To explore the regulatory mechanism of drought stress on the synthesis of chlorogenic acid and luteoloside in Lonicera japonica, we designed five drought gradients (soil water contents of 30%, 24%, 17%, 14%, and 10%) and screened and verified the differentially expressed genes (DEGs) by RNA sequencing (RNA-seq) and reverse transcription quantitative polymerase chain reaction (RT-qPCR). Furthermore, we employed HPLC to systematically measure the content changes of chlorogenic acid and luteoloside. The results revealed that drought significantly reduced the accumulation of secondary metabolites, and severe drought led to more obvious reductions. Under extreme drought (soil water content of 10%), the content of chlorogenic acid and luteoloside decreased significantly to 25.73 mg/g and 11.33 mg/g (with the decrease rates of 37.85% and 9.58%, respectively). A total of 77 454 genes were identified via transcriptome analysis, among which the number of DEGs reached 1 128 under the extraordinary drought. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses revealed that the DEGs were mainly involved in flavonoid synthesis, secondary metabolite biosynthesis, plant hormone signal transduction and the plant-pathogen interaction pathways, and the expression of key genes regulating the synthesis of chlorogenic acid and luteoloside was significantly downregulated. RT-qPCR verified the accuracy of the RNA-seq data. This study revealed that drought stress reduced the content of chlorogenic acid and luteoloside, the main secondary metabolites, by inhibiting the expression of key genes in the secondary metabolism pathways. The findings provide candidate gene resources for molecular breeding of drought-tolerant Lonicera japonica.
Lonicera/physiology* ; Chlorogenic Acid/metabolism* ; Droughts ; Stress, Physiological ; Gene Expression Regulation, Plant ; Glucosides/metabolism* ; Luteolin

OBJECTIVES: To investigate the mechanism of luteolin for inhibiting proliferation of lung cancer A549 cells. METHODS: A549 cells treated with different concentrations of luteolin for 48 h were evaluated for changes in cell viability, proliferation, reactive oxygen species (ROS) production and apoptosis using MTT assay, plate cloning assay, EdU staining, DCFH-DA assay and Hoechst33258 staining. The changes in cell autophagy were examined with MDC staining, and the expressions of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-9), autophagy-related proteins (LC3B, Beclin 1, and P62), AKT/mTOR pathway proteins, and HO-1 protein were detected using Western blotting. RESULTS: Treatment with luteolin dose-dependently inhibited the viability and proliferation of A549 cells, increased intracellular ROS levels, up-regulated the expressions of Bax, cleaved caspase-9, and Beclin 1, increased the LC3B-II/LC3B-I ratio, down-regulated the expressions of Bcl-2 and P62, and induced cell apoptosis and autophagy. Luteolin also significantly inhibited the phosphorylation of AKT and mTOR and down-regulated the expression of HO-1 protein in the cells. CONCLUSIONS Luteolin induces apoptosis and autophagy to inhibit proliferation of A549 cells by increasing ROS production, inhibiting the AKT/mTOR pathway and down-regulating HO-1 protein expression.
Humans ; TOR Serine-Threonine Kinases/metabolism* ; A549 Cells ; Reactive Oxygen Species/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Cell Proliferation/drug effects* ; Signal Transduction/drug effects* ; Lung Neoplasms/pathology* ; Apoptosis/drug effects* ; Luteolin/pharmacology* ; Autophagy/drug effects* ; Heme Oxygenase-1/metabolism* ; Cell Survival/drug effects*

OBJECTIVE: Myocardial ischemia/reperfusion injury (MIRI) is an obstacle to the success of cardiac reperfusion therapy. This study explores whether luteolin can mitigate MIRI by regulating the p53 signaling pathway. METHODS: Model mice were subjected to a temporary surgical ligation of the left anterior descending coronary artery, and administered luteolin. The myocardial infarct size, myocardial enzyme levels, and cardiac function were measured. Latent targets and signaling pathways were screened using network pharmacology and molecular docking. Then, proteins related to the p53 signaling pathway, apoptosis and oxidative stress were measured. Hypoxia/reoxygenation (HR)-incubated HL1 cells were used to validate the effects of luteolin in vitro. In addition, a p53 agonist and an inhibitor were used to investigate the mechanism. RESULTS: Luteolin reduced the myocardial infarcted size and myocardial enzymes, and restored cardiac function in MIRI mice. Network pharmacology identified p53 as a hub target. The bioinformatic analyses showed that luteolin had anti-apoptotic and anti-oxidative properties. Additionally, luteolin halted the activation of p53, and prevented both apoptosis and oxidative stress in myocardial tissue in vivo. Furthermore, luteolin inhibited cell apoptosis, JC-1 monomer formation, and reactive oxygen species elevation in HR-incubated HL1 cells in vitro. Finally, the p53 agonist NSC319726 downregulated the protective attributes of luteolin in the MIRI mouse model, and both luteolin and the p53 inhibitor pifithrin-α demonstrated a similar therapeutic effect in the MIRI mice. CONCLUSION Luteolin effectively treats MIRI and may ameliorate myocardial damage by regulating apoptosis and oxidative stress through its targeting of the p53 signaling pathway. Please cite this article as: Zhai P, Ouyang XH, Yang ML, Lin L, Li JY, Li YM, Cheng X, Zhu R, Hu DS. Luteolin protects against myocardial ischemia/reperfusion injury by reducing oxidative stress and apoptosis through the p53 pathway. J Integr Med. 2024; 22(6): 652-664.
Luteolin/pharmacology* ; Animals ; Myocardial Reperfusion Injury/metabolism* ; Oxidative Stress/drug effects* ; Tumor Suppressor Protein p53/genetics* ; Apoptosis/drug effects* ; Mice ; Signal Transduction/drug effects* ; Male ; Disease Models, Animal ; Mice, Inbred C57BL ; Myocardial Infarction/prevention & control* ; Reactive Oxygen Species/metabolism*

