OBJECTIVE: To investigate the anti-coronavirus potential and the corresponding mechanisms of the two ingredients of Reduning Injection: quercetin and luteolin. METHODS: A pseudovirus system was designed to test the efficacy of quercetin and luteolin to inhibit SARS-CoV-2 infection and the corresponding cellular toxicity. Luteolin was tested for its activities against the pseudoviruses of SARS-CoV-2 and its variants. Virtual screening was performed to predict the binding sites by Autodock Vina 1.1.230 and PyMol. To validate docking results, surface plasmon resonance (SPR) was used to measure the binding affinity of the compounds with various proteins of the coronaviruses. Quercetin and luteolin were further tested for their inhibitory effects on other coronaviruses by indirect immunofluorescence assay on rhabdomyosarcoma cells infected with HCoV-OC43. RESULTS: The inhibition of SARS-CoV-2 pseudovirus by luteolin and quercetin were strongly dose-dependent, with concentration for 50% of maximal effect (EC₅₀) of 8.817 and 52.98 µmol/L, respectively. Their cytotoxicity to BHK21-hACE2 were 177.6 and 405.1 µmol/L, respectively. In addition, luetolin significantly blocked the entry of 4 pseudoviruses of SARS-CoV-2 variants, with EC₅₀ lower than 7 µmol/L. Virtual screening and SPR confirmed that luteolin binds to the S-proteins and quercetin binds to the active center of the 3CLpro, PLpro, and helicase proteins. Quercetin and luteolin showed over 99% inhibition against HCoV-OC43. CONCLUSIONS The mechanisms were revealed of quercetin and luteolin inhibiting the infection of SARS-CoV-2 and its variants. Reduning Injection is a promising drug for COVID-19.
Humans ; SARS-CoV-2 ; COVID-19 ; Luteolin ; Quercetin

Simiao Yong'an Decoction is a classic prescription for treating gangrene. Modern medical evidence has proven that Si-miao Yong'an Decoction has therapeutic effects on atherosclerosis(AS), vascular occlusion angeitides, and hypertension, while its pharmacodynamic mechanism remains unclear. The evidence of network pharmacology, molecular docking, literature review, and our previous study suggests that luteolin and kaempferol are two major flavonoids in Simiao Yong'an Decoction and can inhibit macrophage inflammation and exert anti-AS effects. However, due to lack of the metabolism studies in vivo, little is known about the metabolic characteristics of luteolin and kaempferol. This study employed ultra-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry(UHPLC-LTQ-Orbitrap MS/MS) and relevant software to identify the metabolites and metabolic pathways of luteolin and kaempferol in rat plasma, urine, and feces, after oral administration of luteolin and kaempferol, respectively. After the administration of luteolin, 10, 11, and 3 metabolites of luteolin were detected in the plasma, urine, and feces, respectively. After the administration of kaempferol, 9, 3, and 1 metabolites of kaempferol were detected in the plasma, urine, and feces, respectively. The metabolic pathways mainly involved methylation, glucuronidation, and sulfation. This study enriches the knowledge about the pharmacological mechanism of luteolin and kaempferol and supplies a reference for revealing the metabolic process of other flavonoids in Simiao Yong'an Decoction, which is of great significance for elucidating the pharmacological effects and effective substances of this decoction in vivo.
Rats ; Animals ; Tandem Mass Spectrometry/methods* ; Luteolin/analysis* ; Drugs, Chinese Herbal/chemistry* ; Kaempferols/analysis* ; Chromatography, High Pressure Liquid/methods* ; Molecular Docking Simulation

