Licochalcone A isolated from licorice suppresses lipopolysaccharide-stimulated inflammatory reactions in RAW264.7 cells and endotoxin shock in mice

Isolation and biological activity of natural chalcones based on antibacterial mechanism classification

Bacterial infection, which is still one of the leading causes of death in humans, poses an enormous threat to the worldwide public health system. Antibiotics are the primary medications used to treat bacterial diseases. Currently, the discovery of antibiotics has reached an impasse, and due to the abuse of antibiotics resulting in bacterial antibiotic resistance, researchers have a critical desire to develop new antibacterial agents in order to combat the deteriorating antibacterial situation. Natural chalcones, the flavonoids consisting of two phenolic rings and a three-carbon α, β-unsaturated carbonyl system, possess a variety of biological and pharmacological properties, including anti-cancer, anti-inflammatory, antibacterial, and so on. Due to their potent antibacterial properties, natural chalcones possess the potential to become a new treatment for infectious diseases that circumvents existing antibiotic resistance. Currently, the majority of research on natural chalcones focuses on their synthesis, biological and pharmacological activities, etc. A few studies have been conducted on their antibacterial activity and mechanism. Therefore, this review focuses on the antibacterial activity and mechanisms of seventeen natural chalcones. Firstly, seventeen natural chalcones have been classified based on differences in antibacterial mechanisms. Secondly, a summary of the isolation and biological activity of seventeen natural chalcones was provided, with a focus on their antibacterial activity. Thirdly, the antibacterial mechanisms of natural chalcones were summarized, including those that act on bacterial cell membranes, biological macromolecules, biofilms, and quorum sensing systems. This review aims to lay the groundwork for the discovery of novel antibacterial agents based on chalcones.

Licochalcone A plays dual antiviral roles by inhibiting RSV and protecting against host damage

Respiratory syncytial virus (RSV) causes lower respiratory tract diseases and bronchiolitis in children and elderly individuals. There are no effective drugs currently available to treat RSV infection. In this study, we report that Licochalcone A (LCA) can inhibit RSV replication and mitigate RSV-induced cell damage in vitro, and that LCA exerts a protective effect by reducing the viral titer and inflammation in the lungs of infected mice in vivo. We suggest that the mechanism of action occurs through pathways of antioxidant stress and inflammation. Further mechanistic results demonstrate that LCA can induce nuclear factor erythroid 2-related factor 2 (Nrf2) translocation into the nucleus, activate heme oxygenase 1 (HO-1), and inhibit reactive oxygen species-induced oxidative stress. LCA also works to reverse the decrease in I-kappa-B-alpha (IкBα) levels caused by RSV, which in turn inhibits inflammation through the associated nuclear factor kappa B and tumor necrosis factor-α signaling pathways. The combined action of the two cross-talking pathways protects hosts from RSV-induced damage. To conclude, our study is the first of its kind to establish evidence of LCA as a viable treatment for RSV infection.

Advances in autophagy modulation of natural products in cervical cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Natural products play a critical role in drug development and is emerging as a potential source of biologically active metabolites for therapeutic intervention, especially in cancer therapy. In recent years, there is increasing evidence that many natural products may modulate autophagy through various signaling pathways in cervical cancer. Understanding the mechanisms of these natural products helps to develop medications for cervical cancer treatments.

AIM OF THE STUDY

In recent years, there is increasing evidence that many natural products may modulate autophagy through various signaling pathways in cervical cancer. In this review, we briefly introduce autophagy and systematically describe several classes of natural products implicated in autophagy modulation in cervical cancer, hoping to provide valuable information for the development of cervical cancer treatments based on autophagy.

MATERIALS AND METHODS

We searched for studies on natural products and autophagy in cervical cancer on the online database and summarized the relationship between natural products and autophagy modulation in cervical cancer.

RESULTS

Autophagy is a lysosome-mediated catabolic process in eukaryotic cells that plays an important role in a variety of physiological and pathological processes, including cervical cancer. Abnormal expression of cellular autophagy and autophagy-related proteins has been implicated in cervical carcinogenesis, and human papillomavirus infection can affect autophagic activity. Flavonoids, alkaloids, polyphenols, terpenoids, quinones, and other compounds are important sources of natural products that act as anticancer agents. In cervical cancer, natural products exert the anticancer function mainly through the induction of protective autophagy.

CONCLUSIONS

The regulation of cervical cancer autophagy by natural products has significant advantages in inducing apoptosis, inhibiting proliferation, and reducing drug resistance in cervical cancer.

Chalcones and Gastrointestinal Cancers: Experimental Evidence

Colorectal (CRC) and gastric cancers (GC) are the most common digestive tract cancers with a high incidence rate worldwide. The current treatment including surgery, chemotherapy or radiotherapy has several limitations such as drug toxicity, cancer recurrence or drug resistance and thus it is a great challenge to discover an effective and safe therapy for CRC and GC. In the last decade, numerous phytochemicals and their synthetic analogs have attracted attention due to their anticancer effect and low organ toxicity. Chalcones, plant-derived polyphenols, received marked attention due to their biological activities as well as for relatively easy structural manipulation and synthesis of new chalcone derivatives. In this study, we discuss the mechanisms by which chalcones in both in vitro and in vivo conditions suppress cancer cell proliferation or cancer formation.

Anti-inflammatory effects of Torin2 on lipopolysaccharide-treated RAW264.7 murine macrophages and potential mechanisms

Context

Torin2 has various pharmacological properties. However, its anti-inflammatory activity has not been reported.

Objective

This study focused on the potential anti-inflammatory properties of Torin2 in lipopolysaccharide (LPS)-evoked RAW264.7 murine macrophages. The study aimed to shed light on the molecular mechanisms that ameliorate these effects.

Methods

Torin2 was applied to 100 ng/mL lipopolysaccharide-induced RAW 264.7 macrophages in vitro. Nitric oxide (NO) levels were detected using the Griess reagent kit. Prostaglandin E2 (PGE2), pro-inflammatory cytokines interleukin (IL)-1β, interleukin (IL)-6, and tumor necrosis factor in the supernatant fraction were determined using enzyme-linked immunosorbent assay (ELISA). Gene expression of pro-inflammatory cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) were tested using real-time quantitative polymerase chain reaction (qPCR). Cyclooxygenase-2 and inducible nitric oxide synthase proteins, phosphorylation of mitogen-activated protein kinase (MAPK) subgroups, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38, I-kappa-B-alpha (IκBα), and nuclear factor-kappa-B (NF-κB), and activation in extracts were detected via western blotting. Nuclear factor-kappa-B/p65 nuclear translocation was tested using an immunofluorescence assay.

Results

The results demonstrated that pre-treatment with Torin2 profoundly attenuated the lipopolysaccharide-stimulated levels of nitric oxide and prostaglandin E2, pro-inflammatory cytokines, messenger ribonucleic acid (mRNA), and protein expression of cyclooxygenase-2 and inducible nitric oxide synthase. Collectively, Torin2 pre-treatment notably weakened lipopolysaccharide-induced damage by reducing the phosphorylation of nuclear factor-kappa-B, p38, c-Jun N-terminal kinase, extracellular signal-regulated kinase proteins, and nuclear factor-kappa-B/p65 nuclear translocation.

Conclusion

Numerous pieces of evidence indicated that Torin2 reversed inflammatory activation by regulating nuclear factor-kappa-B and mitogen-activated protein kinase signaling pathways and provided a tentative potential candidate for preventing and treating inflammatory diseases.

Pharmacological Effects and Underlying Mechanisms of Licorice-Derived Flavonoids

Glycyrrhizae Radix et Rhizoma is the most frequently prescribed natural medicine in China and has been used for more than 2,000 years. The flavonoids of licorice have garnered considerable attention in recent decades due to their structural diversity and myriad pharmacological effects, especially as novel therapeutic agents against inflammation and cancer. Although many articles have been published to summarize different pharmacological activities of licorice in recent years, the systematic summary for flavonoid components is not comprehensive. Therefore, in this review, we summarized the pharmacological and mechanistic data from recent researches on licorice flavonoids and their bioactive components.

