Suppression of hepatitis B virus x protein-mediated tumorigenic effects by ursolic Acid

HBx protein as a therapeutic target for functional cure of hepatitis B virus infection

Hepatitis B virus (HBV) is a major cause of acute and chronic liver disease and represents a major public health problem worldwide. Current antiviral therapies with nucleos(t)ide analogues can effectively suppressing viremia but are not curative, and have little or no impact upon the HBV cccDNA minichromosome or the portions of integrated HBV DNA. Several alternative therapeutic strategies targeted at viral components and life cycle are under intense investigation. This article highlights the reasons for considering HBx as a therapeutic target as this may allow targeting of both virus and disease. Recent studies focused at HBx have led to the identification of several new pharmacological agents and development of some novel therapeutic approaches that now deserve to be taken to the next level for better management of hepatitis B. Besides, new therapies could be combined with other established therapies, to provide a functional cure from hepatitis B infection.

Chinese medicine in the treatment of chronic hepatitis B: The mechanisms of signal pathway regulation

Chronic hepatitis B (CHB) is a chronic inflammatory disease of the liver caused by infection with the hepatitis B virus (HBV), which in later stages can lead to the development of end-stage liver diseases such as cirrhosis and hepatocellular carcinoma in severe cases, jeopardizing long-term quality of life, with a poor prognosis, and placing a serious financial burden on many families around the world. The pathogenesis of the disease is complex and closely related to the immune function of the body, which has not yet been fully elucidated. The development of chronic hepatitis B is closely related to the involvement of various signaling pathways, such as JAK/STAT, PI3K/Akt, Toll-like receptor, NF-κB and MAPK signaling pathways. A large number of studies have shown that Chinese medicine has obvious advantages in anti-hepatitis B virus, and it can effectively treat the disease by modulating relevant signaling pathways, strengthening immune resistance and defense, and inhibiting inflammatory responses, and certain research progress has been made, but there is still a lack of a comprehensive review on the modulation of relevant signaling pathways in Chinese medicine for the treatment of CHB. Therefore, this article systematically combed and elaborated the relevant literature on the modulation of relevant signaling pathways by traditional Chinese medicine in recent years, with a view to providing new ideas for the treatment of CHB and further drug development.

Combinatorial drug-loaded quality by design adapted transliposome gel formulation for dermal delivery: In vitro and dermatokinetic study

BACKGROUND

Ursolic acid is a powerful drug that possesses many therapeutic properties, such as hepatoprotection, immunomodulation, anti-inflammatory, antidiabetic, antibacterial, antiviral, antiulcer, and anticancer activity. Centella asiatica (L.) Urban (Umbelliferae) contains a triterpene called asiatic acid, which has been used effectively in traditional Chinese and Indian medicine system for centuries. Anticancer, anti-inflammatory, and neuroprotective properties are only some of the many pharmacological actions previously attributed to asiatic acid .

AIM

The present work developed an optimized combinatorial drug-loaded nano-formulation by Quality by design approach.

MATERIALS AND METHODS

The optimize transliposome for accentuated dermal delivery of dual drug. The optimization of drug-loaded transliposome was done using the "Box-Behnken design." The optimized formulation was characterized for vesicles size, entrapment efficiency (%), and in vitro drug release. Additionally, transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), and dermatokinetic study were performed for further evaluation of drug-loaded optimized transliposome formulation.

RESULTS

The optimized combinatorial drug-loaded transliposome formulation showed a particle size of 86.36 ± 2.54 nm, polydispersity index (PDI) 0.230 ± 0.008, and an entrapment efficiency of 87.43 ± 2.66% which depicted good entrapment efficiency. In vitro drug release of ursolic acid and asiatic acid transliposomes was found to be 85.12 ± 2.54% and 80.23 ± 3.23%, respectively, as compared to optimized ursolic acid and asiatic acid transliposome gel drug release that was 67.18 ± 2.85% and 60.28 ± 4.12%, respectively. The skin permeation study of ursolic and asiatic acid conventional formulation was only 32.48 ± 2.42%, compared with optimized combinatorial drug-loaded transliposome gel (79.83 ± 4.52%) at 12 h. After applying combinatorial drug-loaded transliposome gel, rhodamine was able to more easily cross rat skin, as observed by confocal laser scanning microscopy, in comparison with when the rhodamine control solution was used.

