Glycyrrhizic acid suppresses the development of precancerous lesions via regulating the hyperproliferation, inflammation, angiogenesis and apoptosis in the colon of Wistar rats

Orientin, a C-glycosyl dietary flavone, suppresses colonic cell proliferation and mitigates NF-κB mediated inflammatory response in 1,2-dimethylhydrazine induced colorectal carcinogenesis

Orientin, a C-glycosyl dietary flavone profusely found in rooibos tea and passion fruit have gained much attention owing to their multiple pharmacological potentials. The present study intends to investigate the anti-proliferative and anti-inflammatory efficacy of Orientin in 1,2-dimethyl hydrazine (DMH) induced colorectal cancer (CRC) in rats. Animals were arbitrarily segmented into six groups and fed with high-fat diet. Group 1 served as control. Group 2 received weekly subcutaneous injections of DMH (20 mg/kg b.w.), for first 15 weeks. Group 3 administered with Orientin (10 mg/kg b.w., i.p.) whereas Groups 4-6 treated with Orientin in three phases, namely initiation (along with DMH), post-initiation (post-DMH injection) and entire period. Orientin ameliorates tumor marker levels significantly (p < 0.05) and reinstates the histological changes induced by DMH. The proliferative markers (PCNA and Ki67) were observed to be suppressed significantly (p < 0.05) in Orientin treated rats. Orientin abrogates (p < 0.05) the inflammatory mast cells and diminishes the expression of pro-inflammatory NF-κB and cytokines (TNF-α and IL-6). It also down-regulates over expression of inflammatory inducible enzymes (iNOS and COX-2) significantly (p < 0.05) and further substantiated by GLIDE XP and QPLD studies. Overall results promptly elucidate the anti-proliferative and anti-inflammatory efficacy of Orientin against CRC. Orientin can be developed as a promising chemotherapeutic agent, on further validation of other molecular mechanisms.

Glycyrrhizic acid: A promising carrier material for anticancer therapy

Drug delivery systems have become an integral part of anticancer drugs today. Design of novel drug carriers may lead to significant enhancement in antineoplastic therapy. Glycyrrhizic acid (GL), which is the most important active ingredient extracted from the licorice root shows great potential as a carrier material in this field. Recent studies have indicated that the combination of GL and first-line drugs had better therapeutic effects on cancers. GL showed a series of anti-cancer-related pharmacological activities, such as broad-spectrum anti-cancer ability, resistance to the tissue toxicity caused by chemotherapy and radiation, drug absorption enhancing effects and anti-multidrug resistance (MDR) mechanisms, as a carrier material in drug delivery systems. This review introduced the current research progress on pharmacological mechanisms of GL and development of GL-based drug carriers in anti-cancer field to provide basis for the application prospects of GL. The design of novel GL-based drug delivery systems will bring new opportunities and challenges to anti-cancer therapy.

Antineoplastic effects of clove buds (Syzygium aromaticum L.) in the model of breast carcinoma

It is supposed that plant functional foods, rich in phytochemicals, may potentially have preventive effects in carcinogenesis. In this study, the anticancer effects of cloves in the in vivo and in vitro mammary carcinoma model were assessed. Dried flower buds of cloves (CLOs) were used at two concentrations of 0.1% and 1% through diet during 13 weeks after the application of chemocarcinogen. After autopsy, histopathological and immunohistochemical analyses of rat mammary carcinomas were performed. Moreover, in vitro evaluation using MCF‐7 cells was carried out. Dietary administered CLO caused the dose‐dependent decrease in tumour frequency by 47.5% and 58.5% when compared to control. Analysis of carcinoma cells in animals showed bcl‐2, Ki67, VEGFA, CD24 and CD44 expression decrease and Bax, caspase‐3 and ALDH1 expression increase after high‐dose CLO administration. MDA levels were substantially decreased in rat carcinomas in both CLO groups. The evaluation of histone modifications revealed increase in lysine trimethylations and acetylations (H4K20me3, H4K16ac) in carcinomas after CLO administration. TIMP3 promoter methylation levels of CpG3, CpG4, CpG5 islands were altered in treated cancer cells. An increase in total RASSF1A promoter methylation (three CpG sites) in CLO 1 group was found. In vitro studies showed antiproliferative and pro‐apoptotic effects of CLO extract in MCF‐7 cells (analyses of cytotoxicity, Brdu, cell cycle, annexin V/PI, caspase‐7, Bcl‐2 and mitochondrial membrane potential). This study showed a significant anticancer effect of clove buds in the mammary carcinoma model in vivo and in vitro.