Chalcone Scaffolds, Bioprecursors of Flavonoids: Chemistry, Bioactivities, and Pharmacokinetics

Chalcones are secondary metabolites belonging to the flavonoid (C6-C3-C6 system) family that are ubiquitous in edible and medicinal plants, and they are bioprecursors of plant flavonoids. Chalcones and their natural derivatives are important intermediates of the flavonoid biosynthetic pathway. Plants containing chalcones have been used in traditional medicines since antiquity. Chalcones are basically α,β-unsaturated ketones that exert great diversity in pharmacological activities such as antioxidant, anticancer, antimicrobial, antiviral, antitubercular, antiplasmodial, antileishmanial, immunosuppressive, anti-inflammatory, and so on. This review provides an insight into the chemistry, biosynthesis, and occurrence of chalcones from natural sources, particularly dietary and medicinal plants. Furthermore, the pharmacological, pharmacokinetics, and toxicological aspects of naturally occurring chalcone derivatives are also discussed herein. In view of having tremendous pharmacological potential, chalcone scaffolds/chalcone derivatives and bioflavonoids after subtle chemical modification could serve as a reliable platform for natural products-based drug discovery toward promising drug lead molecules/drug candidates.

Licochalcone A inhibits enterovirus A71 replication in vitro and in vivo

Enterovirus A71 (EV-A71) is one of the main causative agents of hand-foot-mouth disease (HFMD) and causes serious neurological complications. However, no effective therapy is currently available for treating these infections. Therefore, effective drugs to prevent and treat EV-A71 infections are urgently needed. Here, we demonstrated that treatment with Licochalcone A (LCA) significantly inhibited EV-A71 replication in a dose-dependent manner, with an EC₅₀ of 9.30 μM in RD cells and 5.73 μM in Vero cells. The preliminary results on the inhibition mechanism showed that LCA exerted antiviral effects by interfering with the early step of viral replication. We further demonstrated that LCA showed potent antiviral activity against many enteroviruses, including EV-A71 (strain C4), EV-A71 (strain H), and coxsackievirus A16 (CV-A16). Furthermore, LCA could effectively prevent the clinical symptoms and death of virus infected mice and decreased viral load in EV-A71-infected mice. Taken together, our studies showed for the first time, that LCA is a promising EV-A71 inhibitor and provide important information for the clinical development of LCA as a potential new anti-EV-A71 agent.

Natural Product Inhibitors of Cyclooxygenase (COX) Enzyme: A Review on Current Status and Future Perspectives

BACKGROUND

Several clinically used COX-1 and COX-2 inhibitor drugs were reported to possess severe side effects like GI ulcers and cardiovascular disturbances, respectively. Natural products being structurally diverse always attracted the attention of chemists/ medicinal chemists as a potential source of lead molecules in the drug discovery process. COX-2 inhibitory natural products also possess potential cancer chemopreventive property against various cancers including that of colon, breast and prostate.

METHODS

Various in vitro, in vivo and in silico standardized methods were used to evaluate COX inhibition property of different secondary metabolites isolated from plant, microbial and marine origin.

RESULTS

We had earlier reported a detailed account of natural product inhibitors of COX reported during 1995-2005, in 2006. In the proposed review, we report 158 natural product inhibitors of COX during 2006 to 2019 belonging to various secondary metabolite classes such as alkaloids, terpenoids, polyphenols as flavonoids, chromones, coumarins, lignans, anthraquinones, naphthalenes, curcuminoids, diarylheptanoids and miscellaneous compounds of plant and marine origin. Further Structure Activity Relationship (SAR) studies of possible leads are also included in the article.

CONCLUSION

COX inhibitors served as a potential source of lead molecules for the discovery and development of anti-inflammatory drugs. Compilation of natural product and semisynthetic inhibitors of COX may serve as valuable information to the researchers who are looking for possible lead molecules from a natural source to conduct further preclinical and clinical studies.

ERK Activation-Mediated Autophagy Induction Resists Licochalcone A-Induced Anticancer Activities in Lung Cancer Cells in vitro

Introduction

The incidence and mortality rates of lung cancer rank top in the different types of cancers in China. Licochalcone A (LA) is a flavonoid extracted from the roots of licorice with antitumor effects in various cancers in vitro and in vivo. However, the role of LA in non-small cell lung cancer (NSCLC) remains largely unclear.

Methods

The cell viability was measured by MTT assay, Edu staining and colony formation assay. Apoptosis was investigated using Annexin V/PI double-stained assays with flow cytometry. Real-time quantitative RT-PCR was carried out to investigate the expression of mRNA of related proteins. Western blotting was used to investigate the expression of related proteins.

Results

The results show that LA inhibits the proliferation of NSCLC cells in a dose-dependent manner and induces apoptotic cell death. Moreover, LA significantly suppresses the expression of c-IAP1, c-IAP2, XIAP, Survivin, c-FLIP_L and RIP1 without influencing the level of mRNA. Cycloheximide chase assay demonstrates that LA greatly decreases the stability of Survivin, XIAP and RIP1. Mechanistic studies indicate that LA induces cytoprotective autophagy since block of autophagy with CQ greatly enhances LA-induced anticancer activities. Furthermore, LA rapidly induces ERK and p38 activation in a time-dependent manner in both A549 and H460 cells, but suppresses the activities of c-Jun N-terminal kinase (JNK); suppression of ERK not p38 with inhibitor attenuates LA-induced autophagy, while it remarkably enhances LA-induced cytotoxicity in lung cancer cells and further promotes the degradation of apoptosis-related proteins.

Discussion

The results of this study provide novel insights on the role of apoptosis-related proteins and the MAPKs pathway in the anticancer activities of LA.

A Review: The Anti-inflammatory, Anticancer and Antibacterial Properties of Four Kinds of Licorice Flavonoids Isolated from Licorice

Plants have always been an important source of medicines for humans, and licorice is a very significant herb in the development of humans. As a traditional herb, it is widely cultivated in China, Japan, Russia, Spain and India. With the development of organic chemistry and biochemistry, various chemical ingredients extracted from licorice have been studied and identified. Among them, many chemical components were considered to have strong pharmacological activities, such as anti-inflammatory, anti-ulcer, antibacterial, anticancer and so on. Based on those reports, licorice has attracted the attention of many researchers in recent years, and they are devoted to discovering the active ingredients and mechanism of action of active compounds. Licorice flavonoids are one of the main extracts of licorice root and stem and have many potential biological properties. This paper aims to summarize the four kinds of licorice flavonoids, including liquiritigenin, isoliquiritigenin, licochalcone (including licochalcone A and licochalcone B) and glabridin, about their biological activities of anti-inflammatory, anticancer, antibacterial.

Licochalcone A Selectively Resensitizes ABCG2-Overexpressing Multidrug-Resistant Cancer Cells to Chemotherapeutic Drugs

The overexpression of the ATP-binding cassette (ABC) transporter ABCG2 has been linked to clinical multidrug resistance in solid tumors and blood cancers, which remains a significant obstacle to successful cancer chemotherapy. For years, the potential modulatory effect of bioactive compounds derived from natural sources on ABCG2-mediated multidrug resistance has been investigated, as they are inherently well tolerated and offer a broad range of chemical scaffolds. Licochalcone A (LCA), a natural chalcone isolated from the root of Glycyrrhiza inflata, is known to possess a broad spectrum of biological and pharmacological activities, including pro-apoptotic and antiproliferative effects in various cancer cell lines. In this study, the chemosensitization effect of LCA was examined in ABCG2-overexpressing multidrug-resistant cancer cells. Experimental data demonstrated that LCA inhibits the drug transport function of ABCG2 and reverses ABCG2-mediated multidrug resistance in human multidrug-resistant cancer cell lines in a concentration-dependent manner. Results of LCA-stimulated ABCG2 ATPase activity and the in silico docking analysis of LCA to the inward-open conformation of human ABCG2 suggest that LCA binds ABCG2 in the transmembrane substrate-binding pocket. This study provides evidence that LCA should be further evaluated as a modulator of ABCG2 in drug combination therapy trials against ABCG2-expressing drug-resistant tumors.

