Natural antioxidant-isoliquiritigenin ameliorates contractile dysfunction of hypoxic cardiomyocytes via AMPK signaling pathway

A comprehensive account on ethnobotany, phytochemistry and pharmacological insights of genus Celtis

The plants of Celtis L. genus have been traditionally used to cure aches, sore throats, fevers, cancer, sexually transmitted diseases, sexual weakness, diarrhea, stomach problems, amenorrhea, menstrual disorders, kidney stones, and pain. The review aims to give a comprehensive account of the current state of ethnopharmacology, phytochemistry, and biological activities of the Celtis genus, as well as to describe the potential area of future avenues. Information on the Celtis genus was obtained from internet sources such as Google Scholar, Web of Science, PubMed, ScienceDirect, and so on by using appropriate keywords, including ethnobotanical, pharmacological, pharmaceutical, bioactivity, phytochemistry, and botanical features of the Celtis genus. This review identified 14 species in the genus Celtis that have a phytopharmacological investigation, including C.africana Burm. f., C. australis L., C. occidentalis L., C. sinensis Pers., C. philippensis Blanco., C. tetrandra Roxb., C. tessmannii Rendle., C. jessoensis Koidz., C. adolfi-friderici Engl., C. iguanaea (Jacq.) Sarg., C. laevigata Wild., C. pallida Torr., C. zenkeri Engl., and C. tournefortii Lam. This genus contains many classified phytoconstituents, such as terpenoids, organic acids, flavonoids, and volatile compounds. Their extracts and pure substances have been shown to have the same anticancer, antibacterial, anti-inflammatory, antioxidant, hepatoprotective, cardioprotective, urease-inhibiting, and antidiarrheal properties as their traditional uses. In terms of current information on ethnopharmacology, phytochemicals, and pharmacological uses, the data acquired in this review could be beneficial and needed for future research. Some phytoconstituents (for instance, kaempferol, myricetin, quercetin, and eugenol) and extracts (for example, leaves, seeds, and ripe fruits extracts of C. australis) showed tremendous results in preliminary testing with promising antimicrobial, anticancer, and urease inhibitory effects. Further research and clinical investigations are needed to develop them as lead compounds and neutraceuticals, which may provide an advance over traditional medicinal systems.

A combination of isoliquiritigenin with Artemisia argyi and Ohwia caudata water extracts attenuates oxidative stress, inflammation, and apoptosis by modulating Nrf2/Ho-1 signaling pathways in SD rats with doxorubicin-induced acute cardiotoxicity

Ohwia caudata (Thunb.) H. Ohashi (Leguminosae) also called as "Evergreen shrub" and Artemisia argyi H.Lév. and Vaniot (Compositae) also named as "Chinese mugwort" those two-leaf extracts frequently used as herbal medicine, especially in south east Asia and eastern Asia. Anthracyclines such as doxorubicin (DOX) are commonly used as effective chemotherapeutic drugs in anticancer therapy around the world. However, chemotherapy-induced cardiotoxicity, dilated cardiomyopathy, and congestive heart failure are seen in patients who receive DOX therapy, with the mechanisms underlying DOX-induced cardiac toxicity remaining unclear. Mitochondrial dysfunction, oxidative stress, inflammatory response, and cardiomyocytes have been shown to play crucial roles in DOX-induced cardiotoxicity. Isoliquiritigenin (ISL, 10 mg/kg) is a bioactive flavonoid compound with protective effects against inflammation, neurodegeneration, cancer, and diabetes. Here, in this study, our aim is to find out the Artemisia argyi (AA) and Ohwia caudata (OC) leaf extract combination with Isoliquiritigenin in potentiating and complementing effect against chemo drug side effect to ameliorate cardiac damage and improve the cardiac function. In this study, we showed that a combination of low (AA 300 mg/kg; OC 100 mg/kg) and high-dose(AA 600 mg/kg; OC 300 mg/kg) AA and OC water extract with ISL activated the cell survival-related AKT/PI3K signaling pathway in DOX-treated cardiac tissue leading to the upregulation of the antioxidant markers SOD, HO-1, and Keap-1 and regulated mitochondrial dysfunction through the Nrf2 signaling pathway. Moreover, the water extract of AA and OC with ISL inhibited the inflammatory response genes IL-6 and IL-1β, possibly through the NFκB/AKT/PI3K/p38α/NRLP3 signaling pathways. The water extract of AA and OC with ISL could be a potential herbal drug treatment for cardiac hypertrophy, inflammatory disease, and apoptosis, which can lead to sudden heart failure.

