degradation Product

Lansoprazole degradation is accelerated in both acidic and basic medium in water. The present investigation deals with the hydrolytic degradation of Lansoprazole. Acidic medium degradation show all known impurities and degradation products whereas basic degradation studies show new impurity which has higher molecular weight than Lansoprazole. New impurity was identified, isolated using mass based auto purification system and characterised by 1H NMR, 13C NMR, HMBC, HSQC, NOE, COSY and HRMS experiments. Isolated impurity was showing molecular weight of 467.10, molecular formula of C23H16F3N5OS and its name is 7-(3-Methyl-4-(2,2,2-trifluoroethoxy) pyridin-2-yl)-7H-benzo[4,5]imidazo[2,1-b]benzo[4,5]imidazo[2,1-d][1,3,5]thiadiazine.

Oxidation of hindered aniline to iminocyclohexa-2,4-dienone by copper(II) complex of an N-substituted bis-benzimidazolyl ligand

Copper(II) complex of an N-octylated bis-benzimidazolyl ligand is synthesized and characterized. X-ray diffraction study revealed that copper(II) is in a distorted square-planar environment of two benzimidazolyl imine nitrogens and two nitrato ligands. This complex carries out the oxidation of 2,4,6-tri-tert-butylaniline at room temperature utilizing low amounts of tert-butylhydroperoxide (TBHP) as an alternate source of oxygen. 3,5-Di-tert-butyl-6-iminocyclohexa-2,4-dienone is found to be the major product along with 3,5-di-tert-butylcyclohexa-3,5-diene-1,2-dione. The oxidation products have been isolated and characterized by 1H NMR, 13C NMR and COSY experiments. The catalytic oxidation proceeds via a copper(II)/copper(III) cycle.

Iridoid Glycosides from Roots of Verbascum laxum

A new dimeric iridoid laxoside with the structure 6′′′-O-[6-O-(4″-trans-p-methoxycinnamoyl)-5-hydroxyaucubigenin-(1→1′)-O-β-D-galactopyranosyl]-6″″-O-trans-p-methoxycinnamoylaucubin and 10-O-p-coumaroylharpagide (harpagoside) were isolated from roots of Verbascum laxum Fil. & Jav. The structures of the iridoids were established based on chemical transformations; UV, IR, PMR, and 13C NMR spectral data; two-dimensional HSQC, HMBC, DEPT, and COSY experiments; and mass spectrometry.

Antitrypanosomal quinoline alkaloids from the roots of Waltheria indica.

Chemical investigation of the dichloromethane root extract of Waltheria indica led to the isolation and characterization of 10 quinoline alkaloids, namely, 8-deoxoantidesmone (1), waltheriones E-L (2-9), and antidesmone (10). Among these, compounds 2-9 have not yet been described in the literature. Their chemical structures were established by means of spectroscopic data interpretation including (1)H and (13)C NMR, HSQC, HMBC, COSY, and NOESY experiments and UV, IR, and HRESIMS. The absolute configurations of the compounds were established by comparison of experimental and TDDFT-calculated ECD spectra. In addition, the isolated constituents were evaluated for their in vitro antitrypanosomal activity. Compounds 4, 5, and 8 showed potent and selective growth inhibition toward Trypanosoma cruzi with IC50 values between 0.02 and 0.04 μM. Cytotoxicity for mouse skeletal L-6 cells was also determined for these compounds.

Antiproliferative activity of Artemisia asiatica extract and its constituents on human tumor cell lines.