Glycyrrhizae Radix et Rhizoma Processed by Sulfur Fumigation Damaged the Chemical Profile Accompanied by Immunosuppression and Liver Injury

Glycyrrhizae Radix et Rhizoma (GRER) has been used as a medicinal plant and dietary supplements for its beneficial effect in immunomodulatory effects. Sulfur fumigation (SF) processing was widely used in the storage and maintenance of Chinese medicine because of its convenience and cheapness. However, the disadvantage of SF has been reported, but the systematic study of SF on GRER was deficient. In this paper, the active ingredients, sulfur-fumigated products, immunomodulatory effect, and liver injury of SF-GRER were studied. After SF, the liquiritin decreased from 4.49 ± 0.03 mg/g to 3.94 ± 0.08 mg/g (P < 0.01). Compared with the NSF-GRER group, the SF-GRER group showed a decreased immunoregulation in the thymus index, spleen index, and serum IL-6 and SOD levels (P < 0.05). After 2 weeks of continuous intragastric administration of SF-GRER in healthy mice, the level of serum aspartate aminotransferase (AST) significantly increased (P < 0.05) and the area of liver lesion significantly increased compared with the NSF-GRER (P < 0.05) group. The sulfonated products (m/z, 631.13) corresponding to liquiritin apioside (m/z, 551.17) and isoliquiritin apioside (m/z, 551.17) were screened out in SF-GRER by using UPLC-Orbitrap-MS. The sulfonated products provided in this paper were discovered for the first time and could be powerfully applied for the identification of SF-GRER. SF destroyed the chemical composition of GRER, inhibited immunoregulation, and induced liver injury. The feasibility of this processing method needs to be reconsidered.

Anti-Proliferative and Pro-Apoptotic Effects of Licochalcone A through ROS-Mediated Cell Cycle Arrest and Apoptosis in Human Bladder Cancer Cells

Licochalcone A (LCA) is a chalcone that is predominantly found in the root of Glycyrrhiza species, which is widely used as an herbal medicine. Although previous studies have reported that LCA has a wide range of pharmacological effects, evidence for the underlying molecular mechanism of its anti-cancer efficacy is still lacking. In this study, we investigated the anti-proliferative effect of LCA on human bladder cancer cells, and found that LCA induced cell cycle arrest at G2/M phase and apoptotic cell death. Our data showed that LCA inhibited the expression of cyclin A, cyclin B1, and Wee1, but increased the expression of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP1, and increased p21 was bound to Cdc2 and Cdk2. LCA activated caspase-8 and -9, which are involved in the initiation of extrinsic and intrinsic apoptosis pathways, respectively, and also increased caspase-3 activity, a typical effect caspase, subsequently leading to poly (ADP-ribose) polymerase cleavage. Additionally, LCA increased the Bax/Bcl-2 ratio, and reduced the integrity of mitochondria, which contributed to the discharge of cytochrome c from the mitochondria to the cytoplasm. Moreover, LCA enhanced the intracellular levels of reactive oxygen species (ROS); however, the interruption of ROS generation using ROS scavenger led to escape from LCA-mediated G2/M arrest and apoptosis. Collectively, the present data indicate that LCA can inhibit the proliferation of human bladder cancer cells by inducing ROS-dependent G2/M phase arrest and apoptosis.

Licochalcone A inhibits the invasive potential of human glioma cells by targeting the MEK/ERK and ADAM9 signaling pathways

Licochalcone A (LicA) has been reported to possess antitumor properties. However, its effect on human glioma cells remains unknown. In this study, we observed that LicA significantly suppressed the ADAM9 expression and the migration and invasion activities of human glioma cells (M059K, U-251 MG, and GBM8901) and exhibited no cell cytotoxicity. The human proteinase antibody array and immunoblot analysis indicated that the LicA treatment inhibited the expression of ADAM9 protein in human glioma cells. Recombinant human ADAM-9 (Rh-ADAM9) treatment significantly reversed the LicA-induced reduction in the ADAM9 level and the migration and invasion activities of human glioma cells. Additionally, the phosphorylation/activation of the mitogen-activated protein kinase kinase (MEK)-extracellularly responsive kinases (ERK) signaling pathway was significantly suppressed in LicA-treated human glioma cells. Cotreatment with LicA and PD98059 synergistically inhibited the ADAM9 expression, cell migration, and cell invasion, which suggested that the MEK-ERK signaling pathway was involved in the LicA-induced inhibition of the ADAM9 expression and the invasion activity of human glioma cells. These findings are the first evidence of LicA's anti-invasive properties against human glioma cells.

Licochalcone A Protects the Blood-Milk Barrier Integrity and Relieves the Inflammatory Response in LPS-Induced Mastitis

Background/Aims: Mastitis is an acute clinical inflammatory response. The occurrence and development of mastitis seriously disturb women's physical and mental health. Licochalcone A, a phenolic compound in Glycyrrhiza uralensis, has anti-inflammatory properties. Here, we examined the effect of licochalcone A on blood-milk barrier and inflammatory response in LPS-induced mice mastitis.

Methods:In vivo, we firstly established mice models of mastitis by canal injection of LPS to mammary gland, and then detected the effect of licochalcone A on pathological indexes, inflammatory responses and blood-milk barrier in this model. In vivo, Mouse mammary epithelial cells (mMECs) were treated with licochalcone A prior to the incubation of LPS, and then the inflammatory responses, tight junction which is the basic structure of blood-milk barrier were analyzed. Last, we elucidated the anti-inflammatory mechanism by examining the activation of mitogen-activated protein kinase (MAPK) and AKT/NF-κB signaling pathways in vivo and in vitro.

Result: The in vivo results showed that licochalcone A significantly decreased the histopathological impairment and the inflammatory responses, and improved integrity of blood-milk barrier. The in vitro results demonstrated that licochalcone A inhibited LPS-induced inflammatory responses and increase the protein levels of ZO-1, occludin, and claudin3 in mMECs. The in vivo and in vitro mechanistic study found that the anti-inflammatory effect of licochalcone A in LPS-induced mice mastitis was mediated by MAPK and AKT/NF-κB signaling pathways.

Conclusions and Implications: Our experiments collectively indicate that licochalcone A protected against LPS-induced mice mastitis via improving the blood–milk barrier integrity and inhibits the inflammatory response by MAPK and AKT/NF-κB signaling pathways.

Synergistic antimetastatic effect of cotreatment with licochalcone A and sorafenib on human hepatocellular carcinoma cells through the inactivation of MKK4/JNK and uPA expression

To improve the clinical outcome of tumor chemotherapy, more effective combination treatments against tumor metastasis and recurrence are required. Licochalcone A (LicA) is the root of Glycyrrhiza inflata and has been reported to possess anti-inflammatory, antimicrobial, and antitumor effects. Sorafenib (Sor), a multikinase inhibitor, is used to treat patients with solid tumors such as advanced hepatocellular carcinoma (HCC). However, the synergistic effects of LicA and Sor on the metastasis of human HCC cells have not been reported. We found that LicA and Sor did not have cytotoxic effects or arrest growth in human SK-Hep-1 and Huh-7 cells. In addition, treatment with LicA or Sor alone inhibited migration and invasion in human SK-Hep-1 and Huh-7 HCC cells. Furthermore, cotreatment with LicA and Sor synergistically inhibited the migration and invasion of HCC cells and significantly inhibited uPA protein expression. Notably, cotreatment of LicA and Sor synergistically and significantly downregulated MKK4-JNK expression. Through tail vein injection in nude mice, the aforementioned cotreatment synergistically suppressed SK-Hep-1 cell-mediated lung metastasis. These findings first revealed the synergistic effects of LicA and Sor cotreatment against human HCC cells, further suggesting that beneficial effects on tumor regression could be confirmed through prospective clinical trials.

