AMPK activation by isorhamnetin protects hepatocytes against oxidative stress and mitochondrial dysfunction

Deoxynivalenol exposure-related male reproductive toxicity in mammals: Molecular mechanisms, detoxification and future directions

An increasing body of evidence indicates that exposure to widespread, environmental and food contaminants such as mycotoxins may cause endocrine disorders and infertility. Deoxynivalenol (DON), which is a toxic secondary metabolite produced by Fusarium fungi, can lead to multiple harmful effects in humans and animals, such as hepatotoxicity, nephrotoxicity, immunotoxicity, gastrointestinal toxicity, neurotoxicity, genetic toxicity and carcinogenicity. Recently, there has been growing concern about DON-induced male infertility. Exposure to DON and its metabolites can damage the structure and function of male reproductive organs, resulting in impairment of gametogenesis and thus impaired fertility. Potential molecular mechanisms involve oxidative stress, inflammatory response, mitochondrial dysfunction, apoptosis, cell cycle arrest, pyroptosis, and ferroptosis. Moreover, several signaling pathways, including nuclear factor-kappa B, mitogen-activated protein kinase, NLR family pyrin domain containing 3, nuclear factor erythroid 2-related factor 2, AMP-activated protein kinase, mitochondrial apoptotic pathways, and microRNAs are involved in these detrimental biological processes. Research has shown that several antioxidants, small-molecule inhibitors, or proteins (such as lactoferrin) supplementation can potentially offer protective effects by targeting these signaling pathways. This review comprehensively summarizes the harmful effects of DON exposure on male reproductive function in mammals, the underlying molecular mechanisms and emphasizes the potential of several small molecules as protective therapeutics. In the further, the systematic risk assessment when DON at environmental exposure doses to human reproductive health, the in-depth and precise molecular mechanism investigation using emerging technologies, and the development of more effective intervention strategies warrant urgent investigation.

Investigating the role of the AMPK signaling pathway in preventing CCI-induced neuropathy in rats: focus on anti-inflammatory effects

OBJECTIVE

It has been shown that the AMPK signaling pathway helps maintain the structure of nerve cells and prevent damage caused by hypoxia by preserving the energy available in these cells. This signaling pathway is activated by various drugs, including metformin.

METHODS

In this study, thirty male rats were randomly divided into healthy rats, CCI (chronic constriction injury), CCI + metformin, CCI + dorsomorphin, and CCI + metformin + dorsomorphin groups. Behavioral tests were performed on the third, seventh, and fourteenth days after the induction of CCI. On the last day, the inflammatory cytokines and pathology were investigated after dissecting the spinal cords and sciatic nerves of the animals, respectively.

RESULTS

The results of this study indicated that metformin could improve performance in behavioral tests and reduce the levels of inflammatory cytokines. Histological analyses further revealed that metformin could decrease inflammation and necrosis in sciatic nerve tissue. Notably, this effect was observed despite dorsomorphin injection, which prevented the therapeutic effects of metformin in the fifth group.

CONCLUSION

The results of this study indicated that stimulation of the AMPK signaling pathway could effectively preserve the structure of the sciatic nerve, reduce inflammation, and improve responses to behavioral tests.

A novel peptide derived from Haematococcus pluvialis residue balanced lipid metabolism through NHR-49/PPARα and AAK-2/AMPK pathways in Caenorhabditis elegans

To explore the potential value of Haematococcus pluvialis residue after astaxanthin extraction, a novel peptide (HPp) was identified as a bioactive component. However, the possible lipid-lowering effect in vivo remains unclear. Thus, the classic model of Caenorhabditis elegans (C. elegans) was employed to evaluate the anti-obesity effects and underlying mechanism. The results showed that 100 μM HPp significantly reduced the overall fat and triglyceride contents, while also remarkably decreasing the lipid droplets size and promoting desaturation of C18:0 to C18:1n9. Subsequent analysis indicated that HPp increased energy expenditure and alleviated intestinal distension. Further molecular research revealed that HPp activated the gene expression of fat-6, fat-7, nhr-49, acs-2, aak-2, atgl-1. Notably, the lipid-lowering effects were abolished in fat-6, fat-7, nhr-49 mutants, and further verified in GFP-tagged nematodes, indicating that HPp balanced lipid metabolism by activating NHR-49/PPARα and AAK-2/AMPK pathways in C. elegans. These findings highlight the high-value applications of marine microalgae.

Isorhamnetin as a potential therapeutic agent for diabetes mellitus through PGK1/AKT activation

CONTEXT

Type 2 Diabetes Mellitus (T2D) is a significant health concern worldwide, necessitating novel therapeutic approaches beyond conventional treatments.

OBJECTIVE

To assess isorhamnetin's potential in improving insulin sensitivity and mitigating T2D characteristics through oxidative and glycative stress modulation.

MATERIALS AND METHODS

T2D was induced in mice with a high-fat diet and streptozotocin injections. Isorhamnetin was administered at 10 mg/kg for 12 weeks. HepG2 cells were used to examine in vitro effects on stress markers and insulin sensitivity. Molecular effects on the PGK1 and AKT signalling pathway were also analyzed.

RESULTS

The administration of isorhamnetin significantly impacted both in vivo and in vitro models. In HepG2 cells, oxidative and glycative stresses were markedly reduced, indicating a direct effect of isorhamnetin on cellular stress pathways, which are implicated in the deterioration of insulin sensitivity. Specifically, treated cells showed a notable decrease in markers of oxidative stress, such as malondialdehyde, and advanced glycation end products, highlighting isorhamnetin's antioxidant and antiglycative properties. In vivo, isorhamnetin-treated mice exhibited substantially lower fasting glucose levels compared to untreated T2D mice, suggesting a strong hypoglycemic effect. Moreover, these mice showed improved insulin responsiveness, evidenced by enhanced glucose tolerance and insulin tolerance tests. The molecular investigation revealed that isorhamnetin activated PGK1, leading to the activation of the AKT signalling pathway, crucial for promoting glucose uptake and reducing insulin resistance. This molecular action underscores the potential mechanism through which isorhamnetin exerts its beneficial effects in T2D management.

DISCUSSION

The study underscores isorhamnetin's multifaceted role in T2D management, emphasizing its impact on oxidative and glycative stress reduction and molecular pathways critical for insulin sensitivity.

CONCLUSION

Isorhamnetin presents a promising avenue for T2D treatment, offering a novel approach to enhancing insulin sensitivity and managing glucose levels through the modulation of key molecular pathways. Further research is needed to translate these findings into clinical practice.

Research progress on antitumor effects of sea buckthorn, a traditional Chinese medicine homologous to food and medicine

Sea buckthorn (Hippophae Fructus), as a homologous species of medicine and food, is widely used by Mongolians and Tibetans for its anti-tumor, antioxidant and liver-protecting properties. In this review, the excellent anti-tumor effect of sea buckthorn was first found through network pharmacology, and its active components such as isorhamnetin, quercetin, gallic acid and protocatechuic acid were found to have significant anti-tumor effects. The research progress and application prospect of sea buckthorn and its active components in anti-tumor types, mechanism of action, liver protection, anti-radiation and toxicology were reviewed, providing theoretical basis for the development of sea buckthorn products in the field of anti-tumor research and clinical application.

The Antioxidant Action of Astragali radix: Its Active Components and Molecular Basis

Astragali radix is a traditional medicinal herb with a long history and wide application. It is frequently used in prescriptions with other medicinal materials to replenish Qi. According to the classics of traditional Chinese medicine, Astragali radix is attributed with properties such as Qi replenishing and surface solidifying, sore healing and muscle generating, and inducing diuresis to reduce edema. Modern pharmacological studies have demonstrated that some extracts and active ingredients in Astragali radix function as antioxidants. The polysaccharides, saponins, and flavonoids in Astragali radix offer beneficial effects in preventing and controlling diseases caused by oxidative stress. However, there is still a lack of comprehensive research on the effective components and molecular mechanisms through which Astragali radix exerts antioxidant activity. In this paper, we review the active components with antioxidant effects in Astragali radix; summarize the content, bioavailability, and antioxidant mechanisms; and offer a reference for the clinical application of Astragalus and the future development of novel antioxidants.

Hepatoprotective Effects of Flavonoids against Benzo[a]Pyrene-Induced Oxidative Liver Damage along Its Metabolic Pathways

Benzo[a]pyrene (B[a]P), a highly carcinogenic polycyclic aromatic hydrocarbon primarily formed during incomplete organic matter combustion, undergoes a series of hepatic metabolic reactions once absorbed into the body. B[a]P contributes to liver damage, ranging from molecular DNA damage to the onset and progression of various diseases, including cancer. Specifically, B[a]P induces oxidative stress via reactive oxygen species generation within cells. Consequently, more research has focused on exploring the underlying mechanisms of B[a]P-induced oxidative stress and potential strategies to counter its hepatic toxicity. Flavonoids, natural compounds abundant in plants and renowned for their antioxidant properties, possess the ability to neutralize the adverse effects of free radicals effectively. Although extensive research has investigated the antioxidant effects of flavonoids, limited research has delved into their potential in regulating B[a]P metabolism to alleviate oxidative stress. This review aims to consolidate current knowledge on B[a]P-induced liver oxidative stress and examines the role of flavonoids in mitigating its toxicity.