The extract of Artemisia asiatica herb with antiproliferative activity against four human tumor cell lines (A2780, A431, HeLa, and MCF7) was analyzed by the MTT assay, and bioassay-directed fractionation was carried out in order to identify the compounds responsible for the cytotoxic activity. Guaianolide (1-4), seco-guianolide (5), germacranolide (6) and eudesmanolide sesquiterpenes (7), monoterpenes (8, 9), including the new compound artemisia alcohol glucoside (8), and flavonoids (10-16) were isolated as a result of a multistep chromatographic procedure (CC, CPC, PLC, and gel filtration). The compounds were identified by means of UV, MS, and NMR spectroscopy, including (1)H-and (13)C-NMR, (1)H-(1)H COSY, NOESY, HSQC, and HMBC experiments. The isolated compounds 1-16 were evaluated for their tumor cell growth-inhibitory activities on a panel of four adherent cancer cell lines, and different types of secondary metabolites were found to be responsible for the cytotoxic effects of the extract. Especially cirsilineol (13), 3β-chloro-4α,10α-dihydroxy-1α,2α-epoxy-5α,7αH-guai-11(13)-en-12,6α-olide (3), and iso-seco-tanapartholide 3-O-methyl ester (5) exerted marked cytotoxic effects against the investigated cell lines, while jaceosidin (12), 6-methoxytricin (15), artecanin (2), and 5,7,4',5'-tetrahydroxy-6,3'-dimethoxyflavone (14) were moderately active. All the sesquiterpenes and monoterpenes are reported here for the first time from this species, and in the case of artecanin (2), 3α-chloro-4β,10α-dihydroxy-1β,2β-epoxy-5α,7αH-guai-11(13)-en-12,6α-olide (4), ridentin (6), and ridentin B (7), previously unreported NMR spectroscopic data were determined.

Antimicrobial chemical constituents from endophytic fungus Phoma sp.

ObjectiveTo evaluate the antimicrobial potential of different extracts of the endophytic fungus Phoma sp. and the tentative identification of their active constituents. MethodsThe extract and compounds were screened for antimicrobial activity using the Agar Well Diffusion Method. Four compounds were purified using column chromatography and their structures were assigned using 1H and 13C NMR spectra, DEPT, 2D COSY, HMQC and HMBC experiments. ResultsThe ethyl acetate fraction of Phoma sp. showed good antifungal, antibacterial, and algicidal properties. One new dihydrofuran derivative, named phomafuranol (1), together with three known compounds, phomalacton (2), (3R)-5-hydroxymellein (3) and emodin (4) were isolated from the ethyl acetate fraction of Phoma sp. Preliminary studies indicated that phomalacton (2) displayed strong antibacterial, good antifungal and antialgal activities. Similarly (3R)-5-hydroxymellein (3) and emodin (4) showed good antifungal, antibacterial and algicidal properties. ConclusionsAntimicrobial activities of the ethyl acetate fraction of the endophytic fungus Phoma sp. and isolated compounds clearly demonstrate that Phoma sp. and its active compounds represent a great potential for the food, cosmetic and pharmaceutical industries.

New phenolics from the root of Scutellariaprostrata JACQ. ex BENTH.

Scutellariaprostrata (Lamiaceae), a perennial herb growing as a lonely species in Kashmir, Himalayas, was subjected to repetitive column and flash chromatographic isolation for its chemical documentation-cum-bioevaluation. The methanolic extract of S.prostrata afforded the isolation of ten compounds (1–10), including two new compounds – scutellapbiflavanone (1) and scutellaprostin M (2). The known compounds were found to be scutellarin (3), hispidulin-7-O-β-d-glucopyranoside (4), baicalin (5), wogonoside (6), scutellaprostin C (7), acetoside (8), martynoside (9) and scutellaric acid-3-O-β-d-glucopyranoside (10). Isolation of biflavonoids, phenolics and phenylethanoid compounds from S.prostrata seals a deal of chemotaxonomic importance of this particular species. The characterisation of the compounds was achieved by 1H, 13C, 1H–1H DFQ COSY, HMBC, HSQC, HMQC and ROESY NMR experiments. All the compounds were tested for antioxidant, antimicrobial and cytotoxic activities.

Phosphorescent PtII Systems Featuring Both 2,2′‐Dipyridylamine and 1,3,5‐Triazapentadiene Ligands

AbstractThe treatment of cis‐[Pt(dpa)(RCN)2][SO3CF3]2 {dpa = 2,2′‐dipyridylamine, R = Me, Et, CH2Ph, Ph; [2a–d](OTf)2} (OTf = SO3CF3) with 2 equiv. of N,N′‐diphenylguanidine [NH=C(NHPh)2] in CH2Cl2 solutions at room temp. for 16 h gives [Pt(dpa){NH=C(R)NC(NHPh)=NPh}][SO3CF3] {[3a,b,d](OTf)} as the addition products and [Pt(dpa){NH=C(R)NHC(R)=NH}][SO3CF3]2 {[4a,b](OTf)2} as the tailoring products. The formulation of complexes [3a,b,d](OTf) and [4a,b](OTf)2 was supported by satisfactory C, H, and N elemental analyses and agreeable high‐resolution ESI‐MS, IR, and 1H (including 1H–1H COSY experiments) and 13C{1H} NMR data. The structures of all of the platinum species were determined by single‐crystal X‐ray diffraction. The resultant complexes are nonemissive in solution, mainly because of the interaction between the empty d orbital in a square‐planar configuration and solvent molecules. However, in the solid state, complexes [3a,b,d](OTf) exhibit strong phosphorescence with quantum yields (peak wavelength) of 0.23 (490 nm), 0.27 (483 nm), and 0.20 (532 nm), respectively.

