Benzophenanthridine Alkaloids Research Articles

De novo production of protoberberine and benzophenanthridine alkaloids through metabolic engineering of yeast

Protoberberine alkaloids and benzophenanthridine alkaloids (BZDAs) are subgroups of benzylisoquinoline alkaloids (BIAs), which represent a diverse class of plant-specialized natural metabolites with many pharmacological properties. Microbial biosynthesis has been allowed for accessibility and scalable production of high-value BIAs. Here, we engineer Saccharomyces cerevisiae to de novo produce a series of protoberberines and BZDAs, including palmatine, berberine, chelerythrine, sanguinarine and chelirubine. An ER compartmentalization strategy is developed to improve vacuole protein berberine bridge enzyme (BBE) activity, resulting in >200% increase on the production of the key intermediate (S)-scoulerine. Another promiscuous vacuole protein dihydrobenzophenanthridine oxidase (DBOX) has been identified to catalyze two-electron oxidation on various tetrahydroprotoberberines at N7-C8 position and dihydrobenzophenanthridine alkaloids. Furthermore, cytosolically expressed DBOX can alleviate the limitation on BBE. This study highlights the potential of microbial cell factories for the biosynthesis of a diverse group of BIAs through engineering of heterologous plant enzymes.

Chelerythrine inhibits NR2B NMDA receptor independent of PKC activity

N-methyl-D-aspartate receptors (NMDAR), the ligand ion glutamate receptor channels, mediate major excitatory neurotransmission in central nervous system (CNS). They highly express in CNS and involve in multiple physiological processes. Many studies implicated that NMDAR plays a crucial role in number of neurological disorders, including ischemia, dementia, and pain, indicating its potential as a therapeutic target for treatments. Chelerythrine (CHE) is a benzo-phenanthridine alkaloid extracted from Chelidonium majus with many biological activities including anti-inflammatory, anticancer effect, and antidiabetic effect. But the mechanism of CHE is not well understood. The aim of this study was to investigate the effect of CHE on the NMDAR. The results demonstrated that CHE effectively suppressed NMDA-induced currents in primary cultured cortical neurons. To elucidate the underlying mechanism, we expressed NMDARs in HEK293 cells and found that CHE and some of its structural analogues inhibited NMDAR currents and facilitated the desensitization of GluN2B NMDARs. Notably, these effects were independent of protein kinase C activity, suggesting that the effect of CHE on GluN2B-containing NMDAR may occur through a mechanism of directly interaction with NMDAR. Moreover, the inhibitory effect of CHE on GluN2B NMDARs is pH-dependent. Molecular docking prediction in conjunction with mutagenesis analysis revealed that the M3 α-helical segment of the NMDAR in close proximity to the GluN2B Thr647 amino acid plays an important role in CHE inhibition of GluN2B. This study revealed a novel function of CHE and its structural analogues in inhibiting the NMDARs and promoting GluN2B-mediated desensitization by obstructing the receptor at the channel pore region.

A Comparative Study on the DNA Interactions and Biological Activities of Benzophenanthridine and Protoberberine Alkaloids.

Numerous small molecules exert antitumor effects by interacting with DNA, thereby influencing processes, such as DNA replication, transcription, meiosis, and gene recombination. Benzophenanthridine and protoberberine alkaloids are known to bind DNA and exhibit many pharmacological activities. In this study, we conducted a comparative analysis of the interactions between these two classes of alkaloids with G-quadruplex (G4) DNA and double-stranded DNA (dsDNA). Protoberberine alkaloids showed a greater affinity for binding with G4s than with dsDNA, while benzophenanthridine alkaloids exhibited a significantly stronger binding capacity for dsDNA, especially in regions that are rich in AT base pairs. Benzophenanthridine alkaloids also exhibited much stronger toxicity to various cancer cells. Compared with protoberberine alkaloids, benzophenanthridine alkaloids displayed much stronger activity in inhibiting cellular DNA and RNA synthesis, arresting the cell cycle in the G2/M phase, inducing cell apoptosis, and leading to intracellular DNA damage. Given that dsDNA constitutes the predominant form of DNA within cells for the majority of the cell cycle, the significant antiproliferative activity of benzophenanthridine alkaloids could be attributed, in part, to their higher binding affinity for dsDNA, thereby exerting a more significant impact on cellular proliferation. These findings have valuable implications for understanding the biological activities of isoquinoline alkaloids and their antitumor applications.

