Luteolin attenuate thed-galactose-induced renal damage by attenuation of oxidative stress and inflammation

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/β-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.

L-theanine protects rat kidney from D-galactose-induced injury via inhibition of the AGEs/RAGE signaling pathway

As the irreversible products of the non-enzymatic reduction of sugars and the amino groups of proteins or peptides, advanced glycation end products (AGEs) are metabolized and excreted via the kidneys. However, if AGEs are not metabolized, they are deposited in the kidneys and bind to AGE receptors (RAGE), which can induce various pathological changes, including oxidative stress, apoptosis, and inflammation. This study used the D-galactose (DG)-induced rat model to explore the potential role and mechanism of L-theanine in inhibiting AGEs/RAGE-related signaling pathways in renal tissues. L-theanine increased the activities of glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) while downregulating the contents of malondialdehyde (MDA) and AGEs in renal tissues induced by DG (P < 0.05). By inhibiting the upregulation of RAGE protein expression attributed to AGEs accumulation (P < 0.05), L-theanine downregulated phosphorylated nuclear factor (p-NF-κB (p65)), Bax, and cleaved-caspase-3 expression and increased Bcl-2 protein expression (P < 0.05), thereby alleviating the oxidative stress damage and reducing the inflammation and cell injury induced by DG. In addition, the Congo red staining section of renal tissue also showed that the natural product L-theanine can protect against AGEs-induced renal damage in DG-induced rat model.

Luteolin attenuates angiotensin II‑induced renal damage in apolipoprotein E‑deficient mice

Renal damage is a common and severe condition encountered in the clinic. Luteolin (Lut) exhibits anti-inflammatory, anti-fibrotic and anti-apoptotic effects. Thus, the present study aimed to investigate the pharmacological effects of Lut on angiotensin II (AngII)-induced renal damage in apolipoprotein E-deficient (ApoE^−/−) mice. Male ApoE^−/− mice (age, 8 weeks) were randomly divided into the following three groups: i) Control group (n=6); ii) AngII group (n=6); and iii) AngII + Lut group (n=6). Lut was administered by gavage (100 mg/kg/d). ApoE^−/− mice were implanted with Alzet osmotic minipumps, filled with either saline vehicle or AngII solution for a maximum period of 4 weeks. After 4 weeks, metabolic characteristics were measured and the histopathological alterations in the kidney tissue were observed. The metabolic characteristics of blood creatinine (CRE) levels were lower in the AngII + Lut group compared with in the AngII group. The expression levels of collagen I and III were lower in the kidney tissues of the AngII + Lut group compared with the corresponding tissues of the AngII group. The gene expression levels of IL-1β, IL-6, TNF-α and IL-10 were also suppressed in the kidney tissues of the AngII + Lut group compared with those in the corresponding tissues of the AngII group. Furthermore, the AngII + Lut group exhibited markedly increased LC3 protein expression and notably decreased p62 protein expression in the kidney tissues compared with the expression levels in the AngII group. The data demonstrated that Lut attenuated AngII-induced collagen deposition and inflammation, while inducing autophagy. Collectively, the results suggested that Lut treatment exhibited a exerted effect on AngII-induced renal injury in ApoE^−/− mice.

Luteolin Attenuates Glycerol-Induced Acute Renal Failure and Cardiac Complications Through Modulation of Kim-1/NF-κB/Nrf2 Signaling Pathways

Acute renal failure (ARF) has been documented as a life-threatening disease with high morbidity and mortality. We investigated the protective effect of Luteolin against ARF. In this study, forty-male Wistar albino rats were randomly divided into four groups (n = 10). Group A received normal saline. Group B received glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.). Groups C and D were pretreated with Luteolin 100 and 200 mg/kg for 7 days, and thereafter administered Glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.). Administration of glycerol significantly increased systolic blood pressure, diastolic blood pressure and mean arterial pressure. Renal protein carbonyl and xanthine oxidase increased significantly while significant reduction in the activity of renal glutathione peroxidase, glutathione S-transferase and glutathione reductase was observed in the glycerol intoxicated rats. Furthermore, administration of glycerol led to significant increases in serum creatinine and blood urea nitrogen together with reduction in nitric oxide (NO) bioavailability. Immunohistochemistry revealed that glycerol intoxication enhanced expressions of kidney injury molecule 1, nuclear factor kappa beta and cardiac troponin (CTnI). However, Luteolin pretreatment normalized blood pressure, reduced markers of oxidative stress, renal damage, and improved NO bioavailability. Luteolin also downregulated the expressions of kidney injury molecule 1, nuclear factor kappa beta and cardiac troponin. Together, Luteolin might open a novel therapeutic window for the treatment of acute renal failure and cardiac complication.