DISCUSSION

The UA_AA-TL gel formulation absorbed more ursolic acid and asiatic acid than the UA_AA-CF gel formulation, as per dermatokinetic study. Even after being incorporated into transliposome vesicles, the antioxidant effects of ursolic and asiatic acid were still detectable. In most cases, transliposomes vesicular systems generate depots in the skin's deeper layers and gradually release the medicine over time, allowing for fewer applications.

CONCLUSION

In overall our studies, it may be concluded that developed dual drug-loaded transliposomal formulation has great potential for effective topical drug delivery for skin cancer.

Combination of Oncolytic Measles Virus and Ursolic Acid Synergistically Induces Oncolysis of Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) remains a difficult-to-treat cancer due to late diagnosis and limited curative treatment options. Developing more effective therapeutic strategies is essential for the management of HCC. Oncolytic virotherapy is a novel treatment modality for cancers, and its combination with small molecules merits further exploration. In this study, we combined oncolytic measles virus (MV) with the natural triterpenoid compound ursolic acid (UA) and evaluated their combination effect against HCC cells, including those harboring hepatitis B virus (HBV) or hepatitis C virus (HCV) replication. We found that the combination of MV and UA synergistically induced more cell death in Huh-7 HCC cells through enhanced apoptosis. In addition, increased oxidative stress and loss of mitochondrial potential were observed in the treated cells, indicating dysregulation of the mitochondria-dependent pathway. Similar synergistic cytotoxic effects were also found in HCC cells harboring HBV or HCV genomes. These findings underscore the potential of oncolytic MV and UA combination for further development as a treatment strategy for HCC.

Ligand-free high loading capacity ursolic acid self-carried nanovesicles enable hepatocyte targeting via absorbing apolipoproteins

Ursolic acid (UA), a natural pentacyclic terpenoid carboxylic acid that can exert a potent hepatoprotective activity, has been developed into various types of nanoparticles to improve its pharmacological effects, however, the phagocytosis of nanoparticles by Kupffer cells greatly limits its efficacy. Herein, UA/Tween 80 nanovesicles (V-UA) were constructed and despite its simple composition, it fulfills multiple functions simultaneously: UA served as not only an active ingredient in the nanovesicle drug delivery system, but also acts as part of the carrier to stabilize UA/Tween 80 nanostructure; with a molar ratio of UA to Tween 80 up to 2:1, the formulation possesses a significant advantage of higher drug loading capacity; relative to liposomal UA (Lipo-UA), a conditional cellular uptake and higher accumulation of V-UA in hepatocytes provide insights into the hepatocytes targeting mechanisms of this nanovesicles. Favorable hepatocyte targeting ability also facilitates the treatment of liver diseases, which was well validated in three liver disease models.

Design, synthesis, anticancer activity and mechanism studies of novel 2-amino-4-aryl-pyrimidine derivatives of ursolic acid

A series of novel 2-amino-4-aryl-pyrimidine derivatives of ursolic acid were designed, synthesized, and evaluated for their anticancer activities against four cancer cell lines (MCF-7, HeLa, HepG2, and A549) and a human hepatocyte cell line (LO2) via MTT assay.

Ursolic acid from Prunella vulgaris L. efficiently inhibits IHNV infection in vitro and in vivo

Infectious hematopoietic necrosis virus (IHNV) is a fish viral pathogen that causes severe disease and huge economic losses in the salmonid aquaculture industry. However, anti-IHNV drugs currently are scarce. For the purpose of seeking out anti-IHNV drugs, the anti-IHNV activities of 32 medicinal plants were investigated by using epithelioma papulosum cyprini (EPC) cells. Among these plants, Prunella vulgaris L. (PVL) showed the strongest inhibition on IHNV replication with an inhibitory percentage of 99.3% at the concentration 100 mg/L. Further studies demonstrated that ursolic acid (UA), a major constituent of PVL, also showed a highly effective anti-IHNV activity. The half-maximal inhibitory concentration (IC50) at 72 h of UA on IHNV was 8.0 μM. Besides, UA could significantly decrease cytopathic effect (CPE) and the viral titer induced by IHNV in EPC cells. More importantly, UA also showed a strong anti-IHNV activity in vivo, as indicated by increasing the survival rate of rainbow trout and inhibiting viral gene expression. Intraperitoneal injection of UA increased the relative percentage of survival of rainbow trout by 18.9% and inhibited IHNV glycoprotein mRNA expression by > 90.0% in the spleen at the 1st-day post-infection. Altogether, UA was expected to be a therapeutic agent against IHNV infection in aquaculture.