Antileishmanial, antitrypanosomal and anti-coronavirus activities of benzophenanthridine alkaloids and other specialized metabolites isolated from the root bark of Zanthoxylum zanthoxyloides (Lam.) B.Zepernick & Timler

Strong antileishmanial and antitrypanosomal activities were highlighted for the crude methanolic extract (IC50 = 0.61 and 2.15 μg/mL, respectively) of Zanthoxylum zanthoxyloides (Lam.) B.Zepernick & Timler root bark, as well as for its apolar partitions (cyclohexane: IC50 = 0.66 and 5.17 μg/mL, respectively and dichloromethane: IC50 = 0.07 and 0.22 μg/mL, respectively), with a good selectivity index (SI) towards WI-38 cells. In addition, cyclohexane and dichloromethane extracts exhibited a dose-dependent inhibition of human coronavirus HCoV-229E infection in hepatoma Huh-7 cells expressing or not the cellular protease TMPRSS2 (IC50 values of 5.29 μg/mL and 4.87 μg/mL, respectively). Fractionation of these active extracts led to the isolation of a new racemic benzophenanthridine alkaloid named zanthoxyloithrine (1), together with 13 known compounds. Their structures were elucidated by spectroscopic techniques including IR, UV, HR-MS, 1D and 2D NMR and electronic circular dichroism. In parallel, HR-ESI-MS/MS based dereplication and molecular networking analysis were performed to identify unpurified compounds in cyclohexane and dichloromethane extracts. Zanthoxyloithrine (1) showed strong antileishmanial (IC50 = 0.14 μM, SI = 52.0) and antitrypanosomal (IC50 = 0.36 μM, SI = 20.8) activities. In addition, compound (1) demonstrated a high antiviral activity against HCoV-229E with IC50 value of 6.70 μM in presence of TMPRRS2 and without significant toxicity on Huh-7 cells. Other purified benzo[c]phenanthridine alkaloids also showed anti-coronavirus and antiparasitic activities.

6-Methoxyldihydrochelerythrine Chloride Inhibiting Intra and Extracellular Drug-Resistant Bacteria.

Vancomycin-resistant enterococcus (VRE) is a major nosocomial pathogen that exhibits enhanced infectivity due to its robust virulence and biofilm-forming capabilities. In this study, 6-methoxyldihydrochelerythrine chloride (6-MDC) inhibited the growth of exponential-phase VRE and restored VRE's sensitivity to vancomycin. 6-MDC predominantly suppressed the de novo biosynthetic pathway of pyrimidine and purine in VRE by the RNA-Seq analysis, resulting in obstructed DNA synthesis, which subsequently weakened bacterial virulence and impeded intracellular survival. Furthermore, 6-MDC inhibited biofilm formation, eradicated established biofilms, reduced virulence, and enhanced the host immune response to prevent intracellular survival and replication of VRE. Finally, 6-MDC reduced the VRE load in peritoneal fluid and cells significantly in a murine peritoneal infection model. This paper provides insight into the potential antimicrobial target of benzophenanthridine alkaloids for the first time.

Vasorelaxant and tracheorelaxant effects of Bocconia arborea and their isolated benzophenanthridine alkaloids

Bocconia arborea S. Watson (Papaveraceae) is an abundant medicinal plant in the North of Morelos State, Mexico, which is used for the treatment of several diseases. The aim of current investigation was to isolate the compounds responsible of the relaxant effect shown by the active extracts. Thus, phytochemical bio-guided fractionation allowed the isolation of angoline (1), dihydrosanguinarine (2), bocconarborine A (3), oxisanguinarine (4), and oxychelerithrine (5) from dichloromethanic and methanolic extracts from the bark of Bocconia arborea (Papaveraceae). The relaxant study on aortic and tracheal rat rings of all benzophenanthridines indicates that 1 was the most active compound of the entire series investigated. Angoline (1) induces its relaxant effect by a concentration-dependent manner through the calcium channel blockade in both tissues.