Economic Importance

The beneficial effects of liquorice in treating chills, colds, and coughs have been fully discussed in Ayurveda, as well as in the texts of ancient Egyptians, Greeks, and Romans. The plant has been prescribed for dropsy during the period of famous Hippocrates. The reason being that it was quite helpful as thirst-quenching drugs (Biondi et al. in J Nat Prod 68:1099–1102, 2005; Mamedov and Egamberdieva in Herbals and human health-phytochemistry. Springer Nature Publishers, 41 pp, 2017). No doubt, the clinical use of liquorice in modern medicine started around 1930; Pedanios Dioscorides of Anazarba (Adana), first century AD-Father of Pharmacists, mentions that it is highly effective in the treatment of stomach and intestinal ulcers. In Ayurveda, people in ancient Hindu culture have used it for improving sexual vigor.

Vam3, a Compound Derived from Vitis amurensis Rupr., Attenuated Colitis-Related Tumorigenesis by Inhibiting NF-κB Signaling Pathway

BACKGROUND

Chronic inflammation is one of the important mediators of colitis-related colon cancer (CRC). Abundant mast cells (MCs) were observed in the tumor microenvironment and mediators released upon MC activation play an important role in the process of chronic inflammation. Previously, we found that activation of intestine mucosal MCs recruited and modulated the inflammatory CD11b(+)Gr1(+) cells to promote the CRC development. In the current study we investigated the effects of Vam3, a resveratrol dimer with potent anti-inflammatory effects, on CRC development.

METHODS

RBL-2H3 cells, a basophilic leukemia cell line, were pretreated with 2.5 or 5 µM Vam3 and then stimulated with dinitrophenol-conjugated bovine serum albumin (DNP-BSA) plus lipopolysaccharide (LPS). The MC degranulation was determined by measuring β-hexosaminidase release. Generation of TNF-α and IL-6 in RBL-2H3 cells or in peritoneal macrophages was determined by ELISA and real-time qPCR. NF-κB p65 and phospho-NF-κB p65 expression was determined by Western blotting. NF-κB activity in RAW264.7 cells was determined by luciferase reporter assay. CRC was induced in C57BL/6 mice by intraperitoneal injection of azoxymethane (AOM), followed by oral exposure to dextran sodium sulfate (DSS). Vam3 at 50 mg/kg, or disodium cromoglycate (DSCG, MC stabilizer) at 100 mg/kg, or vehicle were administrated to the mice 4 weeks after DSS withdrawal. Levels of TNF-α, IL-6, and mouse MC protease-1 were determined by ELISA. Infiltration of CD11b(+)Gr1(+) cells was determined by flow cytometry analysis. One-way ANOVA was used to compare difference between groups.

RESULTS

Pretreatment with Vam3 significantly inhibited RBL-2H3 cell degranulation and inflammatory cytokine production from RBL-2H3 cells and from peritoneal macrophages. After Vam3 treatment, NF-κB activity in RAW264.7 cells, and expressions of phospho-NF-κB p65 in RBL-2H3 cells and in peritoneal macrophages were significantly down-regulated. In the AOM plus DSS-induced CRC murine model, the Vam3 and DSCG-treated mice had less tumor numbers than those treated with vehicle. Expression of phospho-NF-κB p65, production of inflammatory cytokines, and infiltration of MCs and CD11b(+)Gr1(+) cells were attenuated in the Vam3-treated mice.