Ursolic Acid Improves Intestinal Damage and Bacterial Dysbiosis in Liver Fibrosis Mice

Liver fibrosis is a reversible process of extracellular matrix deposition or scar formation after liver injury. Intestinal damage and bacterial dysbiosis are important concomitant intestinal changes in liver fibrosis and may in turn accelerate the progression of liver fibrosis through the gut-liver axis. RhoA, an important factor in the regulation of the cytoskeleton, plays an important role in intestinal damage. We investigated the effects of ursolic acid (UA), a traditional Chinese medicine with anti-fibrotic effects, on intestinal damage and bacterial disorder through the RhoA pathway. UA treatment reduced intestinal damage by inhibiting the inflammatory factor TNF-α and increasing the expression of tight junction proteins and antibacterial peptides to protect the intestinal barrier. Moreover, the corrective effect of UA on bacterial dysbiosis was also confirmed by sequencing of the 16S rRNA gene. Potential beneficial bacteria, such as the phylum Firmicutes and the genera Lactobacillus and Bifidobacterium, were increased in the UA group compared to the CCl₄ group. In liver fibrosis mice with RhoA inhibition via injection of adeno-associated virus, the liver fibrosis, intestinal damage, and flora disturbances were improved. Moreover, UA inhibited the expression of RhoA pathway components. In conclusion, UA improves intestinal damage and bacterial dysbiosis partly via the RhoA pathway. This may be a potential mechanism by which UA exerts its anti-fibrotic effects and provides effective theoretical support for the future use of UA in clinical practice.

Variation of ursolic acid content in flowers of ten Iranian pomegranate (Punica granatum L.) cultivars

Background

Ursolic acid (UA) is an important bioactive component in many traditional medicinal plants including pomegranate (Punica granatum L.) flower.

Methods

This study presents the HPLC analysis of UA contents of ten cultivars of pomegranate flower grown in Iran. The UA contents of fallen flowers of pomegranate were given in each cultivar.

Results

Remarkable quantities of UA were found in ten cultivars of Iranian pomegranate flower evaluated (21.736 to 15.119 mg/g). Lower quantities of UA were determined in pomegranate fallen flowers (16.763 to 5.754 mg/g).

Conclusion

UA values obtained from Iranian cultivars of pomegranate flowers are very significant when compared with other sources of UA. All of the analyzes suggested that the Iranian pomegranate flowers (including flowers on branches and fallen flowers) might be an excellent UA rich source.

Ursolic acid loaded intra nasal nano lipid vesicles for brain tumour: Formulation, optimization, in-vivo brain/plasma distribution study and histopathological assessment

The aim was to formulate an optimized ursolic acid (UA) loaded lipid vesicle using formulation by design approach (FbD) for improving the drug targeting by nasal route for brain tumor. Three factors were evaluated at three different levels using anethole (terpene) (A), ethanol (B) and phospholipid90 G (C) as independent variables and their individual and combined effects were observed for PDI (Y1), vesicle size (Y2) and encapsulation efficiency (Y3) to select an optimal system (UALVopt). The optimized formulation was further converted into gel and evaluated for drug release, nasal permeation study, brain/plasma uptake and histopathology study. The UALVopt formulation containing anethole as terpene (1% as A), ethanol (2.6% as B) and phospholipid90 G (8.8 mg as C) showed low PDI (0.212), vesicle size (115.56 nm) and high entrapment efficiency (76.42%). The in-vitro drug release and ex-vivo permeation study results revealed prolonged drug release and permeation. The brain/blood ratio for UALVGopt remained significantly higher at all the time points with respect to UALVopt indicating higher and prolonged retention of drug at site of action. The histopathological study of the nasal mucosa and brain confirmed non-toxic nature of developed formulation. The formulation UALVGopt could serve as a better alternative for the brain targeting via the intranasal route which in turn could subsequently improve its efficacy.