Liquorice root extract and isoliquiritigenin attenuate high-fat diet-induced hepatic steatosis and damage in rats by regulating AMPK

Objective: This study compared the ability of Liquorice roots aqueous extract (LRE) and its ingredient, isoliquiritigenin (ISL), in alleviating high-fat diet (HFD)-induced hepatic steatosis and examined if this effect involves activation of AMPK.Materials and methods: Control or HFD-fed rats were treated with the vehicle, LRE (200 mg/kg), or ISL (30 mg/kg) for 8 weeks orally.Results: ISL and LRE reduced HFD-induced hyperglycaemia, improved liver structure, lowered serum and hepatic lipids, and attenuated hepatic oxidative stress and inflammation. In the control and HFD-fed rats, ISL and LRE significantly stimulated the muscular and hepatic mRNA and protein levels of AMPK, improved oral glucose tolerance, reduced hepatic mRNA levels of SREBP1/2, and upregulated hepatic levels of PPARα and Bcl2. These effects were comparable for ISL and LRE and were prevented by co-administration of compound C, an AMPK inhibitor.Discussion and conclusion: ISL and LRE provide an effective theory to alleviate hepatic steatosis through activating AMPK.

The importance of natural chalcones in ischemic organ damage: Comprehensive and bioinformatic analysis review

Over the last few decades, extensive research has been conducted, yielding a detailed account of thousands of newly discovered compounds of natural origin and their biological activities, all of which have the potential to be used for a wide range of therapeutic purposes. There are multiple research papers denoting the central objective of chalcones, which have been shown to have therapeutic potential against various forms of ischemia. The various aspects of chalcones are discussed in this review regarding molecular mechanisms involved in the promising anti-ischemic potential of these chalcones. The main mechanisms involved in these protective effects are Nrf2/Akt activation and NF-κB/TLR4 suppression. Furthermore, in-silico studies were carried out to discover the probable binding of these chalcones to Keap-1 (an inhibitor of Nrf2), Akt, NF-κB, and TLR4 protein molecules. Besides, network pharmacology analysis was conducted to predict the interacting partners of these signals. The obtained results indicated that Nrf2, Akt, NF-κB, and TLR4 are involved in the beneficial anti-ischemic actions of chalcones. Conclusively, the present findings show that chalcones as anti-ischemic agents have a valid rationale. The discussed studies will provide a comprehensive viewpoint on chalcones and can help to optimize their effects in different ischemia. PRACTICAL APPLICATIONS: Ischemic organ damage is an unavoidable pathological condition with a high worldwide incidence. According to the current research progress, natural chalcones have been proved to treat and/or prevent various types of ischemic organ damage by alleviating oxidative stress, inflammation, and apoptosis by different molecular mechanisms. This article displays the comprehensive research progress and the molecular basis of ischemic organ damage pathophysiology and introduces natural chalcones' mechanism in the ischemic organ condition.

Isoliquiritigenin attenuates pathological cardiac hypertrophy via regulating AMPKα in vivo and in vitro

Isoliquiritigenin (ISL) is a type of flavonoid, derived from the root of the legume plant Glycyrrhiza, that has multiple pharmacological properties. However, its role in cardiac remodeling induced by pressure overload has yet to be fully elucidated. Aortic banding (AB) surgery was used to establish a cardiac hypertrophy model in male C57BL/6 mice. Mice were randomly divided into four groups (n = 20 per group) as follows: Sham + vehicle, sham + ISL, AB + vehicle and AB + ISL. ISL was administered to the mice intragastrically for 1 week after the operation. To evaluate the role of ISL in mice challenged with AB, echocardiography, histological analysis and molecular biochemistry examinations were performed. ISL treatment decreased cardiac hypertrophy and improved cardiac dysfunction induced by pressure overload. In addition, ISL decreased the cross-sectional area of cardiomyocytes. Furthermore, ISL reversed the AB-mediated increase in phosphorylated (p-)mTOR and p-ERK protein levels and further increased the protein expression of p-AMP-activated protein kinase (AMPK)α in response to AB, whereas knockout of AMPKα abolished the protective effects of ISL. The present study suggested that ISL could suppress pressure overload-induced cardiac hypertrophy through the activation of AMPKα. Therefore, ISL may serve as a therapeutic target for cardiac remodeling.

Therapeutic Intervention in Cancer by Isoliquiritigenin from Licorice: A Natural Antioxidant and Redox Regulator

Oxidative stress could lead to a variety of body dysfunctions, including neurodegeneration and cancer, which are closely associated with intracellular signal transducers such as reactive oxygen species (ROS). It has been suggested that ROS is the upstream regulator of autophagy, and that it provides a negative feedback regulation to remove oxidative damage. Defects in the ROS-autophagic redox homeostasis could lead to the increased production of ROS and the accumulation of damaged organelles that in turn promote metabolic reprogramming and induce tumorigenesis. One significant characteristic of pancreatic cancer is the reprogramming of cellular energy metabolism, which facilitates the rapid growth, invasiveness, and the survival of cancer cells. Thus, the rectification of metabolic dysfunction is essential in therapeutic cancer targeting. Isoliquiritigenin (ISL) is a chalcone obtained from the plant Glycyrrhiza glabra, which is a powdered root licorice that has been consumed for centuries in different regions of the world. ISL is known to be a natural antioxidant that possesses diversified functions, including redox regulation in cells. This review contains discussions on the herbal source, biological properties, and anticancer potential of ISL. This is the first time that the anticancer activities of ISL in pancreatic cancer has been elucidated, with a coverage of the involvement of antioxidation, metabolic redox regulation, and autophagy in pancreatic cancer development. Furthermore, some remarks on related compounds of the isoflavonoid biosynthetic pathway of ISL will also be discussed.