CONCLUSION

Vam3 treatment could attenuate the CRC development. This effect may be due to its inhibition on NF-κB signaling pathway in MCs and macrophages of the inflamed intestines.

Novel Chemical Ligands to Ebola Virus and Marburg Virus Nucleoproteins Identified by Combining Affinity Mass Spectrometry and Metabolomics Approaches

The nucleoprotein (NP) of Ebola virus (EBOV) and Marburg virus (MARV) is an essential component of the viral ribonucleoprotein complex and significantly impacts replication and transcription of the viral RNA genome. Although NP is regarded as a promising antiviral druggable target, no chemical ligands have been reported to interact with EBOV NP or MARV NP. We identified two compounds from a traditional Chinese medicine Gancao (licorice root) that can bind both NPs by combining affinity mass spectrometry and metabolomics approaches. These two ligands, 18β-glycyrrhetinic acid and licochalcone A, were verified by defined compound mixture screens and further characterized with individual ligand binding assays. Accompanying biophysical analyses demonstrate that binding of 18β-glycyrrhetinic acid to EBOV NP significantly reduces protein thermal stability, induces formation of large NP oligomers, and disrupts the critical association of viral ssRNA with NP complexes whereas the compound showed no such activity on MARV NP. Our study has revealed the substantial potential of new analytical techniques in ligand discovery from natural herb resources. In addition, identification of a chemical ligand that influences the oligomeric state and RNA-binding function of EBOV NP sheds new light on antiviral drug development.

Glycyrrhizic acid prevents enteritis through reduction of NF‑κB p65 and p38MAPK expression in rat

Glycyrrhizic acid has a variety of biological properties, including a protective function in the liver, and anti‑inflammatory, anti‑ulcer, anti‑anaphylaxis, anti‑oxidant, immunoregulatory, antiviral and anticancer activities. The efficacy of glycyrrhizic acid can be increased when combined with other medicines. In the present study, the potential protective effects of glycyrrhizic acid against enteritis in rats, and its role in regulating anti‑inflammation, anti‑oxidation, angiogenic and apoptotic mechanisms were investigated using enzyme‑linked immunosorbent and bicinchoninic acid assays, and reverse transcription‑quantitative polymerase chain reaction and western blotting analyses. Adult male Sprague‑Dawley rats were injected with 20 mg/kg methotrexate (MTX) to establish enteritis. Additionally, rats with MTX‑induced enteritis were peritoneally injected with 200 mg glycyrrhizic acid for 9 weeks. The current study demonstrated that glycyrrhizic acid could alleviate MTX‑induced increases of tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6 levels, and raise IL‑10 levels, in rats with enteritis. Treatment with glycyrrhizic acid significantly reduced D‑lactate and intercellular adhesion molecule‑1 gene expression (P<0.01), but did not inhibit diamine oxidase activity in MTX‑induced enteritis. Pretreatment with glycyrrhizic acid significantly suppressed the promotion of p38 mitogen‑activated protein kinase (p38MAPK), nuclear factor‑κB p65 (NF‑κB p65) protein expression, interferon‑γ protein concentration, and caspase‑3 and cycloxygenase‑2 activity in MTX‑induced enteritis (P<0.01). The findings of the current study suggest that glycyrrhizic acid may prevent enteritis by reducing NF‑κB p65 and p38MAPK expression levels, which may inform future therapeutic strategies for the treatment of enteritis.