Flavonoids Effects on Hepatocellular Carcinoma in Murine Models: A Systematic Review

The hepatocellular carcinoma (HCC) is the second most common cause of cancer deaths worldwide. It occurs primarily as manifestation of other pathological processes, such as viral hepatitis, cirrhosis, and toxin exposure that affect directly the cellular process. Studies were selected from PubMed and Scopus databases according to the PRISMA statement. The research filters were constructed using three parameters: flavonoids, hepatocellular carcinoma, and animal model. The bias analysis of the 34 selected works was done using the ARRIVE guidelines. The most widely used flavonoid in the studies was epigallocatechin gallate extracted from green tea. In general, the treatment with different flavonoids presented inhibition of tumor growth and antiangiogenic, antimetastatic, antioxidant, and anti-inflammatory activities. The bias analysis evidenced the absence of methodological processes in all studies, such as the age or weight of the animals, the method of flavonoids' extraction, or the experimental designs, analytical methods, and outcome measures. It has been known that flavonoids have a protective effect against HCC. However, the absence or incomplete characterization of the animal models, treatment protocols, and phytochemical and toxicity analyses impaired the internal validity of the individual studies, making it difficult to determine the effectiveness of plant-derived products in the treatment of HCC.

Ursolic acid activates the apoptosis of prostate cancer via ROCK/PTEN mediated mitochondrial translocation of cofilin-1

Ursolic acid has various pharmacological activities, and can reduce blood fat as well as having antihepatic, antitumoral, anti-inflammatory and antiviral properties. However, the pro-apoptotic mechanism by which ursolic acid influences human prostate cancer requires additional study. The aim of the present study was to assess whether ursolic acid activates the apoptosis of prostate cancer and to investigate the mechanism by which the Rho-associated protein kinase 1 (ROCK1)/phosphatase and tensin homolog (PTEN) signaling pathway performs a role in ursolic acid-mediated cofilin-1 to induce apoptosis in human prostate cancer. Firstly, the present study determined the pro-apoptotic mechanism by which ursolic acid influences the cell proliferation and apoptosis of human prostate LNCaP cancer cells. Caspase-3/9 activities and ROCK1, PTEN, Cofilin-1 and cytochrome c protein expression levels were also analyzed. In the present study, it is reported that the pro-apoptotic mechanism of ursolic acid potently suppressed the cell proliferation of human prostate LNCaP cancer cells. The present study revealed that the mediation of ROCK1/PTEN-cofilin-1/cytochrome c protein expression activates caspase-3/9 activities which subsequently induced the apoptosis of human prostate cancer cells. In conclusion, these findings demonstrated that ursolic acid activates the apoptosis of prostate cancer via ROCK/PTEN mediated cofilin-1/cytochrome c which mediated caspase-3/9 activities.

Design, synthesis, and evaluation of novel ursolic acid derivatives as HIF-1α inhibitors with anticancer potential

Hypoxia-inducible factor-1α (HIF-1α), a key mediator in tumor metastasis and angiogenesis, is associated with poor patient prognosis and has been recognized as an important cancer drug target. In this work, four novel series of ursolic acid derivatives containing oxadiazole, triazolone, and piperazine moieties were designed, synthesized, and evaluated for anti-tumor activity as HIF-1α inhibitors. The majority of the compounds showed an excellent ability to inhibit the expression of HIF-1α. In particular, 11b inhibited HIF-1α transcriptional activity under hypoxic conditions with IC50=36.9μM. The cytotoxicity of these compounds was also assessed in human colon cancer cell HCT116 cells by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, and no compounds showed any appreciable cytotoxic activity (IC50>100μmol/L), which was lower than that of ursolic acid (IC50=23.8μmol/L). The mechanism of action of the representative compound 11b was also investigated.