The effects and mechanisms of isoliquiritigenin loaded nanoliposomes regulated AMPK/mTOR mediated glycolysis in colorectal cancer

In this study, isoliquiritigenin (ISL) incorporated nanoliposomes were prepared and their effects on colorectal cancer (CRC) cell lines were investigated. Herein, we sought to explore the anti-cancer mechanisms of ISL loaded nanoliposomes (ISL-NLs) on AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) pathways mediated glycolysis. Also, the key targets such as caveolin 1 (CAV1), glucose transporters and Akt/mTOR that promote glycolysis, and are activated via the induction of α-enolase (ENO1), fructose bisphosphate aldolase A (ALDOA) and monocarboxylate transporter 4 (MCT4) expressions were also investigated. It was shown that ISL-NLs significantly suppressed the proliferation and glucose uptake of CRC cell by potentially regulating the glycolysis and lactate targets as well as pathways that formed the basis of the anti-CRC effects of ISL-NLs. The mechanism underlying this effect was further validated via the regulation of some key targets such as ENO1, ALDOA, lactate dehydrogenase A (LDHA) and MCT4 in glycolysis coupled with cellular myelocytomatosis oncogene (c-myc), hypoxia-inducible factor 1-alpha (HIF-1α) in protein kinase B/mTOR (Akt/mTOR) pathways. Moreover, the AMPK proteins were identified to be up-regulated while the lactic acid production was suppressed by ISL-NLs in the CRC cells, indicating that ISL-NLs had an inhibitory effect on AMPK mediated glycolysis and lactate production. Altogether, these results have provided insights into the mechanism underlying the key role that liposomal ISL played in the multiple inhibition of AMPK and Akt/mTOR mediated glycolysis and lactate generation, which may be regulated as the alternative metabolic pathways of CRC as well as serve as adjuvant therapy for the disease.

Dietary Flavonoids: Cardioprotective Potential with Antioxidant Effects and Their Pharmacokinetic, Toxicological and Therapeutic Concerns

Flavonoids comprise a large group of structurally diverse polyphenolic compounds of plant origin and are abundantly found in human diet such as fruits, vegetables, grains, tea, dairy products, red wine, etc. Major classes of flavonoids include flavonols, flavones, flavanones, flavanols, anthocyanidins, isoflavones, and chalcones. Owing to their potential health benefits and medicinal significance, flavonoids are now considered as an indispensable component in a variety of medicinal, pharmaceutical, nutraceutical, and cosmetic preparations. Moreover, flavonoids play a significant role in preventing cardiovascular diseases (CVDs), which could be mainly due to their antioxidant, antiatherogenic, and antithrombotic effects. Epidemiological and in vitro/in vivo evidence of antioxidant effects supports the cardioprotective function of dietary flavonoids. Further, the inhibition of LDL oxidation and platelet aggregation following regular consumption of food containing flavonoids and moderate consumption of red wine might protect against atherosclerosis and thrombosis. One study suggests that daily intake of 100 mg of flavonoids through the diet may reduce the risk of developing morbidity and mortality due to coronary heart disease (CHD) by approximately 10%. This review summarizes dietary flavonoids with their sources and potential health implications in CVDs including various redox-active cardioprotective (molecular) mechanisms with antioxidant effects. Pharmacokinetic (oral bioavailability, drug metabolism), toxicological, and therapeutic aspects of dietary flavonoids are also addressed herein with future directions for the discovery and development of useful drug candidates/therapeutic molecules.

Cardioprotective Effect of Echinatin Against Ischemia/Reperfusion Injury: Involvement of Hippo/Yes-Associated Protein Signaling

Background: Echinatin (Ech) has been reported to exert antioxidant and anti-inflammatory activities. In this study, we aimed to characterize the functional role of Ech in myocardial ischemic/reperfusion (MI/R) injury and elucidate its underlying mechanism of action.

Method: We established in vivo and in vitro models of MI/R injury to determine the effect of Ech on MI/R injury. Gene expression was examined using quantitative real-time polymerase chain reaction and western blotting. Myocardial infarction was assessed using tetrazolium chloride staining and the degree of myocardial injury was evaluated by measuring lactate dehydrogenase (LDH) and creatine kinase-myocardial band (CK-MB) levels. Cell apoptosis was detected using the terminal deoxynucleotidyl transfer-mediated dUTP nick end-labeling (TUNEL) assay. The viability of H9c2 cells was determined using Cell Counting Kit-8 assay.

