Inhibition of Gpx4-mediated ferroptosis alleviates cisplatin-induced hearing loss in C57BL/6 mice.

Cisplatin-induced hearing loss is a common side effect of cancer chemotherapy in clinics; however, the mechanism of cisplatin-induced ototoxicity is still not completely clarified. Cisplatin-induced ototoxicity is mainly associated with the production of reactive oxygen species, activation of apoptosis, and accumulation of intracellular lipid peroxidation, which also is involved in ferroptosis induction. In this study, the expression of TfR1, a ferroptosis biomarker, was upregulated in the outer hair cells of cisplatin-treated mice. Moreover, several key ferroptosis regulator genes were altered in cisplatin-damaged cochlear explants based on RNA sequencing, implying the induction of ferroptosis. Ferroptosis-related Gpx4 and Fsp1 knockout mice were established to investigate the specific mechanisms associated with ferroptosis in cochleae. Severe outer hair cell loss and progressive damage of synapses in inner hair cells were observed in Atoh1-Gpx4-/- mice. However, Fsp1-/- mice showed no significant hearing phenotype, demonstrating that Gpx4, but not Fsp1, may play an important role in the functional maintenance of HCs. Moreover, findings showed that FDA-approved luteolin could specifically inhibit ferroptosis and alleviate cisplatin-induced ototoxicity through decreased expression of transferrin and intracellular concentration of ferrous ions. This study indicated that ferroptosis inhibition through the reduction of intracellular ferrous ions might be a potential strategy to prevent cisplatin-induced hearing loss.

Luteolin induces ferroptosis in prostate cancer cells by promoting TFEB nuclear translocation and increasing ferritinophagy.

BACKGROUND: As the second most common cancer in men and the leading cause of cancer-related death, prostate cancer (PCa) could potentially be treated by inducing ferroptosis. In this study, we aimed to investigate whether luteolin could induce ferroptosis in PCa cells through the transcription Factor EB (TFEB). METHODS: Different concentrations of luteolin were applied to treat normal prostate epithelial cells RWPE-1 and PCa cell lines DU145, PC-3, VCaP, and LNcaP. Ferrostatin-1 (Fer-1), Necrostain-1 (Nec-1), 3-methyladenine (3-MA), chloroquine (CQ), and the apoptosis inhibitor benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone (Z-VAD-FMK) were added to treat DU145 and PC-3 cells. Additionally, we knocked down TFEB and performed in vitro cell experiments. Finally, tumor-forming experiments in nude mice were conducted to verify luteolin mechanism in PCa after knocking down TFEB. RESULTS: There was no significant difference in RWPE-1 at 12, 24, and 48 h after treatment with 60 µM luteolin. However, a significant difference was observed between DU145 and PC-3 cells. Luteolin exhibited a promoting effect on PCa cell death. After treatment with luteolin, cell viability, and Ki67 expression were decreased, and AnV-PI-positive dead cells were increased. Fer-1, Nec-1, 3-MA, and Z-VAD-FMK reversed luteolin effects on DU145 and PC-3 cell viability, proliferation, and AnV-PI-positive dead cells. Among them, Fer-1 and 3-MA were more effective. Luteolin-induced increased autophagy and ferroptosis in DU145 and PC-3 cells. Moreover, luteolin promoted ferroptosis by inducing increased autophagy in DU145 and PC-3 cells. However, knockdown of TFEB reversed the ability of luteolin to induce lysosome degradation of ferritin. In addition, luteolin promoted PCa ferroptosis by inducing ferritinophagy in vivo. CONCLUSIONS: Luteolin-induced ferroptosis in PCa cells by promoting TFEB nuclear translocation and increasing ferritinophagy.

Luteolin inhibits the JAK/STAT pathway to alleviate auditory cell apoptosis of acquired sensorineural hearing loss based on network pharmacology, molecular docking, molecular dynamics simulation, and experiments in vitro.