Oral squamous cell carcinoma (OSCC) is a prevalent malignant tumor affecting the head and neck region (Leemans et al., 2018). It is often diagnosed at a later stage, leading to a poor prognosis (Muzaffar et al., 2021; Li et al., 2023). Despite advances in OSCC treatment, the overall 5-year survival rate of OSCC patients remains alarmingly low, falling below 50% (Jehn et al., 2019; Johnson et al., 2020). According to statistics, only 50% of patients with oral cancer can be treated with surgery. Once discovered, it is more frequently at an advanced stage. In addition, owing to the aggressively invasive and metastatic characteristics of OSCC, most patients die within one year of diagnosis. Hence, the pursuit of novel therapeutic drugs and treatments to improve the response of oral cancer to medication, along with a deeper understanding of their effects, remains crucial objectives in oral cancer research (Johnson et al., 2020; Bhat et al., 2021; Chen et al., 2023; Ruffin et al., 2023).
Humans ; Mouth Neoplasms/pathology* ; Carcinoma, Squamous Cell/metabolism* ; Luteolin/therapeutic use* ; Squamous Cell Carcinoma of Head and Neck/drug therapy* ; Head and Neck Neoplasms/drug therapy* ; Cell Line, Tumor

Rats ; Animals ; Myocardial Reperfusion Injury/metabolism* ; Luteolin/metabolism* ; Down-Regulation ; Rats, Sprague-Dawley ; MicroRNAs/metabolism* ; Reperfusion Injury ; Apoptosis

Chemical constituents were isolated and purified from ethyl acetate fraction of Arctium lappa leaves by silica gel, ODS, MCI, and Sephadex LH-20 column chromatography. Their structures were identified with multiple spectroscopical methods including NMR, MS, IR, UV, and X-ray diffraction combined with literature data. Twenty compounds(1-20) were identified and their structures were determined as arctanol(1), citroside A(2), melitensin 15-O-β-D-glucoside(3), 11β,13-dihydroonopordopicrin(4), 11β,13-dihydrosalonitenolide(5), 8α-hydroxy-β-eudesmol(6), syringin(7), dihydrosyringin(8), 3,4,3',4'-tetrahydroxy-δ-truxinate(9),(+)-pinoresinol(10), phillygenin(11), syringaresinol(12), kaeperferol(13), quercetin(14), luteolin(15), hyperin(16), 4,5-O-dicaffeoylquinic acid(17), 1H-indole-3-carboxaldehyde(18), benzyl-β-D-glucopyranoside(19), and N-(2'-phenylethyl) isobutyramide(20). Among them, compound 1 is a new norsesquiterpenoid, and compounds 2-5, 7-8, and 18-20 are isolated from this plant for the first time.
Arctium/chemistry* ; Magnetic Resonance Spectroscopy ; Luteolin/analysis* ; Plant Leaves/chemistry*

This study explored the correlation between color and chemical components of Chrysanthemi Indici Flos(CIF), aiming at providing a reference for its procurement, evaluation, and breeding. Colorimeter and ultra-performance liquid chromatograph(UPLC) were used to determine the color(lightness-shade chromaticity value L~*, red-green chromaticity value a~*, yellow-blue chromati-city value b~*) and chemical components(cynaroside, linarin, luteolin, apigenin, and chlorogenic acid) of 84 CIF germplasms, respectively. Diversity analysis, correlation analysis, regression analysis, and cluster analysis were performed. The results showed that the color and chemical components of CIF were diversified. Chlorogenic acid was in significantly positive correlation with L~* and b~* and significantly negative correlation with a~*. Cynaroside and grey relational grade γ_i of chemical components were in significantly po-sitive correlation with b~* and L~*, respectively, whereas linarin, luteolin, and apigenin had no significant correlation with L~*, a~*, or b~*. The 84 CIF germplasms were clustered into 4 clades. In addition, germplasms in clade Ⅲ had higher γ_i and total color value(E~*_(ab)) than those in other clades, with the best quality and color, and a germplasm with the highest quality, bright yellow color, and highest content of linarin was screened out in this clade. Thus, CIF with bright yellow color had high content of cymaroside and chlorogenic acid and thereby high quality. In summary, the color can be used to quickly predict the quality of CIF. Our results provided data for the evaluation of CIF quality by color and a reference for its procurement and breeding.
Chrysanthemum/chemistry* ; Luteolin/analysis* ; Chlorogenic Acid/analysis* ; Apigenin/analysis* ; Plant Breeding ; Excipients ; Chromatography, High Pressure Liquid/methods*