Synthesis and characterization of 2-(n-alkylamino)-1,4-napthoquinone: Molecular structures of ethyl and hexyl derivatives

We would like to introduce seven analogues of 2-(n-alkylamino)-1,4-napthoquinone (where n-alkyl is methyl in LH-1, ethyl in LH-2, propyl in LH-3, butyl in LH-4, pentyl in LH-5, hexyl in LH-6 and heptyl in LH-7). All the said analogues have been successfully synthesized from 1,4-naphthoquinone and well characterised using different spectroscopic techniques. Furthermore, in order to understand the mechanistic aspects of formation of LH-1–LH-7 compounds we could propose the mechanism. The FT-IR spectroscopic analysis of LH-1–LH-7 compounds indicating that the presence of characteristic band of NH group at ∼3340cm−1. This band could assigned to existence of intramolecular hydrogen bonding interactions. The 13C-NMR spectroscopic technique has been used to study structural feature of LH-1–LH-7 compounds via HSQC, COSY and DEPT experiments. Finally, the structural aspects of the LH-2–LH-6 compounds have been confirmed by single crystal X-ray diffraction studies. We could observed that LH-2 compound crystallises in monoclinic space group P21/c, whereas LH-6 crystallises in triclinic P-1 space group. The molecule of LH-2 and LH-6 compounds forms dimers via NH⋯O hydrogen bonding interaction while polymeric chains of dimers have been seen via CH⋯O hydrogen bonding. It is very interesting to note that the molecules of LH-6 possessing a π–π stacking interaction between C⋯N of the neighbouring chains.

A new coumarin from Calophyllum hosei

A new coumarin, hoseimarin (1), together with four other xanthones, trapezifolizanthone (2), osajaxanthone (3), β-mangostin (4) and caloxanthone A (5), were isolated from the stem bark of Calophyllum hosei. The structures of these compounds were established by using spectroscopic analysis which included 1H NMR, 13C NMR, COSY, DEPT, HMQC and HMBC experiments.

First report of Psyllopsis repens Loginova, 1963 (Hemiptera: Psylloidea) from Isparta, Turkey

Sparsioamide ( 1), a new sphingolipid, and sparsioside ( 2), a new diglyceride galactoside, have been isolated from the ethyl acetate soluble fraction of the 80% ethanolic extract of the whole plant of Croton sparsiorus Morong. Their structures were assigned by 1 H- and 13 C-NMR spectra and DEPT, COSY, NOESY, HMQC, HMBC, and ESI-MS experiments.

Inhibition of Enterococcus faecalis biofilm formation by highly active lactones and lactams analogues of rubrolides

Seven β-aryl substituted γ-alkylidene-γ-lactones analogues of rubrolides were synthesized from mucobromic acid and converted through a lactamization with isobutylamine into their corresponding γ-hydroxy-γ-lactams (76–85%). These lactams were converted into (Z)- and (E)-γ-alkylidene-γ-lactams (23–45%). All compounds were fully characterized by IR, NMR (1H and 13C), COSY and HETCOR bidimensional experiments, and NOE difference spectroscopy experiments when necessary. Evaluation of these three different classes of compounds against Enterococcus faecalis biofilm formation showed that all classes are active and the highest biofilm inhibition activity was caused by lactam 13f (IC50 = 0.76 μg/mL). Moreover, in almost all cases at least one of the lactams is more active than its correspondent γ-alkylidene-γ-lactone. The use of rubrolides as a lead structure has proven successful for the identification of new compounds displaying novel antibacterial activities, namely biofilm inhibition, which have the potential for the development of antimicrobial drugs targeted to inhibition of the initial stages of bacterial infections, rather than bacterial viability. Such drugs are less prompt to induce bacterial resistance, being therefore a more cost-effective investment for pharmaceutical research.

