Rapid identification, isolation, and evaluation on anti-neuroinflammatory activity of limonoids derivatives from the root bark of Dictamnus dasycarpus

Limonin (LM) and its derivatives: Unveiling the neuroprotective and anti-inflammatory potential of LM and V-A-4 in the management of Alzheimer's disease and Parkinson's disease

Neuroinflammation and neuronal apoptosis are central pathogenic consequences associated with Alzheimer's Disease (AD) and Parkinson's Disease (PD). Limonin (LM), a tetracyclic triterpenoid available in citrus fruits, has anti-tumor, antioxidant, anti-inflammatory, hepatoprotective, and neuroprotective actions. LM derivative, V-A-4 emerged as a potential neuroprotective drug due to their ability to target multiple molecular pathways intertwined with neuroinflammation and neuronal apoptosis. To date, the treatment of AD and PD is not successful even though the understanding of the mechanism of neuroinflammation and neuronal apoptosis is vast in the literature. Thus, there is an urgent need to identify novel neuroprotective drugs that could target the multiple molecular pathways associated with neuroinflammation and neuronal apoptosis. The various online databases (Google scholar, Pubmed, Scopus) were searched via keywords: limonin, limonin derivatives and neuroprotection. This review highlights the multifunctional nature of LM and derivatives in combating neuroinflammation and neuronal apoptosis by stimulating PI3K/AKT and downregulating TLR4/NF-κB critical pathways. By intervening in the secretion of NO and TNF-α from glial cells, V-A-4 attenuates the damaging cascade of neuroinflammation by suppressing IKK-α and IKK-β. Furthermore, V-A-4 demonstrates its versatility by suppressing the manifestation of miR-146a and miR-155, both intimately linked to neuroinflammation, this review summarized the activities of LM and its derivatives against AD and PD, with a special focus on V-A-4 as an effective neuroprotective drug. V-A-4's ability to stimulate PI3K/AKT signaling further underscores its neuroprotective effect in combating AD and PD. More in-vitro cell line studies are needed to develop V-A-4 as an upcoming neuroprotective compound.

Obacunone, a Promising Phytochemical Triterpenoid: Research Progress on Its Pharmacological Activity and Mechanism

Obacunone, a natural triterpenoid, is an active component of the herbs Dictamnus dasycarpus Turcz. and Phellodendron amurense Rupr, and an indicator of the herbs' quality. Owing to its multiple health benefits, several studies have investigated the multi-targeting potential action mechanisms of obacunone. To summarize recent developments on the pharmacological actions of obacunone and focus on the underlying molecular mechanisms and signaling networks, we searched PubMed, Europe PMC, Wiley Online Library, Web of Science, Google Scholar, Wanfang Medical Network, and China National Knowledge Infrastructure for articles published prior to March 2024. Existing research indicates obacunone has great potential to become a promising therapeutic option against tumors, fibrotic diseases, bone and cholesterol metabolism diseases, and infections of pathogenic microorganisms, among others. The paper contributes to providing up-to-date references for further research and clinical applications of obacunone.

Dictamnus dasycarpus Turcz. attenuates airway inflammation and mucus hypersecretion by modulating the STAT6-STAT3/FOXA2 pathway

BACKGROUND

Effects of Dictamnus dasycarpus Turcz. on allergic asthma and their underlying mechanisms remain unclarified. Thus, we investigated the effects of D. dasycarpus Turcz. water extract (DDW) on mucus hypersecretion in mice with ovalbumin (OVA)-induced asthma and human bronchial epithelial cells.

METHODS

BALB/c mice were used to establish an OVA-induced allergic asthma model. Mice were grouped into the OVA sensitization/challenge, 100 and 300 mg/kg DDW treatment, and dexamethasone groups. In mice, cell counts in bronchoalveolar lavage fluid (BALF), serum and BALF analyses, and histopathological lung tissue analyses were performed. Furthermore, we confirmed the basic mechanism in interleukin (IL)-4/IL-13-treated human bronchial epithelial cells through western blotting.

