Evaluation of aconitine cardiotoxicity with a heart-on-a-particle prepared by a microfluidic device.

A heart-on-a-particle model based on multicompartmental microgel is proposed to simulate the heart microenvironment and study the cardiotoxicity of drugs. The relevant microgel was fabricated by a biocompatible microfluidic-based approach, where heart function-related HL-1 and HUVEC cells were arranged in separate compartments. Finally, the mechanism of aconitine-induced heart toxicity was elucidated using mass spectrometry and molecular biotechnology.

Synthesis and biological evaluation of lycoctonine derivatives with cardiotonic and calcium channels inhibitory activities.

In our previous study, a screening of a variety of lycotonine-type diterpenoid alkaloids were screened for cardiotonic activity revealed that lycoctonine had moderate cardiac effect. In this study, a series of structurally diverse of lycoctonine were synthesized by modifying on B-ring, D-ring, E-ring, F-ring, N-atom or salt formation on lycoctonine skeleton. We evaluated the cardiotonic activity of the derivatives by isolated frog heart, aiming to identify some compounds with significantly enhanced cardiac effects, among which compound 27 with a N-isobutyl group emerged as the most promising cardiotonic candidate. Furthermore, the cardiotonic mechanism of compound 27 was preliminarily investigated. The result suggested that the cardiotonic effect of compound 27 is related to calcium channels. Patch clamp technique confirmed that the compound 27 had inhibitory effects on CaV1.2 and CaV3.2, with inhibition rates of 78.52 % ± 2.26 % and 79.05 % ± 1.59 % at the concentration of 50 µM, respectively. Subsequently, the protective effect of 27 on H9c2 cells injury induced by cobalt chloride was tested. In addition, compound 27 can alleviate CoCl2-induced myocardial injury by alleviating calcium overload. These findings suggest that compound 27 was a new structural derived from lycoctonine, which may serve as a new lead compound for the treatment of heart failure.

Synthesis of structurally diverse derivatives of aconitine-type diterpenoid alkaloids and their anti-proliferative effects on canine breast cancer cells.

As one of the most common malignancies in female dogs, no drugs have been developed specifically for the treatment of canine mammary carcinoma. In our previous study, a series of diterpenoid alkaloids derivatives were synthesized and exhibited good anti-proliferative activity in vitro against both normal and adriamycin-resistant human breast cancer cells lines. In this study, a series of structurally diverse aconitine-type alkaloids derivatives were also synthesized basing on the minimal modification principle, by modifying on A-ring, C-ring, D-ring, N-atom or salt formation on aconitine skeleton. Their anti-proliferative effects and mechanism on canine mammary cancer cells were investigated, exhibiting the importance of the substitution at A ring, the long chain ester at the C8, the hydroxyl group at the C13, the phenyl ring at the C14 and the N-ethyl group, while the methoxy group at the C1 and C16 showed little effect on the activity. The results of the proliferation, apoptosis and ultrastructure tests of the treated canine mammary carcinoma cells referred that the representative compound, aconitine linoleate (25) could block the cell cycle of canine mammary carcinoma cells in the G0/G1 phase, and exhibit the anti-proliferative effect by inducing apoptosis.

Structural characterization, in vivo toxicity and biological activity of two new pyro-type diterpenoid alkaloids derived from 3-acetylaconitine.

OBJECTIVE: The transformations that occur in diterpenoid alkaloids during the process of sand frying for Chinese herbal medicine preparation have yet to be clarified. This study investigated the structural changes that take place in 3-acetylaconitine during a simulation of heat-processing and evaluated the toxicity and biological activity of the pyrolysis products. METHODS: The diterpenoid alkaloid 3-acetylaconitine was heated at 180 °C for 15 min to simulate the process of sand frying. The pyrolysis products were separated using column chromatography, and their structures were investigated using high-resolution electrospray ionization mass spectroscopy and nuclear magnetic resonance spectroscopy. Further, in vivo cardiotoxicity and acute toxicity of 3-acetylaconitine and its pyrolysis products were compared, and the aconitine-induced arrhythmia model was employed to evaluate the antiarrhythmic effect of the pyrolysis products. RESULTS: Two new diterpenoid alkaloids, pyroacetylaconitine and 16-epi-pyroacetylaconitine, a pair of epimers at C-16, were isolated. After comparing the structures of these compounds, possible transformation pathways were proposed. Compared with the prototype compound, 3-acetylaconitine, the cardiotoxicity and acute toxicity of the heat-transformed products were significantly decreased. In the biological activity assay, the two pyrolysis products exhibited an effective increase in ventricular premature beat latency, a reduction in the occurrence of ventricular tachycardia, as well as an increase in the rate of arrhythmia inhibition, implying strong antiarrhythmic activity. CONCLUSION: Compared with 3-acetylaconitine, its pyrolysis products displayed lower toxicity and good antiarrhythmic effects; thus, they have potential for being developed into antiarrhythmic medicines. Please cite this article as: Wang YJ, Wang Y, Tao P. Structural characterization, in vivo toxicity and biological activity of two new pyro-type diterpenoid alkaloids derived from 3-acetylaconitine. J Integr Med. 2023; 21(3): 302-314.