Comparative study on the morpho-physiological responses and alkaloids content in Eschscholzia californica cham to foliar applied α-Fe2O3 NPs and ferric ions

The effect of iron oxide nanoparticles on medicinal plants biomass biosynthesis and antioxidant defense compounds should be assessed critically to ensure their safe and sustainable use within the agricultural fields and food chains. Current focus has been given to the effects of hematite nanoparticles (α-Fe2O3 NPs, ∼ 27 nm) and ferric ions (Fe3+) at different concentrations [(0, control), 10, 100 and 1000 mg L−1)] on morpho-physiological and biochemical parameters and benzophenanthridine alkaloids content in Eschscholzia californica plants. Upon exposure to α-Fe2O3 NPs, a significant (P < 0.05) inhibition (by 26.6%) of root biomass was observed at the high concentration (1000 mg L−1) over the control. As for the total dry weight of plants, significant (P < 0.01) increase (by 22.7%) was observed at all exposures, except that of 1000 mg L−1 α-Fe2O3 NPs/and Fe+3 treatment which was reduced by 12.8%. The treatment of 100 mg L−1 α-Fe2O3 NPs and Fe3+ caused significant increase in chlorophyll a (29.2% and 40%,), chlorophyll b (59.8% and 49.3%,) and carotenoids (14.3% and 25.4%%,) content when compared to control, respectively. However, accumulation of the lipid peroxidation product, malondialdehyde (MDA), in root and leaf tissues was similar (73.5% vs control) that was induced by 1000 mg L−1 α-Fe2O3 NPs. No significant change in MDA content was observed in leaves and roots of Fe+3 treated plants at all exposure doses. Furthermore, total phenolics and flavonoids content of the leaves and roots exposed to α-Fe2O3 NPs at 100 mg L−1 were significantly (P < 0.01) increased by 41–45%, 27–29%, and 44–48%, respectively, over the control. All obtained extracts revealed strong and significant scavenging effects on DPPH˙ as compared to control, but only exposure to 100 mg L−1 Fe+3 and α-Fe2O3 NPs treatment revealed the highest free radical scavenging/antioxidant activity by 44.2% and 37.65%, respectively. The alkaloid accumulation in leaves exhibited significant (P < 0.05) differences between the control plants and those treated with α-Fe2O3 NPs and Fe+3 of all concentrations. The eshchschollzine and sanguinarine contents showed no significant change in plants treated with Fe+3 concentrations; however, the exposure of high Fe+3 concentration increased (33.4%) the content of chelerythrine compared to control. Foliar applied α-Fe2O3 NPs enhanced the content of californidine (35.4%), eshchschollzine (22.3%), and eshchschollzine (19.1%) compared to control. The observed toxicity was dose-dependent for both α-Fe2O3 NPs and Fe+3. The synthesized endogenous secondary metabolites (e.g., phenolics, flavonoids and benzophenanthridine alkaloids) induce defense mechanism in exposed plants. These results suggest that specific concentrations (10–100 mg L−1) of α-Fe2O3 NPs have extra benefits both as a nanoregulator and nanoelicitor for plant growth promotion and biosynthesis of alkaloids and cellular antioxidants.

Nitidine from Zanthoxylum rhetsa and its cytotoxic activities in vitro and in silico ADMET properties

AbstractNitidine, a potential medicinal natural benzophenanthridine alkaloid, has expressed various bioactivities such as antibacterial, antifungal, antiviral, anti‐inflammatory, analgesic, and notably cytotoxicity. In this study, nitidine was isolated from trunk of Zanthoxylum rhetsa (Rutaceae) and its structure was elucidated by spectral data (1D and 2D NMR; and MS). The cytotoxicity of nitidine was assessed in vitro against five cancer cell lines, and normal cell line Vero. As the results, nitidine exhibited potent inhibitory activity against KB, LU‐1, HepG2, LNCaP and MCF7 cell lines with IC50 values of 0.28, 0.26, 0.27, 0.25 and 0.28 µm, respectively, while low‐cytotoxicity against normal cell line Vero with IC50 value of 140.65 µm. Comparing cytotoxic activity of nitidine with docking analysis in previous study, nitidine formed hydrogen bonds with residues Asn101 and Ala317 of tubulin and had a docking score of −14.45 kcal/mol, all the data proved nitidine would be a potential candidate for inhibiting the function of tubulin at the active site regarding binding affinity, dock pose, and ADMET‐where ADMET stands for absorption, distribution, metabolism, excretion and toxicity‐properties analysis.

