Quinolizidine Alkaloids Research Articles

Derivatives of (–)-Cytisine with Thiourea Fragment. Synthesis and Antiviral Activity

New derivatives of the quinolizidine alkaloid, (–)-cytisine, with a substituted 2-pyridone ring and a thiourea moiety in the bispidin fragment of the molecule were synthesized. The ability of the synthesized cytisine-containing thioureas to inhibit the reproduction of human parainfluenza virus type 3 was assessed. It was found that the derivatives obtained by the reaction of benzoyl or phenyl isothiocyanate with (–)-cytisine, as well as its 9-bromo or 9,11-derivative, effectively suppress the reproduction of human parainfluenza virus type 3 (their selectivity indices are 56, 58 and 95, respectively), which confirms the promise of the chosen approach to synthetic modifications of the alkaloid (–)-cytisine in order to obtain effective antiviral agents on its basis.

Preventive effects of matrine on LPS-induced inflammation in RAW 264.7 cells and intestinal damage in mice through the TLR4/NF-κB/MAPK pathway

BackgroundMatrine is a tetracyclic quinolizidine alkaloid with diverse bioactive properties, including anti-inflammatory and neuroprotective properties. However, the underlying anti-inflammatory mechanisms remain unclear. PurposeThis study aimed to explore how matrine reduces Lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 cells and to assess its protective effects against LPS-induced intestinal damage. MethodsThe effect of matrine on cell viability was assessed using the cell counting kit-8 (CCK-8) assay. Additionally, its impact on inflammatory cytokines and macrophage polarization was assessed using enzyme-linked immunosorbent assay (ELISA), flow cytometry, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses. The effects on intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), nitric oxide (NO) production, and oxidative stress were evaluated using 2′,7′-dichlorodihydrofluorescein diacetate staining and JC-1 and Griess assays. Immunofluorescence staining was used to observe the translocation of the NF-κB p65 subunit. Western blotting (WB) and qRT-PCR were employed to analyze the expression levels of proteins related to the toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) pathway. An LPS-induced mouse model was established to study the intestinal inflammation and barrier injury. Mouse feces characteristics, colon length, and disease activity index (DAI) were recorded. Hematoxylin-eosin (H&E) and alcian blue/periodic acid schiff (AB/PAS) staining were used to observe morphological changes and barrier damage in the duodenum, jejunum, ileum, and colon and to measure villus length, crypt depth, goblet cell count, and positive areas in the duodenum, jejunum, and ileum. The content of short-chain fatty acids (SCFAs) in the colon was determined using gas chromatography (GC). ResultsMatrine inhibited LPS-induced inflammatory cytokine levels, suppressed macrophage M1 polarization, and promoted M2 macrophage polarization. Matrine reduced LPS-induced increases in ROS and NO levels and regulates oxidative stress. Additionally, matrine inhibited the nuclear translocation of the NF-κB p65 subunit and exerted anti-inflammatory effects by suppressing the activation of the TLR4/NF-κB/MAPK pathway. In vivo experiments indicated that matrine significantly alleviated LPS-induced diarrhea, increased DAI, and shortened the colon. Matrine reduced the production of the pro-inflammatory cytokine interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α and the pro-inflammatory mediator NO in mouse intestinal tissues while promoting the content of the anti-inflammatory cytokine IL-10. Furthermore, it improved intestinal tissue structure and alleviated LPS-induced intestinal barrier damage. Finally, matrine increased the SCFA levels in the intestine. ConclusionMatrine exerted its anti-inflammatory effects and protects against intestinal injury through the TLR4/NF-κB/MAPK signaling pathway.

The genome of Lupinus mutabilis: Evolution and genetics of an emerging bio-based crop.

Lupinus mutabilis is an under-domesticated legume species from the Andean region of South America. It belongs to the New World lupins clade, which groups several lupin species displaying large genetic variation and adaptability to highly different environments. L. mutabilis is attracting interest as a potential multipurpose crop to diversify the European supply of plant proteins, increase agricultural biodiversity, and fulfill bio-based applications. This study reports the first high-quality L. mutabilis genome assembly, which is also the first sequenced assembly of a New World lupin species. Through comparative genomics and phylogenetics, the evolution of L. mutabilis within legumes and lupins is described, highlighting both genomic similarities and patterns specific to L. mutabilis, potentially linked to environmental adaptations. Furthermore, the assembly was used to study the genetics underlying important traits for the establishment of L.mutabilis as a novel crop, including protein and quinolizidine alkaloids contents in seeds, genomic patterns of classic resistance genes, and genomic properties of L. mutabilis mycorrhiza-related genes. These analyses pointed out copy number variation, differential genomic gene contexts, and gene family expansion through tandem duplications as likely important drivers of the genomic diversity observed for these traits between L. mutabilis and other lupins and legumes. Overall, the L. mutabilis genome assembly will be a valuable resource to conduct genetic research and enable genomic-based breeding approaches to turn L.mutabilis into a multipurpose legume crop.