Four New C19 -Diterpenoid Alkaloids from Aconitum nagarum Stapf.

Four new aconitine-type C19 -diterpenoid alkaloids, were isolated from the roots of Aconitum nagarum Stapf which were named as nagarutines A-D (1-4), together with eleven known compounds (5-15). The structures of the compounds were identified by IR, HR-ESI-MS, 1D and 2D NMR spectra. All compounds were tested for the inhibitory effect on LPS induced NO production in RAW 264.7 macrophages, compound 7 showed moderate anti-inflammatory activity effect and Inhibition rate is about 44.50%.

Antinociceptive diterpenoid alkaloids from the roots of Aconitum austroyunnanense.

A phytochemical investigation on the roots of Aconitum austroyunnanense afforded three undescribed aconitine-type C19-diterpenoid alkaloids, austroyunnanines A-C (1-3). Structural elucidation of all the compounds were performed by spectral methods such as 1 D and 2 D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. The isolated alkaloids were tested in vivo for their antinociceptive properties. Consequently, austroyunnanine B (2) exhibited significant antinociceptive effect and its ID50 value (48.0 µmol/kg) was 2-fold less than those of the positive control drugs aspirin and acetaminophen.

Structural characterization, in vivo toxicity and biological activity of two new pyro-type diterpenoid alkaloids derived from 3-acetylaconitine / 中西医结合学报

OBJECTIVE@#The transformations that occur in diterpenoid alkaloids during the process of sand frying for Chinese herbal medicine preparation have yet to be clarified. This study investigated the structural changes that take place in 3-acetylaconitine during a simulation of heat-processing and evaluated the toxicity and biological activity of the pyrolysis products.@*METHODS@#The diterpenoid alkaloid 3-acetylaconitine was heated at 180 °C for 15 min to simulate the process of sand frying. The pyrolysis products were separated using column chromatography, and their structures were investigated using high-resolution electrospray ionization mass spectroscopy and nuclear magnetic resonance spectroscopy. Further, in vivo cardiotoxicity and acute toxicity of 3-acetylaconitine and its pyrolysis products were compared, and the aconitine-induced arrhythmia model was employed to evaluate the antiarrhythmic effect of the pyrolysis products.@*RESULTS@#Two new diterpenoid alkaloids, pyroacetylaconitine and 16-epi-pyroacetylaconitine, a pair of epimers at C-16, were isolated. After comparing the structures of these compounds, possible transformation pathways were proposed. Compared with the prototype compound, 3-acetylaconitine, the cardiotoxicity and acute toxicity of the heat-transformed products were significantly decreased. In the biological activity assay, the two pyrolysis products exhibited an effective increase in ventricular premature beat latency, a reduction in the occurrence of ventricular tachycardia, as well as an increase in the rate of arrhythmia inhibition, implying strong antiarrhythmic activity.@*CONCLUSION@#Compared with 3-acetylaconitine, its pyrolysis products displayed lower toxicity and good antiarrhythmic effects; thus, they have potential for being developed into antiarrhythmic medicines. Please cite this article as: Wang YJ, Wang Y, Tao P. Structural characterization, in vivo toxicity and biological activity of two new pyro-type diterpenoid alkaloids derived from 3-acetylaconitine. J Integr Med. 2023; 21(3): 302-314.