Forsythiaside A Activates AMP-Activated Protein Kinase and Regulates Oxidative Stress via Nrf2 Signaling

Forsythiaside A (FA) is an active constituent isolated from Forsythia suspensa, a beneficial herb used in traditional medicine known for its antioxidant and anti-inflammatory properties. Although various studies have suggested that FA has the protective effects, its impacts on arachidonic acid (AA) plus iron in vitro models and carbon tetrachloride (CCl₄)-induced mouse liver damage in vivo have not been explored. In this study, HepG2 cells were subjected to AA + iron treatment to induce apoptosis and mitochondrial impairment and determine the molecular mechanisms. FA exhibited protective effects by inhibiting cell damage and reactive oxygen species (ROS) production induced by AA + iron, as assessed via immunoblot and flow cytometry analyses. Further molecular investigations revealed that FA resulted in the activation of extracellular-signal-related protein kinase (ERK), which subsequently triggered the activation of AMP-activated protein kinase (AMPK), a critical regulator of cellular oxidative stress. Additionally, FA modulated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, which is a significant antioxidant transcription factor regulated by the AMPK pathway. For in vivo studies, mice were orally administered FA and then subjected to induction of CCl₄-based hepatotoxicity. The protective effect of FA was confirmed via blood biochemistry and immunohistochemical analyses. In conclusion, our findings demonstrated the protective effects of FA against oxidative stress both in vitro and in vivo, thus indicating that FA is a potential candidate for liver protection. Our study sheds light on the mechanistic pathways involved in the antioxidant effects of FA, highlighting the hepatoprotective potential of naturally occurring compounds in traditional herbs, such as FA.

CaMKK2 alleviates myocardial ischemia/reperfusion injury by inhibiting oxidative stress and inflammation via the action on the AMPK-AKT-GSK-3β/Nrf2 signaling cascade

OBJECTIVE

Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) can regulate numerous biological processes and is implicated in diverse pathological processes. Yet its role in myocardial ischemia/reperfusion (MI/R) injury remains unknown. This project explored the possible functions and mechanisms of CaMKK2 in MI/R injury.

METHODS

A rat model of MI/R in vivo was established using the left anterior descending coronary artery ligation method. Rat cardiomyocytes were exposed to hypoxia/reoxygenation (H/R) in vitro to establish a cell model. Overexpression of CaMKK2 was achieved by infecting recombinant adeno-associated virus or adenovirus expressing CaMKK2. Real-time quantitative PCR, immunoblotting, TTC staining, TUNEL assay, ELISA, oxidative stress detection assays, flow cytometry, and CCK-8 assay were carried out.

RESULTS

A decline in CaMKK2 levels was induced by MI/R in vivo or H/R in vitro. Up-modulation of CaMKK2 in rats ameliorated the cardiac injury evoked by MI/R injury accompanied by suppression of cardiac apoptosis, oxidative stress, and proinflammatory response. Rat cardiomyocytes with CaMKK2 overexpression were also protected from H/R damage by inhibiting apoptosis, oxidative stress, and proinflammatory response. CaMKK2 overexpression led to increased phosphorylation of AMPK, AKT, and GSK-3β, and enhanced activation of Nrf2 under MI/R or H/R conditions. Inhibition of AMPK abolished CaMKK2-mediated Nrf2 activation and relevant cardioprotective effect. Restraint of Nrf2 also diminished CaMKK2-mediated relevant cardioprotective effect.

CONCLUSIONS

Up-regulation of CaMKK2 provides a therapeutic benefit in the rat model of MI/R injury by boosting the Nrf2 pathway through regulation of AMPK/AKT/GSK-3β, which suggests CaMKK2 as a new molecular target for the treatment of MI/R injury.

Patulin alleviates hepatic lipid accumulation by regulating lipogenesis and mitochondrial respiration

AIMS

The aim of this study is to evaluate the effects of patulin on hepatic lipid metabolism and mitochondrial oxidative function and elucidate the underlying molecular mechanisms.

MAIN METHODS

The effects of patulin on hepatic lipid accumulation were evaluated in free fatty acid-treated AML12 or HepG2 cells through oil red O staining, triglyceride assay, real-time polymerase chain reaction, and western blotting. Alteration of mitochondrial oxidative capacity by patulin treatment was determined using Seahorse analysis to measure the oxygen consumption rate.

KEY FINDINGS

The increased amounts of lipid droplets induced by free fatty acids were significantly reduced by patulin treatment. Patulin markedly activated the CaMKII/AMP-activated protein kinase (AMPK)/proliferator-activated receptor-γ coactivator (PGC)-1α signaling pathway in hepatocytes, reduced the expression of sterol regulatory element binding protein 1c (SREBP-1c) and lipogenic genes, and increased the expression of genes related to mitochondrial fatty acid oxidation. In addition, patulin treatment enhanced the mitochondrial consumption rate and increased the expression of mitochondrial oxidative phosphorylation proteins in HepG2 hepatocytes. The effects of patulin on anti-lipid accumulation; SREBP-1c, PGC-1α, and carnitine palmitoyltransferase 1 expression; and mitochondrial oxidative capacity were significantly prevented by compound C, an AMPK inhibitor.

SIGNIFICANCE

Patulin is a potent inducer of the AMPK pathway, and AMPK-mediated mitochondrial activation is required for the efficacy of patulin to inhibit hepatic lipid accumulation. This study is the first to report that patulin is a promising bioactive compound that prevents the development and worsening of fatty liver diseases, including non-alcoholic fatty liver disease, by improving mitochondrial quality and lipid metabolism.

Traditional Chinese medicine monomers: Targeting pulmonary artery smooth muscle cells proliferation to treat pulmonary hypertension

Pulmonary hypertension (PH) is a complex multifactorial disease characterized by increased pulmonary vascular resistance and pulmonary vascular remodeling (PVR), with high morbidity, disability, and mortality. The abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) is the main pathological change causing PVR. At present, clinical treatment drugs for PH are limited, which can only improve symptoms and reduce hospitalization but cannot delay disease progression and reduce survival rate. In recent years, numerous studies have shown that traditional Chinese medicine monomers (TCMs) inhibit excessive proliferation of PASMCs resulting in alleviating PVR through multiple channels and multiple targets, which has attracted more and more attention in the treatment of PH. In this paper, the experimental evidence of inhibiting PASMCs proliferation by TCMs was summarized to provide some directions for the future development of these mentioned TCMs as anti-PH drugs in clinical.

Isorhamnetin protects porcine oocytes from zearalenone-induced reproductive toxicity through the PI3K/Akt signaling pathway

BACKGROUND

Zearalenone (ZEA) widely exists in moldy grains, which seriously destroys the fertility of females. Isorhamnetin, a natural flavonoid, has extensive of pharmacological activities. However, the beneficial effect and the underlying molecular mechanism of isorhamnetin involvement in ZEA-induced porcine oocyte damage have not been investigated.

METHODS

Oocytes were treated with different concentrations of ZEA (3, 5, 8 and 10 μmol/L) and isorhamnetin (5, 10, 20 and 30 μmol/L) for 44 h at 39 ℃. ZEA (5 μmol/L) and isorhamnetin (10 μmol/L) were selected for subsequent studies. Polar body exclusion rate, apoptosis rate and apoptosis related proteins, ROS levels and SOD2 protein, mitochondrial membrane potential and distribution, endoplasmic reticulum distribution and proteins expression, and PI3K, Akt and p-Akt proteins expression of oocytes were detected. In addition, the effect of PI3K antagonist (LY294002) on oocyte nuclear maturation and apoptosis were used to determine the involvement of PI3K/Akt signaling pathway.

RESULTS

Our findings showed that ZEA exposure damaged oocytes and isorhamnetin therapy restored the developmental capability of porcine oocytes. Isorhamnetin promoted polar body extrusion rate to rescue ZEA-induced meiotic arrest in porcine oocytes. Isorhamnetin alleviated ZEA-induced oxidative stress by stimulating SOD2 protein expression and inhibiting ROS production. Moreover, isorhamnetin enhanced normal mitochondrial distribution and mitochondrial membrane potential to prevent mitochondrial dysfunction induced by ZEA. Changing the expression of endoplasmic reticulum stress-related marker proteins (CHOP, GRP78) and the distribution rate of normal endoplasmic reticulum showed that isorhamnetin relieved ZEA-caused endoplasmic reticulum stress. Mechanistically, isorhamnetin decreased Bax/Bcl-2 protein expression and inhibited ZEA-induced apoptosis through PI3K/Akt signaling pathway.

CONCLUSIONS

Collectively, these results suggest that isorhamnetin protects oocytes from ZEA-caused damage through PI3K/Akt signaling pathway, which enhances meiotic maturation and mitochondrial function, and inhibits early apoptosis, oxidative stress and endoplasmic reticulum stress in porcine oocytes. Our study provides a new strategy for solving the reproductive toxicity induced by ZEA and treating woman infertility. A possible mechanism by which isorhamnetin protected porcine oocytes from ZEA-induced damage. Isorhamnetin inhibited meiosis arrest and apoptosis of porcine oocytes induced by ZEA through the PI3K/Akt signaling pathway. Moreover, isorhamnetin repaired ZEA-induced oocyte damage by alleviating oxidative stress, mitochondrial dysfunction and ER stress.

