Unlocking renal Restoration: Mesaconine from Aconitum plants restore mitochondrial function to halt cell apoptosis in acute kidney injury.

Acute kidney injury (AKI) is characterized by a sudden decline in renal function. Traditional Chinese medicine has employed Fuzi for kidney diseases; however, concerns about neurotoxicity and cardiotoxicity have constrained its clinical use. This study explored mesaconine, derived from processed Fuzi, as a promising low-toxicity alternative for AKI treatment. In this study, we assessed the protective effects of mesaconine in gentamicin (GM)-induced NRK-52E cells and AKI rat models in vitro and in vivo, respectively. Mesaconine promotes the proliferation of damaged NRK-52E cells and down-regulates intracellular transforming growth factor ß1 (TGF-ß1) and kidney injury molecule 1 (KIM-1) to promote renal cell repair. Concurrently, mesaconine restored mitochondrial morphology and permeability transition pores, reversed the decrease in mitochondrial membrane potential, mitigated mitochondrial dysfunction, decreased ATP production, inhibited inflammatory factor release, and reduced early apoptosis rates. In vivo, GM-induced AKI rat models exhibited elevated AKI biomarkers, in which mesaconine was effectively reduced, indicating improved renal function. Mesaconine enhanced superoxide dismutase activity, reduced malondialdehyde content, alleviated inflammatory infiltrate, mitigated tubular and glomerular lesions, and downregulated NF-κB (nuclear factor-κb) p65 expression, leading to decreased tumor necrosis factor-α (TNF-α) and IL-1ß (interleukin-1ß) levels in GM-induced AKI animals. Furthermore, mesaconine inhibited the expression of renal pro-apoptotic proteins (Bax, cytochrome c, cleaved-caspase 9, and cleaved-caspase 3) and induced the release of the anti-apoptotic protein bcl-2, further suppressing apoptosis. This study highlighted the therapeutic potential of mesaconine in GM-induced AKI. Its multifaceted mechanisms, including the restoration of mitochondrial dysfunction, anti-inflammatory and antioxidant effects, and apoptosis mitigation, make mesaconine a promising candidate for further exploration in AKI management.

[Mechanism of bulleyaconitine A in inhibiting bone destruction of rheumatoid arthritis via Src/PI3K/Akt signaling pathway].

Based on the sarcoma receptor coactivator(Src)/phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt) signaling pathway, the mechanism of action of bulleyaconitine A in the treatment of bone destruction of experimental rheumatoid arthritis(RA) was explored. Firstly, key targets of RA bone destruction were collected through GeneCards, PharmGKB, and OMIM databa-ses. Potential targets of bulleyaconitine A were collected using SwissTargetPrediction and PharmMapper databases. Next, intersection targets were obtained by the Venny 2.1.0 platform. Protein-protein interaction(PPI) network and topology analysis were managed by utilizing the STRING database and Cytoscape 3.8.0. Then, Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were conducted in the DAVID database. AutoDock Vina was applied to predict the molecular docking and binding ability of bulleyaconitine A with key targets. Finally, a receptor activator of nuclear factor-κB(RANKL)-induced osteoclast differentiation model was established in vitro. Quantitative real-time polymerase chain reaction(qRT-PCR) was used to detect the mRNA expression levels of related targets, and immunofluorescence and Western blot were adopted to detect the protein expression level of key targets. It displayed that there was a total of 29 drug-disease targets, and Src was the core target of bulleyaconitine A in anti-RA bone destruction. Furthermore, KEGG enrichment analysis revealed that bulleyaconitine A may exert an anti-RA bone destruction effect by regulating the Src/PI3K/Akt signaling pathway. The molecular docking results showed that bulleyaconitine A had better bin-ding ability with Src, phosphatidylinositol-4,5-diphosphate 3-kinase(PIK3CA), and Akt1. The result of the experiment indicated that bulleyaconitine A not only dose-dependently inhibited the mRNA expression levels of osteoclast differentiation-related genes cathepsin K(CTSK) and matrix metalloproteinase-9(MMP-9)(P<0.01), but also significantly reduced the expression of p-c-Src, PI3K, as well as p-Akt in vitro osteoclasts(P<0.01). In summary, bulleyaconitine A may inhibit RA bone destruction by regulating the Src/PI3K/Akt signaling pathway. This study provides experimental support for the treatment of RA bone destruction with bulleyaconitine A and lays a foundation for the clinical application of bulleyaconitine A.