Identification and quantification of eight alkaloids in Aconitum heterophyllum using UHPLC-DAD-QTOF-IMS: A valuable tool for quality control.

INTRODUCTION: Aconitum spp. are prime medicinal plants rich in alkaloids and have been used as the main constituents of traditional medicine in India and China. The whole plant can be toxic and creates pathophysiological conditions inside the human body. Therefore, simultaneous quantification of alkaloids within plant parts and herbal medicines associated with this genus is essential for quality control. OBJECTIVE: We aimed to develop and validate methods using ultra-high-performance liquid chromatography-diode array detector-quadrupole time-of-flight ion mobility mass spectrometry (UHPLC-DAD-QTOF-IMS) and to develop an analytical strategy for the identification and quantification of alkaloid compounds (aconitine, hypaconitine, mesaconitine, aconine, benzoylmesaconitine, benzoylaconine, bulleyaconitine A, and deoxyaconitine) from Aconitum heterophyllum. METHODOLOGY: We developed a simultaneous identification and quantification method for eight alkaloids using UHPLC-DAD-QTOF-IMS. The method was validated as per International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines and also in IMS mode. RESULTS: The developed method has good linearity (r2 = 0.997-0.999), LOD (0.63-8.31 µg/mL), LOQ (0.63-2.80 µg/mL), recovery (86.01-104.33%), reproducibility, intra- and inter-day variability (<3.25%), and stability. Significant qualitative and quantitative variations were found among different plant parts (flower, leaf, stem, root, and tuber) and five market products of A. heterophyllum. Furthermore, a total of 21 metabolites were also profiled based on the fragmentation pattern of MS2 using the validated method. CONCLUSION: An appropriate mobile phase using acetonitrile and water in a gradient elution gave a satisfactory chromatographic separation of eight Aconitum alkaloids with their adjacent peaks. Therefore, this method could provide a scientific and technical platform for quality control assurance.

Novel methyllycaconitine analogues selective for the α4ß2 over α7 nicotinic acetylcholine receptors.

Analogues of methyllycaconitine (MLA) based on a (3-ethyl-9-methylidene-3-azabicyclo[3.3.1]nonan-1-yl)methanol template have been designed and synthesised that incorporate the modified ester sidechains distinct from that present in the natural product. Electrophysiology experiments using Xenopus oocytes expressing nicotinic acetylcholine receptors (nAChRs) revealed selected analogues served as non-competitive inhibitors that showed selectivity for the α4ß2 over α7 nAChR subtypes, and selectivity for the (α4)3(ß2)2 over (α4)2(ß2)3 stoichiometry. This study more clearly defines the biological effects of MLA analogues and identifies strategies for the development of MLA analogues as selective ligands for the α4ß2 nAChR subtype.

A New Strategy for the Rapid Identification and Validation of the Direct Targets of Aconitine-Induced Cardiotoxicity.

BACKGROUND: The interaction of small molecules with direct targets constitutes the molecular initiation events of drug efficacy and toxicity. Aconitine, an active compound of the Aconitum species, has various pharmacological effects but is strongly toxic to the heart. The direct targets of aconitine-induced cardiotoxicity remain unclear. METHODS: We predicted the toxic targets of aconitine based on network pharmacology and followed a novel proteomic approach based on the "drug affinity responsive target stability" technology combined with LC-MS/MS to identify the direct targets of aconitine. The identified targets were analysed from the perspective of multilevel and multidimensional bioinformatics through a network integration method. The binding sites were investigated via molecular docking to explore the toxicity mechanism and predict the direct targets of aconitine. Finally, atomic force microscopy (AFM) imaging was performed to verify the affinity of aconitine to the direct targets. RESULTS: PTGS2, predicted by network pharmacology as a toxic target, encodes cyclooxygenase 2 (COX-2), which is closely related to myocardial injury. Furthermore, cytosolic phospholipase A2 (cPLA2) is the upstream signal protein of PTGS2, and it is a key enzyme in the metabolism of arachidonic acid during an inflammatory response. We determined cPLA2 as a direct target, and AFM imaging verified that aconitine could bind to cPLA2 well; thus, aconitine may cause the expression of PTGS2/COX-2 and release inflammatory factors, thereby promoting myocardial injury and dysfunction. CONCLUSION: We developed a complete set of methods to predict and verify the direct targets of aconitine, and cPLA2 was identified as one. Overall, the novel strategy provides new insights into the discovery of direct targets and the molecular mechanism of toxic components that are found in traditional Chinese medicine.