Chinese Herbal Medicine Glycyrrhiza inflataReduces Aβ Aggregation and Exerts Neuroprotection through Anti-Oxidation and Anti-Inflammation

Amyloid [Formula: see text] (A[Formula: see text]) plays a major role in the pathogenesis of Alzheimer's disease (AD). The accumulation of misfolded A[Formula: see text] causes oxidative and inflammatory damage leading to apoptotic cell death. Chinese herbal medicine (CHM) has been widely used in clinical practice to treat neurodegenerative diseases associated with oxidative stress and neuroinflammation. This study examined the neuroprotection effects of CHM extract Glycyrrhiza inflata (G. inflata) and its active constituents, licochalcone A and liquiritigenin in AD. We examined A[Formula: see text] aggregation inhibition, anti-oxidation and neuroprotection in Tet-On A[Formula: see text]-GFP 293/SH-SY5Y cells and anti-inflammatory potential in lipopolysaccharide (LPS)-stimulated RAW 264.7 and LPS and interferon (IFN)-[Formula: see text] (LPS/IFN-[Formula: see text])-activated BV-2 cells. In addition, we applied conditioned media (CM) of BV-2 cells primed with LPS/IFN-[Formula: see text] to A[Formula: see text]-GFP SH-SY5Y cells to uncover the neuroprotective mechanisms. Our results showed that G. inflata extract and its two constituents displayed potentials of A[Formula: see text] aggregation inhibition and radical-scavenging in biochemical assays, A[Formula: see text] misfolding inhibition and reactive oxygen species (ROS) reduction in A[Formula: see text]-GFP 293 cells, as well as neurite outgrowth promotion, acetylcholinesterase inhibition and SOD2 up-regulation in A[Formula: see text]-GFP SH-SY5Y cells. Meanwhile, both G. inflata extract and its constituents suppressed NO, TNF-[Formula: see text], IL-1[Formula: see text], PGE2 and/or Iba1 productions in inflammation-stimulated RAW 264.7 or BV-2 cells. G. inflata extract and its constituents further protected A[Formula: see text]-GFP SH-SY5Y cells from BV-2 CM-induced cell death by ameliorating reduced BCL2 and attenuating increased IGFBP2, cleaved CASP3, BAD and BAX. Collectively, G. inflata extract, licochalcone A and liquiritigenin display neuroprotection through exerting anti-oxidative and anti-inflammatory activities to suppress neuronal apoptosis.

Licochalcone A Upregulates Nrf2 Antioxidant Pathway and Thereby Alleviates Acetaminophen-Induced Hepatotoxicity

Acetaminophen (APAP) overdose-induced fatal hepatotoxicity is majorly characterized by overwhelmingly increased oxidative stress while enhanced nuclear factor-erythroid 2-related factor 2 (Nrf2) is involved in prevention of hepatotoxicity. Although Licochalcone A (Lico A) upregulates Nrf2 signaling pathway against oxidative stress-triggered cell injury, whether it could protect from APAP-induced hepatotoxicity by directly inducing Nrf2 activation is still poorly elucidated. This study aims to explore the protective effect of Lico A against APAP-induced hepatotoxicity and its underlying molecular mechanisms. Our findings indicated that Lico A effectively decreased tert-butyl hydroperoxide (t-BHP)- and APAP-stimulated cell apoptosis, mitochondrial dysfunction and reactive oxygen species generation and increased various anti-oxidative enzymes expression, which is largely dependent on upregulating Nrf2 nuclear translocation, reducing the Keap1 protein expression, and strengthening the antioxidant response element promoter activity. Meanwhile, Lico A dramatically protected against APAP-induced acute liver failure by lessening the lethality; alleviating histopathological liver changes; decreasing the alanine transaminase and aspartate aminotransferase levels, malondialdehyde formation, myeloperoxidase level and superoxide dismutase depletion, and increasing the GSH-to-GSSG ratio. Furthermore, Lico A not only significantly modulated apoptosis-related protein by increasing Bcl-2 expression, and decreasing Bax and caspase-3 cleavage expression, but also efficiently alleviated mitochondrial dysfunction by reducing c-jun N-terminal kinase phosphorylation and translocation, inhibiting Bax mitochondrial translocation, apoptosis-inducing factor and cytochrome c release. However, Lico A-inhibited APAP-induced the lethality, histopathological changes, hepatic apoptosis, and mitochondrial dysfunction in WT mice were evidently abrogated in Nrf2^-/- mice. These investigations firstly implicated that Lico A has protective potential against APAP-induced hepatotoxicity which may be strongly associated with the Nrf2-mediated defense mechanisms.

LicA induces autophagy through ULK1/Atg13 and ROS pathway in human hepatocellular carcinoma cells

Chemotherapy is the best choice for the vast majority of hepatocellular carcinoma patients at late stage, but few effective chemotherapy drugs are available in clinic. Licochalcone A (LicA) is a new chemotherapy drug inducing apoptosis as Bcl-2 inhibitor, but few studies report on LicA-induced autophagy. This study investigated the phenomenon and mechanisms of LicA-induced autophagy looking for a targeted combination drug. Human hepatocellular carcinoma cells (HCCs) were treated with LicA, to detect markers of autophagy and to investigate the mechanisms. In order to investigate the role of reactive oxygen species (ROS) in LicA-induced autophagy, ROS, glutathione (GSH) and O₂⁻ were measured in LicA treated HCCs, and antioxidant N-Acetyl-L-cysteine (NAC) was cotreated with LicA in HCCs, then mechanisms of ROS-induced autophagy was investigated in LicA or LicA combined with NAC treated HCCs. Finally, the LicA-induced apoptosis was detected in LicA combined with NAC treated HCCs. We first report that LicA can induce autophagy through ULK1/Atg13 and ROS pathway in HCCs, suppression of LicA-induced ROS through antioxidant NAC can enhance LicA-induced apoptosis, promoting the function of LicA killing HCCs. LicA can activate the ULK1/Atg13 complex which is upstream of autophagy, additionally, LicA also can promote ROS generation, ROS trigger the expression level of TSC1/2 complex, PRAS40, CTMP, PP2A, PDK1 and Rubicon change, these molecules are upstream of autophagy. In conclusion, LicA can induce autophagy through ULK1/Atg13 and ROS pathway in HCCs, LicA combined with NAC can enhance LicA-induced apoptosis. Our results may provide a novel design for clinical hepatocellular carcinoma therapy trials.

Licochalcone A activates Keap1-Nrf2 signaling to suppress arthritis via phosphorylation of p62 at serine 349

Licochalcone A (LCA) is derived from glycyrrhizae radix with antimicrobial, antitumor and anti-inflammatory activities. However, the anti-arthritic function of LCA and underlying mechanism has not been yet explored. The current study investigated the anti-arthritic effect of LCA and elucidated the underlying mechanism. The results showed that LCA significantly suppressed arthritis via the activation of SQSTM1 (p62)/nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling in the collagen-induced arthritis (CIA) model of DBA mice. In coincided with the results, this anti-arthritic effect of LCA was remarkably diminished in the collagen antibody-induced arthritis (CAIA) model of Nrf2-/- mice. These findings indicate that p62/Nrf2 signaling is a crucial pathway for the induction and treatment of arthritis. To further validate the effect of LCA on the arthritis, rheumatoid arthritis synovial fibroblasts (RASFs) isolated from the synovium of RA patients were employed in the study. In coincided with in vivo results, LCA inhibited the cell proliferation and arrested the cell cycle, induced apoptosis, suppressed pro-inflammatory cytokine secretion and increased expression of antioxidant enzymes via the activation of Keap1-Nrf2 signaling by enhancing p62 phosphorylation and expression, Nrf2 accumulation and Nrf2 nucleus translocation. Findings in the current study provide evidence that p62-Keap1-Nrf2 axis is a pivotal signaling pathway in development of arthritis and therapeutic efficacy of drugs, and LCA activates of Keap1-Nrf2 signaling to suppress arthritis by phosphorylation of p62 at Ser349. Collectively, LCA is valuable to be further investigated as a lead compound for application in anti-arthritis, and interference with the interaction between Nrf2 and Keap1 by phosphorylation of p62 may be a promising strategy for the discovery of anti-arthritic agents.