Results: MI/R induced myocardial infarction, which was mitigated by Ech treatment. Moreover, Ech treatment resulted in a marked decline of LDH and CK-MB levels in the serum and myocardium of MI/R rats. Ech treatment also restrained cardiomyocyte apoptosis in vivo and in vitro, as evidenced by reduction in LDH release, the number of TUNEL-positive cells, and caspase-3 activity. Furthermore, Ech administration inhibited MI/R-induced activation of Hippo/Yes-associated protein signaling in vivo and in vitro, as indicated by inhibition of mammalian sterile 20-like protein kinase 1, large tumor suppressor one, and YAP phosphorylation and promotion of YAP nuclear translocation. However, silencing of YAP counteracted the protective effect of Ech on hypoxia/reoxygenation-induced myocardial injury in vitro.

Conclusion: Ech exerted its protective effect against MI/R injury at least partially by suppressing the Hippo/YAP signaling pathway, providing novel insights into the remission of MI/R injury.

Isoliquiritigenin Reduces LPS-Induced Inflammation by Preventing Mitochondrial Fission in BV-2 Microglial Cells

Excessive microglial cell activation in the brain can lead to the production of various neurotoxic factors (e.g., pro-inflammatory cytokines, nitric oxide) which can, in turn, initiate neurodegenerative processes. Recent research has been reported that mitochondrial dynamics regulate the inflammatory response of lipopolysaccharide (LPS). Isoliquiritigenin (ISL) is a compound found in Glycyrrhizae radix with anti-inflammatory and antioxidant properties. In this study, we investigated the function of ISL on the LPS-induced pro-inflammatory response in BV-2 microglial cells. We showed that ISL reduced the LPS-induced increase in pro-inflammatory mediators (e.g., nitric oxide and pro-inflammatory cytokines) via the inhibition of ERK/p38/NF-κB activation and the generation of reactive oxygen species (ROS). Furthermore, ISL inhibited the excessive mitochondrial fission induced by LPS, regulating mitochondrial ROS generation and pro-inflammatory response by suppressing the calcium/calcineurin pathway to dephosphorylate Drp1 at the serine 637 residue. Interestingly, the ISL pretreatment reduced the number of apoptotic cells and levels of cleaved caspase3/PARP, compared to LPS-treated cells. Our findings suggested that ISL ameliorated the pro-inflammatory response of microglia by inhibiting dephosphorylation of Drp1 (Ser637)-dependent mitochondrial fission. This study provides the first evidence for the effects of ISL against LPS-induced inflammatory response related and its link to mitochondrial fission and the calcium/calcineurin pathway. Consequently, we also identified the protective effects of ISL against LPS-induced microglial apoptosis, highlighting the pharmacological role of ISL in microglial inflammation-mediated neurodegeneration.

Protective effect of isoliquiritigenin on experimental diabetic nephropathy in rats: Impact on Sirt-1/NFκB balance and NLRP3 expression

The prevalence of diabetes mellitus (DM) drastically increases worldwide. Persistent hyperglycemia affects body microvasculature causing injuries to kidney producing diabetic nephropathy (DNE). Manifestation of these microvascular complications is associated with disturbed redox homeostasis. The current study evaluated the effect of isoliquiritigenin (ISLQ), a bioactive chalcone found in licorice which is known for its antioxidant effect, on diabetes-induced renal injury. DM was prompted in male rats by streptozotocin (STZ, 50 mg/kg, intraperitoneally). ISLQ was administrated by oral gavage for 8 weeks at a dose (20 mg/kg/day). Features of renal injury were observed in kidneys of diabetic rats including, albuminuria and deteriorated renal function. Renal dysfunction was associated with reduced sirtuin-1 (Sirt-1) expression, increased renal oxidative stress, nucleotide-binding domain and leucine-rich repeat containing protein-3 (NLRP3), nuclear factor-κB (NFκB) and inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Moreover, there was significant downregulation of anti-inflammatory cytokine interleukin-10 (IL-10), glomerular and tubular injury and collagen accumulation. ISLQ administration preserved renal function and architecture, restored Sirt1 and renal oxidant-antioxidant balance, dampened inflammation and attenuated collagen accumulation. It can be inferred that ISLQ possess a protective effect and could have a potential as a food supplement to halt development and progression of DNE.

Dietary Compound Isoliquiritigenin, an Antioxidant from Licorice, Suppresses Triple-Negative Breast Tumor Growth via Apoptotic Death Program Activation in Cell and Xenograft Animal Models

Patients with triple-negative breast cancer have few therapeutic strategy options. In this study, we investigated the effect of isoliquiritigenin (ISL) on the proliferation of triple-negative breast cancer cells. We found that treatment with ISL inhibited triple-negative breast cancer cell line (MDA-MB-231) cell growth and increased cytotoxicity. ISL reduced cell cycle progression through the reduction of cyclin D1 protein expression and increased the sub-G1 phase population. The ISL-induced apoptotic cell population was observed by flow cytometry analysis. The expression of Bcl-2 protein was reduced by ISL treatment, whereas the Bax protein level increased; subsequently, the downstream signaling molecules caspase-3 and poly ADP-ribose polymerase (PARP) were activated. Moreover, ISL reduced the expression of total and phosphorylated mammalian target of rapamycin (mTOR), ULK1, and cathepsin B, whereas the expression of autophagic-associated proteins p62, Beclin1, and LC3 was increased. The decreased cathepsin B cause the p62 accumulation to induce caspase-8 mediated apoptosis. In vivo studies further showed that preventive treatment with ISL could inhibit breast cancer growth and induce apoptotic and autophagic-mediated apoptosis cell death. Taken together, ISL exerts an effect on the inhibition of triple-negative MDA-MB-231 breast cancer cell growth through autophagy-mediated apoptosis. Therefore, future studies of ISL as a supplement or alternative therapeutic agent for clinical trials against breast cancer are warranted.