PURPOSE: The study aimed to explore the mechanisms of luteolin in acquired sensorineural hearing loss (SNHL) through network pharmacology, molecular docking, molecular dynamics simulation, and experimental verification. METHODS: First, the practices of network pharmacology were used to obtain the intersecting targets of luteolin and acquired SNHL, construct the PPI (Protein-Protein Interaction) network, conduct GO and KEGG enrichments, and establish luteolin-acquired SNHL-target-pathway network, aiming to gain the core targets and pathways. Then, the affinity between the core targets and luteolin was verified by molecular docking. Moreover, molecular dynamics (MD) simulation was applied to simulate the binding between targets and luteolin. Finally, with the HEI-OC1 cell line, some molecular biology techniques were adopted to verify the pharmacological actions of luteolin and the significance of the pathway from KEGG enrichment in luteolin-protecting auditory cell damage related to acquired SNHL. RESULTS: 14 intersecting targets were obtained, and the 10 core targets were further verified through molecular docking and MD simulation to get 5 core targets. The JAK/STAT was selected as the critical pathway through KEGG enrichment. Luteolin could dose-dependently alleviate auditory cell apoptosis by inhibiting the JAK/STAT pathway, confirmed by a series of experiments in vitro. CONCLUSION: This study manifested that luteolin could reduce acquired SNHL-related auditory cell apoptosis through the JAK/STAT pathway, which provided a new idea for acquired SNHL pharmacological treatment.

Molecular basis of ligand recognition specificity of flavone glucosyltransferases in Nemophila menziesii.

Of the more than 100 families of glycosyltransferases, family 1 glycosyltransferases catalyze glycosylation using uridine diphosphate (UDP)-sugar as a sugar donor and are thus referred to as UDP-sugar:glycosyl transferases. The blue color of the Nemophila menziesii flower is derived from metalloanthocyanin, which consists of anthocyanin, flavone, and metal ions. Flavone 7-O-ß-glucoside-4'-O-ß-glucoside in the plant is sequentially biosynthesized from flavons by UDP-glucose:flavone 4'-O-glucosyltransferase (NmF4'GT) and UDP-glucose:flavone 4'-O-glucoside 7-O-glucosyltransferase (NmF4'G7GT). To identify the molecular mechanisms of glucosylation of flavone, the crystal structures of NmF4'G7GT in its apo form and in complex with UDP-glucose or luteolin were determined, and molecular structure prediction using AlphaFold2 was conducted for NmF4'GT. The crystal structures revealed that the size of the ligand-binding pocket and interaction environment for the glucose moiety at the pocket entrance plays a critical role in the substrate preference in NmF4'G7GT. The substrate specificity of NmF4'GT was examined by comparing its model structure with that of NmF4'G7GT. The structure of NmF4'GT may have a smaller acceptor pocket, leading to a substrate preference for non-glucosylated flavones (or flavone aglycones).

Luteolin Is More Potent than Cromolyn in Their Ability to Inhibit Mediator Release from Cultured Human Mast Cells.

INTRODUCTION: Mast cells are known for their involvement in allergic reactions but also in inflammatory reactions via secretion of numerous pro-inflammatory chemokines, cytokines, and enzymes. Drug development has focused on antiproliferative therapy for systemic mastocytosis and not on inhibitors of mast cell activation. The only drug available as a "mast cell blocker" is disodium cromoglycate (cromolyn), but it is poorly absorbed after oral administration, is a weak inhibitor of histamine release from human mast cells, and it develops rapid anaphylaxis. Instead, certain natural flavonoids, especially luteolin, can inhibit mast cell activation. METHODS: Here, we compared pretreatment (0-120 min) with equimolar concentration (effective dose for 50% inhibition = 100 mm for inhibition of histamine release by cromolyn) of cromolyn and luteolin on release of mediators from the cultured human LADR mast cell line stimulated either by immunoglobulin E (IgE) and anti-IgE or with IL-33. RESULTS: We show that luteolin is significantly more potent than cromolyn inhibiting release of histamine, tryptase, metalloproteinase-9, and vascular endothelial growth factor. Moreover, while luteolin also significantly inhibited release of IL-1ß, IL-6, and IL-8 (CXCL8) and TNF, cromolyn had no effect. CONCLUSION: These findings support the use of luteolin, especially in liposomal form to increase oral absorption, may be a useful alternative to cromolyn.