RNA-sequencing analysis of the effect of luteolin on methamphetamine-induced hepatotoxicity in rats: a preliminary study

In this study, RNA-sequencing (RNA-seq) was utilized to investigate the effects of luteolin on hepatotoxicity caused by methamphetamine (METH). The rats in METH group were administrated with METH (15 mg/kg, two times per day) via intraperitoneal (i.p.) injections for four consecutive days. The rats in luteolin + METH group were firstly administrated with luteolin (100 mg/kg, once a day) by oral gavage for 3 days before METH treatment. Lueolin attenuated the hepatotoxicity induced by METH via histopathological and biochemical analysis. The results of RNA-seq showed that luteolin could regulate 497 differentially expressed genes (DEGs), and the selected DEGs were mainly enriched in eight pathways, according to KEGG analysis. Furthermore, qRT-PCR was utilized to verify the results of RNA-seq. Six genes were selected as follows: liver enriched antimicrobial peptide 2 (Leap2), fatty acid synthase (Fasn), fatty acid binding protein 5 (Fabp5), patatin like phospholipase domain containing 3 (Pnpla3), myelin basic protein (Mbp) and calmodulin 3 (Calm3). Though because of the design flaws, the luteolin group has not been included, this study demonstrated that luteolin might exert hepato-protective effects from METH via modulation of oxidative phosphorylation, cytochrome P450 and certain signaling pathways.

Luteolin confers renoprotection against ischemia-reperfusion injury via involving Nrf2 pathway and regulating miR320

This work aims to evaluate the renoprotective effect of luteolin on expression of Nrf2 and miR320 in ischemia-reperfusion (I/R) injury in rats. Thirty rats were randomly divided into five groups; control, Luteolin (50 mg/kg), ischemia-reperfusion (I/R), DMSO (0/1%) + I/R and Luteolin+I/R, (n = 6 each). Administration of luteolin and DMSO was carried out by gavage for 3 days before renal I/R. Then, the rats were subjected to bilateral renal ischemia for 45 min and followed by reperfusion for 2 h. All rats were killed and the renal function, histological changes, oxidative stress degree, in all of groups were evaluated. In addition, the effects of luteolin on renal expression of Nrf2 and miR320 were examined by immunohistochemistry and real time- PCR. Luteolin significantly improved the creatinine (Cr) and blood urea nitrogen (BUN) levels in Luteolin + I/R group compared to I/R group (p < 0.001 and p < 0.001 respectively). Reduction of enzymatic activity of superoxide dismutase, glutathione peroxidase and catalase in I/R and DMSO + I/R groups, was significantly improved by Luteolin (p < 0.05) in Luteolin + I/R group. Pre-treatment with luteolin also resulted in significant reduction in tissue MDA level (p < 0.001), Nrf2 (p < 0.001) and miR320 expression (P < 0.05) that were increased by renal I/R. Also, the rats pretreated with luteolin had nearly normal structure of the kidney. These results indicate that luteolin protects the kidney against I/R injury via reducing oxidative stress, increasing antioxidant enzymes and reducing expression of Nrf2 and miR320.

Application of Herbal Traditional Chinese Medicine in the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) is a clinical syndrome characterized by a rapid loss of renal function, which may further develop into chronic kidney damage (CKD) or even end-stage renal disease (ESRD). AKI is a global health problem associated with high morbidity and costly treatments, and there is no specific or effective strategy to treat AKI. In recent years, Traditional Chinese Medicine (TCM) has attracted more attention, with lines of evidence showing that application of TCM improved AKI, and the mechanisms of action for some TCMs have been well illustrated. However, reviews summarizing the progress in this field are still lacking. In this paper, we reviewed TCM preparations and TCM monomers in the treatment of AKI over the last 10 years, describing their renal protective effects and mechanisms of action, including alleviating inflammation, programmed cell death, necrosis, and reactive oxygen species. By focusing on the mechanisms of TCMs to improve renal function, we provide effective complementary evidence to promote the development of TCMs to treat AKI. Moreover, we also summarized TCMs with nephrotoxicity, which provides a more comprehensive understanding of TCMs in the treatment of AKI. This review may provide a theoretical basis for the clinical application of TCMs in the future.