Multi-faceted potential of sophoridine compound's anti-arrhythmic and antioxidant effects through ROS/CaMKII pathway

Cardiac arrhythmias remain a significant cause of mortality and morbidity, for novel antiarrhythmic therapies. This study states that the first report of sophoridine (SPN), a quinolizidine alkaloid derived from traditional Chinese herbs, shows promise as a potential candidate due to its anti-arrhythmic and antioxidant properties. The study found that cell viability in H9C2 rat cardiomyocytes remained stable even when treated with SPN at a higher dosage of 100 μg/ml. This phenomenon was accompanied by increases in mitochondria-derived reactive oxygen species (ROS) and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling, at 50 and 100 μg/ml. Glucose fluctuations regulate ventricular arrhythmias caused by SPN by activating the ROS/CaMKII pathway. Experimental models using zebrafish provided additional evidence supporting the regulatory effects of SPN on heart rate. In addition, the administration of SPN resulted in substantial deregulation of crucial genes involved in heart development (nppa, nppb, tnnt2a) at the transcriptional level in zebrafish. These findings provide insight into the various pharmacological properties of SPN and this opens up new possibilities for anti-arrhythmic treatment strategies.

Discovery of Aloperine as a Potential Antineoplastic Agent for Cholangiocarcinoma Harboring Mutant IDH1.

Intrahepatic cholangiocarcinoma (ICC) is a universally lethal malignancy with increasing incidence. However, ICC patients receive limited benefits from current drugs; therefore, we must urgently explore new drugs for treating ICC. Quinolizidine alkaloids, as essential active ingredients extracted from Sophora alopecuroides Linn, can suppress cancer cell growth via numerous mechanisms and have therapeutic effects on liver-related diseases. However, the impact of quinolizidine alkaloids on intrahepatic cholangiocarcinoma has not been fully studied. In this article, the in vitro anti-ICC activities of six natural quinolizidine alkaloids were explored. Aloperine was the most potent antitumor compound among the tested quinolizidine alkaloids, and it preferentially inhibited RBE cells rather than HCCC-9810 cells. Mechanistically, aloperine can potentially decrease glutamate content by inhibiting the hydrolysis of glutamine, reducing D-2-hydroxyglutarate levels and, consequently, leading to preferential growth inhibition in isocitrate dehydrogenase (IDH)-mutant ICC cells. In addition, aloperine preferentially resensitizes RBE cells to 5-fluorouracil, AGI-5198 and olaparib. This article demonstrates that aloperine shows preferential antitumor effects in intrahepatic cholangiocarcinoma cells harboring the mutant IDH1 by decreasing D-2-hydroxyglutarate, suggesting that aloperine could be used as a lead compound or adjuvant chemotherapy drug to treat ICC harboring the mutant IDH.

Fingerprinting alkaloids for traceability: Semi-untargeted UHPLC-MS/MS approach in raw lupins as a case study

Lupin seeds are recognized for their nutritional value and potential health benefits, but they contain also a significant amount of alkaloids, an anti-nutritive class of compounds, which vary significantly in composition within and between species due to environmental factors. In this study, we developed a predictive multi-experiment approach using ultra-high performance liquid chromatography coupled with triple quadrupole with linear ionic trap tandem mass spectrometry (UHPLC-QqQ-LIT-MS/MS) for comprehensive alkaloid profiling and geographical classification of Lupinus albus L. samples originating from four different Italian regions. Six targeted quinolizidine alkaloids were detected and 21 other alkaloids were putatively identified. Hierarchical Cluster Analysis (HCA) and partial least squares discriminant analysis (PLS-DA) were applied to explore the data structure and successfully classify samples according to their geographical origin. The data demonstrate the efficacy of the developed approach in providing valuable insights in alkaloid profiles of lupin seeds and their potential as markers for geographical traceability.