Exploration of the sensitization effect of Chaihu Shugan powder on chemotherapy for triple-negative breast cancer and its active ingredients.

Chemotherapy plays a crucial role in the clinical treatment of triple-negative breast cancer (TNBC), but drug resistance limits its clinical application. The active ingredients of Chaihu Shugan Powder (CSP; Bupleurum Liver-Coursing Powder), quercetin and luteolin, both belong to flavonoid compounds and have significant anti-tumor potential, which can promote chemotherapy sensitivity. However, the correlation between the two and TNBC paclitaxel (PTX) chemotherapy sensitivity is unknown. We collected herbal components of CSP from the TCMSP database, and screened effective molecules and corresponding targets. STRING database was utilized to construct a protein-protein interaction network combining effective molecules and target genes. The top 50 nodes ranked by affinity were chosen for subsequent functional analysis, and the drug-active ingredient-gene interaction network was established using Cytoscape software. Molecular docking was used to determine the small molecules that target TNBC PTX resistance. The "clusterProfiler" package was utilized for GO and KEGG enrichment analyses on the top 50 genes to determine the pathways affected by CSP. Cell counting and colony formation assays evaluated cell viability, IC50 values, and proliferation capacity. Flow cytometry tested PTX intracellular accumulation. Western blot assayed the expression of TNF pathway-related proteins. Active ingredients of CSP, quercetin and luteolin, could inhibit TNBC cell proliferation and promote PTX chemotherapy sensitization. Quercetin and luteolin repressed the TNF signaling pathway and promoted PTX chemotherapy sensitization. Quercetin and luteolin could inhibit TNBC cell proliferation and promote PTX chemotherapy sensitization through the TNF signaling pathway. Therefore, the use of quercetin and luteolin plus PTX treatment provides a prospective strategy for TNBC treatment.

Luteolin Protects Against 6-Hydoroxydopamine-Induced Cell Death via an Upregulation of HRD1 and SEL1L.

Parkinson's Disease (PD) is caused by many factors and endoplasmic reticulum (ER) stress is considered as one of the responsible factors for it. ER stress induces the activation of the ubiquitin-proteasome system to degrade unfolded proteins and suppress cell death. The ubiquitin ligase 3-hydroxy-3-methylglutaryl-coenzyme A reductase degradation 1 (HRD1) and its stabilizing molecule, the suppressor/enhancer lin-12-like (SEL1L), can suppress the ER stress via the ubiquitin-proteasome system, and that HRD1 can also suppress cell death in familial and nonfamilial PD models. These findings indicate that HRD1 and SEL1L might be key proteins for the treatment of PD. Our study aimed to identify the compounds with the effects of upregulating the HRD1 expression and suppressing neuronal cell death in a 6-hydroxydopamine (6-OHDA)-induced cellular PD model. Our screening by the Drug Gene Budger, a drug repositioning tool, identified luteolin as a candidate compound for the desired modulation of the HRD1 expression. Subsequently, we confirmed that low concentrations of luteolin did not show cytotoxicity in SH-SY5Y cells, and used these low concentrations in the subsequent experiments. Next, we demonsrated that luteolin increased HRD1 and SEL1L mRNA levels and protein expressions. Furthermore, luteolin inhibited 6-OHDA-induced cell death and suppressed ER stress response caused by exposure to 6-OHDA. Finally, luteolin did not reppress 6-OHDA-induced cell death when expression of HRD1 or SEL1L was suppressed by RNA interference. These findings suggest that luteolin might be a novel therapeutic agent for PD due to its ability to suppress ER stress through the activation of HRD1 and SEL1L.

Luteolin: Nature's promising warrior against Alzheimer's and Parkinson's disease.