Anti-inflammatory effects of luteolin: A review of in vitro, in vivo, and in silico studies

ETHNOPHARMACOLOGICAL RELEVANCE

Luteolin (3', 4', 5,7-tetrahydroxyflavone) has been identified as commonly present in plants. Plants with a high luteolin content have been used ethnopharmacologically to treat inflammation-related symptoms. Both isolated luteolin and extracts from luteolin-rich plants have been studied using various models and exhibited anti-inflammatory activity.

AIM OF THE REVIEW

This paper uses recent research findings with a broad range of study models to describe the anti-inflammatory activity of luteolin, particularly its mechanisms at the molecular level; provide guidance for future research; and evaluate the feasibility of developing luteolin into an anti-inflammatory drug.

MATERIALS AND METHODS

We summarize reports about the anti-inflammatory activity of luteolin published since 2009, which we found in MEDLINE/PubMed, Scopus, Web of Knowledge, and Google Scholar. To acquire broad information, we extended our search to online FDA documents.

RESULTS

Luteolin is a flavonoid commonly found in medicinal plants and has strong anti-inflammatory activity in vitro and in vivo. Some of its derivatives, such as luteolin-7-O-glucoside, have also shown anti-inflammatory activity. The action mechanism of luteolin varies, but Src in the nuclear factor (NF)-κB pathway, MAPK in the activator protein (AP)- 1 pathway, and SOCS3 in the signal transducer and activator of transcription 3 (STAT3) pathway are its major target transcription factors. A clinical trial with a formulation containing luteolin showed excellent therapeutic effect against inflammation-associated diseases.

CONCLUSION

In silico, in vitro, in vivo, and clinical studies strongly suggest that the major pharmacological mechanism of luteolin is its anti-inflammatory activity, which derives from its regulation of transcription factors such as STAT3, NF-κB, and AP-1. Much work remains to ensure the safety, quality, and efficacy of luteolin before it can be used to treat inflammation-related diseases in humans.

Angelica sinensis Supercritical Fluid CO2 Extract Attenuates D-Galactose-Induced Liver and Kidney Impairment in Mice by Suppressing Oxidative Stress and Inflammation

Angelica sinensis (AS, Danggui in Chinese) is an important herbal component of various traditional formulae for the management of asthenia and its tonic effects. Although AS has been shown to ameliorate cognitive damage and nerve toxicity in D-galactose (D-gal)-elicited senescent mice brain, its effects on liver and kidney injury have not yet been explored. In this work, mice were subjected to hypodermic injection with D-gal (200 mg/kg) and orally gavaged with AS (20, 40, or 80 mg/kg) once a day for 8 successive weeks. Results revealed that AS significantly improved liver and kidney function as assessed by organ index and functional parameters. In addition, AS pretreatment effectively ameliorated the histological deterioration. AS attenuated the MDA level and markedly enhanced the activities and gene expressions of antioxidative enzymes, namely Cu, Zn-SOD, CAT, and GPx. Furthermore, AS markedly inhibited the D-gal-mediated increment of expressions of inflammatory cytokines iNOS, COX-2, IκBα, p-IκBα, and p65 and promoted the IκBα expression level in both hepatic and renal tissues. In sum, AS pretreatment could effectively guard the liver and kidney of mice from D-gal-induced injury, and the underlying mechanism was deemed to be intimately related to attenuating oxidative response and inflammatory stress.

Luteolin Treatment Protects against Renal Ischemia-Reperfusion Injury in Rats

Renal ischemia-reperfusion (I/R) injury is a common but severe scientific problem. Luteolin has great anti-inflammatory and antioxidant effects. In this study, we studied the effect of luteolin on renal I/R injury in rats. Intragastric administration of luteolin or saline was performed in Sprague-Dawley rats before (40 mg/kg for three days) and after (one day) renal I/R modeling. Kidney and blood samples were harvested to detect the severity of renal injury 24 hours after operation. The results showed that luteolin-treated rats exhibited milder histomorphological changes with lower scores of renal histological lesions; lower blood urea nitrogen and creatinine levels; lower renal malondialdehyde (MDA), 8-oxo-deoxyguanosine (8-OHdG), and myeloperoxidase (MPO) levels; and higher superoxide dismutase (SOD) and catalase (CAT) activities in the kidney. Luteolin attenuated the increased levels of serum and renal tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, renal high mobility group box-1 (HMGB1), and nuclear factor kappa β (NF-κB) expression levels in I/R rats. Furthermore, luteolin treatment significantly reduced renal cell apoptosis and endoplasmic reticulum (ER) stress caused by renal I/R injury. In conclusion, luteolin improved renal function in I/R rats by reducing oxidative stress, neutrophil infiltration, inflammation, renal cell apoptosis, and expression of HMGB1 and NF-κB, and ER stress.