Iron overload injury is considered to be a part of blood stasis syndrome of arthralgia in traditional Chinese medicine. Its primary therapies include clearing heat and detoxification, activating blood circulation, and removing blood stasis. Lonicera japonica flos (LJF) has long been known as an excellent antipyretic and antidote. Luteoloside (Lut) is one of the main components of LJF and exhibits antioxidant, anti-inflammatory, and cytoprotective properties. However, the protection of Lut against iron overload injury and its underlying mechanisms remain unclear. Therefore, HUVECs were exposed to 50 μmol·L^-1 iron dextran for 48 h to establish an iron overload damage model and the effects of Lut were assessed. Our results showed that 20 μmol·L^-1 Lut not only increased cell viability and weakened LDH activity, but also significantly up-regulated DDAHⅡ expression and activity, increased p-eNOS/eNOS ratio and NO content, and reduced ADMA content in HUVECs exposed to iron overload. Furthermore, Lut significantly attenuated intracellular/mitochondrial ROS generation, improved SOD, CAT, and GSH-Px activities, reduced MDA content, maintained MMP, inhibited mPTP opening, prevented cyt c from mitochondria released into cytoplasm, reduced cleaved-caspase3 expression, and ultimately decreased cell apoptosis induced by iron overload. The effects of Lut were similar to those of L-arginine (an ADMA competitive substrate), cyclosporin A (a mPTP blocker agent), and edaravone (a free radical scavenger) as positive controls. However, addition of pAD/DDAH II-shRNA adenovirus reversed the above beneficial effects of Lut. In conclusion, Lut can protect HUVECs against iron overload injury via the ROS/ADMA/DDAH II/eNOS/NO pathway. The mitochondria are the target organelles of Lut's protective effects.
Endothelium, Vascular ; Glucosides ; Humans ; Iron Overload ; Luteolin ; Reactive Oxygen Species

OBJECTIVE: To screen the effective antioxidant components in Trichosanthes extract based on the mean value of Deng's correlation degree and assess the antioxidant activity of the identified components. METHOD: High-performance liquid chromatography (HPLC) was used to obtain the fingerprints of Trichosanthes extract, and the clearance rates of DPPH · and O₂^-· by 3, 9 and 27 mg/mL Trichosanthes extract were determined. The antioxidant spectrum effect of Trichosanthes extract was analyzed by calculating the mean value of Deng's correlation degree to screen the effective antioxidant component group. According to the contents of each known components in the antioxidant effective component group, mixed solutions of the components were prepared and tested for their clearance rates of DPPH · and O₂^-·. RESULTS: The 36 common peaks in HPLC fingerprints of Trichosanthes extract showed different degrees of correlation with DPPH · and O₂^-· clearance. The common peaks with a correlation degree greater than the median value included peaks 21, 36, 8, 31, 14, 5, 27, 2, 24, 15, 18, 33, 22, 34, 35, 19, 28 and 25. The 5 components, namely kaempferol (peak 36), isoquercitrin (peak 8), luteolin (peak 31), rutin (peak 5) and apigenin (peak 35), were tentatively identified to constitute the effective antioxidant component group with a mass ratio 3∶2∶2∶ 1∶1 in Trichosanthes extract. The prepared mixed solutions of antioxidant effective component group (6.12, 2.04, and 0.68 μg/mL) showed clearance rates of DPPH · of 65.4%, 64.0% and 61.0%, and clearance rates of O₂^-· of 12.9%, 9.5% and 8.3%, respectively. CONCLUSION We identified the material basis for the antioxidant activity of Trichosanthes and screened the antioxidant effective component group in Trichosanthes extract.
Antioxidants/pharmacology* ; Chromatography, High Pressure Liquid/methods* ; Luteolin ; Plant Extracts/pharmacology* ; Trichosanthes/chemistry*