Pharmacokinetics of yunaconitine and indaconitine in mouse blood by UPLC-MS/MS.

Yunaconitine and indaconitine are active ingredients from the rhizomes of Aconitum plants. In this study, an ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to measure the concentrations of the yunaconitine and indaconitine in mouse blood, and the method was applied in measuring the pharmacokinetics of the two alkaloids after oral and intravenous administration. A UPLC HSS T3 column (2.1 mm × 100 mm, 1.8 µm particle size) was used for chromatographic separation by gradient elution using acetonitrile-water (0.1% formic acid) as the mobile phase at a flow rate of 0.4 mL/min. Multiple reaction monitoring (MRM) mode and electrospray ionization (ESI) (positive-ion mode) were used to monitor the transitions of each analyte by tandem mass spectrometry for quantitative analysis. Yunaconitine and indaconitine were administered to the mice orally at 2 mg/kg and intravenously at 0.05 mg/kg. Blood was collected at various time intervals, and the blood samples were processed after collection and analyzed by UPLC-MS/MS. The standard curve generated for each analyte was linear over the concentration range of 0.5-500 ng/mL. The intra-day and inter-day accuracy of yunaconitine and indaconitine were 90%-103% and 86%-106%, respectively, and the precision (RSD, %) was less than 15% for both intra-day and inter-day measurements. The matrix effect ranged from 96% to 109%, and the recovery was higher than 72%. The UPLC-MS/MS method developed herein was successfully applied to measuring the pharmacokinetic parameters of yunaconitine and indaconitine in mice after intravenous and oral administration. The bioavailability of yunaconitine and indaconitine were 27.4% and 25.8%, respectively.

2-((1-Phenyl-1H-1,2,3-triazol-4-yl)methyl)-2-azabicyclo[3.2.1]octan-3-one derivatives: Simplification and modification of aconitine scaffold for the discovery of novel anticancer agents.

The molecular chaperone heat shock protein 90 (Hsp90) is a promising target for cancer therapy. Natural product aconitine is a potential Hsp90 inhibitor reported in our previous work. In this study, we designed and synthesized a series of 2-((1-phenyl-1H-1,2,3-triazol-4-yl)methyl)-2-azabicyclo[3.2.1]octan-3-one derivatives as potent Hsp90 inhibitors by simplifying and modifying aconitine scaffold. Among these compounds, 14t exhibited an excellent antiproliferative activity against LoVo cells with an IC50 value of 0.02 µM and a significant Hsp90α inhibitory activity with an IC50 value of 0.71 nM. Molecular docking studies provided a rational binding model of 14t in complex with Hsp90α. The following cell cycle and apoptosis assays revealed that compound 14t could arrest cell cycle at G1/S phase and induce cell apoptosis via up-regulation of bax and cleaved-caspase 3 protein expressions while inhibiting the expressions of bcl-2. Moreover, 14t could inhibit cell migration in LoVo and SW620 cell lines. Consistent with in vitro results, 14t significantly repressed tumor growth in the SW620 xenograft mouse model.

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.

Supramolecular structure, in vivo biological activities and molecular-docking-based potential cardiotoxic exploration of aconine hydrochloride monohydrate as a novel salt form.

Despite the high profile of aconine in WuTou injection, there has been no preparative technology or structural studies of its salt as the pharmaceutical product. The lack of any halide salt forms is surprising as aconine contains a tertiary nitrogen atom. In this work, aconine was prepared from the degradation of aconitine in Aconiti kusnezoffii radix (CaoWu). A green chemistry technique was applied to enrich the lipophilic-poor aconine. Reaction of aconine with hydrochloride acid resulted in protonation of the nitrogen atom and gave a novel salt form (C25H42NO9+·Cl-·H2O; aconine hydrochloride monohydrate, AHM), whose cation in the crystal structure was elucidated based on extensive spectroscopic and X-ray crystallographic analyses. The AHM crystal had a Z' = 3 structure with three independent cation-anion pairs, with profound conformational differences among the aconine cations. The central framework of each aconine cation was compared with that of previously reported aconitine, proving that protonation of the nitrogen atom induced the structure rearrangement. In the crystal of AHM, aconine cations, chloride anions and water molecules interacted through inter-species O-H...Cl and O-H...O hydrogen bonds; this complex hydrogen-bonding network stabilizes the supramolecular structure. The seriously disordered solvent molecules were treated using the PLATON SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9-18] and their atoms were therefore omitted from the refinement. Bioactivity studies indicated that AHM promoted in vitro proliferative activities of RAW264.7 cells. Molecular docking suggested AHM could target cardiotoxic protein through the hydrogen-bonding interactions. The structural confirmation of AHM offers a rational approach for improving the pharmaceutical technology of WuTou injection.