Anti-hepatocellular carcinoma activity and mechanism of chemopreventive compounds: ursolic acid derivatives

CONTEXT

Hepatocellular carcinoma (HCC) is a common cancer around the world, with high mortality rate. Currently, there is no effective drug for the therapy of HCC. Ursolic acid (UA) is a natural product which exists in various medicinal herbs and fruits, exhibiting multiple biological effects such as its outstanding anticancer and hepatoprotective activity, which has drawn many pharmacists' attention.

OBJECTIVE

This paper summarizes the current status of the hepatoprotective activity of UA analogues and explains the related mechanism, providing a clear direction for the development of novel anti-HCC drugs.

METHODS

All of the data resources were derived from PubMed. By comparing the IC50 values and analyzing the structure-activity relationships, we listed compounds with good pharmacological activity from the relevant literature, and summarized their anti-HCC mechanism.

RESULTS

From the database, 58 new UA derivatives possessing wonderful anticancer and hepatoprotective effects were listed, and the relevant anti-HCC mechanism were discussed.

CONCLUSION

UA's anti-HCC effect is the result of combined action of many mechanisms. These 58 new UA derivatives, particularly compounds 45 and 53, can be used as potential drugs for the treatment of liver cancer.

Betaine Inhibits Hepatitis B Virus with an Advantage of Decreasing Resistance to Lamivudine and Interferon α

Betaine (BET) is a native compound known for its ability to protect the liver from toxicants. However, few studies have examined the effects of BET on the most common cause of liver disease, hepatitis B virus (HBV). In this study, the anti-HBV activity of BET was assessed in vitro and in vivo using enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, and Southern blotting. The resistance of HBV to lamivudine and interferon α is challenging in the clinical treatment of HBV. The effect of BET on resistance was also investigated. The results showed that the secretion of HBsAg (HBV surface antigen), HbeAg (HBV e antigen), and HBV DNA in HepG2.2.15 cells was significantly decreased by BET via suppression of GRP78 expression. In duck HBV (DHBV)-infected ducklings, 1.0 or 2.0 g/kg BET significantly reduced serum DHBV DNA, and DHBV DNA did not rebound after the 5 day withdrawal period. BET suppressed HBV DNA rebound produced by the resistance of HBV to lamivudine and decreased the resistance mutation (rtM204V/I) of HBV DNA. Supplementation of BET may improve the anti-HBV effect of interferon α by increasing the expression of antiviral dsRNA-dependent protein kinase induced by the JAK-STAT (JAK = Janus kinase; STAT = signal transducer and activator of transcription) signaling pathway. These results may provide useful information for the clinical application of BET and solution of HBV drug resistance in anti-HBV therapy.

Inhibitory effects and actions of pentacyclic triterpenes upon glycation

Pentacyclic triterpenic compounds including asiatic, betulinic, maslinic, oleanolic and ursolic acid occur naturally in many herbs and plant foods. It is well known that these triterpenoids possess anti-oxidative and anti-inflammatory activities. Furthermore, recent in vitro and in vivo researches indicated that these compounds could inhibit the production of advanced glycation end-products (AGEs). The impact of these triterpenes upon the activity and protein expression of enzymes involved in polyol pathway including aldose reductase and sorbitol dehydrogenase has been examined, and positive results are reported. These studies suggest that certain triterpenes are potent anti-glycative agents, and may benefit the prevention and/or therapy of glycation-related diseases such as diabetes mellitus and Alzheimer’s disease. In this review article, the anti-glycative activity and action mode of certain triterpenes are highlighted. These information may promote the anti-glycative application of these natural compounds.

Self-assembly and cytotoxicity study of PEG-modified ursolic acid liposomes

While ursolic acid (UA), one of the most broadly known triterpene compounds, has proved to be effective in cancer therapy, the applications of UA is limited due to its poor aqueous solubility and low bioavailability. The aim of our study was to prolong circulation time and enhance uptake of liposomes in tumor tissues through the modification of UA liposomes via water-soluble polyethylene glycol (PEG). In addition, this research also focuses on physicochemical properties of the liposome formulations, including encapsulation efficiency, particle morphology, size, stability, release rate in vitro and cytotoxicity test. The obtained liposomes were spherical particles with mean particle diameters around 100-200 nm. And the Fourier transform infrared spectroscopy (FTIR) indicated that PEG had been anchored successfully to the liposomes. Based on our experimental data achieved, PEG-modified UA liposomes possessed higher stability than conventional liposomes, and the release rate of UA from PEG-modified liposomes was slower when compared with those of UA solution and conventional liposomes. Meanwhile, the liposomal UA showed relatively low cytotoxic effect than UA conventional liposomes within 24h, which was consistent with their release rates.