A new benzophenanthridine alkaloid from stem bark of Zanthoxylum rhetsa and its biological activities

A new benzophenanthridine alkaloid 6-butanoyldihydrochelerythrine (1) and five known alkaloids 6-acetonyldihydronitidine (2), 6-acetonyldihydrochelerythrine (3), isocorydine (4), (O)-methyltembamide (5), N-(4-methoxyphenethyl)benzamide (6) were isolated from the stem barks of Zanthoxylum rhetsa. These structures were elucidated by 1D, 2D NMR spectroscopy and by mass spectrometry. This is the first time that compounds 2–6 were identified from Zanthoxylum rhetsa and the first time that compounds 4 and 6 were identified from the genus Zanthoxylum. Bioactivity results of isolated compounds showed that 1, 2, 5 and 6 exhibited inhibitory activity against MCF7 and A549 cell lines, while 3 showed the inhibitory activity against A549 cell line; all isolated compounds 1–6 inhibited at least two strain microorganisms; compound 4 showed angiotensin II converting enzyme inhibitory activity in vitro with IC50 value of 65.58 µM and in silico with a docking score of −11.52 kcal/mol.

Quaternary Benzophenanthridine Alkaloids Act as Smac Mimetics and Overcome Resistance to Apoptosis.

Defects in cell death signaling pathways are one of the hallmarks of cancer and can lead to resistance to conventional therapy. Natural products are promising compounds that can overcome this resistance. In the present study we studied the effect of six quaternary benzophenanthridine alkaloids (QBAs), sanguinarine, chelerythrine, sanguirubine, chelirubine, sanguilutine, and chelilutine, on Jurkat leukemia cells, WT, and cell death deficient lines derived from them, CASP3/7/6-/- and FADD-/-, and on solid tumor, human malignant melanoma, A375 cells. We demonstrated the ability of QBAs to overcome the resistance of these deficient cells and identified a novel mechanism for their action. Sanguinarine and sanguirubine completely and chelerythrine, sanguilutine, and chelilutine partially overcame the resistance of CASP3/7/6-/- and FADD-/- cells. By detection of cPARP, a marker of apoptosis, and pMLKL, a marker of necroptosis, we proved the ability of QBAs to induce both these cell deaths (bimodal cell death) with apoptosis preceding necroptosis. We identified the new mechanism of the cell death induction by QBAs, the downregulation of the apoptosis inhibitors cIAP1 and cIAP2, i.e., an effect similar to that of Smac mimetics.

Chelerythrine chloride inhibits Zika virus infection by targeting the viral NS4B protein

Zika virus (ZIKV) is a mosquito-borne virus that has re-emerged as a significant threat to global health in the recent decade. Whilst infections are primarily asymptomatic, the virus has been associated with the manifestation of severe neurological complications. At present, there is still a lack of approved antivirals for ZIKV infections. In this study, chelerythrine chloride, a benzophenanthridine alkaloid, was identified from a mid-throughput screen conducted on a 502-compound natural products library to be a novel and potent inhibitor of ZIKV infection in both in-vitro and in-vivo assays. Subsequent downstream studies demonstrated that the compound inhibits a post-entry step of the viral replication cycle and is capable of disrupting viral RNA synthesis and protein expression. The successful generation and sequencing of a ZIKV resistant mutant revealed that a single S61T mutation on the viral NS4B allowed ZIKV to overcome chelerythrine chloride inhibition. Further investigation revealed that chelerythrine chloride could directly inhibit ZIKV protein synthesis, and that the NS4B–S61T mutation confers resistance to this inhibition. This study has established chelerythrine chloride as a potential candidate for further development as a therapeutic agent against ZIKV infection.

Benzophenanthridine Alkaloid Chelerythrine Elicits Necroptosis of Gastric Cancer Cells via Selective Conjugation at the Redox Hyperreactive C-Terminal Sec498 Residue of Cytosolic Selenoprotein Thioredoxin Reductase.