Arrhythmia onsets triggered by acute myocardial ischemia are not mediated by lysophosphoglycerides accumulation in ventricular myocardium.

Lysophosphoglycerides (LPLs) have been reported to accumulate in myocardium and serve as a cause of arrhythmias in acute myocardial ischemia. However, in this study we found that LPLs level in the ventricular myocardium was decreased by the onset of acute myocardial ischemia in vivo in rats. Decreasing of LPLs level in left ventricular myocardium, but not right, was observed within 26 min of left myocardial ischemia, regardless of whether arrhythmias were triggered. Lower LPLs level in the ventricular myocardium was also observed in aconitine-simulated ventricular fibrillation (P < 0.0001) and ouabain-simulated III° atrioventricular block (P < 0.0001). Shot-lasting electric shock, e.g., ≤ 40 s, decreased LPLs level, while long-lasting, e.g., 5 min, increased it (fold change = 2.27, P = 0.0008). LPLs accumulation was observed in long-lasting myocardial ischemia, e.g., 4 h (fold change = 1.20, P = 0.0012), when caspase3 activity was elevated (P = 0.0012), indicating increased cell death, but not coincided with higher frequent arrhythmias. In postmortem human ventricular myocardium, differences of LPLs level in left ventricular myocardium was not observed among coronary artery disease- and other heart diseases-caused sudden death and non-heart disease caused death. LPLs level manifested a remarkable increasing from postmortem 12 h on in rats, thus abolishing the potential for serving as biomarkers of sudden cardiac death. Token together, in this study we found that LPLs in ventricular myocardium were initially decreased by the onset of ischemia, LPLs accumulation do not confer arrhythmogenesis during acute myocardial ischemia. It is necessary to reassess the roles of LPLs in myocardial infarction.

Protective effect of ginsenoside Rb1 against aconitine cardiotoxicity studied by myocardial injury, action potential, and calcium signaling.

Aconitine is the main active component of Aconitum plants. Although aconitine has effects that include strengthening the heart, analgesia, anti-tumor, and immune-regulating effects, aconitine has both efficacy and toxicity, especially cardiotoxicity. Severe effects can include arrhythmia and cardiac arrest, which limits the clinical application of aconitine-containing traditional Chinese medicine. Ginsenoside Rb1(Rb1) is mainly found in plants, such as ginseng and Panax notoginseng, and has cardiovascular-protective and anti-arrhythmia effects. This study aimed to investigate the detoxifying effects of Rb1 on aconitine cardiotoxicity and the electrophysiological effect of Rb1 on aconitine-induced arrhythmia in rats. Pathological analysis, myocardial enzymatic indexes, and Western blotting were used to investigate the ameliorating effect of Rb1 on aconitine cardiotoxicity. Optical mapping was used to evaluate the effect of Rb1 on action potential and calcium signaling after aconitine-induced arrhythmia. Rb1 inhibited pathological damage caused by aconitine, decreased myocardial enzyme levels, and restored the balance of apoptotic protein expression by reducing the expression of Bax and cleaved caspase 3 and increasing the expression of Bcl-2, thereby reducing myocardial damage caused by aconitine. Rb1 also reduced the increase in heart rate caused by aconitine, accelerated action potential conduction and calcium signaling, and reduced the dispersion of action potential and calcium signal conduction. Rb1 reduced the cardiotoxicity of aconitine by attenuating aconitine-induced myocardial injury and inhibiting the aconitine-induced retardation of ventricular action potential and calcium signaling in rats.

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.

Polyelectrolyte Microcapsules: An Extended Release System for the Antiarrhythmic Complex of Allapinin with Glycyrrhizic Acid Salt.