Protective effects of ursolic acid in an experimental model of liver fibrosis through Nrf2/ARE pathway

AIM

Liver fibrosis is a reversible wound-healing response that occurs following liver injury. In this study, we aimed to investigate the possible protective effects of ursolic acid in liver fibrosis induced by carbon tetrachloride (CCl4).

METHODS

ICR mice were randomly divided into six groups (Group 1: normal; Group 2: CCl4-treated group; Group 3: CCl4 plus ursolic acid 25mg/kg group; Group 4: CCl4 plus ursolic acid 50mg/kg group; Group 5: CCl4 plus colchicine 1mg/kg group; Group 6: ursolic acid 50mg/kg group). Mice were administered with CCl4 (2 mL of CCl4 in olive oil (1:1, v/v) per kg body weight twice weekly) by intraperitoneal injection and oral injection of colchicine (1mg/kg) or ursolic acid (25, 50mg/kg) daily. After six weeks, serum aminotransferase activity, hepatic reactive oxygen species (ROS) production, thiobarbituric acid reactive substances (TBARS), antioxidase (SOD, CAT, GPx) activity and histopathological analysis were performed. The levels of nuclear factor E2-related factor 2 (Nrf2), NAD(P)H: quinone oxidoreductase-1 (NQO1), glutathione S-transferase (GST) and heme oxygenase-1 (HO-1), tumor necrosis factor-alpha (TNF-α), prostaglandin E2 (PGE2) and inducible nitric oxide synthase (iNOS), Bcl-2 and caspase-3 were measured.

RESULTS

Ursolic acid significantly prevented CCl4-induced hepatotoxicity and fibrosis, indicated by both diagnostic indicators and histopathological analysis. CCl4-induced profound elevations of oxidative stress, inflammation and apoptosis in liver were suppressed by ursolic acid.

CONCLUSIONS

These results suggest that ursolic acid has the hepatoprotective actions. The inhibition of CCl4-induced liver fibrosis, inflammation and apoptosis by ursolic acid is due at least in part to its ability to modulate the Nrf2/ARE signalling pathway.

Evolution in medicinal chemistry of ursolic acid derivatives as anticancer agents

Currently, there is a renewed interest in common dietaries and plant-based traditional medicines for the prevention and treatment of cancer. In the search for potential anticancer agents from natural sources, ursolic acid (UA), a pentacyclic triterpenoid widely found in various medicinal herbs and fruits, exhibits powerful biological effects including its attractive anticancer activity against various types of cancer cells. However, the limited solubility, rapid metabolism and poor bioavailability of UA restricted its further clinical applications. In the past decade, with substantial progress toward the development of new chemical entities for the treatment of cancer, numerous UA derivatives have been designed and prepared to overcome its disadvantages. Despite extensive effort, discovery of effective UA derivatives has so far met with only limited success. This review summarizes the current status of the structural diversity and evolution in medicinal chemistry of UA analogues and provides a detailed discussion of future direction for further research in the chemical modifications of UA.

Antimicrobial activity of oleanolic and ursolic acids: an update

Triterpenoids are the most representative group of phytochemicals, as they comprise more than 20,000 recognized molecules. These compounds are biosynthesized in plants via squalene cyclization, a C30 hydrocarbon that is considered to be the precursor of all steroids. Due to their low hydrophilicity, triterpenes were considered to be inactive for a long period of time; however, evidence regarding their wide range of pharmacological activities is emerging, and elegant studies have highlighted these activities. Several triterpenic skeletons have been described, including some that have presented with pentacyclic features, such as oleanolic and ursolic acids. These compounds have displayed incontestable biological activity, such as antibacterial, antiviral, and antiprotozoal effects, which were not included in a single review until now. Thus, the present review investigates the potential use of these triterpenes against human pathogens, including their mechanisms of action, via in vivo studies, and the future perspectives about the use of compounds for human or even animal health are also discussed.