Coordination of AMPK and YAP by Spatholobi Caulis and Procyanidin B2 Provides Antioxidant Effects In Vitro and In Vivo

The liver is vulnerable to oxidative attacks from heavy metals, such as iron, as well as some drugs, including acetaminophen. It has been shown that enhanced oxidative stress in the liver leads to excessive ROS production and mitochondrial dysfunction, resulting in organ injury. The beneficial effects of Spatholobi Caulis (SC), a natural herbal medicine, include treating ischemic stroke, inhibiting tumor cell invasion, pro-angiogenic activities, and anti-inflammatory properties. Scientific studies on its effects against hepatotoxic reagents (e.g., iron and acetaminophen), as well as their underlying mechanisms, are insufficient. This study examined the antioxidant effects and mechanisms of SC in vitro and in vivo. In cells, the proinflammatory mediator, arachidonic acid (AA), plus iron, significantly induced an increase in ROS generation, the damage in mitochondrial membrane potential, and the resulting apoptosis, which were markedly blocked by SC. More importantly, SC affected the activation of AMP-activated protein kinase (AMPK)-related proteins, which were vital to regulating oxidative stress in cells. In addition, SC mediated the expression of Yes-associated protein (YAP)-related proteins. Among the active compounds in SC, the procyanidin B2, but not liquiritigenin, daidzein, and genistein, significantly inhibited the cytotoxicity induced by AA + iron, and activated the LKB1-AMPK pathway. In mice, the oral administration of SC alleviated the elevations of ALT and histological changes by the acetaminophen-induced liver injury. These results reveal the potential of SC and a key bioactive component, procyanidin B2, as antioxidant candidates for hepatoprotection.

Is metformin a possible treatment for diabetic neuropathy?

Metformin is a hypoglycemic drug widely used in the treatment of type 2 diabetes. It has been proven to have analgesic and neuroprotective effects. Metformin can reverse pain in rodents, such as diabetic neuropathic pain, neuropathic pain caused by chemotherapy drugs, inflammatory pain and pain caused by surgical incision. In clinical use, however, metformin is associated with reduced plasma vitamin B12 levels, which can further neuropathy. In rodent diabetes models, metformin plays a neuroprotective and analgesic role by activating adenosine monophosphate-activated protein kinase, clearing methylgloxal, reducing insulin resistance, and neuroinflammation. This paper also summarized the neurological adverse reactions of metformin in diabetic patients. In addition, whether metformin has sexual dimorphism needs further study.

An integrative approach to uncover the components, mechanisms, and functions of traditional Chinese medicine prescriptions on male infertility

Male infertility is a major and growing health problem with an estimated global prevalence of 4.2%. The current therapy is limited by the unknown etiology of MI, emphasizing the critical requirement forward to a more efficient method or medication. Through thousands of years, Traditional Chinese Medicine (TCM) has been shown to be effective in treating MI effectively. However, the components, mechanisms and functions of TCM prescriptions on MI are still obscure, severely limiting its clinical application. In order to discover the molecular mechanism of TCM against MI, our study presents a comprehensive approach integrated data mining, network pharmacology, molecular docking, UHPLC-Q-Orbitrap HRMS, and experimental validation. Here, we begin to acquire 289 clinical TCM prescriptions for MI from a TCM hospital's outpatient department. Then, Core Chinese Materia Medica (CCMM) was then retrieved from the TCM Inheritance Support System (TCMISS), which was utilized to discover the underlying rules and connections in clinical prescriptions. After that, 98 CCMM components and 816 MI targets were obtained from ten distinct databases. Additionally, the network pharmacology methods, including network construction, GO and KEGG pathway enrichment, PPI analysis, were utilized to reveal that kaempferol, quercetin, isorhamnetin, and beta-sitosterol are the core components of CCMM in treating MI. The mechanisms and functions of CCMM against MI are hormone regulation, anti-apoptosis, anti-oxidant stress, and anti-inflammatory. Furthermore, the strong connections between four core components and six key targets were verified using a molecular docking method. Following that, the core components of the CCMM extract were identified using UHPLC-Q-Orbitrap HRMS analysis. Finally, in vivo experiments demonstrated that CCMM and four core components could improve the density, motility, viability of sperm, lecithin corpuscle density, decrease the rate of sperm malformation and testis tissue damage, and regulate the protein expressions of AKT1, MAPK3/1, EGFR, and TNF-α in a mouse model of MI. UHPLC-Q-Orbitrap HRMS analysis and in vivo experiments further validated the results of data mining, network pharmacology, and molecular docking. Our study could uncover the components, mechanisms, and functions of TCM prescriptions against MI and develop a new integrative approach to demonstrate TCM's multi-component, multi-target, and multi-pathway approach to disease treatment.

Therapeutic Potential of Isorhamnetin following Acetaminophen-Induced Hepatotoxicity through Targeting NLRP3/NF-κB/Nrf2

Acetaminophen (APAP)-induced acute liver injury (ALI) is the principal cause of acute liver failure (ALF) in some countries including the United States and with few available treatments. Isorhamnetin is a bioflavonoid that is found in medicinal plants like Hippophae rhamnoides L. and Ginkgo biloba L. with promising potential to regulate inflammatory responses. In this study, we evaluated the possible effect of isorhamnetin in prevention of APAP-induced ALI and analyzed further the involvement of oxidative stress and inflammation-associated factors. Male C57BL/6 mice were given isorhamnetin (25 or 100 mg/kg b.w., p.o.) three times at 48, 24, and 1 h before APAP administration (300 mg/kg b.w., i.p.). Functional indicators of liver injury were measured as well as analysis of oxidative stress- and inflammation-associated indices and liver histopathology was also conducted. Isorhamnetin at the higher dose of 100 mg/kg significantly lowered serum levels of ALT, ALP, and AST in addition to reduction of ROS, TBARS, IL-6, TNFα, NF-kB, NLRP3, caspase 1, and MPO and significantly prevented reduction of GSH, SOD activity, sirtuin 1, and Nrf2. Additionally, isorhamnetin alleviated pathological changes of the liver tissue and suitably reversed NF-kB and Nrf2 immunoreactivity. These findings show protective effect of isorhamnetin against acetaminophen-induced liver injury through reducing oxidative stress, inflammation, and pyroptosis which is attributed to its regulation of NF-kB, Nrf2, NLRP3, and sirtuin 1.

Effects of Isorhamnetin on Diabetes and Its Associated Complications: A Review of In Vitro and In Vivo Studies and a Post Hoc Transcriptome Analysis of Involved Molecular Pathways

Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is characterized by high levels of glycemia and insulinemia due to impaired insulin secretion and insulin sensitivity of the cells, known as insulin resistance. T2DM causes multiple and severe complications such as nephropathy, neuropathy, and retinopathy causing cell oxidative damages in different internal tissues, particularly the pancreas, heart, adipose tissue, liver, and kidneys. Plant extracts and their bioactive phytochemicals are gaining interest as new therapeutic and preventive alternatives for T2DM and its associated complications. In this regard, isorhamnetin, a plant flavonoid, has long been studied for its potential anti-diabetic effects. This review describes its impact on reducing diabetes-related disorders by decreasing glucose levels, ameliorating the oxidative status, alleviating inflammation, and modulating lipid metabolism and adipocyte differentiation by regulating involved signaling pathways reported in the in vitro and in vivo studies. Additionally, we include a post hoc whole-genome transcriptome analysis of biological activities of isorhamnetin using a stem cell-based tool.

A comprehensive review on phytochemicals for fatty liver: are they potential adjuvants?

Non-alcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome and, as such, is associated with obesity. With the current and growing epidemic of obesity, NAFLD is already considered the most common liver disease in the world. Currently, there is no official treatment for the disease besides weight loss. Although there are a few synthetic drugs currently being studied, there is also an abundance of herbal products that could also be used for treatment. With the World Health Organization (WHO) traditional medicine strategy (2014-2023) in mind, this review aims to analyze the mechanisms of action of some of these herbal products, as well as evaluate toxicity and herb-drug interactions available in literature.

Enhanced anti-amnestic effect of donepezil by Ginkgo biloba extract (EGb 761) via further improvement in pro-cholinergic and antioxidative activities

ETHNOPHARMACOLOGICAL RELEVANCE

EGb 761 is a standardized dry extract of Ginkgo biloba L. leaves traditionally used by Eastern Asia and has been associated with beneficial effects on neurodegeneration disorders, including Alzheimer's disease.

AIM OF THE STUDY

Since beneficial interactions between EGb 761 and donepezil have been observed in previous clinical studies, the current study was proposed aiming to further explore related mechanisms from both pharmacokinetics and pharmacodynamics aspects.

MATERIALS AND METHODS

Pharmacodynamic interactions were studied in scopolamine-induced cognitive impairment rats received two-weeks treatment of vehicle, EGb 761 and/or donepezil by the Morris water maze test and ex vivo evaluation of biomarkers of cholinergic transmission and oxidative stress in rat brain. In the meantime, pharmacokinetic profiles of donepezil and bilobalide were obtained and compared among all treatment groups. In addition, impact of the bioavailable EGb 761 components on donepezil brain penetration was evaluated with the hCMEC/D3 cell monolayer model.

RESULTS

Scopolamine-induced rats with co-treatment of EGb 761 and donepezil had significantly improved cognitive function in the Morris water maze test with increased brain levels of superoxide dismutase and decreased brain levels of acetylcholinesterase and malondialdehyde than that with treatment of only EGb 761 or donepezil. Despite such beneficial pharmacodynamics outcomes, the two-week co-treatment of EGb 761 and donepezil did not alter the plasma pharmacokinetics and brain uptake of donepezil or bilobalide, which was further verified in the hCMEC/D3 monolayer model.

CONCLUSION

Co-administration of EGb 761 and donepezil exerted better anti-amnestic effect via further enhanced pro-cholinergic and antioxidative effects of EGb 761 or donepezil in scopolamine-induced cognitive impairment rat without alteration in their systemic/brain exposure.