Allapinin has antiarrhythmic activity and can be used to prevent and treat various supraventricular and ventricular arrhythmias. Nevertheless, it is highly toxic and has a number of side effects associated with non-specific accumulation in various tissues. The complex of this substance with the monoammonium salt of glycyrrhizic acid (Al:MASGA) has less toxicity and improved antiarrhythmic activity. However, the encapsulation of Al:MASGA in polyelectrolyte microcapsules (PMC) for prolonged release will reduce the residual adverse effects of this drug. In this work, the possibility of encapsulating the allapinin-MASGA complex in polyelectrolyte microcapsules based on polyallylamine and polystyrene sulfonate was investigated. The encapsulation methods of the allapinin-MASGA in polyelectrolyte microcapsules by adsorption and coprecipitation were compared. It was found that the coprecipitation method did not result in the encapsulation of Al:MASGA. The sorption method facilitated the encapsulation of up to 80% of the original substance content in solution in PMC. The release of the encapsulated substance was further investigated, and it was shown that the release of the encapsulated Al:MASGA was independent of the substance content in the capsules, but at pH 5, a two-fold decrease in the rate of drug release was observed.

Benzoylaconitine: A promising ACE2-targeted agonist for enhancing cardiac function in heart failure.

Benzoylaconitine is a natural product in the treatment of cardiovascular disease. However, its pharmacological effect, direct target protein, and molecular mechanisms for the treatment of heart failure are unclear. In this study, benzoylaconitine inhibited Ang II-induced cell hypertrophy and fibrosis in rat primary cardiomyocytes and rat fibroblasts, while attenuating cardiac function and cardiac remodeling in TAC mice. Using the limited proteolysis-mass spectrometry (LiP-MS) method, the angiotensin-converting enzyme 2 (ACE2) was confirmed as a direct binding target of benzoylaconitine for the treatment of heart failure. In ACE2-knockdown cells and ACE2-/- mice, benzoylaconitine failed to ameliorate cardiomyocyte hypertrophy, fibrosis, and heart failure. Online RNA-sequence analysis indicated p38/ERK-mediated mitochondrial reactive oxygen species (ROS) and nuclear factor kappa B (NF-κB) activation are the possible downstream molecular mechanisms for the effect of BAC-ACE2 interaction. Further studies in ACE2-knockdown cells and ACE2-/- mice suggested that benzoylaconitine targeted ACE2 to suppress p38/ERK-mediated mitochondrial ROS and NF-κB pathway activation. Our findings suggest that benzoylaconitine is a promising ACE2 agonist in regulating mitochondrial ROS release and inflammation activation to improve cardiac function in the treatment of heart failure.

Anti-rheumatic potential vis-à-vis aconitine and hypaconitine content analysis in different Aconitum spp. from Sikkim Himalayas (India).

Aconitum spp. are important medicinal plants mentioned in Ayurveda as Ativisa or Vatsanabha. The present study aims to evaluate anti-rheumatic potential in seven Aconitum species and correlation with aconitine and hypaconitine content. Anti-rheumatic potential was analyzed through in vitro xanthine oxidase inhibition, anti-inflammatory and ROS scavenging assays; and quantification of aconitine and hypaconitine with RP-HPLC method validated as per ICH guidelines. The findings reveal that A. palmatum possessed the most promising response (IC50 =12.68±0.15 µg/ml) followed by A. ferox (IC50 =12.912±1.87 µg/ml) for xanthin oxidase inhibition. We observed a wide variation in aconitine and hypaconitine content ranging from 0.018 %-1.37 % and 0.0051 %-0.077 % respectively on dry weight basis. Aconitine and hypaconitine showed moderate positive correlation (r=0.68 and 0.59 respectively) with anti-rheumatic potential. The study identifies potential alternative species of Aconitum that can help in sustainable availability of quality raw material.

In vitro and in†vivo biological evaluation of Lappaconitine derivatives as potential anti-inflammatory agents.