Anti‑inflammatory effect of quercetin and galangin in LPS‑stimulated RAW264.7 macrophages and DNCB‑induced atopic dermatitis animal models

Flavonols are compounds that have been shown to possess potent anti-inflammatory effects in cellular and animal models of inflammation. In the present study, the anti-inflammatory effects and mechanisms of two natural flavonols, quercetin and galangin, in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were investigated. It was identified that quercetin and galangin markedly reduced the production of nitric oxide (NO), inducible NO synthase and interleukin-6, and the nuclear translocation of nuclear factor-κB (NF-κB). In addition, LPS-induced activation of extracellular signal-regulated kinase 1/2 (Erk1/2) and c-Jun N-terminal kinase (JNK) was suppressed by quercetin and galangin. Taken together, these data implied that NF-κB, Erk1/2 and JNK may be potential molecular targets of quercetin and galangin in an LPS-induced inflammatory response. Subsequently, the effects of oral administration of quercetin or galangin, either alone or in combination, in a 2,4-dinitrochlorobenzene-induced atopic dermatitis (AD) mouse model were investigated. As a result, measurements of ear thickness and the levels of serum immunoglobulin E, and histological analysis revealed that the two flavonols led to a decrease in inflammation, whereas, in combination, they were even more effective. These results suggested that quercetin and galangin may be promising therapeutic agents for AD. Additionally, their combination may be a novel therapeutic strategy for the prevention of AD.

Licochalcone A Prevents the Loss of Dopaminergic Neurons by Inhibiting Microglial Activation in Lipopolysaccharide (LPS)-Induced Parkinson's Disease Models

The neuroprotective effects of Licochalcone A (Lico.A), a flavonoid isolated from the herb licorice, in Parkinson's disease (PD) have not been elucidated. The prominent pathological feature of PD is the loss of dopaminergic neurons. The crucial role of neuroinflammation induced by activated microglia in dopaminergic neurodegeneration has been validated. In this study, we explore the therapeutic effects of Lico.A in lipopolysaccharide (LPS)-induced PD models in vivo and in vitro. We find that Lico.A significantly inhibits LPS-stimulated production of pro-inflammatory mediators and microglial activation by blocking the phosphorylation of extracellular signal-regulated kinase (ERK1/2) and nuclear factor κB (NF-κB) p65 in BV-2 cells. In addition, through cultured primary mesencephalic neuron-glia cell experiments, we illustrate that Lico.A attenuates the decrease in [³H] dopamine (DA) uptake and the loss of tyrosine hydroxylase-immunoreactive (TH-ir) neurons in LPS-induced PD models in vitro. Furthermore, LPS intoxication in rats results in microglial activation, dopaminergic neurodegeneration and significant behavioral deficits in vivo. Lico.A treatment prevents microglial activation and reduction of dopaminergic neuron and ameliorates PD-like behavioral impairments. Thus, these results demonstrate for the first time that the neuroprotective effects of Lico.A are associated with microglia and anti-inflammatory effects in PD models.

Licochalcone A Inhibits the Proliferation of Human Lung Cancer Cell Lines A549 and H460 by Inducing G2/M Cell Cycle Arrest and ER Stress

Licochalcone A (LicA), a flavonoid isolated from the famous Chinese medicinal herb Glycyrrhiza uralensis Fisch, has wide spectrum of pharmacological activities. In this study, the anti-cancer effects and potential mechanisms of LicA in non-small cell lung cancer (NSCLC) cells were studied. LicA decreased cell viability and induced apoptosis in a dose-dependent manner in NSCLC cells. LicA inhibited lung cancer cells growth by blocking cell cycle progression at the G2/M transition and inducing apoptosis. LicA treatment decreased the expression of MDM2, Cyclin B1, Cdc2 and Cdc25C in H460 and A549 cancer cell lines. In addition, LicA induced caspase-3 activation and poly-ADP-ribose polymerase (PARP) cleavage, which displayed features of apoptotic signals. Furthermore, LicA increased the expression of endoplasmic reticulum (ER) stress related proteins, such as p-EIF2α and ATF4. These data provide evidence that LicA has the potential to be used in the treatment of lung cancer.

Licochalcone A Prevents Platelet Activation and Thrombus Formation through the Inhibition of PLCγ2-PKC, Akt, and MAPK Pathways

Platelet activation is involved in cardiovascular diseases, such as atherosclerosis and ischemic stroke. Licochalcone A (LA), an active ingredient of licorice, exhibits multiple biological activities such as anti-oxidation and anti-inflammation. However, its role in platelet activation remains unclear. Therefore, the study investigated the antiplatelet mechanism of LA. Our data revealed that LA (2-10 μM) concentration dependently inhibited platelet aggregation induced by collagen, but not thrombin and U46619. LA markedly attenuated collagen-stimulated ATP release, P-selectin secretion, calcium mobilization, and GPIIbIIIa activation, but did not interfere with the collagen binding to platelets. Moreover, LA significantly reduced the activation of PLCγ2, PKC, Akt and MAPKs. Thus, LA attenuates platelet activation, possibly by inhibiting collagen receptor downstream signaling but not by blocking the collagen receptors. In addition, LA prevented adenosine diphosphate (ADP)-induced acute pulmonary thrombosis, fluorescein sodium-induced platelet thrombus formation, and middle cerebral artery occlusion/reperfusion-induced brain injury in mice, but did not affect normal hemostasis. This study demonstrated that LA effectively reduced platelet activation and thrombus formation, in part, through the inhibition of PLCγ2-PKC, Akt, and MAPK pathways, without the side effect of bleeding. These findings also indicate that LA may provide a safe and alternative therapeutic approach for preventing thromboembolic disorders such as stroke.

Antioxidative and anticancer properties of Licochalcone A from licorice

ETHNOPHARMACOLOGICAL RELEVANCE

Licochalcone A (LCA) is a characteristic chalcone that is found in licorice, which is a traditional medicinal plant. In traditional medicine, LCA possesses many potential biological activities, including anti-parasitic, anti-inflammatory and antitumor activities.

AIM OF THE STUDY

To determine the antioxidant activity of LCA and, on this basis, to investigate the role of its anticancer activity.

MATERIALS AND METHODS

To validate the antioxidant activity of LCA, the proteins SOD, CAT and GPx1 were analyzed using western blotting and cellular antioxidant activity (CAA) assays. Oxidative free radicals are associated with cancer cells. Therefore, the anticancer activity of LCA was also evaluated. To assess the anticancer activity, cell viability assays were performed and apoptosis was evaluated. In addition, MAPK-related proteins were analyzed using western blotting.

RESULTS

The experimental data showed that the EC₅₀ of LCA is 58.79±0.05μg/mL and 46.29±0.05μg/mL under the two conditions tested, with or without PBS. In addition, LCA at a concentration of approximately 2-8μg/mL can induce the expression of SOD, CAT and GPx1 proteins. Further, LCA inhibits the growth of HepG2 cells through cell proliferation arrest and the subsequent induction of apoptosis, and LCA attenuated the p38/JNK/ERK signaling pathway in a dose-dependent manner.

CONCLUSION

The results showed that LCA suppresses the oxidation of cells and markedly inhibits the proliferation of cancer cells. These findings confirm the traditional use of LCA in folk medicine.

Licochalcone A Attenuates Lipopolysaccharide-Induced Acute Kidney Injury by Inhibiting NF-κB Activation

Licochalcone A (Lico A), a flavonoid found in licorice root (Glycyrrhiza glabra), has been reported to have anti-inflammatory activity. However, the protective effects of Lico A on lipopolysaccharide (LPS)-induced acute kidney injury (AKI) remains unclear. In this study, using a mouse model of LPS-induced AKI, we investigated the protective effects and mechanism of Lico A on LPS-induced AKI in mice. LPS-induced kidney injury was assessed by detecting kidney histological study, blood urea nitrogen (BUN), and creatinine levels. The production of inflammatory cytokines TNF-α, IL-6, and IL-1β in serum and kidney tissues was detected by ELISA. The activation of NF-κB was measured by western blot analysis. Our results showed that Lico A dose-dependently attenuated LPS-induced kidney histopathologic changes, serum BUN, and creatinine levels. Lico A also suppressed LPS-induced TNF-α, IL-6, and IL-1β production both in serum and kidney tissues. Furthermore, our results showed that Lico A significantly inhibited LPS-induced NF-κB activation. In conclusion, our results suggest that Lico A has protective effects against LPS-induced AKI and Lico A exhibits its anti-inflammatory effects through inhibiting LPS-induced NF-κB activation.