Curcumin Ameliorated Oxidative Stress and Inflammation-Related Muscle Disorders in C2C12 Myoblast Cells

The purpose of the current study was to investigate antioxidant and anti-inflammatory effects of spray dry powder containing 40% curcumin (CM-SD) in C2C12 myoblast cells. CM-SD increased DPPH radical scavenging activity in a dose-dependent manner, and up to 30 μg/mL of CM-SD did not express cytotoxicity in C2C12 cells. Exposure to hydrogen peroxide (H2O2) drastically decreased the viability of C2C12 cells, but pre-treatment of CM-SD significantly increased the cell viability (p < 0.01). CM-SD significantly transactivated the nuclear factor erythroid-2-related factor 2 (Nrf2)-dependent luciferase activity in a dose-dependent manner and enhanced the levels of heme oxygenase (HO)-1, glutamate cysteine ligase catalytic subunit (GCLC), and NAD(P)H-dependent quinone oxidoreductase (NQO)-1. CM-SD also significantly reduced reactive oxygen species (ROS) production and lipid peroxidation and restored glutathione (GSH) depletion in H2O2-treated C2C12 cells. Moreover, CM-SD significantly reduced lipopolysaccharides (LPS)-mediated interleukin (IL)-6 production in the conditioned medium. Results from the current study suggest that CM-SD could be a useful candidate against oxidative stress and inflammation-related muscle disorders.

Epigenetic modulation of autophagy genes linked to diabetic nephropathy by administration of isorhamnetin in Type 2 diabetes mellitus rats

Aim: To assess isorhamnetin efficacy for diabetic kidney disease in a Type 2 diabetes mellitus rat model, through investigating its effect at the epigenetic, mRNA and protein levels. Materials & methods: Type 2 diabetes mellitus was induced in rats by streptozotocin and high-fat diet. Rats were treated with isorhamnetin (50 mg/kg/d) for 4 or 8 weeks. Fasting blood glucose, renal and lipid profiles were evaluated. Renal tissues were examined by light and electron microscopy. Autophagy genes (FYCO1, ULK, TECPR1 and WIPI2) and miR-15b, miR-34a and miR-633 were assessed by qRT-PCR, and LC3A/B by immunoblotting. Results: Isorhamnetin improved fasting blood glucose, renal and lipid profiles with increased autophagosomes in renal tissues. It suppressed miRNA regulation of autophagy genes. Conclusion: We propose a molecular mechanism for the isorhamnetin renoprotective effect by modulation of autophagy epigenetic regulators.

Garlic flavonoids alleviate H2 O2 induced oxidative damage in L02 cells and induced apoptosis in HepG2 cells by Bcl-2/Caspase pathway

Liver damage is a common liver disorder, which could induce liver cancer. Oral antioxidant is one of the effective treatments to prevent and alleviate liver damage. In this study, three flavonoids namely myricetin, isoquercitrin, and isorhamnetin were isolated and identified from Laba garlic. The isolated compounds were investigated on the protective effects against H₂ O₂ -induced oxidative damages in hepatic L02 cells and apoptosis inducing mechanism in hepatic cancer cells HepG2 by using MTT assay, flow cytometry and western blotting analysis. Myricetin, isoquercitrin, and isorhamnetin showed proliferation inhibition on HepG2 cells with IC₅₀ value of 44.32 ± 0.213 µM, 49.68 ± 0.192 µM, and 54.32 ± 0.176 µM, respectively. While they showed low toxicity on normal cell lines L02. They could significantly alleviate the oxidative damage towards L02 cells (P < 0.05), via inhibiting the morphological changes in mitochondria and upholding the integrity of mitochondrial structure and function. The fluorescence intensity of L02 cells pre-treated with myricetin, isoquercitrin, and isorhamnetin (100 µM) was 89.23 ± 1.26%, 89.35 ± 1.43% and 88.97 ± 0.79%, respectively. Moreover, the flavonoids could induce apoptosis in HepG2 cells via Bcl-2/Caspase pathways, where it could up-regulate the expression of Bax and down-regulate the expression of Bcl-2, Bcl-xL, pro-Caspase-3, and pro-Caspase-9 proteins in a dose dependent manner. Overall, the results suggested that the flavonoids from Laba garlic might be a promising candidate for the treatment of various liver disorders. PRACTICAL APPLICATION: Flavonoids from Laba garlic showed selective toxicity towards HepG2 cells in comparison to L02 cells via regulating Bcl-2/caspase pathway. Additionally, the isolated flavonoids expressively barred the oxidative damage induced by H₂ O₂ in L02 cells. These results suggested that the flavonoids from laba garlic could be a promising agent towards the development of functional foods.

Emodin in Rheum undulatum inhibits oxidative stress in the liver via AMPK with Hippo/Yap signalling pathway

Context: Emodin is a compound in Rheum undulatum Linne (Polygonaceae) that has been reported to exert anti-inflammatory, antibacterial, and antiallergic effects.Objective: Oxidative stress is a causative agent of liver inflammation that may lead to fibrosis and hepato-carcinoma. In this study, we investigated the antioxidant effects of emodin and its mechanism.Materials and methods: We used the hepatocyte stimulated by arachidonic acid (AA) + iron cotreatment and the C57B/6 mice orally injected with acetaminophen (APAP, 500 mg/kg, 6 h), as assessed by immunoblot and next generation sequencing (NGS). Emodin was pre-treated in hepatocyte (3 ∼ 30 μM) for 1 h before AA + iron, and in mice (10 and 30 m/kg, P.O.) for 3 days before APAP.Results: In vitro, emodin treatment inhibited the cell death induced by AA + iron maximally at a dose of 10 μM (EC₅₀ > 3 μM). In addition, emodin attenuated the decrease of anti-apoptotic proteins, and restored mitochondria membrane potential as mediated by the liver kinase B1 (LKB1)-AMP-activated protein kinase (AMPK) pathway. LKB1 mediated AMPK activation was verified using the LKB1 deficient cell line, HeLa. Emodin (10 μM; after 10 min) also induced the phosphorylation of Yes-associated protein 1 (YAP1), the main downstream target of the Hippo signalling pathway that mediated oxidative stress or the ROS-initiated signalling pathway. In vivo, the oral treatment of emodin (10 and 30 m/kg, 3 days) decreased APAP-induced hepatic damage, as indicated by decreases in antioxidant genes as well as tissue damage.Conclusion: Our results show that emodin inhibits oxidative liver injury via the AMPK/YAP mediated pathway.

Discovery of Quality Markers in Hugan Qingzhi Formula by Integrating a Lipid-Lowering Bioassay with UHPLC-QQQ-MS/MS

Nonalcoholic fatty liver disease (NAFLD) is a prevalent chronic liver disease. The Hugan Qingzhi formula (HGQZ) has been proven effective in treating NAFLD through clinical and pharmacological mechanism studies. A screening study of the chemical components was carried out to better control the quality of this formula. Current research has combined biological activity assessment with chemical analysis to screen and identify the bioactive compounds in HGQZ for use as potential quality markers (Q-markers) to control the quality of this herbal product. The HGQZ extracted by three different solvents was evaluated in a free fatty acid-induced hepatic steatosis LO2 cell model. Simultaneously, the twelve major chemical constituents of these extracts were quantitatively measured by ultrahigh-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QQQ-MS/MS). Extraction with 50% ethanol showed the most potent lipid-lowering effect in steatosis LO2 cells and the highest extraction rate of major chemical constituents. Correlation analysis was used to establish the relationship between the biological activities and chemical characteristics of these extracts. The results showed that the contents of typhaneoside, hyperoside, isoquercitrin, isorhamnetin-3-O-neohesperidoside, notoginsenoside R1, and alisol B 23-acetate were positively correlated to the lipid-lowering effect. The subsequent bioassay confirmed that typhaneoside, isoquercitrin, and alisol B 23-acetate played the role of reducing the lipid effect. In conclusion, 50% of ethanol extraction produced the most active extract of HGQZ. Typhaneoside, isoquercitrin, and alisol B 23-acetate could be considered potential Q-markers for the quality control of HGQZ.

A complete map of the Calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2) signaling pathway

Calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2) is a serine/threonine-protein kinase belonging to the Ca²⁺/calmodulin-dependent protein kinase subfamily. CAMKK2 has an autocatalytic site, which gets exposed when Ca²⁺/calmodulin (CAM) binds to it. This results in autophosphorylation and complete activation of CAMKK2. The three major known downstream targets of CAMKK2 are 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPKα), calcium/calmodulin-dependent protein kinase 1 (CAMK1) and calcium/calmodulin-dependent protein kinase 4 (CAMK4). Activation of these targets by CAMKK2 is important for the maintenance of different cellular and physiological processes within the cell. CAMKK2 is found to be important in neuronal development, bone remodeling, adipogenesis, and systemic glucose homeostasis, osteoclastgensis and postnatal myogensis. CAMKK2 is reported to be involved in pathologies like Duchenne muscular dystrophy, inflammation, osteoporosis and bone remodeling and is also reported to be overexpressed in prostate cancer, hepatic cancer, ovarian and gastric cancer. CAMKK2 is involved in increased cell proliferation and migration through CAMKK2/AMPK pathway in prostate cancer and activation of AKT in ovarian cancer. Although CAMKK2 is a molecule of great importance, a public resource of the CAMKK2 signaling pathway is currently lacking. Therefore, we carried out detailed data mining and documentation of the signaling events associated with CAMKK2 from published literature and developed an integrated reaction map of CAMKK2 signaling. This resulted in the cataloging of 285 reactions belonging to the CAMKK2 signaling pathway, which includes 33 protein-protein interactions, 74 post-translational modifications, 7 protein translocation events, and 22 activation/inhibition events. Besides, 124 gene regulation events and 25 activator/inhibitors involved in CAMKK2 activation were also cataloged. The CAMKK2 signaling pathway map data is made freely accessible through WikiPathway database ( https://www.wikipathways.org/index.php/Pathway:WP4874 ). We expect that data on a signaling map of CAMKK2 will provide the scientific community with an improved platform to facilitate further molecular as well as biomedical investigations on CAMKK2 and its utility in the development of biomarkers and therapeutic targets.