The Active Compounds of Yixin Ningshen Tablet and Their Potential Action Mechanism in Treating Coronary Heart Disease- A Network Pharmacology and Proteomics Approach

Yixin Ningshen tablet is a CFDA-approved TCM formula for treating coronary heart disease (CHD) clinically. However, its active compounds and mechanism of action in treating CHD are unknown. In this study, a novel strategy with the combination of network pharmacology and proteomics was proposed to identify the active components of Yixin Ningshen tablet and the mechanism by which they treat CHD. With the application of network pharmacology, 62 active compounds in Yixin Ningshen tablet were screened out by text mining, and their 313 potential target proteins were identified by a tool in SwissTargetPrediction. These data were integrated with known CHD-related proteomics results to predict the most possible targets, which reduced the 313 potential target proteins to 218. The STRING database was retrieved to find the enriched pathways and related diseases of these target proteins, which indicated that the Calcium, MAPK, PI3K-Akt, cAMP, Rap1, AGE-RAGE, Relaxin, HIF-1, Prolactin, Sphingolipid, Estrogen, IL-17, Jak-STAT signaling pathway, necroptosis, arachidonic acid metabolism, insulin resistance, endocrine resistance, and steroid hormone biosynthesis might be the main pathways regulated by Yixin Ningshen tablet for the treatment of CHD. Through further enrichment analysis and literature study, EGFR, ERBB2, VGFR2, FGF1, ESR1, LOX15, PGH2, HMDH, ADRB1, and ADRB2 were selected and then validated to be the target proteins of Yixin Ningshen tablet by molecular docking, which indicated that Yixin Ningshen tablet might treat CHD mainly through promoting heart regeneration, new vessels' formation, and the blood supply of the myocardial region and reducing cardiac output, oxygen demand, and inflammation as well as arteriosclerosis (promoting vasodilation and intraplaque neoangiogenesis, lowering blood lipid). This study is expected to benefit the clinical application of Yixin Ningshen tablet for the treatment of CHD.

Isoliquiritigenin Inhibits Ovarian Cancer Metastasis by Reversing Epithelial-to-Mesenchymal Transition

The epithelial-to-mesenchymal transition (EMT) plays a prominent role in cancer metastasis. Isoliquiritigenin (ISL), one of the flavonoids in licorice, has been shown to exhibit anticancer activities in many cancer types through various mechanisms. However, it is unknown whether ISL impacts the EMT process. Here, we show that ISL is able to suppress mesenchymal features of ovarian cancer SKOV3 and OVCAR5 cells, evidenced by an apparent morphological change from a mesenchymal to an epithelial phenotype and reduced levels of mesenchymal markers accompanied by the gain of E-cadherin expression. The suppression of EMT is also supported by the observed decrease in cell migration and in vitro invasion upon ISL treatment. Moreover, we show that ISL effectively blocks the intraperitoneal xenograft development of the SKOV3 cell line and prolonged the survival of tumor-bearing mice. These data suggest that ISL inhibits intraperitoneal ovary tumor development through the suppression of EMT, indicating that ISL may be an effective therapeutic agent against ovarian cancer.

Isoliquiritigenin Suppresses E2-Induced Uterine Leiomyoma Growth through the Modulation of Cell Death Program and the Repression of ECM Accumulation

Uterine leiomyomas, also known as fibroids, are common and prevalent in women of reproductive age. In this study, the effect of Isoliquiritigenin (ISL), a licorice flavonoid, on the anti-proliferation of uterine leiomyoma was investigated. We found that the survival of uterine leiomyoma ELT3 cells and primary uterine smooth muscle (UtSMC) cells was reduced by treatment with ISL alone or with ISL plus estradiol (E2). Cell cycles were arrested through the reduction of G2/M- and S-phase populations in ELT3 and UtSMC cells, respectively. Furthermore, increased sub-G1 phase and nucleus condensation were observed in ELT3 cells but not in UtSMC cells. Co-treatment of ELT3 cells with E2 and ISL inhibited ERK1/2 activation, whereas p38 and c-Jun N-terminal kinase (JNK) activation was enhanced. Moreover, ISL-induced apoptosis and autophagy cell death in ELT3 cells were observed. Serum E2 and P4 levels were reduced in a E2-enhanced uterine myometrium hyperplasia mouse model by ISL treatment, which contributed to the downregulation of the expression of extracellular matrix (ECM) associated proteins and matrix metalloproteinase (MMPs). Taken together, these results showed that ISL exerted a higher effect on the inhibition of estrogen-induced uterine leiomyoma growth for both in vitro and in vivo ECM accumulation, demonstrating its potential as a new option for treatment of uterine leiomyoma.