Structure of the O-specific polysaccharide from a marine bacterium Echinicola vietnamensis KММ 6221Т

The O-specific polysaccharide was isolated from the lipopolysaccharide of Echinicola vietnamensis and studied by chemical methods along with 1H and 13C NMR spectroscopy, including 2D 1H, 1H COSY, TOCSY, ROESY, 1H, 13C HSQC, HMBC, and H2BC experiments. It was found that the polysaccharide is built up of branched tetrasaccharide repeating units, containing 2-acetamido-2-deoxy-d-glucuronic acid (GlcNAcA), 2-acetamido-2-deoxy-d-galactose (GalNAc), and d-glucuronic acid (GlcA) with a terminal residue of 3,6-dideoxy-l-xylo-hexose (colitose, Col) and has the following structure. [Display omitted]

Odorasides A and B, new sphingolipid glucosides from Klienia odora

Two new sphingolipid glucosides, odoraside A (1) and odoraside B (2), have been isolated from chloroform-soluble fraction of the total methanolic extract of Klienia odora, together with five known compounds, β-sitosterol (3), oleanolic acid (4), betulone (5), 2,3-dihydroxy-12-oleanen-28-oic acid (6), and β-sitosterol 3-O-β-d-glucopyranoside (7). Their structures were assigned from 1H and 13C NMR spectra, DEPT and by 2D COSY, NOESY, HMQC, and HMBC experiments.

A Bifunctional Glycosyltransferase from Agrobacterium tumefaciens Synthesizes Monoglucosyl and Glucuronosyl Diacylglycerol under Phosphate Deprivation

Glycolipids are mainly found in phototrophic organisms (like plants and cyanobacteria), in Gram-positive bacteria, and a few other bacterial phyla. Besides the function as bulk membrane lipids, they often play a role under phosphate deprivation as surrogates for phospholipids. The Gram-negative Agrobacterium tumefaciens accumulates four different glycolipids under phosphate deficiency, including digalactosyl diacylglycerol and glucosylgalactosyl diacylglycerol synthesized by a processive glycosyltransferase. The other two glycolipids have now been identified by mass spectrometry and nuclear magnetic resonance spectroscopy as monoglucosyl diacylglycerol and glucuronosyl diacylglycerol. These two lipids are synthesized by a single promiscuous glycosyltransferase encoded by the ORF atu2297, with UDP-glucose or UDP-glucuronic acid as sugar donors. The transfer of sugars differing in their chemistry is a novel feature not observed before for lipid glycosyltransferases. Furthermore, this enzyme is the first glucuronosyl diacylglycerol synthase isolated. Deletion mutants of Agrobacterium lacking monoglucosyl diacylglycerol and glucuronosyl diacylglycerol or all glycolipids are not impaired in growth or virulence during infection of tobacco leaf discs. Our data suggest that the four glycolipids and the nonphospholipid diacylglyceryl trimethylhomoserine can mutually replace each other during phosphate deprivation. This redundancy of different nonphospholipids may represent an adaptation mechanism to enhance the competitiveness in nature.

Methicillin-resistant Staphylococcus aureus, Vancomycin-resistant Enterococcus faecalis and Enterococcus faecium active Dimeric Isobutyrylphloroglucinol from Ivesia gordonii