Fat-lowering effects of isorhamnetin are via NHR-49-dependent pathway in Caenorhabditis elegans

Isorhamnetin (3-O-methylquercetin), a flavonol found in dill weed, sea buckthorn berries, kale and onions, has been suggested to have anti-obesity effects, but there is limited evidence of its mechanisms of action on lipid metabolism. The goal of this study was to investigate the effects of isorhamnetin on lipid metabolism using Caenorhabditis elegans as an animal model. Isorhamnetin reduced fat accumulation without affecting food intake or energy expenditure in C. elegans. The isorhamnetin's fat-lowering effects were dependent on nhr-49, a homolog of the human peroxisome proliferator-activated receptor alpha (PPARα). Isorhamnetin upregulated an enoyl-CoA hydratase (ech-1.1, involved in fatty acid β-oxidation) and adipose triglyceride lipase (atgl-1, involved in lipolysis) via NHR-49-dependent pathway at transcriptional levels. Isorhamnetin also upregulated the C. elegans AMP-activated protein kinase (AMPK) subunits homologs (aak-1 and aak-2), involved in energy homeostasis. These results suggest that isorhamnetin reduces body fat by increasing fat oxidation in part via NHR-49/PPARα-dependent pathway.

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Isorhamnetin reduced fat accumulation in Caenorhabditis elegans.

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Food intake and energy expenditure were not changed by isorhamnetin.

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Isorhamnetin's fat-lowering effects were dependent on nhr-49/PPARα.

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Isorhamnetin upregulated transcriptionally AAK/AMPK, which may activate NHR-49.

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Isorhamnetin increased fat breakdown by upregulating ech-1.1/HADHA and atgl-1/ATGL.

Morphine induces dysfunction of PINK1/Parkin-mediated mitophagy in spinal cord neurons implying involvement in antinociceptive tolerance

The development of opioid-induced analgesic tolerance is a clinical challenge in long-term use for managing chronic pain. The mechanisms of morphine tolerance are poorly understood. Mitochondria-derived reactive oxygen species (ROS) is a crucial signal inducing analgesic tolerance and pain. Chronic administration of morphine leads to robust ROS production and accumulation of damaged mitochondria, which are immediately removed by mitophagy. Here, we show that morphine inhibits mitochondria damage-induced accumulation of PTEN-induced putative kinase 1 (PINK1) in neurons. It interrupts the recruitment of Parkin to the impaired mitochondria and inhibits the ubiquitination of mitochondrial proteins catalyzed by Parkin. Consequently, morphine suppresses the recognition of autophagosomes to the damaged mitochondria mediated by LC3 and sequestosome-1 (SQSTM1/p62). Thus, morphine inhibits autophagy flux and leads to the accumulation of SQSTM1/p62. Finally, the impaired mitochondria cannot be delivered to lysosomes for degradation and ultimately induces robust ROS production and morphine tolerance. Our findings suggest that the dysfunction of mitophagy is involved in morphine tolerance. The deficiency of PINK1/Parkin-mediated clearance of damaged mitochondria is crucial for the generation of excessive ROS and important to the development of analgesic tolerance. These findings suggest that the compounds capable of stabilizing PINK1 or restoring mitophagy may be utilized to prevent or reduce opioid tolerance during chronic pain management.

Hepatoprotective Effect of Pericarpium zanthoxyli Extract Is Mediated via Antagonism of Oxidative Stress

Pericarpium zanthoxyli has been extensively used in traditional Oriental medicine to treat gastric disorders and has anti-inflammatory and antioxidative activities. Therefore, the present study examined a possible hepatoprotective effect of a P. zanthoxyli extract (PZE) and investigated the underlying molecular mechanisms. We employed an in vitro model of arachidonic acid (AA) + iron-induced hepatocyte damage and an in vivo model of CCl₄-induced liver injury to assess the effects of PZE and evaluated the relevant molecular targets using biochemical assays, flow cytometry analysis, Western blot, and histopathological analysis. The PZE inhibited AA + iron-induced hepatotoxicity in HepG2 cells, improved mitochondrial dysfunction, and reversed an increase in the cellular H₂O₂ production and a decrease in the reduced GSH levels induced by AA + iron. Treatment with either 30 or 100 μg/ml PZE significantly increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) protein, and the latter dose also increased the antioxidant response element- (ARE-) driven luciferase activity and enhanced the protein expressions of glutamate-cysteine ligase catalytic subunit and NAD(P)H:quinone oxidoreductase 1. In addition, treatment with 100 μg/ml PZE for 3 or 6 h increased the phosphorylation rates of Nrf2 and the extracellular signal-regulated kinase. In the in vivo experiment, oral treatment with both 100 and 300 mg/kg PZE inhibited the plasma aspartate aminotransferase activity, and the latter also inhibited the plasma alanine aminotransferase activity. In addition, both doses of PZE ameliorated the parenchymal degeneration and necrosis in the liver induced by CCl₄ administration, which was associated with reduced expressions of cleaved caspase-3, cleaved poly (ADP-ribose) polymerase, nitrotyrosine, and 4-hydroxynonenal by PZE. These findings suggest that PZE has protective effects against hepatotoxicity both in vitro and in vivo, which are mainly mediated via its antioxidant activity.

Isorhamnetin: A review of pharmacological effects

Isorhamnetin is one of the most important active ingredients in the fruits of Hippophae rhamnoides L. and the leaves of Ginkgo biloba L., which possesses extensive pharmacological activities. At present, there have been numerous investigations on isorhamnetin, which has the effects of cardiovascular and cerebrovascular protection, anti-tumor, anti-inflammatory, anti-oxidation, organ protection, prevention of obesity, etc. The related mechanisms involve the regulation of PI3K/AKT/PKB, NF-κB, MAPK and other signaling pathways as well as the expression of related cytokines and kinases. Isorhamnetin has a high value of development and application. However, the investigations on its mechanism of action are limited and lack of detailed scientific validation. The manuscript reviewed the pharmacological effects of isorhamnetin and related mechanisms of action for the development of its medicinal properties further.

Protective effects of isorhamnetin on pulmonary arterial hypertension: in vivo and in vitro studies

Pulmonary arterial hypertension (PAH) is a malignant disease with high mortality and closely involves the bone morphogenetic protein (BMP) pathway. Mutations in BMPR2 caused proliferation of pulmonary artery smooth muscle cells (PASMCs) leading to PAH. Isorhamnetin, one of the main naturally occurring flavonoids extracted from Hippophae rhamnoides L, shows antiinflammatory and anti-proliferative properties. Nevertheless, the effects of isorhamnetin on PAH remain unclear. This study aimed to investigate whether isorhamnetin has protective effects against PAH and explore possible mechanisms. An in vivo model of PAH induced by monocrotaline (MCT) was employed, and sildenafil and isorhamnetin were orally administered for 21 consecutive days. An in vitro model induced by TNF-α was employed, and cell proliferation of HPASMCs was detected. Results indicated that isorhamnetin significantly improved hemodynamic, histopathological, and echocardiographic changes in MCT-induced PAH in rats. In vitro, isorhamnetin suppressed TNF-α-induced HPASMCs proliferation. Furthermore, isorhamnetin improved protein expression of BMPR2 and suppressed protein expression of TNF-α and IL-6 in rat lungs. Isorhamnetin improved protein expression of BMPR2 and p-smad1/5 and mRNA expression of Id1 and Id3 in HPASMCs. Isorhamnetin ameliorated MCT-induced PAH in rats and inhibited TNF-α-induced HPASMCs proliferation by a mechanism likely involving the regulation of the BMP signaling pathway.

Rifampicin activates AMPK and alleviates oxidative stress in the liver as mediated with Nrf2 signaling

Although rifampicin could have a hepatic toxic effect, it has also been shown that this chemical acts as a cellular protectant against oxidative stress. Therefore, we wondered whether rifampicin has a beneficial effect such as an anti-oxidant in the liver, because the efficacy of some drugs sometimes relates with their toxicity as well as protective effects. The present study aimed to investigate the antioxidant effect of rifampicin against arachidonic acid (AA) plus iron (AA + iron) cotreatment and against acetaminophen (APAP, 500 mg/kg)-induced oxidative stress, in vitro and in vivo, respectively. In vivo, oral administration of rifampicin (100 or 200 mg/kg) attenuated elevation of serum alanine aminotransferase (ALT) and aspartate transaminase (AST), serum liver injury markers, against APAP treatment and, histologically, ameliorated tissue damage. Under in vitro examination, MTT assays were used to assess the cell death inhibitory effect of rifampicin against AA + iron-induced oxidative stress. In addition, DCFH-DA and Rh 123 staining showed that rifampicin treatment reduced reactive oxygen species (ROS) production and mitochondrial membrane damage, which had been induced by AA + iron treatment. Further, we explored whether rifampicin treatment enhanced phosphorylation of AMP-activated protein kinase (AMPK) by activation of liver kinase B1 (LKB1), the upstream kinase of AMPKα. Activated AMPKα induced activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), which are proteins functioning in redox balance. Moreover, we confirmed a reversed cell protective effect of rifampicin under compound C (an AMPK inhibitor) treatment. Overall, our data demonstrate that rifampicin effectively protects the liver against cellular oxidative stress through AMPKα and Nrf2 pathway.