In Vitro and in Vivo Inhibitory Effects of Glycyrrhetinic Acid in Mice and Human Cytochrome P450 3A4

Glycyrrhetinic acid (GA) has been used clinically in the treatment of patients with chronic hepatitis. This study evaluated the effect of GA on the activity of five P450(CYP450) cytochrome enzymes: CYP2A6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, in human liver microsomes (HLMs) and recombinant cDNA-expressed enzyme systems using a HPLC-MS/MS CYP-specific probe substrate assay. With midazolam as the probe substrate, GA greatly decreased CYP3A4 activity with IC50 values of 8.195 μM in HLMs and 7.498 μM in the recombinant cDNA-expressed CYP3A4 enzyme system, respectively. It significantly decreased CYP3A4 activity in a dose- but not time-dependent manner. Results from Lineweaver-Burk plots showed that GA could inhibit CYP3A4 activity competitively, with a Ki value of 1.57 μM in HLMs. Moreover, CYP2C9 and CYP2C19 could also be inhibited significantly by GA with IC50 of 42.89 and 40.26 μM in HLMs, respectively. Other CYP450 isoforms were not markedly affected by GA. The inhibition was also confirmed by an in vivo study of mice. In addition, it was observed that mRNA expressions of the Cyps2c and 3a family decreased significantly in the livers of mice treated with GA. In conclusion, this study indicates that GA may exert herb-drug interactions by competitively inhibiting CYP3A4.

Evasion of anti-growth signaling: A key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting.

Terpenoid and flavonoid spectrum of in vitro cultures of Glycyrrhiza glabra revealed high chemical heterogeneity: platform to understand biosynthesis

Simultaneous qualitative and quantitative assessment of eight flavonoids and two terpenoids were performed in fourteen in vitro raised morphogenic cultures of Glycyrrhiza glabra. Our study revealed that the spectrum and production of ten compounds, under investigation, were higher in organized tissue than the undifferentiated mass, however, aerial portions of the in vitro raised plants (leaf and stem) were found to be devoid of therapeutically relevant triterpenoid, glycyrrhizin. A correlation was observed between cell maturation, morphological differentiation and glycyrrhizin accumulation. Mature stolons (4 months) were characterized by the maximum accumulation of glycyrrhizin (8.60 µg/mg) in in vitro plantlets. The cytotoxic effect of the extracts evaluated against a panel of human cancer cell lines (in vitro) indicated that the pancreatic cell line (MIA-PaCa-2) were sensitive to all the fourteen extracts investigated. To the best of our knowledge this is the first comprehensive report relating plant growth regulators to metabolite spectrum and cytotoxic assessment in in vitro raised G. glabra cultures. Overall, our findings demonstrated that the metabolite spectrum of in vitro raised morphogenetic lines, under different stages of maturation, might offer a platform to understand the regulatory aspects of the concerned metabolite pathway and their consequent role in differentiation.

Chemopreventive activity of grape juice concentrate (G8000TM) on rat colon carcinogenesis induced by azoxymethane

Colorectal cancer is the third most common cancer worldwide in both sexes, with similar geographic patterns between genders. This neoplasm has good prognosis if the disease is diagnosed at early stages. The aim of this study was to evaluate the effect of red grape juice on the expression of COX-2 and Ki-67 expression following colon carcinogenesis induced by azoxymethane (AOM). Thirty-five rats were randomly distributed into seven groups (n=5 per group): G1: SHAM or negative control received only saline; G2 (positive control): animals received 15 mg/kg AOM; G3: animals received 1% red grape juice 2 weeks before the administration of AOM; G4: animals received 2% red grape juice 2 weeks before the administration of AOM; G5: animals received 1% red grape juice 4 weeks after the last administration of AOM; G6: animals received 2% red grape juice 4 weeks after the last administration of AOM; G7: animals received only 2% red grape juice. COX-2 mRNA expression was reduced in animals treated with 1% red grape juice before AOM induction or 2% red grape juice after AOM induction. COX-2 immunoexpression was also reduced to groups treated with red grape juice at 1% before and after AOM induction or 2% red grape juice after AOM induction. Decreased immunoexpression of Ki-67 positive cells was observed in animals treated with 1% grape juice before AOM-treated animals. Taken together, grape juice concentrate is able to exert some chemopreventive activity on rat colon carcinogenesis.