Targeting thioredoxin reductase (TXNRD) with low-weight molecules is emerging as a high-efficacy anti-cancer strategy in chemotherapy. Sanguinarine has been reported to inhibit the activity of TXNRD1, indicating that benzophenanthridine alkaloid is a fascinating chemical entity in the field of TXNRD1 inhibitors. In this study, the inhibition of three benzophenanthridine alkaloids, including chelerythrine, sanguinarine, and nitidine, on recombinant TXNRD1 was investigated, and their anti-cancer mechanisms were revealed using three gastric cancer cell lines. Chelerythrine and sanguinarine are more potent inhibitors of TXNRD1 than nitidine, and the inhibitory effects take place in a dose- and time-dependent manner. Site-directed mutagenesis of TXNRD1 and in vitro inhibition analysis proved that chelerythrine or sanguinarine is primarily bound to the Sec498 residue of the enzyme, but the neighboring Cys497 and remaining N-terminal redox-active cysteines could also be modified after the conjugation of Sec498. With high similarity to sanguinarine, chelerythrine exhibited cytotoxic effects on multiple gastric cancer cell lines and suppressed the proliferation of tumor spheroids derived from NCI-N87 cells. Chelerythrine elevated cellular levels of reactive oxygen species (ROS) and induced endoplasmic reticulum (ER) stress. Moreover, the ROS induced by chelerythrine could be completely suppressed by the addition of N-acetyl-L-cysteine (NAC), and the same is true for sanguinarine. Notably, Nec-1, an RIPK1 inhibitor, rescued the chelerythrine-induced rapid cell death, indicating that chelerythrine triggers necroptosis in gastric cancer cells. Taken together, this study demonstrates that chelerythrine is a novel inhibitor of TXNRD1 by targeting Sec498 and possessing high anti-tumor properties on multiple gastric cancer cell lines by eliciting necroptosis.

Insights on Antitumor Activity and Mechanism of Natural Benzophenanthridine Alkaloids.

Benzophenanthridine alkaloids are a class of isoquinoline compounds, which are widely found in the plants of papaveraceae, corydalis, and rutaceae. Biological activities and clinical studies have shown that benzophenanthridine alkaloids have inhibitory effects on many cancers. Considering that the anticancer activities and mechanisms of many natural benzophenanthridine alkaloids have been discovered in succession, the purpose of this paper is to review the anticancer effects of benzophenanthridine alkaloids and explore the application potential of these natural products in the development of antitumor drugs. A literature survey was carried out using Scopus, Pubmed, Reaxys, and Google Scholar databases. This review summarizes and analyzes the current status of research on the antitumor activity and antitumor mechanism of natural products of benzophenanthridine from different sources. The research progress of the antitumor activity of natural products of benzophenanthridine from 1983 to 2023 was reviewed. The antitumor activities of 90 natural products of benzophenanthridine and their related analogues were summarized, and the results directly or indirectly showed that natural products of benzophenanthridine had the effects of antidrug-resistant tumor cell lines, antitumor stem cells, and inducing ferroptosis. In conclusion, benzophenanthridine alkaloids have inhibitory effects on a variety of cancers and have the potential to counteract tumor resistance, and they have great application potential in the development of antitumor drugs.

Developmental toxicity induced by chelerythrine in zebrafish embryos via activating oxidative stress and apoptosis pathways

Chelerythrine (CHE), a natural benzophenanthridine alkaloid, possesses various biological and pharmacological activities, such as antimicrobial, antitumor and anti-inflammatory effects. However, its adverse side effect has not been fully elucidated. Therefore, this study was designed to investigate the developmental toxicity of CHE in zebrafish. We found that CHE could lead to a notably increase of the mortality and malformation rate, while lead to reduction of the hatching rate and body length. CHE also could affect the normal developing processes of the heart, liver and phagocytes in zebrafish. Furthermore, the reactive oxygen species (ROS) and apoptosis levels were notably increased. In addition, the mRNA expressions of genes (bax, caspase-9, p53, SOD1, KEAP1, TNF-α, STAT3 and NF-κB) were significantly increased, while the bcl2 and nrf2 were notably inhibited by CHE. These results indicated that the elevation of ROS and apoptosis were involved in the developmental toxicity induced by CHE. In conclusion, CHE exhibits a developmental toxicity in zebrafish, which helps to understand the potential toxic effect of CHE.