Licochalcone A induces autophagy through PI3K/Akt/mTOR inactivation and autophagy suppression enhances Licochalcone A-induced apoptosis of human cervical cancer cells

The use of dietary bioactive compounds in chemoprevention can potentially reverse, suppress, or even prevent cancer progression. However, the effects of licochalcone A (LicA) on apoptosis and autophagy in cervical cancer cells have not yet been clearly elucidated. In this study, LicA treatment was found to significantly induce the apoptotic and autophagic capacities of cervical cancer cells in vitro and in vivo. MTT assay results showed dose- and time-dependent cytotoxicity in four cervical cancer cell lines treated with LicA. We found that LicA induced mitochondria-dependent apoptosis in SiHa cells, with decreasing Bcl-2 expression. LicA also induced autophagy effects were examined by identifying accumulation of Atg5, Atg7, Atg12 and microtubule-associated protein 1 light chain 3 (LC3)-II. Treatment with autophagy-specific inhibitors (3-methyladenine and bafilomycin A1) enhanced LicA-induced apoptosis. In addition, we suggested the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of mTOR pathway by LicA. Furthermore, the inhibition of PI3K/Akt by LY294002/si-Akt or of mTOR by rapamycin augmented LicA-induced apoptosis and autophagy. Finally, the in vivo mice bearing a SiHa xenograft, LicA dosed at 10 or 20 mg/kg significantly inhibited tumor growth. Our findings demonstrate the chemotherapeutic potential of LicA for treatment of human cervical cancer.

New Potential Pharmacological Functions of Chinese Herbal Medicines via Regulation of Autophagy

Autophagy is a universal catabolic cellular process for quality control of cytoplasm and maintenance of cellular homeostasis upon nutrient deprivation and environmental stimulus. It involves the lysosomal degradation of cellular components such as misfolded proteins or damaged organelles. Defects in autophagy are implicated in the pathogenesis of diseases including cancers, myopathy, neurodegenerations, infections and cardiovascular diseases. In the recent decade, traditional drugs with new clinical applications are not only commonly found in Western medicines, but also highlighted in Chinese herbal medicines (CHM). For instance, pharmacological studies have revealed that active components or fractions from Chaihu (Radix bupleuri), Hu Zhang (Rhizoma polygoni cuspidati), Donglingcao (Rabdosia rubesens), Hou po (Cortex magnoliae officinalis) and Chuan xiong (Rhizoma chuanxiong) modulate cancers, neurodegeneration and cardiovascular disease via autophagy. These findings shed light on the potential new applications and formulation of CHM decoctions via regulation of autophagy. This article reviews the roles of autophagy in the pharmacological actions of CHM and discusses their new potential clinical applications in various human diseases.

Lico A Enhances Nrf2-Mediated Defense Mechanisms against t-BHP-Induced Oxidative Stress and Cell Death via Akt and ERK Activation in RAW 264.7 Cells

Licochalcone A (Lico A) exhibits various biological properties, including anti-inflammatory and antioxidant activities. In this study, we investigated the antioxidative potential and mechanisms of Lico A against tert-butyl hydroperoxide- (t-BHP-) induced oxidative damage in RAW 264.7 cells. Our results indicated that Lico A significantly inhibited t-BHP-induced cytotoxicity, apoptosis, and reactive oxygen species (ROS) generation and reduced glutathione (GSH) depletion but increased the glutamate-cysteine ligase modifier (GCLM) subunit and the glutamate-cysteine ligase catalytic (GCLC) subunit genes expression. Additionally, Lico A dramatically upregulated the antioxidant enzyme heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2), which were associated with inducing Nrf2 nuclear translocation, decreasing Keap1 protein expression and increasing antioxidant response element (ARE) promoter activity. Lico A also obviously induced the activation of serine/threonine kinase (Akt) and extracellular signal-regulated kinase (ERK), but PI3K/Akt and ERK inhibitors treatment displayed clearly decreased levels of LicoA-induced Nrf2 nuclear translocation and HO-1 expression, respectively. Furthermore, Lico A treatment markedly attenuated t-BHP-induced oxidative damage, which was reduced by treatment with PI3K/Akt, ERK, and HO-1 inhibitors. Therefore, Lico A might have a protective role against t-BHP-induced cytotoxicity by modulating HO-1 and by scavenging ROS via the activation of the PI3K/Akt and ERK/Nrf2 signaling pathways.

Licochalcone A, a polyphenol present in licorice, suppresses UV-induced COX-2 expression by targeting PI3K, MEK1, and B-Raf

Licorice is a traditional botanical medicine, and has historically been commonly prescribed in Asia to treat various diseases. Glycyrrhizin (Gc), a triterpene compound, is the most abundant phytochemical constituent of licorice. However, high intake or long-term consumption of Gc has been associated with a number of side effects, including hypertension. However, the presence of alternative bioactive compounds in licorice with anti-carcinogenic effects has long been suspected. Licochalcone A (LicoA) is a prominent member of the chalcone family and can be isolated from licorice root. To date, there have been no reported studies on the suppressive effect of LicoA against solar ultraviolet (sUV)-induced cyclooxygenase (COX)-2 expression and the potential molecular mechanisms involved. Here, we show that LicoA, a major chalcone compound of licorice, effectively inhibits sUV-induced COX-2 expression and prostaglandin E2 PGE₂ generation through the inhibition of activator protein 1 AP-1 transcriptional activity, with an effect that is notably more potent than Gc. Western blotting analysis shows that LicoA suppresses sUV-induced phosphorylation of Akt/ mammalian target of rapamycin (mTOR) and extracellular signal-regulated kinases (ERK)1/2/p90 ribosomal protein S6 kinase (RSK) in HaCaT cells. Moreover, LicoA directly suppresses the activity of phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase kinase (MEK)1, and B-Raf, but not Raf-1 in cell-free assays, indicating that PI3K, MEK1, and B-Raf are direct molecular targets of LicoA. We also found that LicoA binds to PI3K and B-Raf in an ATP-competitive manner, although LicoA does not appear to compete with ATP for binding with MEK1. Collectively, these results provide insight into the biological action of LicoA, which may have potential for development as a skin cancer chemopreventive agent.

Chemopreventive Effects of Licorice and Its Components

Cancer is still a major health issue worldwide and identifying novel but safe compounds for prevention and treatment is a high priority. Licorice (Glycyrrhiza) is a perennial plant that is cultivated in many countries and has been reported to exert antioxidant, anti-inflammatory and anticancer effects. However, some components of licorice exert unwanted side effects and therefore identifying safer licorice components would be ideal. The anticancer activities of many of the licorice components appear to include cycle arrest, apoptosis induction, and general antioxidant effects. Commonly reported indirect protein targets important in tumorigenesis include many cell cycle-related proteins, apoptosis-associated proteins, MMP proteins, COX-2, GSK-β, Akt, NF-κB, and MAP kinases. Importantly, several licorice components were reported to directly bind to and inhibit the activities of PI3-K, MKK4, MKK7, JNK1, mTOR, and Cdk2, resulting in decreased carcinogenesis in several cell and mouse models with no obvious toxicity. This review focuses on specific components of licorice for which a direct protein target has been identified.

Anti-Inflammatory Effects of Water Chestnut Extract on Cytokine Responses via Nuclear Factor-κB-signaling Pathway

Water chestnut (Trapa japonica Flerov.) is an annual aquatic plant. In the present study, we showed that the treatment of water chestnut extracted with boiling water resulted in a significant increase 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and decrease the intracellular H₂O₂-induced accumulation of reactive oxygen species. In addition, water chestnut extract (WCE) inhibited lipopolysaccharide (LPS)-induced nitric oxide production and suppressed mRNA and protein expression of the inducible nitric oxide synthase gene. The cytokine array results showed that WCE inhibited inflammatory cytokine secretion. Also, WCE reduced tumor necrosis factor-α-and interleukin-6-induced nuclear factor-αB activity. Furthermore, during sodium lauryl sulfate (SLS)-induced irritation of human skin, WCE reduced SLS-induced skin erythema and improved barrier regeneration. These results indicate that WCE may be a promising topical anti-inflammatory agent.