The antiviral and antimicrobial activities of licorice, a widely-used Chinese herb

Licorice is a common herb which has been used in traditional Chinese medicine for centuries. More than 20 triterpenoids and nearly 300 flavonoids have been isolated from licorice. Recent studies have shown that these metabolites possess many pharmacological activities, such as antiviral, antimicrobial, anti-inflammatory, antitumor and other activities. This paper provides a summary of the antiviral and antimicrobial activities of licorice. The active components and the possible mechanisms for these activities are summarized in detail. This review will be helpful for the further studies of licorice for its potential therapeutic effects as an antiviral or an antimicrobial agent.

Taurine ameliorates 5-flourouracil-induced intestinal mucositis, hepatorenal and reproductive organ damage in Wistar rats: A biochemical and histological study

5-Fluorouracil is one of the most commonly used anticancer drugs for the treatment of various types of cancer but has potential adverse effects such as intestinal mucositis, renal, hepatic, and reproductive organ toxicity. Attention has been given to approaches to reduce the side effects and improve the therapeutic effectiveness of chemotherapeutic drugs. In this study, we have investigated the protective effect of taurine (Tau) on 5-fluorouracil (5-FU) induced adverse effects in Wistar rats. Animals were divided into four groups with six animals (n = 6) in each group. Group I received vehicle only and served as control group. Groups II, III, and IV animals were given oral gavage of 5-FU at 50 mg/kg body weight for 4 days. Tau was given to the animals of groups III and IV 30 min prior to 5-FU administration. We observed marked elevation in the myeloperoxidase (MPO) activity after 5-FU administration, which was reversed by Tau pretreatment. Histological observation of liver, kidney, intestine, testis, and prostate revealed that 5-FU administration resulted in anomalies like distortion of normal cellular architecture, infiltration of inflammatory cells, and loss of cellular integrity. These histopathological changes were markedly suppressed by Tau treatment. In conclusion, biochemical and histological findings of this study suggest that Tau has strong preventive potential against complications of anticancer drug 5-FU and hence Tau may play an important role in combinational chemotherapy to enhance the therapeutic efficacy of anticancer drugs.

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.

Dietary non-nutritive factors in targeting of regulatory molecules in colorectal cancer: an update

Colorectal cancer (CRC), a complex multi-step process involving progressive disruption of homeostatic mechanisms controlling intestinal epithelial proliferation/inflammation, differentiation, and programmed cell death, is the third most common malignant neoplasm worldwide. A number of promising targets such as inducible nitric acid (iNOS), cyclooxygenase (COX)-2, NF-E2-related factor 2 (Nrf2), Wnt/β-catenin, Notch and apoptotic signaling have been identified by researchers as useful targets to prevent or therapeutically inhibit colon cancer development. In this review article, we aimed to explore the current targets available to eliminate colon cancer with an update of dietary and non-nutritional compounds that could be of potential use for interaction with regulatory molecules to prevent CRC.

Emerging potential of natural products for targeting mucins for therapy against inflammation and cancer

Deregulated mucin expression is a hallmark of several inflammatory and malignant pathologies. Emerging evidence suggests that, apart from biomarkers, these deregulated mucins are functional contributors to the pathogenesis in inflammation and cancer. Both overexpression and downregulation of mucins in various organ systems is associated with pathobiology of inflammation and cancer. Restoration of mucin homeostasis has become an important goal for therapy and management of such disorders has fueled the quest for selective mucomodulators. With improved understanding of mucin regulation and mechanistic insights into their pathobiological roles, there is optimism to find selective non-toxic agents capable of modulating mucin expression and function. Recently, natural compounds derived from dietary sources have drawn attention due to their anti-inflammatory and anti-oxidant properties and low toxicity. Considerable efforts have been directed towards evaluating dietary natural products as chemopreventive and therapeutic agents; identification, characterization and synthesis of their active compounds; and improving their delivery and bioavailability. We describe the current understanding of mucin regulation, rationale for targeting mucins with natural products and discuss some natural products that modulate mucin expression and functions. We further discuss the approaches and parameters that should guide future research to identify and evaluate selective natural mucomodulators for therapy.