Aloperine Inhibits ASFV via Regulating PRLR/JAK2 Signaling Pathway In Vitro.

African swine fever (ASF) has become a global pandemic due to inadequate prevention and control measures, posing a significant threat to the swine industry. Despite the approval of a single vaccine in Vietnam, no antiviral drugs against the ASF virus (ASFV) are currently available. Aloperine (ALO), a quinolizidine alkaloid extracted from the seeds and leaves of bitter beans, exhibits various biological functions, including anti-inflammatory, anti-cancer, and antiviral activities. In this study, we found that ALO could inhibit ASFV replication in MA-104, PK-15, 3D4/21, and WSL cells in a dose-dependent manner without cytotoxicity at 100 μM. Furthermore, it was verified that ALO acted on the co- and post-infection stages of ASFV by time-of-addition assay, and inhibited viral internalization rather than directly inactivating the virus. Notably, RT-qPCR analysis indicated that ALO did not exert anti-inflammatory activity during ASFV infection. Additionally, gene ontology (GO) and KEGG pathway enrichment analyses of transcriptomic data revealed that ALO could inhibit ASFV replication via the PRLR/JAK2 signaling pathway. Together, these findings suggest that ALO effectively inhibits ASFV replication in vitro and provides a potential new target for developing anti-ASFV drugs.

Sophoridine exerts anti-arthritic effects on fibroblast-like synoviocytes and collagen-induced arthritis in rats.

The discovery of alternative medicines with fewer adverse effects is urgently needed for rheumatoid arthritis (RA). Sophoridine (SR), the naturally occurring quinolizidine alkaloid isolated from the leguminous sophora species, has been demonstrated to possess a wide range of pharmacological activities. However, the effect of SR on RA remains unknown. In this study, the collagen-induced arthritis (CIA) rat model and tumor necrosis factor alpha (TNFα)-induced fibroblast-like synoviocytes (FLSs) were utilized to investigate the inhibitory effect of SR on RA. The anti-arthritic effect of SR was evaluated using the CIA rat model in vivo and TNFα-stimulated FLSs in vitro. Mechanistically, potential therapeutic targets and pathways of SR in RA were analyzed through drug target databases and disease databases, and validation was carried out through immunofluorescence, immunohistochemistry, and Western blot. The in vivo results revealed that SR treatment effectively ameliorated synovial inflammation and bone erosion in rats with CIA. The in vitro studies showed that SR could significantly suppress the proliferation and migration in TNFα-induced arthritic FLSs. Mechanistically, SR treatment efficiently inhibited the activation of MAPKs (JNK and p38) and NF-κB pathways in TNFα-induced arthritic FLSs. These findings were further substantiated by Immunohistochemistry results in the CIA rat. SR exerts an anti-arthritic effect in CIA rats through inhibition of the pathogenic characteristic of arthritic FLSs via suppressing NF-κB and MAPKs (JNK and p38) signaling pathways. SR may have a great potential for development as a novel therapeutic agent for RA treatment.

The Chemistry of the Defensive Secretions of Three Species of Millipedes in the Genus Brachycybe.

Millipedes have long been known to produce a diverse array of chemical defense agents that deter predation. These compounds, or their precursors, are stored in high concentration within glands (ozadenes) and are released upon disturbance. The subterclass Colobognatha contains four orders of millipedes, all of which are known to produce terpenoid alkaloids-spare the Siphonophorida that produce terpenes. Although these compounds represent some of the most structurally-intriguing millipede-derived natural products, they are the least studied class of millipede defensive secretions. Here, we describe the chemistry of millipede defensive secretions from three species of Brachycybe: Brachycybe producta, Brachycybe petasata, and Brachycybe rosea. Chemical investigations using mass spectrometry-based metabolomics, chemical synthesis, and 2D NMR led to the identification of five alkaloids, three of which are new to the literature. All identified compounds are monoterpene alkaloids with the new compounds representing indolizidine (i.e. hydrogosodesmine) and quinolizidine alkaloids (i.e. homogosodesmine and homo-hydrogosodesmine). The chemical diversity of these compounds tracks the known species phylogeny of this genus, rather than the geographical proximity of the species. The indolizidines and quinolizidines are produced by non-sympatric sister species, B. producta and B. petasata, while deoxybuzonamine is produced by another set of non-sympatric sister species, B. rosea and Brachycybe lecontii. The fidelity between the chemical diversity and phylogeny strongly suggests that millipedes generate these complex defensive agents de novo and begins to provide insights into the evolution of their biochemical pathways.