A new triterpene and protective effect of Periploca somaliensis Browicz fruits against CCl₄-induced injury on human hepatoma cell line (Huh7)

The potential hepatoprotective effect of the methanolic extract of Periploca somaliensis Browicz fruits, its different fractions (n-hexane, chloroform and n-butanol) and the major isolated compound ursolic acid was evaluated using the human hepatoma cell line (Huh7) based on the changes in the activity of aspartate aminotransferase, alanine transaminase, glutathione and superoxide dismutase. Each sample was tested at three different concentrations (1000, 100 and 10 μg/mL). All tested samples exhibited a potent concentration-independent cytoprotective effect relative to silymarin as a reference standard. Chromatographic fractionation of the chloroform-soluble fraction of the methanol extract of P. somaliensis Browicz fruits afforded two known triterpenes, namely ursolic acid, and 11α,12α-epoxy-3β-hydroxy-olean-13β,28-olide, and a newly discovered one, namely 3β-hydroxy-urs-11-en-13β,28-olide. The structures of the isolated compounds were elucidated by the analysis of 1D and 2D NMR spectral data.

Ursolic acid protects mouse liver against CCl4-induced oxidative stress and inflammation by the MAPK/NF-κB pathway

Ursolic acid (UA), a natural pentacyclic triterpenoid, has been reported to have many benefits and medicinal properties. However, its protective effects against carbon tetrachloride (CCl(4)) induced hepatotoxicity have not been clarified. The aim of the present study was to investigate the effects of UA on oxidative stress and inflammation in liver of CCl(4) treated mice. Male ICR mice were injected with CCl(4) with or without UA co-administration (25 and 50 mg/kg intragastrically once daily) for one week. Our data showed that UA significantly prevented CCl(4)-induced hepatotoxicity in a dose-dependent manner, indicated by both diagnostic indicators of liver damage (serum aminotransferase activities) and histopathological analysis. Moreover, CCl(4)-induced profound elevation of reactive oxygen species (ROS) production and oxidative stress, as evidenced by increasing of lipid peroxidation level and depleting of the total antioxidant capacity (TAC) level in liver, were suppressed by treatment with UA. Furthermore, western blot analysis showed that UA significantly decreased CYP2E1 expression levels and production of pro-inflammatory markers including TNF-α, IL-1β and COX-2 in CCl(4)-treated mouse liver. In exploring the underlying mechanisms of UA action, we found that UA decreased the activation of mitogen-activated protein kinases (JNK, p38 MAPK, ERK), which in turn inactivated the immunoregulatory transcription factor nuclear factor kappa B (NF-κB) in liver of CCl(4) treated mice. In conclusion, these results suggested that the inhibition of CCl(4)-induced inflammation by UA is due at least in part to its anti-oxidant activity and its ability to modulate the MAPK and NF-κB signaling pathway.

Suppression of AMF/PGI-mediated tumorigenic activities by ursolic acid in cultured hepatoma cells and in a mouse model

Our previous studies demonstrated that autocrine motility factor/phosphoglucose isomerase (AMF/PGI) possesses tumorigenic activities through the modulation of intracellular signaling. We then investigated the effects of ursolic acid (UA), oleanolic acid (OA), tangeretin, and nobiletin against AMF/PGI-mediated oncogenesis in cultured stable Huh7 and Hep3B cells expressing wild-type or mutated AMF/PGI and in a mouse model in this study. The working concentrations of the tested compounds were lower than their IC10 , which was determined by Brdu incorporation and colony formation assay. Only UA efficiently suppressed the AMF/PGI-induced Huh7 cell migration and MMP-3 secretion. Additionally, UA inhibited the AMF/PGI-mediated protection against TGF-β-induced apoptosis in Hep3B cells, whereas OA, tangeretin, and nobiletin had no effect. In Huh7 cells and tumor tissues, UA disrupted the Src/RhoA/PI 3-kinase signaling and complex formation induced by AMF/PGI. In the Hep3B system, UA dramatically suppressed AMF/PGI-induced anti-apoptotic signaling transmission, including Akt, p85, Bad, and Stat3 phosphorylation. AMF/PGI enhances tumor growth, angiogenesis, and pulmonary metastasis in mice, which is correlated with its enzymatic activity, and critically, UA intraperitoneal injection reduces the tumorigenesis in vivo, enhances apoptosis in tumor tissues and also prolongs mouse survival. Combination of sub-optimal dose of UA and cisplatin, a synergistic tumor cell-killing effects was found. Thus, UA modulates intracellular signaling and might serve as a functional natural compound for preventing or alleviating hepatocellular carcinoma.