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

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

The study is aimed to explore the effects of stress at different temperatures( 35,45,55 ℃) on membrane permeability,active oxygen metabolism and accumulation of effective substances in Lonicera japonica,and provide theoretical basis for reducing deterioration and revealing browning mechanism during postharvest processing of L. japonica. The cell membrane permeability( relative conductivity,MDA content),active oxygen metabolism( SOD,POD,PPO,CAT activity) and the accumulation of effective substances( chlorogenic acid,luteolin,neochlorogenic acid,cryptochlorogenic acid,3,5-dicaffeoylquinic acid,3,4-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid) of L. japonica were all studied by constant temperature drying method,and the results were analyzed by the SPSS 17. 0 statistical software. The results showed that MDA content in L. japonica was increased by 151. 14% at 35 ℃,SOD,POD,PPO and CAT activity were 29. 73%,42. 86%,105. 02% and 10. 74% higher than at 45 ℃,respectively. The order of effective substance content in L. japonica was 35 ℃ >45 ℃ >55 ℃. The changes of membrane permeability,activity of active oxygen metabolizing enzyme and accumulation of active components were significantly affected by different temperature stress. The indexes showed that physiological and active oxygen metabolizing enzyme activity of L. japonica was the highest under 35 ℃ stress,chlorogenic acid and luteolin were effectively accumulated,which provides basic data for solving browning problem in the postharvest processing of L. japonica.
Cell Membrane Permeability ; Chlorogenic Acid/metabolism* ; Hot Temperature ; Lonicera/physiology* ; Luteolin/metabolism* ; Oxygen/metabolism* ; Stress, Physiological

OBJECTIVE: To study the effects of myo-inositol and luteolin on human lung cancer A549 cells and explore the possible mechanisms. METHODS: A549 cells were treated with different concentrations of myo-inositol and luteolin, either alone or in combination, and the cell viability was examined using MTT assay. A549 cells and human bronchial epithelial Beas-2B cells were treated for 48 h with 10 mmol/L myo-inositol and 20 μmol/L luteolin, alone or in combination, and the cell proliferation was detected using MTT assay; the colony formation and migration of the cells were examined with colony formation assay and wound healing assay, respectively. The protein expression levels in A549 cells were detected using Western blotting. RESULTS: Both myo-inositol and luteolin could dose-dependently inhibit the viability of A549 cells. Treatments with 10 mmol/L myo-inositol, 20 μmol/L luteolin, and both for 48 h caused significant reduction in the cell viability (92%, 83% and 70% of the control level, respectively) and colony number (79%, 73% and 43%, respectively), and significantly lowered the wound closure rate (24.61%, 13.08% and 8.65%, respectively, as compared with 29.99% in the control group). Similar treatments with myoinositol and luteolin alone or in combination produced no significant inhibitory effect on the growth, colony formation or migration of Beas-2B cells. The expressions of p-PDK1 and p-Akt in myo-inositol-treated A549 cells and the expression of pPDK1 in luteolin-treated cells were significantly decreased ( < 0.05), and the decrements were more obvious in the combined treatment group ( < 0.05). CONCLUSIONS Luteolin combined with myo-inositol can selectively inhibit the proliferation and migration of A549 cells, and these effects are probably mediated, at least in part, by suppressing the activation of PDK1 and Akt.
A549 Cells ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Humans ; Inositol ; administration & dosage ; therapeutic use ; Lung Neoplasms ; drug therapy ; metabolism ; Luteolin ; administration & dosage ; therapeutic use ; Protein-Serine-Threonine Kinases ; drug effects ; metabolism ; Proto-Oncogene Proteins c-akt ; drug effects ; metabolism ; Vitamin B Complex

OBJECTIVETo study the regulation of luteolin on spleen cells and sarcoma S180 cells in normal ICR mice.