Quinolizidine alkaloids and phomopsin A in animal feed containing lupins: co-occurrence and carry-over into veal products

Lupins are used in animal feed because of their excellent nutritional composition. Australian and European Lupinus angustifolius seeds are incorporated in compound feed of calves for veal production in Belgium. To investigate the co-occurrence of quinolizidine alkaloids (QAs) and phomopsin A (PHO A) in lupin seeds and lupin-containing feed, and the potential transfer to animal-derived foods, representative samples were obtained from various actors in the chain. A UHPLC-MS/MS method was validated for the simultaneous quantification of seven QAs and PHO A in relevant matrices. Results indicate highly consistent total QA (TQA) levels in Australian lupins (173 ± 24 mg/kg) (n = 25), while European samples showed a high variability (1442 ± 1497 mg/kg) (n = 15). PHO A was detected in 7 of 40 samples. Lupin-containing feed had a mean TQA content of 42 ± 28 mg/kg (n = 20). An in vivo feeding trial demonstrated the transfer of QAs to muscle and liver of calves that were fed the lupin-containing feed. Highest concentrations were found for lupanine in liver tissue samples (67 ± 46 µg/kg). PHO A concentrations were below the LOD in all feed and tissue samples. These results indicate that animal-derived foods (veal meat/liver) are a potential route for QAs to enter the food chain.

Oxymatrine attenuates sepsis-induced inflammation and organ injury via inhibition of HMGB1/RAGE/NF-κB signaling pathway.

Sepsis is a life-threatening organ dysfunction that endangers patient lives and is caused by an imbalance in the host defense against infection. Sepsis continues to be a significant cause of morbidity and mortality in critically sick patients. Oxymatrine (OMT), a quinolizidine alkaloid derived from the traditional Chinese herb Sophora flavescens Aiton, has been shown to have anti-inflammatory effects on a number of inflammatory illnesses according to research. In this study, we aimed to evaluate the therapeutic effects of OMT on sepsis and explore the underlying mechanisms. We differentiated THP-1 cells into THP-1 macrophages and studied the anti-inflammatory mechanism of OMT in a lipopolysaccharide (LPS)-induced THP-1 macrophage sepsis model. Activation of the receptor for advanced glycation end products (RAGE), as well as NF-κB, was assessed by Western blot analysis and immunofluorescence staining. ELISA was used to measure the levels of inflammatory factors. We found that OMT significantly inhibited HMGB1-mediated RAGE/NF-κB activation and downstream inflammatory cytokine production in response to LPS stimulation. Finally, an in vivo experiment was performed on septic mice to further study the effect of OMT on injured organs. The animal experiments showed that OMT significantly inhibited HMGB1-mediated RAGE/NF-κB activation, protected against the inflammatory response and organ injury induced by CLP, and prolonged the survival rate of septic mice. Herein, we provide evidence that OMT exerts a significant therapeutic effect on sepsis by inhibiting the HMGB1/RAGE/NF-κB signaling pathway.

Rapid assessment of the main economic value indicators in lupine flour samples using infrared spectroscopy

Background. A calibration model has been developed for rapid assessment of economic value indicators (protein, oil, and quinolizidine alkaloid contents) in the seeds of narrowleaf lupine accessions from VIR using near-infrared spectroscopy, with the help of which it is possible to decide on the further use of the accessions.Materials and methods. Biochemical quality indicators (protein, oil, and quinolizidine alkaloid content) were studied in the seeds of narrowleaf lupine (Lupinus angustifolius L.) grown in 2019 in the northwest of Russia. Calibration models for measuring protein, oil and alkaloids in lupine seeds (62 accessions) were developed using a MATRIX-I IR analyzer (Bruker Optics, Germany). To construct calibration models, we used the values obtained by chemical analysis methods accepted at VIR. The oil content in lupine seeds was assessed by the defatted dry residue technique in Soxhlet extractors, protein by the Kjeldahl method, and quinolizidine alkaloids by gas chromatography coupled with mass spectrometry. All indicators were recalculated on the dry-weight basis.Results and conclusion. Statistical significance of the developed models was verified according to the results of measuring the content of protein, oil and alkaloids in the seeds of the test batch. The protein and oil content data obtained using a calibration curve did not differ significantly from the results of chemical studies, in contrast to alkaloid indicators. Consequently, the developed calibration model for the MATRIX-I IR analyzer can be used for rapid assessment of protein and oil content in narrowleaf lupine flour samples, thus accelerating the process of obtaining data on the main economic value indicators. The analysis does not require reagents and is safe.