Separation rule of oleanane and ursane pentacyclic triterpenoids isomers from nature plants by coordination chromatography

Many of oleanolic and ursolic pentacyclic triterpenoid isomers generally coexist. There is a small difference in their structures. Based on coordination chromatography theory, a reversed-phase high-performance thin-layer chromatography (HPLC) method has been investigated for improving the isomers' resolution by adding suitable agents in mobile phase, and the separation rule was summarized. With the calculation analysis, the space sizes of isomers were in the range of 3.77-5.65 Å. The total minimum energy in the inclusion of guest and β-CD had the biggest reduction, compared with the energy in the simple mixture of guest and β-CD (such as "asiaticoside-B" and "β-CD," from 196.4406 to 95.0670 kJ mol(-1)). So, β-CD (the cavity space size is in the range of 6.00-6.50 Å) and its derivatives were selected as the suitable agents. The experiment results showed that the resolution might be improved by adding the hydrophilic β-CD derivatives in mobile phase, such as Glu-β-CD, when the isomer structures carry big hydrophilic groups.

Hepatitis B virus X protein upregulates Lin28A/Lin28B through Sp-1/c-Myc to enhance the proliferation of hepatoma cells

Hepatitis B virus X protein (HBx) plays critical roles in the pathogenesis of hepatocellular carcinoma (HCC). Here, we were interested in knowing whether the oncogene Lin28A and its homolog Lin28B are involved in the hepatocarcinogenesis mediated by HBx. We showed that the expression levels of Lin28A and Lin28B were increased in clinical HCC tissues, HepG2.2.15 cell line and liver tissues of p21-HBx transgenic mice. Interestingly, the expression levels of HBx were positively associated with those of Lin28A/Lin28B in clinical HCC tissues. Moreover, the overexpression of HBx resulted in the upregulation of Lin28A/Lin28B in hepatoma HepG2/H7402 cell lines by transient transfection, suggesting that HBx was able to upregulate Lin28A and Lin28B. Then, we examined the mechanism by which HBx upregulated Lin28A and Lin28B. We identified that the promoter region of Lin28A regulated by HBx was located at nt -235/-66 that contained Sp-1 binding element. Co-immunoprecipitation showed that HBx was able to interact with Sp-1 in HepG2-X cells. Moreover, chromatin immunoprecipitation (ChIP) demonstrated that HBx could bind to the promoter of Lin28A, which failed to work when Sp-1 was silenced. Electrophoretic mobility shift assay (EMSA) further identified that HBx was able to interact with Sp-1 element in Lin28A promoter via transcription factor Sp-1. In addition, we found that c-Myc was involved in the activation of Lin28B mediated by HBx. In function, Lin28A/Lin28B played important roles in HBx-enhanced proliferation of hepatoma cells in vitro and in vivo. In conclusion, HBx activates Lin28A/Lin28B through Sp-1/c-Myc in hepatoma cells. Lin28A/Lin28B serves as key driver genes in HBx-induced hepatocarcinogenesis.

Ursane-type pentacyclic triterpenoids as useful platforms to discover anticancer drugs

This review highlights the potential of natural and semisynthetic ursane-type triterpenoids as candidates for the design of multi-target bioactive compounds, with focus on their anticancer effects. A brief illustration of the biosynthesis, sources, and general biological effects of the main classes of naturally occurring pentacyclic triterpenoids (PTs) are provided.