Neurodegenerative disorders (NDs) are defined as the slow loss of a group of neurons that are particularly sensitive. Due to the intricate pathophysiological processes underlying neurodegeneration, no cure exists for these conditions despite the extensive research and advances in our knowledge of the onset and course of NDs. Hence, there is a medical need for the creation of a novel therapeutic approach for NDs. By focusing on numerous signaling pathways, some natural substances derived from medicinal herbs and foods have demonstrated potent activity in treating various NDs. In this context, flavonoids have recently attracted increased popularity and research attention because of their alleged beneficial effects on health. By acting as antioxidant substances, nutritional supplements made up of flavonoids have been found to lessen the extent of NDs like Alzheimer's disease (AD) and Parkinson's disease (PD). Luteolin is a flavone that possesses potent antioxidant and anti-inflammatory properties. As a consequence, luteolin has emerged as an option for treatment with therapeutic effects on many brain disorders. More research has focused on luteolin's diverse biological targets as well as diverse signaling pathways, implying its potential medicinal properties in several NDs. This review emphasizes the possible use of luteolin as a drug of choice for the treatment as well as the management of AD and PD. In addition, this review recommends that further research should be carried out on luteolin as a potential treatment for AD and PD alongside a focus on mechanisms and clinical studies.

Discovery and characterization of natural product luteolin as an effective inhibitor of human pyridoxal kinase.

Pyridoxal kinase (PDXK) is an essential enzyme in the synthesis of pyridoxal 5-phosphate (PLP), the active form of vitamin B6, which plays a pivotal role in maintaining the enzyme activity necessary for cell metabolism. Thus, PDXK has garnered attention as a potential target for metabolism regulation and tumor therapy. Despite this interest, existing PDXK inhibitors have faced limitations, including weak suppressive activity, unclear mechanisms of action, and associated toxic side effects. In this study, we present the discovery of a novel PDXK inhibitor, luteolin, through a high-throughput screening approach based on enzyme activity. Luteolin, a natural product, exhibits micromolar-level affinity for PDXK and effectively inhibits the enzyme's activity in vitro. Our crystal structures reveal that luteolin occupies the ATP binding pocket through hydrophobic interactions and a weak hydrogen bonding pattern, displaying reversible characteristics as confirmed by biochemical assays. Moreover, luteolin disrupts vitamin B6 metabolism by targeting PDXK, thereby inhibiting the proliferation of leukemia cells. This research introduces a novel screening method for identifying high-affinity and potent PDXK inhibitors and sheds light on clarification of the structural mechanism of PDXK-luteolin for subsequent structure optimization of inhibitors.

Antiviral activity of luteolin against porcine epidemic diarrhea virus in silico and in vitro.

BACKGROUND: Porcine epidemic diarrhea virus (PEDV) mainly causes acute and severe porcine epidemic diarrhea (PED), and is highly fatal in neonatal piglets. No reliable therapeutics against the infection exist, which poses a major global health issue for piglets. Luteolin is a flavonoid with anti-viral activity toward several viruses. RESULTS: We evaluated anti-viral effects of luteolin in PEDV-infected Vero and IPEC-J2 cells, and identified IC50 values of 23.87 µM and 68.5 µM, respectively. And found PEDV internalization, replication and release were significantly reduced upon luteolin treatment. As luteolin could bind to human ACE2 and SARS-CoV-2 main protease (Mpro) to contribute viral entry, we first identified that luteolin shares the same core binding site on pACE2 with PEDV-S by molecular docking and exhibited positive pACE2 binding with an affinity constant of 71.6 µM at dose-dependent increases by surface plasmon resonance (SPR) assay. However, pACE2 was incapable of binding to PEDV-S1. Therefore, luteolin inhibited PEDV internalization independent of PEDV-S binding to pACE2. Moreover, luteolin was firmly embedded in the groove of active pocket of Mpro in a three-dimensional docking model, and fluorescence resonance energy transfer (FRET) assays confirmed that luteolin inhibited PEDV Mpro activity. In addition, we also observed PEDV-induced pro-inflammatory cytokine inhibition and Nrf2-induced HO-1 expression. Finally, a drug resistant mutant was isolated after 10 cell culture passages concomitant with increasing luteolin concentrations, with reduced PEDV susceptibility to luteolin identified at passage 10. CONCLUSIONS: Our results push forward that anti-PEDV mechanisms and resistant-PEDV properties for luteolin, which may be used to combat PED.