Isorhamnetin ameliorates inflammatory responses and articular cartilage damage in the rats of monosodium iodoacetate-induced osteoarthritis

Context: Osteoarthritis (OA) is a degenerative joint disease with damage to the articular cartilage. Active production of inflammatory cytokine/chemokine and matrix metalloproteinases may be found during the progression of OA. Isorhamnetin had the effects of anti-inflammatory, antioxidant, anti-ischemia, anti-atherosclerotic hepatoprotective and anticancer activities. Objective: Our study was focused on the effects of isorhamnetin treatment in OA. Materials and methods: We used monosodium iodoacetate (MIA)-induced OA rats to evaluate the effects of isorhamnetin related anti-inflammatory process. The rats in all groups were sacrificed on four weeks post-MIA injection. The measurements of knee joint swelling, histological analysis, serum inflammatory biomarkers and western blot were evaluated. Results: We found that isorhamnetin may reduce MIA-induced knee swelling by significantly reduction of articular cartilage damage.in rats. Suppression of pro-inflammatory cytokines production was found after isohamnetin treatment. Isorhamnetin inhibited the production of NO and PGE2, and the expression of iNOS and COX-2. The production of COMP, CTX-II and osteopontin (OPN) were also inhibited in MIA-induced OA rats. Discussion and conclusions: Isorhamnetin may modulate the inflammatory progression of OA in MIA-induced OA rats. The prevention of cartilage damage was found in OA after adequate isorhamnetin treatment. Isorhamnetin may serve as a potential agent for the management of OA.

Resveratrol protects against nonalcoholic fatty liver disease by improving lipid metabolism and redox homeostasis via the PPARα pathway

Resveratrol (RSV), a well-known bioactive compound, has been reported to exert a broad range of health benefits. Accumulating evidence suggests that RSV is beneficial for many metabolic diseases, including nonalcoholic fatty liver disease (NAFLD). This study investigated the preventive and therapeutic effects of RSV on high-fat diet (HFD)-induced NAFLD in rats and palmitate acid (PA)-induced hepatocyte steatosis in HepG2 cells. Hepatocytes were incubated with inhibitors of peroxisome proliferator-activated receptor α (PPARα) or short interfering RNAs (siRNAs) targeting PPARα, AMP-activated protein kinase (AMPK), and protein kinase A (PKA) to determine the underlying mechanisms. We found that RSV noticeably ameliorated HFD-induced hepatic steatosis in rats and inhibited PA-induced lipid accumulation in HepG2 cells. Moreover, RSV improved lipid metabolism, enhanced antioxidant capacity, and restored mitochondrial respiratory chain activities. Incubation with inhibitors of PPARα or PPARα siRNA abolished the protective effects of RSV on lipid metabolism and redox homeostasis. Furthermore, RSV activated the PKA/AMPK/PPARα signaling pathway. Our results provided direct evidence for a novel, PPARα-mediated mechanism responsible for the beneficial effects of RSV on hepatic steatosis. These findings may have important theoretical and application prospects for the prevention and treatment of NAFLD. Novelty RSV improved lipid metabolism and redox homeostasis and oxidative stress in NAFLD via the PKA/AMPK/PPARα signaling pathway. RSV may have a greater beneficial effect in the early prevention of hepatic steatosis.

Aspidosperma species: A review of their chemistry and biological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Species of Aspidosperma are known popularly as "peroba, guatambu, carapanaúba, pau-pereiro" and "quina". The genus can be found in the Americas, mainly between Mexico and Argentina. Many species of Aspidosperma are used by the population in treating cardiovascular diseases, malaria, fever, diabetes and rheumatism. The phytochemical aspects of the species of the genus Aspidosperma have been studied extensively. The monoterpene indole alkaloids are the main secondary metabolites in Aspidosperma species, and about 250 of them have been isolated showing a considerable structural diversity. Several of them have showed some important pharmacological activities. Aspidosperma subincanum Mart. and Aspidosperma tomentosum Mart. (Apocynaceae) are Brazilian species widely used by the population to treat diabetes mellitus, hypercholesterolemia. The pharmacological activities of both species have been investigated and the biological properties described can be related to their isolated indole alkaloids. However, more pharmacological studies are needed in order to justify the use of these species in folk medicine. In this review, we present reports mainly focused on chemical and biological studies and their relationship with the ethnopharmacological use of both Aspidosperma species.

AIM OF THE STUDY

The aim of this review is to present their ethnopharmacological use as correlated to their biological activities as described for the extracts and isolated compounds from Aspidosperma subincanum Mart. and Aspidosperma tomentosum Mart. In addition, some aspects related to the biosynthetic pathways are discussed, also NMR assignments and some synthesis information about indole alkaloids from both Aspidosperma species are included.

MATERIAL AND METHODS

The bibliographic search was made in theses and dissertations using some databases such as NDLTD (Networked Digital Library of Theses and Dissertations), OATD (Open Access Theses and Dissertations) and Google Scholar. More data were gathered from books, Brazilian journals and articles available on electronic databases such as, Google Scholar, PubChem, Scifinder, Web of Science, SciELO, PubMed and Science Direct. Additionally, the Google Patents and Espacenet Patent Search (EPO) were also consulted. The keywords Aspidosperma, A. subincanum, A. tomentosum, indole alkaloids were used in the research. The languages were restricted to Portuguese, English and Spanish and references were selected according to their relevance.

RESULTS

A. subincanum Mart. and A. tomentosum Mart. (Apocynaceae) are Brazilian species widely used by the population to treat a few diseases. Extracts and isolated compounds of both species have shown antitumor and antimalarial activities. The antitumor activity of isolated compounds has been extensively studied. However, the antiplasmodial activity needs to be investigated further as well as the anti-inflammatory, anti-hyperlipidemic and anorexigenic activities. From A. subincanum twenty-one indole alkaloids were isolated and some of them have been extensively studied. From the leaves and bark of A. tomentosum four alkaloids and one flavonoid were isolated. Furthermore, CG-MS analysis of seeds, branches, leaves and arils identified nine indole alkaloids. Stemmadenine has been proposed as a precursor of indole alkaloids obtained from some species of Aspidosperma. Many of the biosynthetic steps have been characterized at the enzymatic level and appropriate genes have been identified, however, other steps have yet to be investigated and they are still controversial. Some isolated alkaloids from A. subincanum and A. tomentosum were identified only by mass spectrometry. In many cases, their NMR data was either not available or was incomplete. The described meta-analysis of the available NMR data revealed that the chemical shifts belonging to the indole ring might be used to characterize this class of alkaloids within complex matrices such as plant extracts. The biological activities and the structural complexity of these compounds have stimulated the interest of many groups into their synthesis. In this review, some information about the synthesis of indole alkaloids and their derivatives was presented.

CONCLUSIONS

A. subincanum and A. tomentosum are used by the population of Brazil to treat many diseases. A few biological activities described for the extracts and isolated compounds of both species are in agreement with the ethnopharmacological use for others species of Aspidosperma, such as, antimalarial, the treatment of diabetes and other illnesses. These species are sources of leading compounds which can be used for developing new drugs. In addition, other biological activities reported and suggested by ethnopharmacological data have yet to be investigated and could be an interesting area in the search for new bioactive compounds.

Suppression of Hyperglycemia and Hepatic Steatosis by Black-Soybean-Leaf Extract via Enhanced Adiponectin-Receptor Signaling and AMPK Activation

Yellow-soybean-leaf extract includes kaempferol glycosides and pheophorbides that reduce obesity and plasma glucose levels. This study researched the molecular mechanisms underlying the glucose-lowering effect of the extract of black-soybean leaves (EBL), which mainly contains quercetin glycosides and isorhamnetin glycosides, in mice with high-fat-diet (HFD)-induced obesity and diabetes and in HepG2 cells. Twelve weeks of EBL supplementation decreased body weight and fasting glucose, glycated hemoglobin, insulin, triglyceride, and nonesterified fatty acid levels. Histological analyses manifested that EBL suppressed hepatic steatosis. Interestingly, EBL significantly improved plasma adiponectin levels and increased adiponectin-receptor-gene ( AdipoR1 and AdipoR2) expression in the liver. EBL restored the effects of HFD on hepatic AMP-activated protein kinase (AMPK) and on the family of peroxisome proliferator-activated receptors (PPARα, PPARδ, and PPARγ), which are associated with fatty acid metabolism and are downstream of the adiponectin receptors. Hence, EBL effectively diminished hyperglycemia and hepatic steatosis through enhancing adiponectin-induced signaling and AMPK activation in the liver.

Bamboo Stems (Phyllostachys nigra variety henosis) Containing Polyphenol Mixtures Activate Nrf2 and Attenuate Phenylhydrazine-Induced Oxidative Stress and Liver Injury

This study was designed to investigate the hepatoprotective effect of bamboo stems using in vitro and in vivo experimental liver damage models. Ethyl acetate fraction of 80% ethanol extract of Phyllostachys nigra stem (PN3) containing polyphenols had a higher NQO1-ARE reporter gene activity as monitored by the activity of the NF-E2-related factor (Nrf2) antioxidant pathway in cells in comparison to extracts from other species and under other conditions. The Nrf2 was translocated from the cytosol to the nucleus in response to PN3, followed by induction of the Nrf2 target gene expression, including HO-1, GCL, and NQO-1 in HepG2 cells. Phosphorylation of Nrf2 in HepG2 cells was enhanced in PN3, which was mediated by PKCδ, ERK, and p38 MAPK. Consequently, PN3 inhibited arachidonic acid (AA) + iron-induced reactive oxygen species generation and glutathione depletion, and, thus, highlighted their role in cytotoxicity. Treatment with major polyphenols of PN3, including catechin, chlorogenic acid, caffeic acid, and p-coumaric acid, also improved AA + iron-mediated oxidative stress and, thus, improved cell viability. Treatment with phenylhydrazine in mice, i.e., the iron overload liver injury model, increased plasma alanine aminotransferase and aspartate aminotransferase levels and changed histological features in mice—a response that was almost completely blocked by PN3 administration. Moreover, PN3 extract mitigated phenylhydrazine-induced oxidative stress and inflammatory responses. Conclusively, PN3 can exert a hepatoprotective effect against iron overload-induced acute liver damage due to its antioxidant properties.