American ginseng significantly reduced the progression of high-fat-diet-enhanced colon carcinogenesis in Apc (Min/+) mice

BACKGROUND

Colorectal cancer (CRC) is a leading cause of death worldwide. Chronic gut inflammation is recognized as a risk factor for tumor development, including CRC. American ginseng is a very commonly used ginseng species in the West.

METHODS

A genetically engineered Apc (Min/+) mouse model was used in this study. We analyzed the saponin composition of American ginseng used in this project, and evaluated its effects on the progression of high-fat-diet-enhanced CRC carcinogenesis.

RESULTS

After oral ginseng administration (10-20 mg/kg/d for up to 32 wk), experimental data showed that, compared with the untreated mice, ginseng very significantly reduced tumor initiation and progression in both the small intestine (including the proximal end, middle end, and distal end) and the colon (all p < 0.01). This tumor number reduction was more obvious in those mice treated with a low dose of ginseng. The tumor multiplicity data were supported by body weight changes and gut tissue histology examinations. In addition, quantitative real-time polymerase chain reaction analysis showed that compared with the untreated group, ginseng very significantly reduced the gene expression of inflammatory cytokines, including interleukin-1α (IL-1α), IL-1β, IL-6, tumor necrosis factor-α, granulocyte-colony stimulating factor, and granulocyte-macrophage colony-stimulating factor in both the small intestine and the colon (all p < 0.01).

CONCLUSION

Further studies are needed to link our observed effects to the actions of the gut microbiome in converting the parent ginsenosides to bioactive ginseng metabolites. Our data suggest that American ginseng may have potential value in CRC chemoprevention.

The synergic effect of glycyrrhizic acid and low frequency electromagnetic field on angiogenesis in chick chorioallantoic membrane

OBJECTIVE

Much attention is paid to angiogenesis due to its mutual role in health and disease. Therefore, the effect of various chemical and physical agents on inhibition of this process has been recently studied. This study was conducted to investigate the synergic effect of glycyrrhizic acid and electromagnetic field on angiogenesis.

MATERIALS AND METHODS

In this experimental study, 44 Ross fertilized chicken eggs were randomly divided into four groups, one control and three experimental. Control group was kept with dimethyl sulfoxide on the eighth day, experimental group 1 treated with 200 gauss, 50 Hz electromagnetic field on the 10th day, experimental group 2 treated with 1 mg/ml glycyrrhizic acid on the eighth day, and experimental group 3 simultaneously treated with glycyrrhizic acid on the eighth day and electromagnetic field on the 10th day. On the 12th day, the images of chorioallantoic membrane samples were prepared using photostreomicroscope and the number and length of vessels were measured.

RESULTS

The mean number of vessels in the experimental groups 1 and 3 (29.31±3.60 and 27.43±4.61, respectively) was not significantly different from that in the control group (29.11±4.76) (p>0.05). The length of vessels in the experimental groups 1 and 3 (52.35±3.25 mm and 54.94±4.70 mm, respectively) decreased significantly (p<0.05) compared with the control group (61.79±6.46 mm). In experimental group 2, both length and number of vessels (54.53±5.85 mm and 23.96±3.94) decreased significantly compared with the control group (p<0.05).

CONCLUSION

Electromagnetic field and glycyrrhizic acid separately led to inhibition of angiogenesis. However, use of electromagnetic field accompanied with glycyrrhizic acid not only did not increase but also decreased the inhibitory effect.

Co-administration of glycyrrhizic acid with the antileishmanial drug sodium antimony gluconate (SAG) cures SAG-resistant visceral leishmaniasis