Isoliquiritigenin Attenuates Monocrotaline-Induced Pulmonary Hypertension via Inhibition of the Inflammatory Response and PASMCs Proliferation

Pulmonary hypertension (PH) is a progressive and serious disease, where exacerbated inflammatory response plays a critical role. Isoliquiritigenin (ISL), an important flavonoid isolated from Glycyrrhizae radix, exhibits a wide range of pharmacological actions including anti-inflammation. Previously we found ISL alleviated hypoxia-induced PH; in the present study, to extend this, we evaluated the effects of ISL on monocrotaline (MCT)-induced PH and the relevant mechanisms. Rats received a single intraperitoneal injection of MCT, followed by intragastric treatments with ISL (10 mg/kg/d or 30 mg/kg/d) once a day for 28 days. The MCT administration increased the right ventricular systolic pressure (RVSP) (p < 0.001), the median width of pulmonary arteries (p < 0.01), and the weight ratio of the right ventricular wall/left ventricular wall plus septum (Fulton index) (p < 0.01) in rats; however, these changes were inhibited by both doses of ISL (p < 0.05). In addition, treatment with ISL suppressed the upregulated production of serum interleukin-6 (p < 0.01) and tumor necrosis factor-α (p < 0.05) by MCT and reversed the increases in the numbers of proliferating cell nuclear antigen (PCNA)-positive cells (p < 0.01) in the medial wall of pulmonary arteries. In in vitro experiments, ISL (10 μM, 30 μM, and 100 μM) inhibited excessive proliferation of cultured primary pulmonary artery smooth muscle cells (PASMCs) (p < 0.05, p < 0.01, and p < 0.001) in a dose-dependent manner and prevented an increase in the expressions of PCNA (p < 0.01) and phospho-Akt (p < 0.05) in PASMCs induced by hypoxia. These results suggest that ISL can attenuate MCT-induced PH via its anti-inflammatory and antiproliferative actions.

Anti-proliferative and cytotoxic activities of the flavonoid isoliquiritigenin in the human neuroblastoma cell line SH-SY5Y

Neuroblastoma is a common childhood cancer with high mortality. We evaluated the capacity of the flavonoid, isoliquiritigenin (4,2',4'-trihydroxychalcone; ISL) to inhibit cellular proliferation and migration in the human neuroblastoma cell line SH-SY5Y. Incubation of cultured SH-SY5Y cells with 20-100 μM ISL decreased cell confluency (15-70%) after 24 h incubation, while 10-100 μM ISL (24 h) depleted intracellular ATP stores (15-90% vs vehicle-treated control) after 24 h incubation. ISL-mediated cell toxicity did not involve intracellular caspase 3/7 activation, externalization of phosphatidylserine on the cell membrane or stimulation of TNF and IL-1β release, all indicating that the flavonoid did not induce apoptosis. Pre-treatment of cells with necrostatin-1, a necroptosis inhibitor, significantly restored ATP levels (ATP levels increased 12-42%) in ISL-treated neuroblastoma cells indicative of enhanced viability. By contrast, RIP1 phosphorylation status remained unchanged in cells treated with ISL although the intracellular ratio of phosphorylated/total parental RIP1 increased after ISL treatment on SH-SY5Y cells indicating that ISL decreased levels of native RIP1. In addition, ISL treatment inhibited SH-SY5Y cell migration/proliferation in a scratch assay and arrested cell cycle transition by significantly decreasing the number of cells in G0/G1 phase and increasing populations by ~10% in S (primarily) and G2/M (lesser extent) phases. The intracellular ratio of phosphorylated/total ERK 1/2 and p38 remained unchanged after ISL treatment (up to 40 μM); ERK activation was only determined at ISL dose well above the experimental IC₅₀ value as judged by ELISA analyses and this did not correlate with ISL cytotoxicity at lower dose <40 μM; Western blot assay confirmed the detection of phosphorylated (p-)ERK1/2 and (p-)p38 in ISL treated cells. Together the results suggest that ISL exerts anti-proliferative and cytotoxic activity on SHSY5Y cells through the loss of ATP, induction of cell cycle arrest, and cell death largely via a necroptotic mechanism in the absence of apoptotic activity.