Anti-hyperuricemic effect of isorhamnetin in cultured hepatocytes and model mice: structure-activity relationships of methylquercetins as inhibitors of uric acid production

Hyperuricemia is an important risk factor for gout. Isorhamnetin (3'-O-methylquercetin) is an O-methylated flavonol, which occurs in onion, almond and sea buckthorn. It is also one of the metabolites of quercetin in mammals. In the present study, we investigated anti-hyperuricemic effect of isorhamnetin adopting both cultured hepatocytes and mice with hyperuricemia induced by purine bodies. In cultured hepatocytes, isorhamnetin as well as quercetin significantly and dose-dependently inhibited uric acid (UA) production. We also examined the inhibitory effects on UA production of other mono-methylquercetins, i.e., tamarixetin, 3-O-methylquercetin, azaleatin, and rhamnetin in addition to isorhamnetin for studying their structure-activity relationships. From the results obtained, hydroxyl groups at C-3, C-5, and especially C-7, but not C-3' and C-4' of quercetin are demonstrated to play a critical role in suppressing UA production in the AML12 hepatocytes. Oral administration of isorhamnetin significantly reduced plasma and hepatic UA levels in the hyperuricemic model mice. Isorhamnetin also decreased hepatic xanthine oxidase (XO) activity without changes in XO protein expression, indicating that anti-hyperuricemic effect of isorhamnetin could be, at least partly, attributable to suppression of UA production by directly inhibiting XO activity in the liver. These findings demonstrate that isorhamnetin has a potent anti-hyperuricemic effect and may be a potential candidate for prevention and remediation of hyperuricemia.

Isorhamnetin alleviates lipopolysaccharide-induced inflammatory responses in BV2 microglia by inactivating NF-κB, blocking the TLR4 pathway and reducing ROS generation

Isorhamnetin, which is a flavonoid predominantly found in fruits and leaves of various plants, including Hippophae rhamnoides L. and Oenanthe javanica (Blume) DC, is known to possess various pharmacological effects. However, the anti‑inflammatory potential of isorhamnetin remains poorly studied. Therefore, the present study aimed to investigate the inhibitory potential of isorhamnetin against inflammatory responses in lipopolysaccharide (LPS)‑stimulated BV2 microglia. To measure the effects of isorhamnetin on inflammatory mediators and cytokines, and reactive oxygen species (ROS) generation, the following methods were used: cell viability assay, griess assay, ELISA, reverse transcriptase‑polymerase chain reaction, flow cytometry, western blotting and immunofluorescence staining. The results revealed that isorhamnetin significantly suppressed LPS‑induced secretion of pro‑inflammatory mediators, including nitric oxide (NO) and prostaglandin E2, without exhibiting significant cytotoxicity. Consistent with these results, isorhamnetin inhibited LPS‑stimulated expression of regulatory enzymes, including inducible NO synthase and cyclooxygenase‑2 in BV2 cells. Isorhamnetin also downregulated LPS‑induced production and expression of pro‑inflammatory cytokines, such as tumor necrosis factor‑α and interleukin‑1β. The mechanism underlying the anti‑inflammatory effects of isorhamnetin was subsequently evaluated; this flavonoid inhibited the nuclear factor (NF)‑κB signaling pathway by disrupting degradation and phosphorylation of inhibitor κB‑α in the cytoplasm and blocking translocation of NF‑κB p65 into the nucleus. In addition, isorhamnetin effectively suppressed LPS‑induced expression of Toll‑like receptor 4 (TLR4) and myeloid differentiation factor 88. It also suppressed the binding of LPS with TLR4 in BV2 cells. Furthermore, isorhamnetin markedly reduced LPS‑induced generation of ROS in BV2 cells, thus indicating a strong antioxidative effect. Collectively, these results suggested that isorhamnetin may suppress LPS‑mediated inflammatory action in BV2 microglia through inactivating the NF‑κB signaling pathway, antagonizing TLR4 and eliminating ROS accumulation. Further studies are required to fully understand the anti‑inflammatory effects associated with the antioxidant capacity of isorhamnetin; however, the findings of the present study suggested that isorhamnetin may have potential benefits in inhibiting the onset and treatment of neuroinflammatory diseases.

Sipjeondaebo-tang Alleviates Oxidative Stress-Mediated Liver Injury through Activation of the CaMKK2-AMPK Signaling Pathway

Sipjeondaebo-tang (SDT) is used frequently as a herbal prescription to treat deficiency syndromes in traditional Korean medicine. We investigated the hepatoprotective effects of SDT against oxidative stress and attempted to clarify the underlying molecular mechanisms. SDT pretreatment reduced arachidonic acid (AA) plus iron-mediated cytotoxicity in a concentration-dependent manner and prevented changes in apoptosis-related protein expression. In addition, SDT pretreatment significantly reduced glutathione depletion, hydrogen peroxide production, and mitochondrial dysfunction via treatment with AA plus iron. SDT increased the phosphorylation of AMP-activated protein kinase (AMPK) in accordance with the phosphorylation of Ca²⁺/calmodulin-dependent protein kinase kinase 2 (CaMKK2). Experiments using an AMPK chemical inhibitor (Compound C) or CaMKK2 chemical inhibitor (STO-609) suggested that the CaMKK2-AMPK signaling pathway contributes to SDT-mediated protection of mitochondria and cells. Moreover, administration of SDT for 4 consecutive days to mice significantly reduced the alanine aminotransferase and aspartate aminotransferase activities induced by carbon tetrachloride, and the numbers of degenerated hepatocytes, infiltrated inflammatory cells, nitrotyrosine-positive cells, and 4-hydroxynonenal-positive cells in liver tissue. Therefore, SDT protects hepatocytes from oxidative stress via CaMKK2-dependent AMPK activation and has the therapeutic potential to prevent or treat oxidative stress-related liver injury.

Effects of Isorhamnetin on Adipocyte Mitochondrial Biogenesis and AMPK Activation

Isorhamnetin (ISOR), 3-O-methylquercetin, is a naturally occurring flavonoid in many plants. It is a metabolite derived from quercetin and is known to exert beneficial effects on the prevention of obesity. However, the molecular mechanism of action involved in ISOR-mediated mitochondrial biogenesis, and AMP-activated protein kinase (AMPK) activation in 3T3-L1 cells remains unclear. The aim of this study was to determine whether ISOR affected mitochondrial biogenesis and AMPK activation, during 3T3-L1 adipocyte differentiation. Intracellular lipid and triglyceride accumulation, and glycerol-3-phosphate dehydrogenase (GPDH) activity decreased in ISOR-treated cells. The mRNA levels of adipogenic genes, such as the proliferator-activated receptor-γ (PPAR-γ), and adipocyte protein 2 (aP2), were inhibited by ISOR. In contrast, mRNA levels of mitochondrial genes, such as peroxisome proliferator-activated reporter gamma coactivator-1α (PGC-1α), nuclear respiratory factor (NRF)-1, transcription factor A (Tfam), and carnitine palmitoyl transferase-1α (CPT-1α), were all stimulated by ISOR treatment. Mitochondria DNA (mtDNA) copy number and AMPK activity were also stimulated by ISOR. The results suggested that the mitochondrial biogenic effect of ISOR in adipocytes might have been associated with stimulation of mitochondrial gene expression, mtDNA replication, and AMPK activation.

Moutan Cortex Protects Hepatocytes against Oxidative Injury through AMP-Activated Protein Kinase Pathway

Moutan Cortex, the root bark of Paeonia suffruticosa ANDREWS in Ranunculaceae, has widely demonstrated analgesic, anti-spasmodic, and anti-inflammatory effects in various cancer and immune cell lines. Oxidative stress is associated with development of several diseases, including liver disease. We prepared the water extract of Moutan Cortex (MCE) to investigate the cytoprotective activities and its mechanism. MCE protected hepatocytes from arachidonic acid (AA)+iron induced oxidative stress, as indicated by reactive oxygen species (ROS) production and cell viability analysis. MCE also suppressed mitochondrial dysfunction in AA+iron-treated human hepatocyte-derived hepatocellular carcinoma cell line, HepG2 cells. In addition, MCE treatment induces AMP-activated protein kinase (AMPK) and liver kinase B1 phosphorylation, which play a role in inhibition of oxidative stress induced cell death. Moreover, one of the MCE compounds, chlorogenic acid, exerted protective effects against oxidative stress and apoptosis. Taken together, MCE protected hepatocytes against AA+iron-induced oxidative stress through AMPK activation, and may be a candidate for the treatment of liver disease.

Alpinumisoflavone rescues glucocorticoid-induced apoptosis of osteocytes via suppressing Nox2-dependent ROS generation

BACKGROUND

Long term use of glucocorticoids is one of the most common causes of secondary osteoporosis. Osteocyte, the most abundant cell type in bone, coordinates the function of osteoblast and osteoclast. This study evaluates the protective effect of alpinumisoflavone (AIF), a naturally occurring flavonoid compound, on dexamethasone (Dex)-induced apoptosis of osteocytes.

METHODS

MLO-Y4 cell was used as a cell model. The effect of AIF on the cell viability was assessed by MTT assay. Apoptosis of MYL-Y4 cells was determined by DNA fragment detection ELISA kit and flow cytometry. Intracellular ROS level was determined by DCFH-DA staining. mRNA and protein expression of target genes were determined by qRT-PCR and western blot, respectively.