Natural products and their derivatives are a precious treasure in the pursuit of potent anti-inflammatory drugs. In this work, we measured the toxicity of 78 LA derivatives at 20 µM using MTT, then we evaluated the NO release of compounds without obvious toxicity in LPS-induced RAW.264.7 by Griess reagent, we identified three compounds, namely compounds 6, 19, 70, which exhibited promising anti-inflammatory potential. These compounds exhibited IC50 values of 10.34±2.05 µM, 18.18±4.80 µM and 15.66±0.88 µM. In addition, through ELISA kits, compounds 6, 19, 70 significantly reduce the production of inflammatory factors (TNF-α, IL-6, IL-1ß). Real-time PCR and western blot analysis showed that compounds 6, 19, 70 inhibited the mRNA and protein expression of iNOS and COX-2. Notably, compound 6 exhibited the most potent inhibitory activity. In vitro, it inhibits LPS-induced phosphorylation of NF-κB p65, IκBα, ERK1/2, JNK, and p38 MAPKs in RAW264.7 cells. In vivo, compound 6 potently inhibits the secretion of inflammatory mediators and neutrophil activation in ALI mice. Our findings suggest that compound 6 may be a potential anti-inflammatory drug.

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.

[Therapeutic effects of alkaloids in Tibetan medicine Bangna (Aconiti Penduli et Aconiti Flavi Radix) on osteoarthritis rats and mechanisms].

This study aims to investigate the therapeutic effects of alkaloids in Tibetan medicine Bangna(Aconiti Penduli et Aconiti Flavi Radix) on osteoarthritis(OA) rats in vitro and in vivo and the underlying mechanisms. Chondrocytes were isolated from 2-3 week-old male SD rats and lipopolysaccharide(LPS) was used to induce OA in chondrocytes in vitro. Methyl thiazolyl tetrazolium(MTT) assay was used to investigate the toxicity of seven alkaloids(12-epi-napelline, songorine, benzoylaconine, aconitine, 3-acetylaconitine, mesaconitine, and benzoylmesaconine) to chondrocytes. Chondrocytes were classified into the control group, model group(induced by LPS 5 µg·mL~(-1) for 12 h), and administration groups(induced by LPS 5 µg·mL~(-1) for 12 h and incubated for 24 h). The protein expression of inflammatory factors cyclooxygenase-2(COX-2), inducible nitric oxide synthetase(iNOS), tumor necrosis factor-α(TNF-α), and interleukin-1ß(IL-1ß) in each group were detected by Western blot, and the protein expression of matrix metalloprotease-13(MMP-13), aggrecan, collagen Ⅱ, fibroblast growth factor 2(FGF2) by immunofluorescence staining. For the in vivo experiment, sodium iodoacetate was used to induce OA in rats, and the expression of MMP-13, TNF-α, and FGF2 in cartilage tissues of rats in each group was detected by immunohistochemistry. The results showed that the viability of chondrocytes could reach more than 90% under the treatment of the seven alkaloids in a certain dose range. Aconitine, 12-epi-napelline, songorine, 3-acetylaconitine, and mesaconitine could decrease the protein expression of inflammatory factors COX-2, iNOS, TNF-α and IL-1ß compared with the model group. Moreover, 12-epi-napelline, aconitine, and mesaconitine could down-regulate the expression of MMP-13 and up-regulate the expression of aggrecan and collagen Ⅱ. In addition, compared with the model group and other Bangna alkaloids, 12-epi-napelline significantly up-regulated the expression of FGF2. Therefore, 12-epi-napelline was selected for the animal experiment in vivo. Immunohistochemistry results showed that 12-epi-napelline could significantly reduce the expression of MMP-13 and TNF-α in cartilage tissues, and up-regulate the expression of FGF2 compared with the model group. In conclusion, among the seven Bangna alkaloids, 12-epi-napelline can promote the repair of OA in rats by down-regulating the expression of MMP-13 and TNF-α and up-regulating the expression of FGF2.

[Comparative study on intestinal absorption kinetics of main active components in Sini Decoction and its separated recipes].