A review on the pharmacology, pharmacokinetics and toxicity of sophocarpine.

Sophocarpine is a natural compound that belongs to the quinolizidine alkaloid family, and has a long history of use and widespread distribution in traditional Chinese herbal medicines such as Sophora alopecuroides L., Sophora flavescens Ait., and Sophora subprostrata. This article aims to summarize the pharmacology, pharmacokinetics, and toxicity of sophocarpine, evaluate its potential pharmacological effects in various diseases, and propose the necessity for further research and evaluation to promote its clinical application. A large number of studies have shown that it has anti-inflammatory, analgesic, antiviral, antiparasitic, anticancer, endocrine regulatory, and organ-protective effects as it modulates various signaling pathways, such as the NF-κB, MAPK, PI3K/AKT, and AMPK pathways. The distribution of sophocarpine in the body conforms to a two-compartment model, and sophocarpine can be detected in various tissues with a relatively short half-life. Although the pharmacological effects of sophocarpine have been confirmed, toxicity and safety assessments and reports on molecular mechanisms of its pharmacological actions have been limited. Given its significant pharmacological effects and potential clinical value, further research and evaluation are needed to promote the clinical application of sophocarpine.

Oxymatrine combined with rapamycin to attenuate acute cardiac allograft rejection

Background and aimSolid organ transplantation remains a life-saving therapeutic option for patients with end-stage organ dysfunction. Acute cellular rejection (ACR), dominated by dendritic cells (DCs) and CD4+ T cells, is a major cause of post-transplant mortality. Inhibiting DC maturation and directing the differentiation of CD4+ T cells toward immunosuppression are keys to inhibiting ACR. We propose that oxymatrine (OMT), a quinolizidine alkaloid, either alone or in combination with rapamycin (RAPA), attenuates ACR by inhibiting the mTOR–HIF–1α pathway. MethodsGraft damage was assessed using haematoxylin and eosin staining. Intragraft CD11c+ and CD4+ cell infiltrations were detected using immunohistochemical staining. The proportions of mature DCs, T helper (Th) 1, Th17, and Treg cells in the spleen; donor-specific antibody (DSA) secretion in the serum; mTOR–HIF–1α expression in the grafts; and CD4+ cells and bone marrow-derived DCs (BMDCs) were evaluated using flow cytometry. ResultsOMT, either alone or in combination with RAPA, significantly alleviated pathological damage; decreased CD4+ and CD11c+ cell infiltration in cardiac allografts; reduced the proportion of mature DCs, Th1 and Th17 cells; increased the proportion of Tregs in recipient spleens; downregulated DSA production; and inhibited mTOR and HIF-1α expression in the grafts. OMT suppresses mTOR and HIF-1α expression in BMDCs and CD4+ T cells in vitro. ConclusionsOur study suggests that OMT-based therapy can significantly attenuate acute cardiac allograft rejection by inhibiting DC maturation and CD4+ T cell responses. This process may be related to the inhibition of the mTOR–HIF–1α signaling pathway by OMT.

Aloperine-Type Alkaloids with Antiviral and Antifungal Activities from the Seeds of Sophora alopecuroides L.

As a continuous flow investigation of novel pesticides from natural quinolizidine alkaloids, the chemical compositions of the seeds of Sophora alopecuroides were thoroughly researched. Fifteen new aloperine-type alkaloids (1-15) as well as six known aloperine-type alkaloids (16-21) were obtained from the extract of S. alopecuroides. The structures of 1-21 were confirmed via HRESIMS, NMR, UV, IR, ECD calculations, and X-ray diffraction. The antiviral activities of 1-21 against tobacco mosaic virus (TMV) were detected following the improved method of half-leaf. Compared with ningnanmycin (protective: 69.7% and curative: 64.3%), 15 exhibited excellent protective (71.7%) and curative (64.6%) activities against TMV. Further biological studies illustrated that 15 significantly inhibited the transcription of the TMV-CP gene and increased the activities of polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD), and phenylalanine ammonia-lyase (PAL). The antifungal activities of 1-21 against Phytophythora capsica, Botrytis cinerea, Alternaria alternata, and Gibberella zeae were screened according to a mycelial inhibition test. Compound 13 displayed excellent antifungal activity against B. cinerea (EC50: 7.38 μg/mL). Moreover, in vitro antifungal mechanism studies displayed that 13 causes accumulation of reactive oxygen species and finally leads to mycelia cell membrane damage and cell death in vitro.