Oxyresveratrol suppresses lipopolysaccharide-induced inflammatory responses in murine macrophages

Excessive inflammation is considered a critical factor in many human diseases. Oxyresveratrol(trans-2,3',4,5'-tetrahydroxystilbene), a natural hydroxystilbene, has been shown to possess antioxidant and free radical-scavenging activity. In this study, we investigated the effects of oxyresveratrol (OxyR) on the lipopolysaccharide (LPS)-induced production of inflammatory cytokines and mediators and further explored the mechanism of action in RAW264.7 murine macrophage cell line. Production of nitric oxide (NO), prostaglandin E2 (PGE2), messenger RNA (mRNA) and protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin 6 (IL-6), and granulocyte macrophage colony-stimulating factor (GM-CSF), phosphorylation of mitogen-activated protein kinases (MAPKs; extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38), and the activation of nuclear factor κ-light chain enhancer of activated B cells (NFκB) with OxyR were assayed in LPS-stimulated RAW264.7 cells. OxyR inhibited the productions of NO, PGE2, IL-6, and GM-CSF significantly in LPS-stimulated RAW264.7 cells. OxyR suppressed mRNA and protein expressions of iNOS, COX-2, IL-6, and GM-CSF in LPS-stimulated RAW264.7 cells. OxyR suppressed the phosphorylation of Akt and JNK and p38 MAPKs and the translocation of NFκB p65 subunit into the nucleus. These results indicate that OxyR inhibits LPS-stimulated inflammatory responses though the blocking of MAPK and NFκB signaling pathway in macrophages, and suggest that OxyR possesses anti-inflammatory effects.

Effects of licochalcone A on the bioavailability and pharmacokinetics of nifedipine in rats: possible role of intestinal CYP3A4 and P-gp inhibition by licochalcone A

The purpose of this study was to investigate the possible effects of licochalcone A (a herbal medicine) on the pharmacokinetics of nifedipine and its main metabolite, dehydronifedipine, in rats. The pharmacokinetic parameters of nifedipine and/or dehydronifedipine were determined after oral and intravenous administration of nifedipine to rats in the absence (control) and presence of licochalcone A (0.4, 2.0 and 10 mg/kg). The effect of licochalcone A on P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4 activity was also evaluated. Nifedipine was mainly metabolized by CYP3A4. Licochalcone A inhibited CYP3A4 enzyme activity in a concentration-dependent manner with a 50% inhibition concentration (IC50 ) of 5.9 μm. In addition, licochalcone A significantly enhanced the cellular accumulation of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp. The area under the plasma concentration-time curve from time 0 to infinity (AUC) and the peak plasma concentration (Cmax ) of oral nifedipine were significantly greater and higher, respectively, with licochalcone A. The metabolite (dehydronifedipine)-parent AUC ratio (MR) in the presence of licochalcone A was significantly smaller compared with the control group. The above data could be due to an inhibition of intestinal CYP3A4 and P-gp by licochalcone A. The AUCs of intravenous nifedipine were comparable without and with licochalcone A, suggesting that inhibition of hepatic CYP3A4 and P-gp was almost negligible.

Special licorice extracts containing lowered glycyrrhizin and enhanced licochalcone A prevented Helicobacter pylori-initiated, salt diet-promoted gastric tumorigenesis

OBJECTIVE

In spite of cytoprotective and anti-inflammatory actions, conventional licorice extracts (c-lico) were limitedly used due to serious side effects of glycyrrhizin. As our group had successfully isolated special licorice extracts (s-lico) lowering troublesome glycyrrhizin, but increasing licochalcone A, we have compared anti-inflammatory, antioxidative, and cytoprotective actions of s-lico and c-lico against either in vitro or in vivo Helicobacter pylori infection.

METHODS

RT-PCR and Western blot were performed to check anti-inflammatory action and electron spin resonance (ESR) and DCFDA spectroscopy to check antioxidative action. s-lico or c-lico was pretreated 1 hours before H. pylori infection on AGS cells. Interleukin-10 deficient mice inoculated H. pylori and followed with high salt containing pallet diets to produce H. pylori-associated chronic atrophic gastritis and gastric tumors, during which s-lico or c-lico-containing pellet diets were administered up to 24 weeks.

RESULTS

s-lico had fabulous efficacy on scavenging ROS which was further confirmed by DCFDA study and ESR measurement. The expressions of COX-2, iNOS, VEGF, and IL-8 were increased after H. pylori infection, of which levels were significantly decreased with s-lico in a dose-dependent manner. s-lico significantly ameliorated hypoxia-induced or H. pylori-induced angiogenic activities. s-lico significantly ameliorated H. pylori-induced gastric damages as well as gastritis. Our animal model showed significant development of gastric tumors including adenoma and dysplasia relevant to H. pylori infection, and s-lico administration significantly attenuated incidence of H. pylori-induced gastric tumorigenesis.

CONCLUSIONS

Special licorice extracts can be anticipating substance afforded significant attenuation of either H. pylori-induced gastritis or tumorigenesis based on potent antioxidative, anti-inflammatory, and antimutagenic actions.

Aqueous extract of Glycyrrhiza inflata inhibits aggregation by upregulating PPARGC1A and NFE2L2-ARE pathways in cell models of spinocerebellar ataxia 3

Spinocerebellar ataxia (SCA) types 1, 2, 3, 6, 7, and 17 and dentatorubropallidoluysian atrophy, as well as Huntington disease, are a group of neurodegenerative disorders caused by a CAG triplet-repeat expansion encoding a long polyglutamine (polyQ) tract in the respective mutant proteins. The cytoplasmic and nuclear aggregate formation, a pathological hallmark of polyQ diseases, is probably the initial process triggering the subsequent pathological events. Compromised oxidative stress defense capacity and mitochondrial dysfunction have emerged as contributing factors to the pathogenesis of polyQ diseases. The roots of licorice (Glycyrrhiza species) have long been used as an herbal medicine. In this study, we demonstrate the aggregate-inhibitory effect of Glycyrrhiza inflata herb extract and its constituents licochalcone A and ammonium glycyrrhizinate (AMGZ) in both 293 and SH-SY5Y ATXN3/Q75 cells, SCA3 cell models. The reporter assay showed that G. inflata herb extract, licochalcone A, and AMGZ could enhance the promoter activity of peroxisome proliferator-activated receptor γ, coactivator 1α (PPARGC1A), a known regulator of mitochondrial biogenesis and antioxidative response genes. G. inflata extract, licochalcone A, and AMGZ upregulated PPARGC1A expression and its downstream target genes, SOD2 and CYCS, in the 293 ATXN3/Q75 cell model. The expression of nuclear factor erythroid 2-related factor 2 (NFE2L2), the principal transcription factor that binds to antioxidant-responsive elements (AREs) to promote ARE-dependent gene expression when the cells respond to oxidative stress, and its downstream genes, HMOX1, NQO1, GCLC, and GSTP1, was also increased by G. inflata herb extract, licochalcone A, and AMGZ. Knockdown of PPARGC1A increased aggregates in ATXN3/Q75 cells and also attenuated the aggregate-inhibiting effect of the tested compounds. G. inflata extract and its constituents significantly elevated GSH/GSSG ratio and reduced reactive oxidative species in ATXN3/Q75 cells. The study results suggest that the tested agents activate PPARGC1A activity and NFE2L2-ARE signaling to increase mitochondrial biogenesis, decrease oxidative stress, and reduce aggregate formation in SCA3 cellular models.

Immune regulation and anti-inflammatory effects of isogarcinol extracted from Garcinia mangostana L. against collagen-induced arthritis

Isogarcinol is a natural compound that we extracted from Garcinia mangostana L., and we were the first to report that it is a new immunosuppressant. In the present study, we investigated the immune regulation and anti-inflammatory effects of isogarcinol on collagen-induced arthritis (CIA) and explored its potential mechanism in the treatment of rheumatoid arthritis. The oral administration of isogarcinol significantly reduced clinical scores, alleviated cartilage and bone erosion, and reduced the levels of serum inflammatory cytokines in CIA mice. Isogarcinol inhibited xylene-induced mouse ear edema in vivo. In vitro, isogarcinol decreased iNOS and COX-2 mRNA expression and NO content by inhibiting NF-κB expression. Furthermore, isogarcinol decreased the activity of NFAT and inhibited IL-2 expression. The mechanism of action of isogarcinol is associated with down-regulation of both autoimmune and inflammatory reactions.