RESULTS

In OVA-induced asthma mice, DDW treatment reduced inflammatory cell number and airway hyperresponsiveness and ameliorated histological changes (immune cell infiltration, mucus secretion, and collagen deposition) in lung tissues and serum total immunoglobulin E levels. DDW treatment lowered BALF IL-4, IL-5, and IL-13 levels; reduced levels of inflammatory mediators, such as thymus- and activation-regulated chemokine, macrophage-derived chemokine, and interferon gamma-induced protein; decreased mucin 5AC (MUC5AC) production; decreased signal transducer and activator of transcription (STAT) 6 and STAT3 expression; and restored forkhead box protein A2 (FOXA2) expression. In IL-4/IL-13-treated human bronchial epithelial cells, DDW treatment inhibited MUC5AC production, suppressed STAT6 and STAT3 expression (related to mucus hypersecretion), and increased FOXA2 expression.

CONCLUSIONS

DDW treatment modulates MUC5AC expression and mucus hypersecretion by downregulating STAT6 and STAT3 expression and upregulating FOXA2 expression. These findings provide a novel approach to manage mucus hypersecretion in asthma using DDW.

Metabolite profiling of remibrutinib in rat and human liver microsomes using liquid chromatography combined with benchtop orbitrap high-resolution mass spectrometry

Remibrutinib is a potent and highly selective covalent Bruton's tyrosine kinase inhibitor that is undergoing clinical development for the treatment of autoimmune diseases. The present study was undertaken to investigate the in vitro metabolism of remibrutinib and to propose its biotransformation pathways. The metabolites were generated by incubating remibrutinib (2 μm) with human and rat liver microsomes at 37°C for 30 min. Ultra-high-performance liquid chromatography combined with benchtop orbitrap high-resolution mass spectrometry was used to identify and characterize the metabolites of remibrutinib. Compound Discoverer software was employed to process the acquired data. In rat liver microsomes, a total of 18 metabolites have been identified and characterized among which three (M8, M12 and M13) were identified as the most abundant metabolites. In human liver microsomes, a total of 16 metabolites have been identified, and M8 and M12 were identified as the predominant metabolites. All the metabolites were nicotinamide adenine dinucleotide phosphate dependent. The major metabolic changes were found to be oxygenation, dealkylation, demethylation, epoxidation and hydrolysis. The present study comprehensively reports the in vitro metabolism of remibrutinib mentioning 20 metabolites. These findings will help investigation of remibrutinib disposition and safety evaluation.

Detection and identification of imperatorin metabolites in rat, dog, monkey, and human liver microsomes by ultra-high-performance liquid chromatography combined with high-resolution mass spectrometry and Compound Discoverer software

Imperatorin, a furanocoumarin that widely exists in many umbelliferous herbs, has been demonstrated to have a variety of pharmacological effects, including anti-inflammatory, antiosteoporosis, and antitumor activities. The purpose of this study was to investigate the metabolism of imperatorin using liver microsomes. The metabolites were generated by individually incubating imperatorin with rat, dog, monkey, and human liver microsomes. To trap the reactive metabolites during microsomal metabolism, glutathione (GSH) was included in the incubation. A LC technique coupled with benchtop orbitrap MS with full mass/data-dependent tandem mass spectrometry acquisition mode was used to detect and identify the generated metabolites. The possible structures of the metabolites were characterized according to their accurate masses and fragment ions. Under the current conditions, a total of 10 metabolites, including four GSH adducts, were identified. The results indicated that imperatorin underwent extensive metabolic reactions including hydroxylation, oxidation, glucuronidation, and GSH conjugation. This study provides essential data on the metabolism of imperatorin, which will be helpful for us to understand the safety and efficacy of this bioactive compound.

The pharmacological and pharmacokinetic properties of obacunone from citrus fruits: A comprehensive narrative review

Limonoids are a class of oxygenated terpenoids that exist mainly in citrus fruits. As a kind of limonoid, obacunone has attracted more and more researchers' attention because of its extensive pharmacological activities. The purpose of the narrative review is to systematically review relevant studies on the pharmacological effects and pharmacokinetic characteristics of obacunone to provide researchers with the latest and useful information. Pharmacological studies have shown that obacunone has a variety of pharmacological activities, such as anticancer, antioxidant, anti-inflammatory, anti-diabetes, neuroprotection, antibiosis, and antivirus. Among them, the anticancer effect is the most prominent. Pharmacokinetic studies have shown that the oral bioavailability of obacunone is low. This indicates the presence of high first-pass metabolism. We hope that this paper can help relevant scholars understand the progress in pharmacological and pharmacokinetic research of obacunone and help the further development of obacunone as a functional food.