The Novel Neuroprotective Compound KMS99220 Has an Early Anti-neuroinflammatory Effect via AMPK and HO-1, Independent of Nrf2

We have previously reported a novel synthetic compound KMS99220 that prevented degeneration of the nigral dopaminergic neurons and the associated motor deficits, suggesting a neuroprotective therapeutic utility for Parkinson's disease. Microglia are closely associated with neuroinflammation, which plays a key role in the pathogenesis of neurodegenerative diseases. In this study, we investigated the effects of KMS99220 on the signaling involving AMP-activated protein kinase (AMPK) and heme oxygenase-1 (HO-1), the enzymes thought to regulate inflammation. KMS99220 was shown to elevate the enzyme activity of purified AMPK, and phosphorylation of cellular AMPK in BV2 microglia. It increased the level of HO-1, and this was attenuated by AMPK inhibitors. KMS99220 lowered phosphorylation of IκB, nuclear translocation of NFκB, induction of inducible nitric oxide synthase, and generation of nitric oxide in BV2 cells that had been challenged with lipopolysaccharide. This anti-inflammatory response involved HO-1, because both its pharmacological inhibition and knockdown of its expression abolished the response. The AMPK inhibitors also reversed the anti-inflammatory effects of KMS99220. The induction of HO-1 by KMS99220 occurred within 1 h, and this appeared not to involve the transcription factor Nrf2, because Nrf2 knockdown did not affect the compound's HO-1 inducing- and anti-inflammatory effects in this time window. These findings indicated that KMS99220 leads to AMPK-induced HO-1 expression in microglia, which in turn plays an important role in early anti-inflammatory signaling. Together with its neuroprotective property, KMS99220 may serve as a feasible therapeutic agent against neuroinflammation and neurodegeneration.

Isoliquiritigenin attenuates glutamate-induced mitochondrial fission via calcineurin-mediated Drp1 dephosphorylation in HT22 hippocampal neuron cells

Numerous studies suggest that glutamate toxicity is a major contributor to neuronal dysfunction and death in several neurodegenerative diseases. In our previous study, isoliquiritigenin (ISL) isolated from Glycyrrhiza uralensis showed neuroprotective effects against neuronal cell death mediated by intracellular reactive oxygen species (ROS) generation and loss of mitochondrial membrane potential. However, the mechanisms by which ISL protects against glutamate-induced oxidative stress are unknown. In the present study, we focused on the cellular and molecular mechanisms underlying the inhibition of ROS production and induction of mitochondrial dysfunction by ISL in glutamate-stimulated HT22 mouse hippocampal neuron cells. The results revealed that ISL inhibited glutamate-induced mitochondrial ROS production and decline of glutathione levels and ATP generation in HT22 cells. Interestingly, we discovered that ISL prevents glutamate-induced mitochondrial fission by inhibiting the dephosphorylation of Drp1 at the serine 637 residue, which is a regulatory factor of mitochondrial dynamics, and both a S637D mutation of Drp1, which resulted in a phosphorylation-mimetic form of Drp1 at Ser637, and mitochondria-targeted antioxidant Mito-TEMPO inhibited glutamate-induced mitochondrial fission. Furthermore, ISL also prevented the increase of intracellular calcium accompanied by activation of calcineurin, which is a key regulator of dephosphorylation of Drp1 (Ser637), in glutamate-treated HT22 cells. Taken together, our results demonstrated that ISL protects against glutamate-induced mitochondrial fission by inhibiting the increase of mitochondrial ROS and intracellular calcium, which are accompanied by dephosphorylation of Drp1 (Ser637), and consequently attenuates glutamate-induced neuronal cell death. Therefore, these findings suggest that ISL exhibits the potential for protection against glutamate toxicity. These results may contribute to the development of new drugs and novel strategies for the treatment of neurodegenerative disorders related to glutamate toxicity.

Effects of Polyphenols on Oxidative Stress-Mediated Injury in Cardiomyocytes

Cardiovascular diseases are the main cause of mortality and morbidity in the world. Hypertension, ischemia/reperfusion, diabetes and anti-cancer drugs contribute to heart failure through oxidative and nitrosative stresses which cause cardiomyocytes nuclear and mitochondrial DNA damage, denaturation of intracellular proteins, lipid peroxidation and inflammation. Oxidative or nitrosative stress-mediated injury lead to cardiomyocytes apoptosis or necrosis. The reactive oxygen (ROS) and nitrogen species (RNS) concentration is dependent on their production and on the expression and activity of anti-oxidant enzymes. Polyphenols are a large group of natural compounds ubiquitously expressed in plants, and epidemiological studies have shown associations between a diet rich in polyphenols and the prevention of various ROS-mediated human diseases. Polyphenols reduce cardiomyocytes damage, necrosis, apoptosis, infarct size and improve cardiac function by decreasing oxidative stress-induced production of ROS or RNS. These effects are achieved by the ability of polyphenols to modulate the expression and activity of anti-oxidant enzymes and several signaling pathways involved in cells survival. This report reviews current knowledge on the potential anti-oxidative effects of polyphenols to control the cardiotoxicity induced by ROS and RNS stress.