Attenuation of cannabis withdrawal symptoms by Prosopis farcta extract, its luteolin and melatonin in mice: Involvement of brain-derived neurotrophic factor and dopamine.

The aim of this study was the identification of luteolin in Prosopis farcta extract (PFE) and melatonin to evaluate its effect on THC withdrawal syndrome in mice. Luteolin was identified by high-performance liquid chromatography (HPCL). Signs of toxicity of mice in PFE and luteolin were monitored for LD50 calculation. The behavioral symptoms of THC withdrawal (stereotypies, ambulation, and inactivity time) induced by the rimonabant challenge were illustrated in THC-dependent mice receiving PFE, luteolin, and melatonin. The expression of mature BDNF (mBDNF) was evaluated by Western blot analysis. The dopamine concentrations were measured using HPLC. PFE and luteolin LD50 were 650 and 220 mg/kg, respectively. PFE (300 mg/kg), all doses of luteolin, and melatonin increased significantly the mBDNF expression and decreased the dopamine concentration. The findings suggest that PFE, luteolin, and melatonin are mighty in reducing the signs of THC withdrawal. It seems these effects were due to a decrease in dopamine concentration level and an increase in mBDNF protein expression in mice brains.

In vitro evaluation of the reductive carbonyl idarubicin metabolism to evaluate inhibitors of the formation of cardiotoxic idarubicinol via carbonyl and aldo-keto reductases.

The most important dose-limiting factor of the anthracycline idarubicin is the high risk of cardiotoxicity, in which the secondary alcohol metabolite idarubicinol plays an important role. It is not yet clear which enzymes are most important for the formation of idarubicinol and which inhibitors might be suitable to suppress this metabolic step and thus would be promising concomitant drugs to reduce idarubicin-associated cardiotoxicity. We, therefore, established and validated a mass spectrometry method for intracellular quantification of idarubicin and idarubicinol and investigated idarubicinol formation in different cell lines and its inhibition by known inhibitors of the aldo-keto reductases AKR1A1, AKR1B1, and AKR1C3 and the carbonyl reductases CBR1/3. The enzyme expression pattern differed among the cell lines with dominant expression of CBR1/3 in HEK293 and MCF-7 and very high expression of AKR1C3 in HepG2 cells. In HEK293 and MCF-7 cells, menadione was the most potent inhibitor (IC50 = 1.6 and 9.8 µM), while in HepG2 cells, ranirestat was most potent (IC50 = 0.4 µM), suggesting that ranirestat is not a selective AKR1B1 inhibitor, but also an AKR1C3 inhibitor. Over-expression of AKR1C3 verified the importance of AKR1C3 for idarubicinol formation and showed that ranirestat is also a potent inhibitor of this enzyme. Taken together, our study underlines the importance of AKR1C3 and CBR1 for the reduction of idarubicin and identifies potent inhibitors of metabolic formation of the cardiotoxic idarubicinol, which should now be tested in vivo to evaluate whether such combinations can increase the cardiac safety of idarubicin therapies while preserving its efficacy.

Luteolin, a flavone ingredient: Anticancer mechanisms, combined medication strategy, pharmacokinetics, clinical trials, and pharmaceutical researches.