6-Methoxydihydrosanguinarine exhibits cytotoxicity and sensitizes TRAIL-induced apoptosis of hepatocellular carcinoma cells through ROS-mediated upregulation of DR5.

6-methoxydihydrosanguinarine (6-MS), a natural benzophenanthridine alkaloid extracted from Macleaya cordata (Willd.) R. Br, has shown to trigger apoptotic cell death in cancer cells. However, the exact mechanisms involved have not yet been clarified. The current study reveals the underlying mechanisms of 6-MS-induced cytotoxicity in hepatocellular carcinoma (HCC) cells and investigates whether 6-MS sensitizes TNF-related apoptosis inducing ligand (TRAIL)-induced apoptosis. 6-MS was shown to suppress cell proliferation and trigger cell cycle arrest, DNA damage, and apoptosis in HCC cells. Mechanisms analysis indicated that 6-MS promoted reactive oxygen species (ROS) generation, JNK activation, and inhibits EGFR/Akt signaling pathway. DNA damage and apoptosis induced by 6-MS were reversed following N-acetyl-l-cysteine (NAC) treatment. The enhancement of PARP cleavage caused by 6-MS was abrogated by pretreatment with JNK inhibitor SP600125. Furthermore, 6-MS enhanced TRAIL-mediated HCC cells apoptosis by upregulating the cell surface receptor DR5 expression. Pretreatment with NAC attenuated 6-MS-upregulated DR5 protein expression and alleviated cotreatment-induced viability reduction, cleavage of caspase-8, caspase-9, and PARP. Overall, our results suggest that 6-MS exerts cytotoxicity by modulating ROS generation, EGFR/Akt signaling, and JNK activation in HCC cells. 6-MS potentiates TRAIL-induced apoptosis through upregulation of DR5 via ROS generation. The combination of 6-MS with TRAIL may be a promising strategy and warrants further investigation.

Interaction and inhibition of lysozyme amyloid fibrillation by benzophenanthridine alkaloid sanguinarine: Photophysical, molecular docking and imaging studies

Protein misfolding lead to pathological amyloid aggregates causing neurodegenerative disorders. Interaction and effect of benzophenanthridine alkaloid, sanguinarine (SNR hereafter), on lysozyme fibrillation was studied in the quest for designing potent antiamyloidogenics. SNR quenched the intrinsic fluorescence of lysozyme and the quenching mechanism was static. There existed one type of binding site for SNR on lysozyme and TRP residues were mainly involved in binding. 3D-fluorescence studies indicated conformational changes in lysozyme upon complexation with SNR. The binding between lysozyme and SNR was also studied by molecular docking to understand the forces involved in the binding. Effect of SNR on lysozyme fibrillation was examined from Thioflavin T assay which revealed that SNR suppressed the fibrillation of lysozyme significantly. Nile red and ANS assay revealed that SNR arrested the fibrillation. FTIR and circular dichroism showed that β-sheet content of the fibrillar species was reduced by SNR implying fibrillogenesis was inhibited as amyloid fibrils have β-sheet rich structures. AFM also revealed that SNR induced a marked decrease in the fibrillar quantity. These results can be utilized for designing potential drugs for amyloidosis.

Pot-Economic Approach to Benzophenanthridine Alkaloids

Key words benzo[c]phenanthrid-ines - sequential reaction - pot-economic approach

Necroptosis signaling and mitochondrial dysfunction cross-talking facilitate cell death mediated by chelerythrine in glioma.