Synthetic Isoliquiritigenin Inhibits Human Tongue Squamous Carcinoma Cells through Its Antioxidant Mechanism

Isoliquiritigenin (ISL), a natural antioxidant, has antitumor activity in different types of cancer cells. However the antitumor effect of ISL on human tongue squamous carcinoma cells (TSCC) is not clear. Here we aimed to investigate the effects of synthetic isoliquiritigenin (S-ISL) on TSCC and elucidate the underlying mechanisms. S-ISL was synthesized and elucidated from its nuclear magnetic resonance spectrum and examined using high performance liquid chromatography. The effects of S-ISL on TSCC cells (Tca8113) were evaluated in relation to cell proliferation, apoptosis and adhesion, migration, and invasion using sulforhodamine B assay, fluorescence microscopy technique, flow cytometry (FCM) analysis, and Boyden chamber assay. The associated regulatory mechanisms were examined using FCM and fluorescence microscopy for intracellular reactive oxygen species (ROS) generation, Gelatin zymography assay for matrix metalloproteinase (MMP) activities, and Western blot for apoptosis regulatory proteins (Bcl-2 and Bax). Our data indicated that S-ISL inhibited Tca8113 cell proliferation, adhesion, migration, and invasion while promoting the cell apoptosis. Such effects were accompanied by downregulation of Bcl-2 and upregulation of Bax, reduction of MMP-2 and MMP-9 activities, and decreased ROS production. We conclude that S-ISL is a promising agent targeting TSCC through multiple anticancer effects, regulated by its antioxidant mechanism.

Flavonoids and mitochondrial pharmacology: A new paradigm for cardioprotection

Acute myocardial ischemia is one of the major causes of illness and of deaths in Western society; therefore the definition of the signaling pathways involved in the cardioprotection represents a challenging goal in order to discover novel pharmacological approaches. In this regard, a number of epidemiologic studies demonstrate a relationship between intake of flavonoid-rich foods and reduction of cardiovascular risk factors and mortality. Moreover, numerous experimental studies have examined flavonoid-induced cardioprotective effects on several animal models of myocardial ischemia/reperfusion. As concerns the mechanisms of action, although the antioxidant effect of flavonoids has been long thought to be a crucial factor accounting for cardioprotection, mitochondrial pathways (ion channels, protein kinases, etc.) are presently emerging as specific pharmacological targets more relevantly involved in the anti-ischemic effects of some flavonoids. Since these pharmacodynamic features seem to be poorly considered, this review examines the mitochondrial role in the cardioprotective mechanisms of some members of this phytochemical class, by describing the biological pathways and reporting an overview of the most important experimental evidence in this field.

Chemical profiling with HPLC-FTMS of exogenous and endogenous chemicals susceptible to the administration of chotosan in an animal model of type 2 diabetes-induced dementia

In our previous study, the daily administration of chotosan (CTS), a Kampo formula consisting of Uncaria and other 10 different crude drugs, ameliorated cognitive deficits in several animal models of dementia including type 2 diabetic db/db mice in a similar manner to tacrine, an acetylcholinesterase inhibitor. The present study investigated the metabonomics of CTS in db/db mice, a type 2 diabetes model, and m/m mice, a non-diabetes control strain, to identify the exogenous and endogenous chemicals susceptible to the administration of CTS using high performance liquid chromatography equipped with an orbitrap hybrid Fourier transform mass spectrometer. The results obtained revealed that the systemic administration of CTS for 20 days led to the distribution of Uncalia plant-derived alkaloids such as rhynchophylline, hirsuteine, and corynoxeine in the plasma and brains of db/db and m/m mice and induced alterations in four major metabolic pathways; i.e., (1) purine, (2) tryptophan, (3) cysteine and methionine, (4) glycerophospholipids in db/db mice. Moreover, glycerophosphocholine (GPC) levels in the plasma and brain were significantly higher in CTS-treated db/db mice than in vehicle-treated control animals. The results of the in vitro experiment using organotypic hippocampal slice cultures demonstrated that GPC (10-30 μM), as well as tacrine, protected hippocampal cells from N-methyl-d-aspartate-induced excitotoxicity in a manner that was reversible with the muscarinic receptor antagonist scopolamine, whereas GPC had no effect on the activity of acetylcholinesterase in vitro. Our results demonstrated that some CTS constituents with neuropharmacological activity were distributed in the plasma and brain tissue following the systemic administration of CTS and may subsequently have affected some metabolic pathways including glycerophospholipid metabolism and cognitive function in db/db mice. Moreover, the present metabonomic analysis suggested that GPC is a putative endogenous chemical that may be involved in the tacrine-like actions of CTS in the present diabetic animal model.

Pharmacological Activities of Sijunzi Decoction Which Are Related to Its Antioxidant Properties

This paper introduces the antioxidant constituents and pharmacological effects of Sijunzi decoction by looking up literatures in recent years. Sijunzi decoction is composed of Ginseng, Atractylodes, Tuckahoe, and Glycyrrhiza. The antioxidant ingredients of Sijunzi decoction include paeonol, dauricine, naringin, and isoliquiritigenin. The study has proved that it possesses wide pharmacological effects of anticardiovascular diseases, antinervous system disease, antidiabetes, antimetabolic syndrome, and antitumor. Research on the antioxidant components of Sijunzi decoction and their targets is a promising study area in the future.