Exploring the Mechanism of Hepatotoxicity Induced by Dictamnus dasycarpus Based on Network Pharmacology, Molecular Docking and Experimental Pharmacology

The root bark of Dictamnus dasycarpus Turcz is a traditional Chinese medicine, Dictamni Cortex (DC), which is mainly used in the clinical treatment of skin inflammation, eczema, rubella, rheumatism, and gynecological inflammation. Unexpectedly, there are some cases of liver injury after the administration of DC. However, the mechanism of hepatotoxicity remains ambiguous. The aim of this study was to explore the mechanism and substance bases of DC hepatotoxicity based on network pharmacology and molecular docking, verified through pharmacological experiments. Partial prototype components and metabolites in vivo of quinoline alkaloids from DC were selected as candidate compounds, whose targets were collected from databases. Network pharmacology was applied to study the potential hepatotoxic mechanism after correlating the targets of candidate compounds with the targets of hepatotoxicity. Molecular docking was simulated to uncover the molecular mechanism. Furthermore, the hepatotoxicity of the extract and its constituents from DC was evaluated in vivo and in vitro. We constructed the "potential toxic components-toxic target-toxic pathway" network. Our results showed that the targets of DC included CYP1A2 and GSR, participating in heterologous steroid metabolism, REDOX metabolism, drug metabolism, heterocyclic metabolic processes, the synthesis of steroid hormone, cytochrome P450 metabolism, chemical carcinogens and bile secretion pathways. In vitro and in vivo experiments displayed that DC could result in a decrease in GSH-Px and oxidative stress, simultaneously inhibiting the expression of CYP1A2 and inducing hepatotoxicity. These results further indicated the mechanism of hepatotoxicity induced by Dictamnus dasycarpus, providing a basic theory to explore and prevent hepatotoxicity in the clinical usage of Dictamnus dasycarpus.

LC-MS and GC-MS Data Fusion Metabolomics Profiling Coupled with Multivariate Analysis for the Discrimination of Different Parts of Faustrime Fruit and Evaluation of Their Antioxidant Activity

The comparative chemical composition of different part of Faustrime fruits (peels, pulp, albedo, and seeds) extracted with different solvents was determined by GC-MS and UHPLC-HRMS QTof. The obtained data were also combined for their in vitro antioxidant activity by multivariate analysis to define a complex fingerprint of the fruit. The principal component analysis model showed the significative occurrence of volatile organic compounds as α-bisabolol and α-trans-bergamotol in the pulp and albedo, hexanoic acid in the seeds, and several coumarins and phenolics in the peels. The higher radical scavenging activity of the pulp was related to the incidence of citric acid in partial least square regression.

Limonoids with anti-inflammatory activity: A review

The natural limonoids distributed mainly in the Meliaceae and Rutaceae plants are known for their unique and complex structure with high degree oxidation and cyclic rearrangement. However, these compounds exhibit a broad range of biological activities such as insecticidal, antibacterial, antifungal, antimalarial, antioxidant, anticancer, antiviral, and anti-inflammatory. There is still limited report about the biological activity of the anti-inflammatory effect of limonoids isolated from plants. Therefore, this study aimed to examine the effect of intact, deformed and rearranged limonoids as anti-inflammatory agents. The majority of anti-inflammatory investigations were evaluated by in vitro and in vivo assays of the isolated pure compounds and their derivatives. For the in vitro study, intact and C-ring seco limonoids showed a potent inhibitory effect against NO production. The in vivo analysis of Intact, C-seco, and AD-seco limonoids showed a potent effect based on the inhibition of pro-inflammatory cytokines expression, indicating their potency as anti-inflammatory agents.