METHODSSpleen cells and S180 cells were incubated with different concentrations of luteolin (50, 100, 200, and 400 μmol/L). The effect of luteolin on spleen cells and sarcoma S180 cells was determined by MTT assay. The apoptosis was detected using propidium iodide staining flow cytometry. Intracellular reactive oxygen species (ROS) was determined by flow cytometric analysis. Activities of free radicals scavenging were determined by hydroxyl radical and DPPH tests.

RESULTSCompared with the solvent control group, 200 and 400 μmol/L luteolin increased the spleen cells viability (P < 0.05). Luteolin at 100, 200, and 400 μmol/L decreased activities of S180 cells (P < 0.01). The proportion of sub-G1 phase spleen cells was reduced after treated with 200 and 400 μmol/L luteolin (P < 0.05). The proportion of sub-G1 phase S180 cells was elevated after treated with 200 and 400 μmol/L luteolin (P < 0.05). Compared with the solvent control group, levels of intracellular ROS in spleen cells of ICR mice all increased; levels of intracellular ROS in S180 cells all decreased after treated with 50, 100, 200, and 400 μmol/L luteolin (P < 0.05). Luteolin scavenged hydroxyl radical and DPPH in a dose dependent manner.

CONCLUSIONLuteolin had bilateral regulation on viability and apoptosis of spleen cells and S180 cells (promoting the viability of spleen cells, inhibiting apoptosis of spleen cells, inhibiting the viability of S180 cells, and promoting apoptosis of S180 cells), which was worth further study and exploration.

Animals ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Cell Survival ; Luteolin ; metabolism ; Mice ; Mice, Inbred ICR ; Reactive Oxygen Species ; Sarcoma ; Spleen ; metabolism

This study analysed the tissue specific expression of critical genes involved in chlorogenic acid and luteolin biosynthesis, for exploiting the molecular mechanism of components biosynthesis in Lonicera confusa. Expression of PAL, 4CL, C4H, CHS, CHI, FNS and HQT gene families of chlorogenic acid and luteolin biosynthesis-related genes in buds and leaves of L. confusa were analyed by Real-time PCR. Expressions of PAL1, C4H1, 4CL1, CHS1, CHI3 and HQT2 in buds were lower than that in leaves, and expressions of PAL3, 4CL2, CHI2 and FNS2 in buds were higher than that in leaves. The results indicated that that PAL3 and 4CL2 may be associated with accumulation of chlorogenic acid, and the expression patterns of PAL1, CHS1, CHI3 and HQT2 in buds and leaves of L. confusa were different with L. japonica. This study provided some theoretical basis for the further research on genetic mechanism of active components differences in L. confusa and L. japonica.
Biosynthetic Pathways ; Chlorogenic Acid ; metabolism ; Gene Expression Regulation, Plant ; Lonicera ; genetics ; metabolism ; Luteolin ; biosynthesis ; Multigene Family ; Plant Proteins ; genetics ; metabolism

OBJECTIVETo investigate the effect of luteolin on cell growth and apoptosis of HepG2 cells in vitro.

METHODSCultured HepG2,HL60,A549 and LO2 cells were treated with luteolin for different doses (0 μg/ml,2.5 μg/ml,10 μg/ml and 20 μg/ml) and varied times (0 h,24 h,48 h and 72 h). Cell viability was measured with MTT assay and IC50 was calculated. The reactive oxygen species (ROS) levels in HepG2 cells treated with luteolin for 6 h and 12 h were measured with flow cytometry. Cell apoptosis of HepG2 cells treated with luteolin for 24h was examined with flow cytometry and Annexin V-FITC/PI. Expression levels of apoptosis pathway proteins (p53,ASPP2 and iASPP) in HepG2 cells were detected with western blot and the dose and time-effect was analyzed.

RESULTSLuteolin effectively inhibited tumor cell proliferation in a dose-and time-dependent manner,and the inhibition rates of 20 μg/ml Luteolin for 72 h were 39.34%,62.90%,57.57% and 62.90% to LO2,HepG2, HL60 and A549 cells,respectively. The intracellular ROS level was decreased in HepG2 cells by 13.88% and 41.11% after being treated with luteolin for 6 h and 12 h,respectively. The apoptosis rate of HepG2 cells treated with luteolin for 24 h was 14.43%,and western blot showed that luteolin reduced the expression level of iASPP by 77.07% and up-regulated the expression of p53 by 179.37% and ASPP2 by 725.02% in HepG2 cells treated with luteolin for 12 h.

CONCLUSIONLuteolin has ant-proliferative and pro-apoptotic activity on hepatoma HepG2 cells, which is associated with the altered expression of pro-apoptotic factors and decreased ROS level in HepG2 cells.

Apoptosis ; drug effects ; Hep G2 Cells ; Humans ; Luteolin ; administration & dosage ; pharmacology ; Reactive Oxygen Species ; metabolism