Luteolin, a novel p90 ribosomal S6 kinase inhibitor, suppresses proliferation and migration in leukemia cells

Ribosomal S6 kinases (RSKs) are directly regulated by extracellular signal-regulated kinase (ERK) signaling and are implicated in cell growth, survival, motility and senescence. The present study observed that RSK1 was overexpressed in primary untreated leukemia patient bone marrow samples compared with the expression at the complete remission stage, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, a high RSK1 expression (relative expression ≥10) was associated with a significantly shorter overall survival (P=0.038) compared with that in patients with low RSK1 expression (relative expression <10). The current study also investigated the effect of luteolin, a novel p90 ribosomal S6 kinase (RSK) inhibitor extracted from Reseda odorata L., which shows strong biochemical functions including anti-allergy, anti-inflammation and anti-cancer functions, in MOLM-13 and Kasumi-1 leukemic cells. The cell viability, apoptosis and migration ability analysis were assessed by performing a cell counting kit-8 assay, Annexin V-FITC/PI double staining and migration filter assay, respectively. The results indicated that luteolin inhibited the growth of the leukemic cell lines through induction of apoptosis, while the migration ability was also suppressed. Overexpression of RSK1 by plasmid transfection was found to decrease the luteolin-induced apoptosis and migration capabilities. By contrast, knockdown of the RSK1 expression by small interfering RNA appeared to induce the same effect as luteolin on MOLM-13 and Kasumi-1 leukemic cells. In conclusion, these results suggest that luteolin inhibits leukemic cell proliferation and induces apoptosis by inhibition of the RSK1 pathways.

Protective Effects of Luteolin on Lipopolysaccharide-Induced Acute Renal Injury in Mice

Background

Sepsis can cause serious acute kidney injury in bacterium-infected patients, especially in intensive care patients. Luteolin, a bioactive flavonoid, has renal protection and anti-inflammatory effects. This study aimed to investigate the effect and underlying mechanism of luteolin in attenuating lipopolysaccharide (LPS)-induced renal injury.

Material/Methods

ICR mice were treated with LPS (25 mg/kg) with or without luteolin pre-treatment (40 mg/kg for three days). The renal function, histological changes, degree of oxidative stress, and tubular apoptosis in these mice were examined. The effects of luteolin on LPS-induced expression of renal tumor necrosis factor-α (TNF-α), NF-κB, MCP-1, ICAM-1, and cleaved caspase-3 were evaluated.

Results

LPS resulted in rapid renal damage of mice, increased level of blood urea nitrogen (BUN), and serum creatinine (Scr), tubular necrosis, and increased oxidative stress, whereas luteolin pre-treatment could attenuate this renal damage and improve the renal functions significantly. Treatment with LPS increased TNF-α, NF-κB, IL-1β, cleaved caspase-3, MCP-1, and ICAM-1 expression, while these disturbed expressions were reversed by luteolin pre-treatment.

Conclusions

These results indicate that luteolin ameliorates LPS-mediated nephrotoxicity via improving renal oxidant status, decreasing NF-κB activation and inflammatory and apoptosis factors, and then disturbing the expression of apoptosis-related proteins.

Evidence of oxidative stress in brain and liver of young rats submitted to experimental galactosemia

Galactosemia is a disorder of galactose metabolism, leading to the accumulation of this carbohydrate. Galactosemic patients present brain and liver damage. For evaluated oxidative stress, 30-day-old males Wistar rats were divided into two groups: galactose group, that received a single injection of this carbohydrate (5 μmol/g), and control group, that received saline 0.9 % in the same conditions. One, twelve or twenty-four hours after the administration, animals were euthanized and cerebral cortex, cerebellum, and liver were isolated. After one hour, it was found a significant increase in TBA-RS levels, nitrate and nitrite and protein carbonyl contents in cerebral cortex, as well as protein carbonyl content in the cerebellum and in hepatic level of TBA-RS, and a significant decrease in nitrate and nitrite contents in cerebellum. TBA-RS levels were also found increased in all studied tissues, as well as nitrate and nitrite contents in cerebral cortex and cerebellum, that also present increased protein carbonyl content and impairments in the activity of antioxidant enzymes of rats euthanized at twelve hours. Finally, animals euthanized after twenty-four hours present an increase of TBA-RS levels in studied tissues, as well as the protein carbonyl content in cerebellum and liver. These animals also present an increased nitrate and nitrite content and impairment of antioxidant enzymes activities. Taken together, our data suggest that acute galactose administration impairs redox homeostasis in brain and liver of rats.