This paper aims to study the difference in the intestinal absorption kinetics of main active components of Sini decoction and its separated recipes and explain the scientificity and rationality of the compatibility of Sini Decoction. A in situ intestinal perfusion rat model was established to evaluate the differences in the absorption of benzoylmesaconine, benzoylaconine, benzoylhypacoitine, mesaconitine, hypaconitine, glycyrrhizic acid, liquiritin and 6-gingerol from Sini Decoction and its separated recipes in the duodenum, jejunum and ileum by high performance liquid chromatography(HPLC). The results indicated that the Sini Decoction group was superior to the Aconiti Lateralis Radix Praeparata group in terms of absorption degree and rate for aconitum alkaloids. The absorption of benzoylmesaconine and hypaconitine in the duodenum, jejunum and ileum was faster and stronger in the Sini Decoction group(P<0.05). The absorption degree of glycyrrhizic acid in the duodenum was significantly higher in the Sini Decoction group than in the Glycyrrhizae Radix et Rhizoma group and the Glycyrrhizae Radix et Rhizoma-Zingiberis Rhizoma group(P<0.05). The absorption rate and degree of 6-gingerol in the ileum in the Sini Decoction group were significantly higher than those in the Zingiberis Rhizoma group(P<0.05). In short, Zingiberis Rhizoma and Glycyrrhizae Radix et Rhizoma can promote the absorption of aconitum alkaloids in different intestinal segments, which reflects the scientific composition of Sini Decoction.

Study on the Mechanism of Mesaconitine-Induced Hepatotoxicity in Rats Based on Metabonomics and Toxicology Network.

Mesaconitine (MA), one of the main diterpenoid alkaloids in Aconitum, has a variety of pharmacological effects, such as analgesia, anti-inflammation and relaxation of rat aorta. However, MA is a highly toxic ingredient. At present, studies on its toxicity are mainly focused on the heart and central nervous system, and there are few reports on the hepatotoxic mechanism of MA. Therefore, we evaluated the effects of MA administration on liver. SD rats were randomly divided into a normal saline (NS) group, a low-dose MA group (0.8 mg/kg/day) and a high-dose MA group (1.2 mg/kg/day). After 6 days of administration, the toxicity of MA on the liver was observed. Metabolomic and network toxicology methods were combined to explore the effect of MA on the liver of SD rats and the mechanism of hepatotoxicity in this study. Through metabonomics study, the differential metabolites of MA, such as L-phenylalanine, retinyl ester, L-proline and 5-hydroxyindole acetaldehyde, were obtained, which involved amino acid metabolism, vitamin metabolism, glucose metabolism and lipid metabolism. Based on network toxicological analysis, MA can affect HIF-1 signal pathway, MAPK signal pathway, PI3K-Akt signal pathway and FoxO signal pathway by regulating ALB, AKT1, CASP3, IL2 and other targets. Western blot results showed that protein expression of HMOX1, IL2 and caspase-3 in liver significantly increased after MA administration (p < 0.05). Combined with the results of metabonomics and network toxicology, it is suggested that MA may induce hepatotoxicity by activating oxidative stress, initiating inflammatory reaction and inducing apoptosis.

Lappaconitine inhibits glutamate release from rat cerebrocortical nerve terminals by suppressing Ca2+ influx and protein kinase A cascade.

The inhibition of the excessive release of glutamate in the brain has emerged as a promising new option for developing therapeutic strategies for neurodegenerative disorders. This study investigated the effect and mechanism of lappaconitine, a diterpenoid alkaloid found in species of Aconitum, on glutamate release in rat cerebral cortex nerve terminals (synaptosomes). Here, we report that in the rat cortical synaptosomal preparation, lappaconitine reduced the K+ channel blocker 4-aminopyridine (4-AP)-evoked Ca2+-dependent release of glutamate. The inhibitory effect of lappaconitine on the evoked glutamate release was blocked by the vesicular transporter inhibitor bafilomycin A1 and calcium-chelating agent ethylene glycol tetraacetic acid (EGTA), but was unaffected by exposure to the glutamate transporter inhibitor dl-threo-beta-benzyloxyaspartate (dl-TBOA). The depolarization-induced elevation of cytosolic calcium concentration ([Ca2+]c) was inhibited by lappaconitine, while the 4-AP-mediated depolarization of the synaptosomal membrane potential was not affected. The inhibition of glutamate release by lappaconitine was markedly decreased in synaptosomes pretreated with the Cav2.3 (R-type) channel blocker SNX-482 or the protein kinase A inhibitor H89. Nevertheless, the lappaconitine-mediated inhibition of glutamate release was not abolished by the intracellular Ca2+-release inhibitors dantrolene and CGP37157. Lappaconitine also significantly decreased the 4-AP-induced phosphorylation of PKA and SNAP-25, a presynaptic substrate for PKA. Our data suggest that lappaconitine reduces Ca2+ influx through R-type Ca2+ channels, subsequently reducing the protein kinase A cascade to inhibit the evoked glutamate release from rat cerebral cortex nerve terminals.