Current pharmaceutical research is energetically excavating the pharmacotherapeutic role of herb-derived ingredients in multiple malignancies' targeting. Luteolin is one of the major phytochemical components that exist in various traditional Chinese medicine or medical herbs. Mounting evidence reveals that this phytoconstituent endows prominent therapeutic actions on diverse malignancies, with the underlying mechanisms, combined medication strategy, and pharmacokinetics elusive. Additionally, the clinical trial and pharmaceutical investigation of luteolin remain to be systematically delineated. The present review aimed to comprehensively summarize the updated information with regard to the anticancer mechanism, combined medication strategies, pharmacokinetics, clinical trials, and pharmaceutical researches of luteolin. The survey corroborates that luteolin executes multiple anticancer effects mainly by dampening proliferation and invasion, spurring apoptosis, intercepting cell cycle, regulating autophagy and immune, inhibiting inflammatory response, inducing ferroptosis, and pyroptosis, as well as epigenetic modification, and so on. Luteolin can be applied in combination with numerous clinical anticarcinogens and natural ingredients to synergistically enhance the therapeutic efficacy of malignancies while reducing adverse reactions. For pharmacokinetics, luteolin has an unfavorable oral bioavailability, it mainly persists in plasma as glucuronides and sulfate-conjugates after being metabolized, and is regarded as potent inhibitors of OATP1B1 and OATP2B1, which may be messed with the pharmacokinetic interactions of miscellaneous bioactive substances in vivo. Besides, pharmaceutical innovation of luteolin with leading-edge drug delivery systems such as host-guest complexes, nanoparticles, liposomes, nanoemulsion, microspheres, and hydrogels are beneficial to the exploitation of luteolin-based products. Moreover, some registered clinical trials on luteolin are being carried out, yet clinical research on anticancer effects should be continuously promoted.

Luteolin: A promising multifunctional natural flavonoid for human diseases.

Natural products are closely associated with human health. Luteolin (LUT), a flavonoid polyphenolic compound, is widely found in fruits, vegetables, flowers, and herbs. It is noteworthy that LUT exhibits a variety of beneficial pharmacological properties and holds significant potential for clinical applications, particularly in antitumor, anti-convulsion, diabetes control, anti-inflammatory, neuroprotection, anti-oxidation, anti-cardiovascular, and other aspects. The potential mechanism of action has been partially elucidated, including the mediation of NF-κB, toll-like receptor, MAPK, Wnt/ß-catenin, PI3K/Akt, AMPK/mTOR, and Nrf-2, among others. The review that aimed to comprehensively consolidate essential information on natural sources, pharmacological effects, therapeutic and preventive potential, as well as potential mechanisms of LUT. The objective is to establish a theoretical basis for the continued development and application of LUT.

Luteolin, apigenin, and chrysin inhibit lipotoxicity-induced NLRP3 inflammasome activation and autophagy damage in macrophages by suppressing endoplasmic reticulum stress.

Lipotoxicity leads to numerous metabolic disorders such as nonalcoholic steatohepatitis. Luteolin, apigenin, and chrysin are three flavones with known antioxidant and anti-inflammatory properties, but whether they inhibit lipotoxicity-mediated NLRP3 inflammasome activation was unclear. To address this question, we used J774A.1 macrophages and Kupffer cells stimulated with 100 µM palmitate (PA) in the presence or absence of 20 µM of each flavone. PA increased p-PERK, p-IRE1α, p-JNK1/2, CHOP, and TXNIP as well as p62 and LC3-II expression and induced autophagic flux damage. Caspase-1 activation and IL-1ß release were also noted after 24 h of exposure to PA. In the presence of the PERK inhibitor GSK2656157, PA-induced CHOP and TXNIP expression and caspase-1 activation were mitigated. Compared with PA treatment alone, Bcl-2 coupled to beclin-1 was elevated and autophagy was reversed by the JNK inhibitor SP600125. With luteolin, apigenin, and chrysin treatment, PA-induced ROS production, ER stress, TXNIP expression, autophagic flux damage, and apoptosis were ameliorated. Moreover, TXNIP binding to NLRP3 and IL-1ß release in response to LPS/PA challenge were reduced. These results suggest that luteolin, apigenin, and chrysin protect hepatic macrophages against PA-induced NLRP3 inflammasome activation and autophagy damage by attenuating endoplasmic reticulum stress.

Effects and Mechanisms of Luteolin, a Plant-Based Flavonoid, in the Prevention of Cancers via Modulation of Inflammation and Cell Signaling Molecules.