Total Synthesis of Talatisamine.

Talatisamine (1) is a member of the C19 -diterpenoid alkaloid family, and exhibits K+ channel inhibitory and antiarrhythmic activities. The formidable synthetic challenge that 1 presents is due to its highly oxidized and intricately fused hexacyclic 6/7/5/6/6/5-membered-ring structure (ABCDEF-ring) with 12 contiguous stereocenters. Here we report an efficient synthetic route to 1 by the assembly of two structurally simple fragments, chiral 6/6-membered AE-ring 7 and aromatic 6-membered D-ring 6. AE-ring 7 was constructed from 2-cyclohexenone (8) through fusing an N-ethylpiperidine ring by a double Mannich reaction. After coupling 6 with 7, an oxidative dearomatization/Diels-Alder reaction sequence generated fused pentacycle 4 b. The newly formed 6/6-membered ring system was then stereospecifically reorganized into the 7/5-membered BC-ring of 3 via a Wagner-Meerwein rearrangement. Finally, Hg(OAc)2 induced an oxidative aza-Prins cyclization of 2, thereby forging the remaining 5-membered F-ring. The total synthesis of 1 was thus accomplished by optimizing and orchestrating 33 transformations from 8.

Benzoylaconitine Inhibits Production of IL-6 and IL-8 via MAPK, Akt, NF-κB Signaling in IL-1ß-Induced Human Synovial Cells.

Benzoylaconitine (BAC), the main hydrolysate of aconitine, is a lower toxic monoester type alkaloid considered as the pharmacodynamic constituent in Aconitum species. In this study, the effects and mechanisms of BAC on production of inflammatory cytokines interleukin (IL)-6 and IL-8 were investigated in IL-1ß-stimulated human synovial SW982 cells. The SW982 cells were incubated with BAC (0, 5 and 10 µM) before stimulating with IL-1ß (10 ng/mL). The results revealed that BAC suppressed gene and protein expression of IL-6 and IL-8 induced by IL-1ß. BAC decreased activation of mitogen-activated protein kinase (MAPK) and phosphorylation of Akt. BAC also inhibited degradation of inhibitor of kappaB (IκB)-α, phosphorylation and nuclear transposition of p65 protein. The results demonstrate that BAC exerts an anti-inflammatory effect dependent on MAPK, Akt and nuclear factor-κB (NF-κB) pathways in human synovial cells stimulated with IL-1ß, suggesting that BAC may be exploited as a potential therapeutic agent for rheumatoid arthritis (RA) treatment.

Evaluation of noninvasive specimens to diagnose livestock exposure to toxic larkspur (Delphinium spp.).

Larkspurs (Delphinium spp.) are native perennial plants that have a serious toxic potential to cattle on foothill and mountain rangelands in the western United States. Livestock death due to larkspur toxicity is attributed to norditerpenoid alkaloids. Diagnosing plant poisonings in livestock is often challenging. The objective of this study was to evaluate the use of three matrices; earwax, oral fluid, and nasal mucus, as noninvasive specimens to determine livestock exposure to larkspurs. Reversed phase high performance liquid chromatography - high resolution mass spectrometry was used to analyze for norditerpene alkaloids, in all three matrices, in cattle administered a single dose of larkspur. Earwax, oral fluid, and nasal mucus were collected over 6 days post-dosing. Methyllycaconitine (MLA) and deltaline concentrations in earwax ranged from 0.4 ±â€¯0.1 to 0.2 ±â€¯0.06 and 0.6 ±â€¯0.5 to 0.11 ±â€¯0.08 ng/mg, respectively. MLA and deltaline concentrations in oral fluid ranged from 0.08 ±â€¯0.03 to 0.01 ±â€¯0.002 ng/mg and 0.07 ±â€¯0.03 ng/mg to not detected (ND), respectively. MLA and deltaline concentrations in nasal mucus ranged from 0.2 ±â€¯0.13 to 0.03 ±â€¯0.01 ng/mg and 0.2 ±â€¯0.12 ng/mg to ND, respectively. The ability to detect differing norditerpene alkaloid chemotypes from two different Delphinium spp. was also possible in the three matrices. This study demonstrates the potential of earwax, oral fluid, and nasal mucus as noninvasive specimens for chemical analyses to aid in the diagnosis of livestock that may have been exposed to and poisoned by larkspur plants.