Investigation into the protective effects of hypaconitine and glycyrrhetinic acid against chronic heart failure of the rats.

BACKGROUND: The present study aimed to determine the protective effects of hypaconitine (HA) and glycyrrhetinic acid (GA) against chronic heart failure (CHF) in the rats and to explore the underlying molecular mechanisms. METHODS: The CHF rat model was established by transverse-aortic constriction (TAC) operation. Transthoracic echocardiography and hematoxylin eosin (HE) staining were used to evaluate the pathophysiological and histopathological changes of CHF model. The total cholesterol (TCHO) and triglyceride (TG) levels were determined by ELISA assay. The protein expression of fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA) and endothelial nitric oxide synthase (eNOS) in the rat ventricular tissues was determined by immunohistochemistry. The serum metabolites were determined by LC-MS/MS assay. RESULTS: After applied the HA + GA, the cardiac tissue and structure were obviously improved, and the HA + GA treatment also significantly reduced the plasma levels of TCHO and TG in the CHF rats. The expression of FGF2 and VEGFA protein was up-regulated and the expression of eNOS protein was down-regulated in the ventricular tissues of CHF rats, which was significantly restored after HA + GA treatment. HA + GA treatment down-regulated serum isonicotinic acid, phosphatidylcholine, cardiolipin, estrogen glucuronide, and glycocholic acid, up-regulated serum sphingosine and deoxycholic acid in the CHF rats. CONCLUSIONS: In conclusion, HA + GA showed protective effects on CHF in the rats, and the HA + GA may exert protective effects by reducing lipid levels, up-regulating the expression of FGF2 and VEGFA proteins, attenuating eNOS protein expression, and modulating metabolic pathways. However, the molecular mechanisms underlying HA + GA-mediated effects still require further examination.

Analysis of Electrophysiological Mechanisms of N-Deacetyllapaconitine Monochlorhydrate, the Main Metabolite of Lappaconitine Hydrobromide.

In in vitro experiments on isolated rat hippocampal neurons, we studied the electrophysiological mechanisms of the antiarrhythmic effects of N-deacetyllappaconitine monochlorhydrate (DALCh), active metabolite of lappaconitine hydrobromide (allapinin). Electrical activity of neurons was recorded by the patch-clamp method in the whole cell configuration. It was shown that DALCh increased the duration of both slow and fast depolarization phases and decreased the amplitude of the action potential. DALCh effectively inhibited transmembrane currents of Na+ ions and partially K+ ions through the corresponding transmembrane voltage-gated ion channels. Thus, DALCh, in contrast to lappaconitine hydrobromide, belongs not to 1C, but to the 1A class of antiarrhythmics according to the Vaughan-Williams classification.

Bulleyaconitine A is a sensitive substrate and competitive inhibitor of CYP3A4: One of the possible explanations for clinical adverse reactions.