The aim of this study was to investigate the mechanism of luteolin regulating lipoxygenase pathway against oxygen-glucose deprivation/reperfusion(OGD/R) injury in H9 c2 cardiomyocytes. First, Discovery Studio 2019 was used for the molecular docking of luteolin with three key enzymes including lipoxygenase 5(ALOX5), lipoxygenase 12(ALOX12), and lipoxygenase 15(ALOX15) in lipoxygenase pathway. The docking results showed that luteolin had high docking score and similar functional groups with the original ligand. From this, H9 c2 cardiomyocytes were cultured in vitro, and then the injury model of H9 c2 cardiomyocytes was induced by deprivation of oxygen-glucose for 8 h, and rehabilitation of oxygen-glucose for 12 h. Cell viability was detected by tetrazolium(MTT) colorimetry. H9 c2 cardiomyocytes were observed with a fluorescence inverted microscope, and colorimetry was used to detect the level of lactate dehydrogenase(LDH) in cell supernatant. The results showed that luteolin could significantly protect the morphology of H9 c2 cells, significantly improve the survival rate of H9 c2 cardiomyocytes in OGD/R injury model, reduce the level of LDH in cell supernatant, inhibit cytotoxicity, and maintain the integrity of cell membrane. The inflammatory cytokines interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) were detected by enzyme-linked immunosorbent assay. Compared with the model group, luteolin can significantly reduce the release of IL-6 and TNF-α. Western blot was employed to detect the protein levels of ALOX5, ALOX12, and ALOX15 in lipoxygenase pathway. After luteolin intervention, the protein levels of ALOX5, ALOX12, and ALOX15 were significantly down-regulated compared with those in model group. These results indicate that luteolin can inhibit the release of IL-6 and TNF-α by restraining the activation of lipoxygenase pathway, thereby playing a protective role in the cardiomyocyte injury model induced by OGD/R.
Apoptosis ; Glucose ; Humans ; Lipoxygenases ; Luteolin/pharmacology* ; Molecular Docking Simulation ; Myocytes, Cardiac ; Oxygen ; Reperfusion Injury ; Signal Transduction

Isomers are widely distributed in Chinese herbal medicines,and can be discriminated by energy-resolved mass spectrometry( ER-MS). However,ER-MS was performed through direct injection of reference compounds with syringe pump,which encountered a significant technical barrier for high-throughput and automated measurements. Herein,online ER-MS was conducted using LC-MS platform,and a pair of isomers,kaempferol vs luteolin,were employed as a case study to illustrate and assess the utility of online ER-MS for isomeric discrimination. High-resolution tandem mass spectrometry data of both flavonoids were acquired on LC-QE-Orbitrap-MS,and the fragmentation pathways responsible for the primary fragment ions were proposed. The primary signal in MS1 occurred at m/z 285( [M-H]-),and the primary signals of either compound generated by retro-Diels-Alder fragmentation were observed at m/z 151 and 133. The spectral information was subsequently transferred onto LC-Qtrap-MS platform to carry out online ER-MS. Two precursor-to-product ion transition candidates were constructed as m/z 285>151 and 285>133,and either afterward derived a set of pseudo-ion transitions( PITs) and so forth,exactly corresponding to a series of progressive collision energies( eg-5,-8,-11 e V,and so on). All PITs were typed into the monitoring list of multiple reaction monitoring program to generate the peak area datasets. Either dataset was normalized using the highest values in the set and imported into Graph Pad Prism software to plot the Gaus-sian-shaped curve that was termed as the break-down graph. The apex of the regressive curve was termed as optimal collision energy( OCE). The OCE values corresponding to m/z 285>151 were calculated as-29. 06 e V and-35. 71 e V for kaempferol and luteolin,respectively. In the case of m/z 285>133,the OCEs were yielded as-44. 15 e V for kaempferol and-49. 01 e V for luteolin. With re-ference to their chemical structures,the location of hydroxyl group was regarded to be responsible for the differences of either m/z 285>151 or 285>133 between the isomers,attributing to their different bond properties. Above all,online ER-MS offers an eligible tool for isomeric discrimination,and provides meaningful information for the accurate chemical composition characterization based on LC-MS,which is not limited to Chinese herbal medicines.
Chromatography, Liquid ; Flavonoids ; Kaempferols ; Luteolin ; Tandem Mass Spectrometry