Bioassay-guided fractionation of the chloroform soluble fraction of stem, leaf, and flower extracts of the American plant Ivesia gordonii led to the isolation of a new dimeric acylphloroglucinol, 3,3'-diisobutyryl-2,6'-dimethoxy-4,6,2',4'-tetrahydroxy-5,5'dimethyldiphenyl methane (1), to which we have assigned the trivial name ofivesinol (1), together with a known monomeric acylphloroglucinol, 1,5-dihydroxy-2-(2'-methylpropionyl)-3-methoxy-6-methylbenzene (2). The structures of the isolated compounds were characterized using 1D- and 2D- NMR spectroscopy, including COSY, HMQC, HMBC, and ROESYexperiments, as well as mass spectrometry. Ivesinol (1) showed potent activity against Staphylococcus aureus (SA) and methicillin-resistant S. aureus (MRSA) with IC50/MIC/MBC values of 0.10/1.25/>20 microg/mL and 0.05/0.31/>20 microg/mL, respectively (vs. IC50/MIC/MBC 0.13/0.5/1.0 microg/mL and 0.13/0.5/1.0 microg/mL of ciprofloxacin), while the corresponding monomer 2 was found to be less active. Compound 1 also demonstrated strong activity against vancomycin-resistant Enterococcus faecium (VRE) with IC50/MlC/MBC values of 0.22/1.25/>20 microg/mL, whereas the reference standard ciprofloxacin was found to be inactive against this strain. In addition, compound 2 showed moderate activity against two species of Candida and Cryptococcus neoformans, while 1 was inactive against these fungi. In order to evaluate the influence of the acyl group(s) in phloroglucinol (3) as a ligand, the mono- (4) and diacetylphloroglucinol (5) were prepared from 3, and evaluated for their in vitro SA, MRSA, and VRE activities; 2,4-diacetylphloroglucinol (5) showed potent activity, like 1, against SA, MRSA, and VRE (ATCC 700221) with IC50/MIC values of 0.3/2.5, 0.23/2.5, and 0.86/2.5 microg/mL, respectively, while 4 was inactive.

Non-cellulosic polysaccharides from the leaves of small balsam (Impatiens parviflora DC.)

The leaves of the annual plant Impatiens parviflora DC., a herbal medicine in Asian countries and invasive in managed forests and natural environments in Central Europe, have the potential as a source of bioactive phenolic compounds and polysaccharides. Extractives accounted for ∼22% of the leaves, whereby, the methanolic extract contains mainly caffeic acid, ferulic acid, kaempferol, and quercetin derivatives, and 1,2,4-trihydroxynaphthalene-1-O-glucoside. From the pre-extracted leaves, non-cellulosic polysaccharides were isolated by a five-step extraction procedure using as extractants cold water, 0.05M EDTA, and DMSO in the first three steps, and 1% and 5% NaOH in the last two steps. The isolated polysaccharide fractions were characterized by chemical, physicochemical, and spectroscopic analyses (FTIR and 1H NMR). The first three fractions contained mainly pectin and the alkali-extracted ones methylglucuronoxylan and arabinogalactan. The suggested structural features were confirmed using HSQC NMR and COSY experiments for polysaccharides of the EDTA-fraction and the Pronase-treated 5% NaOH-fraction. The EDTA fraction comprised a pectin with low degree of methyl-esterification (DM, 37%) with few rhamnogalacturonan RG I segments bearing β-1,4-galactan as side chains. The alkali-extracted fraction comprised a degraded methylglucuronoxylan and type II 3,6-arabinogalactan in about equal amounts.

Diterpene Alkaloids from the Roots of Aconitum moldavicum and Assessment of Nav 1.2 Sodium Channel Activity of Aconitum Alkaloids

A new aconitane alkaloid, 1-O-demethylswatinine (1), was isolated from the root of Aconitum moldavicum together with the known compounds cammaconine (2), columbianine (3), swatinine (4), gigactonine (5), delcosine (6), lycoctonine (7), and ajacine (8). The structures were established by means of HRESIMS, 1D and 2D NMR spectroscopy, including 1H-1H COSY, NOESY, HSQC, and HMBC experiments, resulting in complete 1H-NMR chemical shift assignments for 1-4. The effects of the isolated compounds 4-8, together with eighteen other Aconitum diterpene and norditerpene alkaloids with different skeletal types and substitution patterns, were studied on Nav 1.2 channels by the whole-cell patch clamp technique, using the QPatch-16 automated patch clamp system. Pyroaconitine, ajacine, septentriodine, and delectinine demonstrated significant Nav 1.2 channel inhibition (57-42 %) at 10 µM concentration; several other compounds (acovulparine, acotoxicine, hetisinone, 14-benzoylaconine-8-O-palmitate, aconitine, and lycoctonine) exerted moderate inhibitory activity (30-22 %), while the rest of the tested alkaloids were considered to be inactive. On the basis of these results and by exhaustive comparison of data of previously published computerized QSAR studies on diterpene alkaloids, certain conclusions on the structure-activity relationships of Aconitum alkaloids concerning Nav 1.2 channel inhibitory activity are proposed.