Luteolin, a flavonoid, is mainly found in various vegetables and fruits, including carrots, cabbages, onions, parsley, apples, broccoli, and peppers. Extensive research in vivo and in vitro has been performed to explore its role in disease prevention and treatment. Moreover, this compound possesses the ability to combat cancer by modulating cell-signaling pathways across various types of cancer. The studies have confirmed that luteolin can inhibit cancer-cell survival and proliferation, angiogenesis, invasion, metastasis, mTOR/PI3K/Akt, STAT3, Wnt/ß-catenin, and cell-cycle arrest, and induce apoptosis. Further, scientific evidence describes that this compound plays a vital role in the up/down-regulation of microRNAs (miRNAs) in cancer therapy. This review aims to outline the anti-cancer mechanisms of this compound and its molecular targets. However, a knowledge gap remains regarding the studies on its safety and efficacy and clinical trials. Therefore, it is essential to conduct more research based on safety, efficacy, and clinical trials to explore the beneficial role of this compound in disease management, including cancer.

Luteolin-7-O-ß-d-glucuronide Ameliorates Cerebral Ischemic Injury: Involvement of RIP3/MLKL Signaling Pathway.

Luteolin-7-O-ß-d-glucuronide (LGU) is a major active flavonoid glycoside compound that is extracted from Ixeris sonchifolia (Bge.) Hance, and it is a Chinese medicinal herb mainly used for the treatment of coronary heart disease, angina pectoris, cerebral infarction, etc. In the present study, the neuroprotective effect of LGU was investigated in an oxygen glucose deprivation (OGD) model and a middle cerebral artery occlusion (MCAO) rat model. In vitro, LGU was found to effectively improve the OGD-induced decrease in neuronal viability and increase in neuronal death by a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a lactate dehydrogenase (LDH) leakage rate assay, respectively. LGU was also found to inhibit OGD-induced intracellular Ca2+ overload, adenosine triphosphate (ATP) depletion, and mitochondrial membrane potential (MMP) decrease. By Western blotting analysis, LGU significantly inhibited the OGD-induced increase in expressions of receptor-interacting serine/threonine-protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL). Moreover, molecular docking analysis showed that LGU might bind to RIP3 more stably and firmly than the RIP3 inhibitor GSK872. Immunofluorescence combined with confocal laser analyses disclosed that LGU inhibited the aggregation of MLKL to the nucleus. Our results suggest that LGU ameliorates OGD-induced rat primary cortical neuronal injury via the regulation of the RIP3/MLKL signaling pathway in vitro. In vivo, LGU was proven, for the first time, to protect the cerebral ischemia in a rat middle cerebral artery occlusion (MCAO) model, as shown by improved neurological deficit scores, infarction volume rate, and brain water content rate. The present study provides new insights into the therapeutic potential of LGU in cerebral ischemia.

Chlorogenic acid, caffeic acid and luteolin from dandelion as urease inhibitors: insights into the molecular interactions and inhibition mechanism.

BACKGROUND: Dandelion contains hundreds of active compounds capable of inhibiting urease activity, but the individual compounds have not yet been fully identified, and their effects and underlying mechanisms are not clear. The present study aimed to screen the urease inhibition active compounds of dandelion by urease inhibitory activity evaluation HPLC-tandem mass spectrometry analysis, their mechanism of urease inhibition by polyphenols was explored using enzyme kinetic studies via Lineweaver-Burk plots. Other investigations included isothermal titration calorimetry and surface plasmon resonance sensing, fluorescence quenching experiments, and single ligand molecular docking and two-ligand simultaneous docking techniques. RESULTS: The results indicated that the ethyl acetate fraction of dandelion flower exhibited the greatest inhibition (lowest IC50 0.184 ± 0.007 mg mL-1). Chlorogenic acid, caffeic acid and luteolin could be effective urease inhibitors that acted in a non-competitive inhibition manner. Individually, chlorogenic acid could not only fast bind to urease, but also dissociate rapidly, whereas luteolin might interact with urease with the weakest affinity. The chlorogenic acid-caffeic acid combination exhibited an additive effect in urease inhibition. However, the chlorogenic acid-luteolin and caffeic acid-luteolin combinations exhibited antagonistic effects, with the caffeic acid-luteolin combination showing greater antagonism. CONCLUSION: The present study reveals that chlorogenic acid, caffeic acid and luteolin are major bioactive compounds for urease inhibition, indicating the molecular mechanisms. The antagonistic effects were observed between luteolin and chlorogenic acid/caffeic acid, and the interactions of the catalytic site and flap may account for the antagonistic effects. © 2024 Society of Chemical Industry.