Glioma is the most common primary malignant brain tumor with poor survival and limited therapeutic options. Chelerythrine (CHE), a natural benzophenanthridine alkaloid, has been reported to exhibit the anti-tumor effects in a variety of cancer cells. However, the molecular target and the signaling process of CHE in glioma remain elusive. Here we investigated the underlying mechanisms of CHE in glioma cell lines and glioma xenograft mice model. Our results found that CHE-induced cell death is associated with RIP1/RIP3-dependent necroptosis rather than apoptotic cell death in glioma cells at the early time. Mechanism investigation revealed the cross-talking between necroptosis and mitochondria dysfunction that CHE triggered generation of mitochondrial ROS, mitochondrial depolarization, reduction of ATP level and mitochondrial fragmentation, which was the important trigger for RIP1-dependent necroptosis activation. Meanwhile, PINK1 and parkin-dependent mitophagy promoted clearance of impaired mitochondria in CHE-incubated glioma cells, and inhibition of mitophagy with CQ selectively enhanced CHE-induced necroptosis. Furthermore, early cytosolic calcium from the influx of extracellular Ca2+ induced by CHE acted as important "priming signals" for impairment of mitochondrial dysfunction and necroptosis. Suppression of mitochondrial ROS contributed to interrupting positive feedback between mitochondrial damage and RIPK1/RIPK3 necrosome. Lastly, subcutaneous tumor growth in U87 xenograft was suppressed by CHE without significant body weight loss and multi-organ toxicities. In summary, the present study helped to elucidate necroptosis was induced by CHE via mtROS-mediated formation of the RIP1-RIP3-Drp1 complex that promoted Drp1 mitochondrial translocation to enhance necroptosis. Our findings indicated that CHE could potentially be further developed as a novel therapeutic strategy for treatment of glioma.

Targeting oxeiptosis-mediated tumor suppression: a novel approach to treat colorectal cancers by sanguinarine

Oxeiptosis is a recently identified reactive oxygen species (ROS)-sensitive, caspase independent, non-inflammatory regulated cell death pathway. The activation of Kelch-like ECH-associated protein 1-Phosphoglycerate mutase 5-Apoptosis inducing factor mitochondria associated 1 (KEAP1-PGAM5-AIFM1) pathway is the key signaling event in the execution of oxeiptosis. In the present study, we demonstrate that sanguinarine (SNG), a quaternary benzophenanthridine alkaloid, induces oxeiptosis in human colorectal cancer (CRC) cells via ROS, specifically hydrogen peroxide (H2O2)-dependent activation of KEAP1-PGAM5-AIFM1 signaling axis. Whilst, knockdown of KEAP1, PGAM5, and AIFM1 largely abolishes SNG-induced oxeiptosis, hence reinforcing the importance of the role of this pathway in the SNG-mediated cytotoxicity. Moreover, extracellular addition of H2O2 sensitizes SNG-induced oxeiptosis in CRC cells, while removal of intracellular ROS by ROS scavengers, not only alleviated the overproduction of ROS caused by SNG, but also reversed the biochemical events associated with oxeiptosis. Finally, in vivo study demonstrates that SNG effectively reduces the tumor growth in HT-29 xenograft mouse model through features associated with oxeiptosis. This study highlights oxeiptosis as a novel tumor suppressive mechanism and further investigation of the role of oxeiptosis in cancer treatment is warranted.

Sanguinarine Exhibits Antiviral Activity against Porcine Reproductive and Respiratory Syndrome Virus via Multisite Inhibition Mechanisms

Porcine reproductive and respiratory syndrome virus (PRRSV), the etiological agent of PRRS, is prevalent worldwide, causing substantial and immense economic losses to the global swine industry. While current commercial vaccines fail to efficiently control PRRS, the development of safe and effective antiviral drugs against PRRSV is urgently required. Alkaloids are natural products with wide pharmacological and biological activities. Herein, sanguinarine, a benzophenanthridine alkaloid that occurs in many plants such as Macleaya cordata, was demonstrated as a potent antagonist of PRRSV. Sanguinarine attenuated PRRSV proliferation by targeting the internalization, replication, and release stages of the viral life cycle. Furthermore, ALB, AR, MAPK8, MAPK14, IGF1, GSK3B, PTGS2, and NOS2 were found as potential key targets related to the anti-PRRSV effect of sanguinarine as revealed by network pharmacology and molecular docking. Significantly, we demonstrated that the combination of sanguinarine with chelerythrine, another key bioactive alkaloid derived from Macleaya cordata, improved the antiviral activity. In summary, our findings reveal the promising potential of sanguinarine as a novel candidate for the development of anti-PRRSV agents.