Licochalcone A suppresses migration and invasion of human hepatocellular carcinoma cells through downregulation of MKK4/JNK via NF-κB mediated urokinase plasminogen activator expression

Hepatocellular cell carcinoma (HCC) is one of the most commonly diagnosed cancers worldwide and in Taiwan. Chemoprevention of cancer with dietary bioactive compounds could potentially reverse, suppress, or prevent cancer progression. Licochalcone A (LicA) is a characteristic chalcone of licorice, which is the root of Glycyrrhiza inflate. It had been reported that LicA has anti-inflammatory, anti-microbial, and anti-tumor properties. However, the effects of LicA on the migration and invasion of human HCC cells have not yet been reported. In the present study, it was found that LicA inhibits the migratory and invasion ability of SK-Hep-1 and HA22T/VGH cells in a dose-dependent manner, as assessed by the cell migration and Matrigel cell invasion assay. Using casein zymography, Western blotting, reverse transcriptase polymerase chain reaction, and an immunofluorescence assay, it was found that LicA induces a dose-dependent inhibition of uPA activity and expression, as well as reduces mRNA levels in SK-Hep-1 and HA22T/VGH cells. LicA was also found to inhibit the expression of phosphor-JNK and phosphor-MKK4 in SK-Hep-1 cells. Furthermore, LicA significantly decreased uPA levels in SP600125-treated or si-MKK4-transfected cells alongside a marked reduction in cell migration and invasion, which supports the notion that an inhibition of MKK4/JNK results in anti-metastatic effects. Moreover, LicA inhibited the expression of nuclear NF-κB, as well as the binding ability of NF-κB to the uPA promoter. These findings further our understanding of the role of LicA in suppressing tumor metastasis and its underlying molecular mechanisms, as well as suggest that LicA may be a promising anti-metastatic agent.

Licochalcone A, a natural inhibitor of c-Jun N-terminal kinase 1

The c-Jun N-terminal kinases (JNK) play an important role in many physiologic processes induced by numerous stress signals. Each JNK protein appears to have a distinct function in cancer, diabetes, or Parkinson's disease. Herein, we found that licochalcone A, a major phenolic constituent isolated from licorice root, suppressed JNK1 activity but had little effect on JNK2 in vitro activity. Although licochalcone A binds with JIP1 competitively with either JNK1 or JNK2, a computer simulation model showed that after licochalcone A binding, the ATP-binding cleft of JNK1 was distorted more substantially than that of JNK2. This could reduce the affinity of JNK1 more than JNK2 for ATP binding. Furthermore, licochalcone A inhibited JNK1-mediated, but not JNK2-mediated, c-Jun phosphorylation in both ex vivo and in vitro systems. We also observed that in colon and pancreatic cancer cell lines, JNK1 is highly expressed compared with normal cell lines. In cancer cell lines, treatment with licochalcone A or knocking down JNK1 expression suppressed colon and pancreatic cancer cell proliferation and colony formation. The inhibition resulted in G1 phase arrest and apoptosis. Moreover, an in vivo xenograft mouse study showed that licochalcone A treatment effectively suppressed the growth of HCT116 xenografts, without affecting the body weight of mice. These results show that licochalcone A is a selective JNK1 inhibitor. Therefore, we suggest that because of the critical role of JNK1 in colon cancer and pancreatic carcinogenesis, licochalcone A might have preventive or therapeutic potential against these devastating diseases.

Relaxative effect of core licorice aqueous extract on mouse isolated uterine horns

CONTEXT

Primary dysmenorrhea is one of the most frequent gynecological disorders in young women. Chinese herbal medicine has the advantage in terms of multi-targeting efficacy, lower toxicity, as well as lower cost. Core licorice is the hard and atropurpureus heart part in root and rootstock of Glycyrrhiza uralensis Fisch (Leguminosae), having a therapeutic effect on dysmenorrhea.

OBJECTIVE

This experiment indicated the spasmolytic effect of core licorice aqueous extract (CLE) on spontaneous rhythmic contractions and spasmogen-provoked contractions of stilbestrol primed, estrogen-dominated, non-pregnant mouse isolated uterine horns and its spasmolytic mechanism.

MATERIALS AND METHODS

We investigated the spasmolytic effect of CLE (0.025-0.1 mg/mL) on spontaneous contractions and potassium chloride (KCl, 40 mM), acetylcholine (ACh, 5 μg/mL), carbachol (CCh, 5 μg/mL), oxytocin (OT, 2 U/L) or bradykinin (5 ng/mL)-provoked contractions of mouse isolated uterine horns. Contractions were recorded by tension force transducers using Biolap 420F software on a PC.

RESULTS

Our present study showed that graded, escalated concentrations of CLE (0.025-0.1 mg/mL) significantly inhibited the amplitude of spontaneous phasic contractions (15.03-55.10%), as well as the contractions produced by KCl (40 mM; 20.16-53.99%), ACh (5 μg/mL; 14.65-48.32%), CCh (5 μg/mL; 38.40-76.70%), OT (2 U/L; 21.53-58.49%) or bradykinin (5 ng/mL; 58.01-79.44%) of the estrogen-dominated isolated mice uterine horn preparations in a concentration-related manner.

DISCUSSION AND CONCLUSION

The spasmolytic effect of CLE observed in the present study lends pharmacological support to the traditional use of core licorice in the management, control and treatment of primary dysmenorrhea.

Mechanisms by which licochalcone e exhibits potent anti-inflammatory properties: studies with phorbol ester-treated mouse skin and lipopolysaccharide-stimulated murine macrophages

In this study we found that licochalcone E (LicE), a recently isolated retrochalcone from Glycyrrhiza inflata, exhibits potent anti-inflammatory effects in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema and lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophage models. Topical application of LicE (0.5–2 mg) effectively inhibited TPA-induced (1) ear edema formation; (2) phosphorylation of stress-activated protein kinase/c-Jun-N-terminal kinase (SAPK/JNK), c-Jun, and extracellular signal regulated kinase 1/2; and (3) expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 proteins in mouse skin. The treatment of RAW 264.7 cells with LicE (2.5–7.5 μmol/L) induced a profound reduction in LPS-induced (1) release of NO and prostaglandin E₂; (2) mRNA expression and secretion of interleukin (IL)-6, IL-1β and tumor necrosis factor-α; (3) promoter activity of iNOS and COX-2 and expression of their corresponding mRNAs and proteins; (4) activation of AKT, p38 mitogen activated protein kinase (MAPK), SAPK/JNK and c-Jun; (5) phosphorylation of inhibitor of κB (IκB) kinase-αβ and IκBα, degradation of IκBα, translocation of p65 (RelA) to the nucleus and transcriptional activity of nuclear factor (NF)-κB; and (6) transcriptional activity of activator protein (AP)-1. These results indicate that the LicE inhibition of NF-κB and AP-1 transcriptional activity through the inhibition of AKT and MAPK activation contributes to decreases in the expression of pro-inflammatory cytokines and the inducible enzymes iNOS and COX-2.

XH-14, a novel danshen methoxybenzo[b]furan derivative, exhibits anti-inflammatory properties in lipopolysaccharide-treated RAW 264.7 cells

Background

XH-14 isolated from Salvia miltiorrhiza is a bioactive component and adenosine antagonist. In the present study, we evaluated anti-inflammatory properties of XH-14 in murine macrophages.

Methods

RAW 264.7 murine macrophage cell line was cultured with various concentrations of XH-14 in the absence or presence of lipopolysaccharide (LPS). LPS-induced release and mRNA expression of inflammatory mediators were examined by ELISA and real-time PCR. The modification of signal pathways involved in inflammatory reactions was determined by Western blotting analysis.

Results

XH-14 suppressed the generation of nitric oxide (NO) and prostaglandin E₂, and the expression of inducible NO synthase and cyclooxygenase-2 induced by LPS. Similarly, XH-14 inhibited the release of pro-inflammatory cytokines induced by LPS in RAW 264.7 cells. The underlying mechanism of XH-14 on anti-inflammatory action was correlated with down-regulation of mitogen-activated protein kinase and activator protein-1 activation.

Conclusions

XH-14 inhibits the production of several inflammatory mediators and so might be useful for the treatment of various inflammatory diseases.