Inhibitory effect of aloperine on transient outward potassium currents in rat cardiac myocytes.

Aloperine (ALO) is an effective quinolizidine alkaloid. Previous research has demonstrated its antiarrhythmic effect by inhibiting voltage-gated sodium currents in rat ventricular myocytes. This study explored its effect on transient outward potassium currents (Ito) in rat atrial myocytes to identify potential targets in the context of ion channel currents. The Ito characteristics in rat atrial myocytes were recorded using a whole-cell patch-clamp technique. Molecular docking was performed to validate ligand-protein binding interactions. ALO at concentrations of 3 and 10μM significantly reduced Ito current densities. Gating kinetics analysis revealed ALO's ability to slow Ito activation, hasten inactivation, and prolong transition from inactive to resting state. Molecular docking revealed that ALO could stably bind to KCND2. ALO may inhibit Ito by slowing the activation process, accelerating inactivation, and delaying the recovery time after inactivation, potentially preventing acetylcholine-induced AF.

Environmental conditions affect the nutritive value and alkaloid profiles of Lupinus forage: Opportunities and threats for sustainable ruminant systems

The identification of crops that simultaneously contribute to the global protein supply and mitigate the effects of climate change is an urgent matter. Lupins are well adapted to nutrient-poor or contaminated soils, tolerate various abiotic stresses, and present relevant traits for acting as ecosystem engineers. Lupins are best studied for their seeds, but their full foraging potential needs further evaluation. This study evaluated the effects of location and sowing date on forage production, proximate composition, and the detailed mineral and alkaloid profiles of three species of Lupinus (L. albus cv. Estoril, L. angustifolius cv. Tango, and L. luteus cv. Cardiga). Sowing date and location and their interaction with the plant species significantly affected the vast majority of measured parameters, emphasizing the effects of climate and soil conditions on these crops. The relatively high crude protein and in vitro digestibility support the potential of the lupin species studied as sustainable forage protein sources in diets for ruminant animals. The content of individual essential macro and trace elements was below the maximum tolerable levels for cattle and sheep. Lupanine, smipine, and sparteine were the most abundant quinolizidine alkaloids in L. albus cv. Estoril, lupanine, and sparteine in L. angustifolius cv. Tango, and lupinine, gramine, ammodendrine, and sparteine in L. luteus cv. Cardiga. Based on the maximum tolerable levels of total quinolizidine alkaloid intake, the dietary inclusion of forages of L. albus cv. Estoril and L. angustifolius cv. Tango does not pose a risk to the animals, but the high alkaloid content of L. luteus cv. Cardiga may compromise its utilization at high levels in the diet. Overall, the results reveal a high potential for lupins as protein forage sources well adapted to temperate regions and soils with lower fertility, with a relevant impact on livestock sustainability in a climate change era.

Transcriptome and metabolome analysis reveal the dynamic changes and biosynthesis pathways of alkaloids in Sophora alopecuroides L. under drought stress

Sophora lopecuroides L. is a medicinal plant containing a variety of biologically active substances, in which alkaloids are the main active substances, and a variety of alkaloids have been identified in S. alopecuroides. Drought stress can stimulate the accumulation of biologically active substances in medicinal plants. In this respect, the imposition of appropriate degree of drought stress may be an effective way to increase the alkaloid content in S. alopecuroides. However, the changes in the types and abundance of alkaloids in S. alopecuroides under drought stress and the molecular mechanism of regulating alkaloid biosynthesis are still unclear. In this study, the metabolome and transcriptome analysis were conducted to explore the influence of mild (D1), moderate (D2), and severe (D3) drought stress on the types and abundance of alkaloids in S. alopecuroides, and to identify the key regulatory genes in the alkaloid synthesis pathways. The results showed that the total alkaloid content in S. alopecuroides in the D1 and D2 group significantly decreased by 13.49% and 10.40%, respectively compared with that in the control group, but the total alkaloid content in S. alopecuroides in the D3 group significantly increased by 8.16% compared with that in the control group. Sixty-eight alkaloids were identified in S. alopecuroides, with quinolizidine alkaloids being the main type of alkaloids. Of the 25 differentially accumulated metabolites (DAMs), the number of DAMs with increased relative abundance in the D1, D2, and D3 group were 0, 7, and 20, respectively. The relative abundance of 6 DAMs increased in both D2 and D3 group, and 14 DAMs only increased in the D3 group such as methoxyindoleacetic acid, indole, and piperidine. Besides, the biosynthetic pathways of three major types of alkaloids (quinolizidine-, piperidine-, and plumerane-type alkaloids) were illustrated, and key genes (i.e., asd, DapL, PrAOs, DDC, and ALDH) associated with the alkaloid biosynthesis were identified. This study also found that 22 TFs (SaERF1∼SaERF5, SaWRKY1∼SaWRKY3, SabHLH1∼SabHLH3, SaMYB1∼SaMYB6, SabZIP1∼SabZIP5) were positively correlated with the alkaloid biosynthesis. This study deepens our understanding of the molecular mechanism of S. alopecuroides in response to drought stress, and helps to develop biotechnology strategies to manipulate the level of alkaloids in S. alopecuroides.