Bulleyaconitine A (BLA), a toxic Aconitum alkaloid, is a potent analgesic that is clinically applied to treat rheumatoid arthritis, osteoarthritis and lumbosacral pain. BLA-related adverse reactions occur frequently, but whether the underlying mechanism is related to its metabolic interplay with drug-metabolizing enzymes remains unclear. This study aimed to elucidate the metabolic characteristics of BLA and its affinity action and mechanism to drug-metabolizing enzymes to reveal whether BLA-related adverse reactions are modulated by enzymes. After incubation with human liver microsomes and recombinant human cytochrome P450 enzymes, we found that BLA was predominantly metabolized by CYP3A, in which CYP3A4 had an almost absolute advantage. In vitro, the CYP3A4 inhibitor ketoconazole noticeably suppressed the metabolism of BLA. In vivo, the AUC0-∞ values, cardiotoxicity and neurotoxicity of BLA in Cyp3a-inhibited mice were all obviously enhanced (P < 0.05) compared to those in normal mice. In the enzyme kinetics study, BLA was found to be a sensitive substrate of CYP3A4, and its characteristics were consistent with substrate inhibition (Km = 39.36 ± 10.47 µmol/L, Ks = 83.42 ± 19.65 µmol/L). BLA was further identified to be a competitive inhibitor of CYP3A4 with Ki = 53.64 µmol/L, since the intrinsic clearance (CLint) of midazolam, a selective CYP3A4 substrate, decreased significantly (P < 0.05) when incubated with BLA together in mouse liver microsomes. Overall, BLA is a sensitive substrate and competitive inhibitor of CYP3A4, and clinical adverse reactions of BLA may mechanistically related to the CYP3A4-mediated drug-drug interactions.

Inflammation Regulation via an Agonist and Antagonists of α7 Nicotinic Acetylcholine Receptors in RAW264.7 Macrophages.

The α7 nicotinic acetylcholine receptor (nAChR) is widely distributed in the central and peripheral nervous systems and is closely related to a variety of nervous system diseases and inflammatory responses. The α7 nAChR subtype plays a vital role in the cholinergic anti-inflammatory pathway. In vivo, ACh released from nerve endings stimulates α7 nAChR on macrophages to regulate the NF-κB and JAK2/STAT3 signaling pathways, thereby inhibiting the production and release of downstream proinflammatory cytokines and chemokines. Despite a considerable level of recent research on α7 nAChR-mediated immune responses, much is still unknown. In this study, we used an agonist (PNU282987) and antagonists (MLA and α-conotoxin [A10L]PnIA) of α7 nAChR as pharmacological tools to identify the molecular mechanism of the α7 nAChR-mediated cholinergic anti-inflammatory pathway in RAW264.7 mouse macrophages. The results of quantitative PCR, ELISAs, and transcriptome analysis were combined to clarify the function of α7 nAChR regulation in the inflammatory response. Our findings indicate that the agonist PNU282987 significantly reduced the expression of the IL-6 gene and protein in inflammatory macrophages to attenuate the inflammatory response, but the antagonists MLA and α-conotoxin [A10L]PnIA had the opposite effects. Neither the agonist nor antagonists of α7 nAChR changed the expression level of the α7 nAChR subunit gene; they only regulated receptor function. This study provides a reference and scientific basis for the discovery of novel α7 nAChR agonists and their anti-inflammatory applications in the future.

Transdermal Enhancement Strategy of Lappaconitine: Alteration of Keratin Configuration by Counter-Ion.

The objective of this study was to develop a lappaconitine (LA) transdermal patch with counter-ion to increase the transdermal permeability of the drug, and a theory of counter-ion altering the conformation of the skin keratin was put forward based on the in vitro skin permeation study and physicochemical properties of ion-pairs. Formulation factors including pressure sensitive adhesives (PSAs), drug-loading, counter-ions and molar ratios of counter-ion were screened by in vitro skin permeation study. The optimized formulation was composed of 7% LA, 1.5 mole cinnamic acid and AAOH (PSA containing hydroxyl group synthesized by our laboratory) as an adhesive matrix. The optimized patch was evaluated by the pharmacokinetic and analgesic pharmacodynamic studies. AUC0-t and pain inhibition ratio of the optimized patch were 2450.40 ± 848.52 h ng/mL and 81.18%, which showed good absorption into the skin and excellent analgesic effect. The mechanism of facilitated transdermal drug permeation by counter-ion was investigated by ATR-FTIR, thermal analysis, FTIR, XPS and molecular docking. The results indicated that after the formation of ion-pairs, the excess counter-ions would alter the conformation of the skin keratin, thus increasing the transdermal penetration of LA. In conclusion, the LA patch was successfully optimized, and the effect of counter-ions on the skin was clarified at the molecular level. These findings provided additional references for the application of counter-ion in the transdermal drug delivery system.