Luteolin and apigenin activate the Oct-4/Sox2 signal via NFATc1 in human periodontal ligament cells

Identifying small molecules to activate the Oct-4/Sox2-derived pluripotency network represents a hopeful and safe method to pluripotency without genetic manipulation. Luteolin and apigenin, two major bioactive flavonoids, enhance reprogramming efficiency and increase expression of Oct-4/Sox2/c-Myc, albeit the detailed mechanism regulating pluripotency in dental-derived cells remains unknown. In the present study, to elucidate the effect of luteolin/apigenin on pluripotency of periodontal ligament cells (PDLCs) through interaction with downstream signals, we examined cell cycle, proliferation, apoptosis, expression of Oct-4/Sox2/c-Myc, and multilineage differentiation of PDLCs with luteolin/apigenin treatment. Moreover, we profiled the differentially expressed pluripotency genes by PCR arrays. Our results demonstrated that luteolin/apigenin restrained cell proliferation, increased apoptosis, and arrested PDLCs in G2/M and S phase. Luteolin and apigenin activated expression of Oct-4, Sox2, and c-Myc in a time- and dose-dependent pattern, and repressed lineage-specific differentiation. PCR arrays profiled multiple signals in PDLCs with luteolin/apigenin treatment, among which NFATc1 was the major upregulated gene. Notably, blocking of the NFATc1 signal with INCA-6 significantly decreased mRNA and protein expression of Oct-4, Sox2, and c-Myc in PDLCs with luteolin/apigenin treatment, indicating that NFATc1 may act as an upstream modulator of Oct-4/Sox2 signal. Taken together, this study showed that luteolin and apigenin effectively maintain pluripotency of PDLCs through activation of Oct-4/Sox2 signal via NFATc1.

Bioactive Compounds and Their Neuroprotective Effects in Diabetic Complications

Hyperglycemia, hyperlipidemia and impaired insulin signaling during the development of diabetes can cause diabetic complications, such as diabetic neuropathy, resulting in significant morbidity and mortality. Although various therapeutics are available for the treatment of diabetic neuropathy, no absolute cure exists, and additional research is necessary to comprehensively understand the underlying pathophysiological pathways. A number of studies have demonstrated the potential health benefits of bioactive compounds, i.e., flavonoids and vitamins, which may be effective as supplementary treatments for diabetes and its complications. In this review, we highlight the most recent reports about the mechanisms of action of bioactive compounds (flavonoids and vitamins) possessing potential neuroprotective properties in diabetic conditions. Additional clinical studies are required to determine the appropriate dose and duration of bioactive compound supplementation for neuroprotection in diabetic patients.

Luteolin Prevents H2O2-Induced Apoptosis in H9C2 Cells through Modulating Akt-P53/Mdm2 Signaling Pathway

Introduction. Luteolin, a falconoid compound in many Chinese herbs and formula, plays important roles in cardiovascular diseases. The underlying mechanism of luteolin remains to be further elaborated. Methods. A model of hydrogen peroxide- (H₂O₂-) induced H9C2 cells apoptosis was established. Cell viabilities were examined with an MTT assay. 2′,7′-Dichlorofluorescin diacetate (DCFH-DA) and flow cytometry were used to detect ROS level and apoptosis rate, respectively. The expressions of signaling proteins related to apoptosis were analyzed by western blot and mRNA levels were detected by real-time polymerase chain reaction (PCR). Quercetin was applied as positive drug. Results. Incubation with various concentrations of H₂O₂ (0, 50, 100, and 200 μM) for 1 h caused dose-dependent loss of cell viability and 100 μM H₂O₂ reduced the cell viability to approximately 50%. Treatments with luteolin and quercetin protected cells from H₂O₂-induced cytotoxicity and reduced cellular ROS level and apoptosis rate. Moreover, luteolin could downregulate the expressions of Bax, caspase-8, cleaved-caspase-3, and p53 in apoptotic signaling pathway. Further study showed that the expressions of Akt, Bcl-2, and Mdm2 were upregulated by luteolin. Conclusion. Luteolin protects H9C2 cells from H₂O₂-induced apoptosis. The protective and antiapoptotic effects of luteolin could be mediated by regulating the Akt-P53/Mdm2 apoptotic pathway.