Since there are very few affordable antileishmanial drugs available, antimonial resistance has crippled antileishmanial therapy, thereby emphasising the need for development of novel therapeutic strategies. This study aimed to evaluate the antileishmanial role of combined therapy with sodium antimony gluconate (SAG) and the triterpenoid glycyrrhizic acid (GA) against infection with SAG-resistant Leishmania (GE1F8R). Combination therapy with GA and SAG successfully limited infection with SAG-resistant Leishmania in a synergistic manner (fractional inhibitory concentration index <1.0). At the same time, mice infected with SAG-resistant Leishmania and co-treated with GA and SAG exhibited a significant reduction in hepatic and splenic parasite burden. In probing the mechanism, it was observed that GA treatment suppressed the expression and efflux activity of P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1), two host ABC transporters responsible for antimony efflux from host cells infected with SAG-resistant parasites. This suppression correlated with greater intracellular antimony retention during SAG therapy both in vitro and in vivo, which was reflected in the reduced parasite load. Furthermore, co-administration of GA and SAG induced a shift in the cytokine balance towards a Th1 phenotype by augmenting pro-inflammatory cytokines (such as IL-12, IFNγ and TNFα) and inducing nitric oxide generation in GE1F8R-infected macrophages as well as GE1F8R-infected mice. This study aims to provide an affordable leishmanicidal alternative to expensive antileishmanial drugs such as miltefosine and amphotericin B. Furthermore, this report explores the role of GA as a resistance modulator in MRP1- and P-gp-overexpressing conditions.

Mechanisms underlying cancer growth and apoptosis by DEK overexpression in colorectal cancer

Our previous study indicated that DEK protein was overexpressed in colorectal carcinoma (CRC) compared with the normal colorectal mucosa. DEK was also significantly correlated with the prognostic characteristics of patients with CRC, demonstrating that DEK played an important role in CRC progression. In this work, we evaluate the effects of DEK on biological behaviors in CRC and explore the related molecular mechanisms. The results showed that DEK was overexpressed in human CRC tissues, and was correlated with the Ki-67 index and the apoptotic index. DEK depletion by RNAi in SW-620 and HCT116 cells significantly decreased cell proliferation, but increased cell apoptosis. Upregulation of DEK was involved in the p53/MDM, Bcl-2 family, and caspase pathways. Our study demonstrates that DEK promotes the growth of CRC, and could be a therapeutic target in CRC.

Monoammonium glycyrrhizate suppresses tumor necrosis factor-α induced chemokine production in HMEC-1 cells, possibly by blocking the translocation of nuclear factor-κB into the nucleus

Monoammonim glycyrrhizate (MAG) derived from licorice has been shown to have anti-inflammatory properties. Chemokines are vital inflammatory mediators that are involved with endothelial damage from leukocyte infiltrates in various inflammatory skin diseases. In this study, we investigated the anti-inflammatory effects and mechanisms of MAG on tumor necrosis factor-α (TNF-α) induced chemokine production in a human dermal microvascular endothelial cell line (HMEC-1). HMEC-1 cells were treated with TNF-α, with or without MAG. The results showed that MAG suppressed TNF-α-induced chemokine (including CXCL8, CX3CL1, and CXCL16) mRNA expression in HMEC-1 cells, in a dose-dependent manner, and reduced the secretion of these chemokines in culture supernatant. Moreover, endothelial activation in the presence of MAG blocked the chemotactic activities of TNF-α-stimulated HMEC-1 cell supernatant on the migration of primary neutrophils and primary monocytes. In addition, Western blot and immunofluorescence data revealed that MAG inhibited nuclear translocation of nuclear factor-κB p65 (NF-κB p65). It is the first report to demonstrate that MAG suppresses TNF-α-induced chemokine production in HMEC-1 cells, and that the mechanism may be inhibiting the translocation of NF-κB p65 into the nucleus to prevent the starting of inflammatory signaling pathway. Our results revealed that MAG is a potential anti-inflammatory agent capable of improving inflammatory skin diseases.

ERKs and mitochondria-related pathways are essential for glycyrrhizic acid-mediated neuroprotection against glutamate-induced toxicity in differentiated PC12 cells

The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.