Aloperine Alleviates Myocardial Injury Induced by Myocardial Ischemia and Reperfusion by Activating the ERK1/2/β-catenin Signaling Pathway.

Myocardial ischemia/reperfusion (I/R) injury can cause severe cardiac damage. Aloperine is a quinolizidine alkaloid found in the leaves and seeds of Sophora alopecuroides L. It has been recognized that aloperine has organ-protective properties; however, its role in cardioprotection is poorly characterized. This study aimed to evaluate the cardioprotective effects of aloperine against myocardial I/R injury in vivo. Adult male Sprague‒Dawley rats were randomly divided into sham-operated, control, and aloperine groups. All rats except for the sham-operated rats were subjected to 45min of myocardial ischemia (by left anterior descending ligation) followed by 3h of reperfusion. Aloperine (10mg/kg) was given intravenously at the onset of reperfusion. The cardioprotective effects of aloperine were evaluated by determining infarct size, hemodynamics, histological changes, cardiac biomarkers, and cardiac apoptosis. Aloperine limited infarct size; improved hemodynamics; attenuated myocardial I/R-induced histological deterioration; decreased serum LDH, CK-MB, and α-HBDH levels; and inhibited apoptosis after myocardial I/R injury. Moreover, aloperine stimulated the phosphorylation of ventricular ERK1/2, which is a major module of MAPK signaling pathways. Furthermore, aloperine increased the ventricular expression levels of β-catenin. Pharmacological inhibition of ERK1/2 diminished aloperine-induced cardioprotection and blocked ERK1/2/β-catenin signaling. These data support the cardioprotective effect of aloperine against myocardial I/R injury, which is mediated, at least in part, by the ERK1/2/β-catenin signaling pathway.

Quinolizidine Alkaloids and Isoflavones from the Herb of Thermopsis lupinoides and Their Antiviral, Antifungal, and Insecticidal Activities.

As part of our ongoing investigation of natural bioactive substances from the genus Thermopsis of the tribe Fabaceae for agricultural protection, the chemical constituents of the herb Thermopsis lupinoides were systematically investigated, which led to the isolation of 39 quinolizidine alkaloids (QAs) (1-39), including 14 new QAs (1-14) and 14 isoflavones (40-53). Their structures were elucidated through comprehensive spectroscopic data analysis (IR, UV, NMR, HRESIMS), ECD calculations, and X-ray crystallography. The antitomato spotted wilt virus (TSWV) and antifungal (against Botrytis cinerea, Gibberella zeae, Phytophythora capsica, and Alternaria alternata) and insecticidal (against Aphis fabae and Tetranychus urticae) activities of the isolated compounds were screened using the lesion counting method, mycelial inhibition assay, and spray method, respectively. The bioassay results showed that 34 exhibited excellent protective activity against TSWV, with an EC50 value of 36.04 μg/mL, which was better than that of the positive control, ningnanmycin (86.03 μg/mL). The preliminary mechanistic exploration illustrated that 34 induced systemic acquired resistance in the host plant by acting on the salicylic acid signaling pathway. Moreover, 1 showed significant antifungal activity against B. cinerea (EC50 value of 20.83 μg/mL), while 2 exhibited good insecticidal activity against A. fabae (LC50 value of 24.97 μg/mL). This research is promising for the invention of novel pesticides from QAs with high efficiency and satisfactory ecological compatibility.