Diterpenoid alkaloids from Delphinium naviculare var. lasiocarpum with their antifeedant activity on Spodoptera exigua.

A new lycoctonine diterpenoid alkaloid navicularine, along with eighteen known diterpenoid alkaloids, were isolated from the whole plant of Delphinium naviculare var. lasiocarpum. Their structures were elucidated on the base of extensive spectroscopic analysis (HR-ESI-MS and NMR) and comparison with data reported in the literature. Most of alkaloids were tested for their antifeedant activity against larvae of Spodoptera exigua (Hübner). The compound shawurensine showed considerably potent antifeedant activity (EC50 = 0.42 and 0.81 mg/cm2 in the choice test and no choice test, respectively).

Inhibitory effects of lappaconitine on the neuronal isoforms of voltage-gated sodium channels.

Lappaconitine (LA) has been widely used for postoperative and cancer pain control. LA exhibits excellent analgesic activity with a longer effective time than common local anesthetics such as tetracaine and bupivacaine. However, the mechanisms underlying the featured analgesic activity of LA remain largely unknown. Here, we report that LA is an inhibitor of voltage-gated sodium channel 1.7 (Nav1.7) stably expressed in human embryonic kidney (HEK293) cells. LA inhibited Nav1.7 in a voltage-dependent manner with an IC50 value (with 95% confidence limits) of 27.67 (15.68-39.66) µmol/L when the cell was clamped at -70 mV. In comparison with the quick and reversible inhibition of Nav1.7 by tetracaine and bupivacaine, the inhibitory effect of LA was rather slow and irreversible. It took more than 10 min to achieve steady-state inhibition when LA (300 µmol/L) was administered. Unlike tetracaine and bupivacaine, LA affected neither the voltage-dependent activation nor the inactivation of the channels. Five residues in domain III and domain IV have been reported to be critical for the effects of the two local anesthetics on Nav channels. But our mutant study revealed that only two residues (F1737, N1742) located in domain IV were necessary for the inhibitory activity of LA. The slow onset, irreversibility, and lack of influence on channel activation and inactivation accompanied with the different molecular determinants suggest that LA may inhibit Nav1.7 channels in a manner different from local anesthetics. These results may help to understand the featured analgesic activity of LA, thus benefiting its application in the clinic and future drug development.

Pharmacokinetics of monoester-diterpenoid alkaloids in myocardial infarction and normal rats after oral administration of Sini decoction by microdialysis combined with liquid chromatography-tandem mass spectrometry.

Monoester-diterpenoid alkaloids are the main bioactive components of Sini decoction, which is a well-known traditional Chinese medicine formula for the treatment of myocardial infarction (MI) and heart failure in China. In this work, an ultra-high-performance liquid chromatography-mass spectrometry combined with microdialysis method was successfully established and applied for investigating for the first time comparative plasma pharmacokinetics of three monoester-diterpenoid alkaloids (benzoylmesaconitine, benzoylaconitine and benzoylhypacoitine) in normal and MI rats after oral administration of Sini decoction. The statistical results of pharmacokinetic parameters demonstrated that benzoylmesaconitine, benzoylaconitine and benzoylhypacoitine showed lower peak concentration, longer half-life, smaller area under the concentration-time curve, slower clearance, time to peak concentration and mean residence time in MI rats than in normal rats (p < 0.05), which indicated that monoester-diterpenoid alkaloids exhibited lower systemic exposure and slower elimination in the MI rats. The results provided the experimental basis for understanding the metabolic fate and therapeutic effects of Sini decoction.