Growth inhibitory in vitro effects of glycyrrhizic acid in U251 glioblastoma cell line

Despite dramatic advances in cancer therapy, the overall prognosis of glioblastoma (GBM) remains dismal. Nuclear factor kappa-B (NF-κB) has been previously demonstrated to be constitutively activated in glioblastoma, and it was suggested as a potential therapeutic target. Glycyrrhizic acid (GA) has been proved to have cytotoxic effects in many cancer cell lines. However, its role in glioblastoma has not yet been addressed. Therefore, this study aimed to investigate the effects of GA on human glioblastoma U251 cell line. The effects of GA on proliferation of U251 cells were measured by CCK-8 assay and plate colony-forming test. Cellular apoptosis was detected by Hoechst 33258 fluorescent staining and flow cytometry with annexin V-FITC/PI dual staining. The expression of nuclear p65 protein, the active subunit of NF-κB, was determined by Western blot and immunofluorescence. Our results demonstrated that the survival rate and colony formation of U251 cells significantly decreased in a time- and dose-dependent manner after GA addition, and the apoptotic ratio of GA-treated groups was significantly higher than that of control groups. Furthermore, the expression of NF-κB-p65 in the nucleus was remarkably reduced after GA treatment. In conclusion, our findings suggest that GA treatment can confer inhibitory effects on human glioblastoma U251 cell line including inhibiting proliferation and inducing apoptosis, which is possibly related to the NF-κB mediated pathway.

Chemopreventive effect of sinapic acid on 1,2-dimethylhydrazine-induced experimental rat colon carcinogenesis

Sinapic acid (SA) is a naturally occurring phenolic acid found in various herbal plants which is attributed with numerous pharmacological properties. This study was aimed to investigate the chemopreventive effect of SA on 1,2-dimethylhydrazine (DMH)-induced rat colon carcinogenesis. Rats were treated with DMH injections (20 mg kg(-1) bodyweight (b.w.) subcutaneously once a week for the first 4 consecutive weeks and SA (20, 40 and 80 mg kg(-1) b.w.) post orally for 16 weeks. At the end of the 16-week experimental period, all the rats were killed, and the tissues were evaluated biochemically. Our results reveal that DMH alone treatment decreased the levels/activities of lipid peroxidation by-products such as thiobarbituric acid reactive substances, conjugated dienes and antioxidants such as superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and reduced glutathione in the intestine and colonic tissues which were reversed on supplementation with SA. Moreover, the activities of drug-metabolizing enzymes of phase I (cytochrome P450 and P4502E1) were enhanced and those of phase II (glutathione-S-transferase, DT-diaphorase and uridine diphosphate glucuronosyl transferase) were diminished in the liver and colonic mucosa of DMH alone-treated rats and were reversed on supplementation with SA. All the above changes were supported by the histopathological observations of the rat liver and colon. These findings suggest that SA at the dose of 40 mg kg(-1) b.w. was the most effective dose against DMH-induced colon carcinogenesis, and thus, SA could be used as a potential chemopreventive agent.

Glycyrrhetinic Acid Induces Apoptosis in Leukemic HL60 Cells Through Upregulating of CD95/ CD178

Acute leukemia is characterized by the accumulation of neoplastic cells in the bone marrow and peripheral blood. Currently, chemotherapy and differentiating agents have been used for the treatment of leukemia. Recently, plant extracts, either alone or in combination with chemo agents, have been proposed to be used for the treatment of cancers. The aim of the present research was to study the cytotoxicity and apoptosis effects of an active licorice-derived compound, glycyrrhetinic acid (GA), on human leukemic HL60 cells. HL60 cells were cultured in RPMI1640 containing 10% fetal bovine serum. Cells were treated with different doses of GA and their viability and proliferation were detected by dye exclusion and 3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assays. Apoptosis induction and expression of CD95 and CD178 were analyzed by flow cytometry. We observed that GA decreases cell viability and suppresses cells proliferation in a dose- dependent manner. In addition, our flow cytometry data show that GA not only induces apoptosis in HL60 cells, but also upregulates both CD95 and CD178 expression on the cell surface of these cells in a dose-dependent manner. The combination of GA with cytotoxic drugs and differentiation agents requires further investigation.