Flavonoids and phenolic acids from sugarcane: Distribution in the plant, changes during processing, and potential benefits to industry and health.

Sugarcane (Saccharum sp.) plants are grown in warmer climates throughout the world and processed to produce sugar as well as other useful byproducts such as molasses and bagasse. Sugarcane is rich in (poly)phenols, but there has been no attempt to critically evaluate the published information based on the use of suitable methodologies. The objective of this review is to evaluate the quantitative and qualitative (poly)phenolic profiles of individual parts of the sugarcane plant and its multiple industrial products, which will help develop new processes and uses for sugarcane (poly)phenols. The quantitative analysis involves the examination of extraction, concentration, and analytical techniques used in each study for each plant part and product. The qualitative analysis indicates the identification of various (poly)phenols throughout the sugarcane processing chain, using only compounds elucidated through robust analytical methodologies such as mass spectrometry or nuclear magnetic resonance. In conclusion, sugarcane (poly)phenols are predominantly flavonoids and phenolic acids. The main flavonoids, derivatives of apigenin, luteolin, and tricin, with a substantial proportion of C-glycosides, are consistently found across all phases of sugarcane processing. The principal phenolic acids reported throughout the process include chlorogenic acids, as well as ferulic and caffeic acids mostly observed after hydrolysis. The derivation of precise quantitative information across publications is impeded by inconsistencies in analytical methodologies. The presence of multiple (poly)phenols with potential benefits for industrial applications and for health suggests sugarcane could be a useful provider of valuable compounds for future use in research and industrial processes.

Luteolin ameliorates necroptosis in Glucocorticoid-induced osteonecrosis of the femoral head via RIPK1/RIPK3/MLKL pathway based on network pharmacology analysis.

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) is deeply relevant to damage and dysfunction of bone microvascular endothelial cells (BMECs). Recently, necroptosis, a newly programmed cell death with necrotic appearance, has garnered increasing attention. Luteolin, a flavonoid compound derived from Rhizoma Drynariae, has numerous pharmacological properties. However, the effect of Luteolin on BMECs in GIONFH through the necroptosis pathway has not been extensively investigated. Based on network pharmacology analysis, 23 genes were identified as potential targets for the therapeutic effect of Luteolin in GIONFH via the necroptosis pathway, with RIPK1, RIPK3, and MLKL being the hub genes. Immunofluorescence staining results revealed high expression of vWF and CD31 in BMECs. In vitro experiments showed that incubation with dexamethasone led to reduced proliferation, migration, angiogenesis ability, and increased necroptosis of BMECs. However, pretreatment with Luteolin attenuated this effect. Based on molecular docking analysis, Luteolin exhibited strong binding affinity with MLKL, RIPK1, and RIPK3. Western blotting was utilized to detect the expression of p-MLKL, MLKL, p-RIPK3, RIPK3, p-RIPK1, and RIPK1. Intervention with dexamethasone resulted in a significant increase in the p-RIPK1/RIPK1 ratio, but the effects of dexamethasone were effectively counteracted by Luteolin. Similar findings were observed for the p-RIPK3/RIPK3 ratio and the p-MLKL/MLKL ratio, as anticipated. Therefore, this study demonstrates that Luteolin can reduce dexamethasone-induced necroptosis in BMECs via the RIPK1/RIPK3/MLKL pathway. These findings provide new insights into the mechanisms underlying the therapeutic effects of Luteolin in GIONFH treatment. Additionally, inhibiting necroptosis could be a promising novel approach for GIONFH therapy.