RESULTS

AIF effectively protected MLO-Y4 cells against Dex-induced apoptosis, which was associated with attenuation of Dex-induced ROS generation in MLO-Y4 cells. Furthermore, our data indicated that the expression of NAD(P)H oxidase 2 (Nox2) was suppressed by AIF, which in turn mediated the attenuating effect on Dex-induced ROS generation and apoptosis in MLO-Y4 cells. Moreover, our results showed that AIF modulated the expression of Nox2 by activating AMPK signaling.

CONCLUSION

AIF activated AMPK-dependent Nox2 signaling pathway to suppress Dex-induced ROS production in cultured osteocytes, which might explain its anti-apoptotic effect. These results indicate that activation of AMPK pathway by AIF could have beneficial effects on bone damage induced by excessive oxidative stress and osteocyte apoptosis.

Protective Effects of Isorhamnetin on Cardiomyocytes Against Anoxia/Reoxygenation-induced Injury Is Mediated by SIRT1

It has been reported that apoptosis plays a very important role on anoxia/reoxygenation (A/R)-induced injury, and human silent information regulator type 1 (SIRT1) can inhibit the apoptosis of cardiomyocytes. It has been proved that isorhamnetin (IsoRN), 3'-O-methyl-quecetin, can protect the cardiomyocytes, but the mechanism is still not clear. The aim of the study was to explore whether the protective effects of IsoRN on the cardiomyocytes against the A/R-induced injury are mediated by SIRT1. The effects of IsoRN on cardioprotection against A/R injury in neonatal rat cardiomyocytes were monitored by cell viability, the levels of mitochondrial membrane potential (Δψm), apoptosis, and intracellular reactive oxygen species (ROS), the levels of lactate dehydrogenase (LDH), creatine phosphokinase (CPK) and mitochondrial permeability transition pores (mPTP). The effects on protein expression were measured by western blot assay. The results showed that IsoRN can reduce A/R-induced injury by decreasing the level of lactate dehydrogenase and creatine phosphokinase release from the cardiomyocytes, increasing cell viability and expression of SIRT1, reducing the generation of reactive oxygen species, inhibiting opening of mitochondrial permeability transition pores and loss of Δψm and activation of caspase-3, and decreasing the release of cytochrome c, and reducing apoptosis. In addition, sirtinol, a SIRT1 inhibitor, drastically reduced the protective effects of IsoRN on cardioprotective effects in cardiomocytes. In conclusion, we firstly demonstrated that SIRT1 may be involved in the protective effects of IsoRN on cardiomocytes against the A/R-induced injury.

Previous physical exercise alters the hepatic profile of oxidative-inflammatory status and limits the secondary brain damage induced by severe traumatic brain injury in rats

KEY POINTS

An early inflammatory response and oxidative stress are implicated in the signal transduction that alters both hepatic redox status and mitochondrial function after traumatic brain injury (TBI). Peripheral oxidative/inflammatory responses contribute to neuronal dysfunction after TBI Exercise training alters the profile of oxidative-inflammatory status in liver and protects against acute hyperglycaemia and a cerebral inflammatory response after TBI. Approaches such as exercise training, which attenuates neuronal damage after TBI, may have therapeutic potential through modulation of responses by metabolic organs. The vulnerability of the body to oxidative/inflammatory in TBI is significantly enhanced in sedentary compared to physically active counterparts.

ABSTRACT

Although systemic responses have been described after traumatic brain injury (TBI), little is known regarding potential interactions between brain and peripheral organs after neuronal injury. Accordingly, we aimed to investigate whether a peripheral oxidative/inflammatory response contributes to neuronal dysfunction after TBI, as well as the prophylactic role of exercise training. Animals were submitted to fluid percussion injury after 6 weeks of swimming training. Previous exercise training increased mRNA expression of X receptor alpha and ATP-binding cassette transporter, and decreased inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF)-α and interleukin (IL)-6 expression per se in liver. Interestingly, exercise training protected against hepatic inflammation (COX-2, iNOS, TNF-α and IL-6), oxidative stress (decreases in non-protein sulfhydryl and glutathione, as well as increases in 2',7'-dichlorofluorescein diacetate oxidation and protein carbonyl), which altered hepatic redox status (increases in myeloperoxidase and superoxide dismutase activity, as well as inhibition of catalase activity) mitochondrial function (decreases in methyl-tetrazolium and Δψ, as well as inhibition of citrate synthase activity) and ion gradient homeostasis (inhibition of Na⁺ ,K⁺ -ATPase activity inhibition) when analysed 24 h after TBI. Previous exercise training also protected against dysglycaemia, impaired hepatic signalling (increase in phosphorylated c-Jun NH2-terminal kinase, phosphorylated decreases in insulin receptor substrate and phosphorylated AKT expression), high levels of circulating and neuronal cytokines, the opening of the blood-brain barrier, neutrophil infiltration and Na⁺ ,K⁺ -ATPase activity inhibition in the ipsilateral cortex after TBI. Moreover, the impairment of protein function, neurobehavioural (neuromotor dysfunction and spatial learning) disability and hippocampal cell damage in sedentary rats suggests that exercise training also modulates peripheral oxidative/inflammatory pathways in TBI, which corroborates the ever increasing evidence regarding health-related outcomes with respect to a physically active lifestyle.

Isorhamnetin inhibits IL‑1β‑induced expression of inflammatory mediators in human chondrocytes

Isorhamnetin (ISH) is a flavonoid primarily obtained from the fruit of Hippophae rhamnoides L., which possesses anti‑inflammatory properties. However, the effect of ISH on the expression of inflammatory mediators in response to interleukin (IL)‑1β stimulation has not been elucidated. The present study investigated the effects of ISH on the expression of inflammatory mediators in human chondrocytes, induced by IL‑1β. The results of the present study demonstrated that pretreatment with ISH inhibited the expression of stromelysin‑1 and collagenase 3 in chondrocytes, induced by IL‑1β. Pretreatment with ISH inhibited the IL‑1β‑stimulated synthesis of NO and prostaglandin E2 induced by IL‑1β, in addition to the expression of inducible nitric oxide synthase and prostaglandin G/H synthase 2 in chondrocytes. Additionally, ISH inhibited the expression of nuclear factor (NF)‑κB and transcription factor p65, and the degradation of NF‑κB inhibitor α induced by IL‑1β in chondrocytes. In conclusion, the results of the present study indicated that ISH exhibited anti‑inflammatory and chondroprotective effects in IL‑1β‑stimulated chondrocytes. The results of the present study suggest that ISH may be a potential agent in the future treatment of osteoarthritis.

Hepatoprotective Effect of Polyphenol-Enriched Fraction from Folium Microcos on Oxidative Stress and Apoptosis in Acetaminophen-Induced Liver Injury in Mice

Folium Microcos (FM), the leaves of Microcos paniculata L., shows various biological functions including antioxidant activity and α-glucosidase inhibitory effect. However, its therapeutic potential in acute liver injury is still unknown. This study investigated the hepatoprotective effect and underlying mechanisms of the polyphenol-enriched fraction (FMF) from Folium Microcos. FMF exhibited strong free radical scavenging activities and prevented HepG2/Hepa1-6 cells from hydrogen peroxide- (H₂O₂-) induced ROS production and apoptosis in vitro. Antioxidant activity and cytoprotective effects were further verified by alleviating APAP-induced hepatotoxicity in mice. Western blot analysis revealed that FMF pretreatment significantly abrogated APAP-mediated phosphorylation of MAPKs, activation of proapoptotic protein caspase-3/9 and Bax, and restored expression of antiapoptotic protein Bcl2. APAP-intoxicated mice pretreated with FMF showed increased nuclear accumulation of nuclear factor erythroid 2-related factor (Nrf2) and elevated hepatic expression of its target genes, NAD(P)H:quinine oxidoreductase 1 (NQO1) and hemeoxygenase-1(HO-1). HPLC analysis revealed the four predominantly phenolic compounds present in FMF: narcissin, isorhamnetin-3-O-β-D-glucoside, isovitexin, and vitexin. Consequently, these findings indicate that FMF possesses a hepatoprotective effect against APAP-induced hepatotoxicity mainly through dual modification of ROS/MAPKs/apoptosis axis and Nrf2-mediated antioxidant response, which may be attributed to the strong antioxidant activity of phenolic components.

Activation of AMPK by Buddleja officinalis Maxim. Flower Extract Contributes to Protecting Hepatocytes from Oxidative Stress

The Buddleja officinalis Maxim. flower is used in traditional Chinese and Korean medicine to treat inflammation, vascular diseases, headache, and stroke, as well as enhance liver function. This research investigated the effects of B. officinalis Maxim. flower extract (BFE) on hepatotoxicity. The cytoprotective effects and mechanism of BFE against severe mitochondrial dysfunction and H₂O₂ production in hepatotoxicity induced by coadministration of arachidonic acid (AA) and iron were observed in the HepG2 cell line. In addition, we performed blood biochemical, histopathological, and histomorphometric analyses of mice with carbon tetrachloride- (CCl₄-) induced acute liver damage. BFE inhibited the AA + iron-mediated hepatotoxicity of HepG2 cells. Moreover, it inhibited mitochondrial dysfunction, H₂O₂ production, and glutathione depletion mediated by AA + iron in the same cells. Meanwhile, the cytoprotective effects of BFE against oxidative stress were associated with the activation of AMP-activated protein kinase (AMPK). In particular, based on the histopathological observations, BFE (30 and 100 mg/kg) showed clear hepatoprotective effects against CCl₄-induced acute hepatic damage. Furthermore, it inhibited 4-hydroxynonenal and nitrotyrosine immunoreactivity in hepatocytes. These results provide evidence that BFE has beneficial hepatoprotective effects against hepatic damage via the activation of AMPK pathway. Accordingly, BFE may have therapeutic potential for diverse liver disorders.