Effects of oleanolic acid and ursolic acid on inhibiting tumor growth and enhancing the recovery of hematopoietic system postirradiation in mice

Cytotoxic Autophagy: A Novel Treatment Paradigm against Breast Cancer Using Oleanolic Acid and Ursolic Acid

BACKGROUND

Oleanolic acid (OA) and Ursolic acid (UA) are bioactive triterpenoids. Reported activities vary with the dose used for testing their activities in vitro. Studies using doses of ≥20 µM showed apoptosis activities in cancer cells. However, reported drug levels in circulation achieved by oral administration of UA and OA are ≤2 µM, thus limiting their use for treatment or delivering a combination treatment.

MATERIALS AND METHODS

The present report demonstrates the efficacy of OA, UA, and OA + UA on tumor cell-specific cytotoxicity at low doses (5 µM to 10 µM) in breast cancer (BrCa) cell lines MCF7 and MDA-MB231.

RESULTS

The data show that both OA and UA killed BrCa cells at low doses, but were significantly less toxic to MCF-12A, a non-tumorigenic cell line. Moreover, OA + UA at ≤10 µM was lethal to BrCa cells. Mechanistic studies unraveled the significant absence of apoptosis, but their cytotoxicity was due to the induction of excessive autophagy at a OA + UA dose of 5 µM each. A link to drug-induced cytotoxic autophagy was established by demonstrating a lack of their cytotoxicity by silencing the autophagy-targeting genes (ATGs), which prevented OA-, UA-, or OA + UA-induced cell death. Further, UA or OA + UA treatment of BrCa cells caused an inhibition of PI3 kinase-mediated phosphorylation of Akt/mTOR, the key pathways that regulate cancer cell survival, metabolism, and proliferation.

DISCUSSION

Combinations of a PI3K inhibitor (LY294002) with OA, UA, or OA + UA synergistically inhibited BrCa cell survival. Therefore, the dominance of cytotoxic autophagy by inhibiting PI3K-mediated autophagy may be the primary mechanism of PTT-induced anticancer activity in BrCa cells.

CONCLUSION

These results suggest it would be worthwhile testing combined OA and UA in clinical settings.

Exploring the Potential Use of Natural Products Together with Alkalization in Cancer Therapy

Cancer treatment is a significant focus in medicine, owing to the increasing global incidence of cancers. Patients with advanced cancers that do not respond to conventional therapies have limited options and an unfavorable prognosis. Consequently, researchers are investigating complementary approaches to conventional treatments. One such approach is alkalization therapy, which aims to neutralize the acidic tumor microenvironment (TME) by increasing its pH level. The acidic TME promotes inflammation, tumor progression, and drug resistance. Alkalization therapy has been demonstrated to be effective for various cancers. In addition, natural products, such as triterpenoids, parthenolides, fulvic acid, Taxus yunnanensis, and apple pectin have the potential to alleviate symptoms, maintain physical fitness, and improve treatment outcomes of cancer patients through their anti-inflammatory, antioxidant, and anticancer properties. In this review, we focus on the effects of alkalization therapy and natural products on cancer. Furthermore, we present a case series of advanced cancer patients who received alkalization therapy and natural products alongside standard treatments, resulting in long-term survival. We posit that alkalization therapy together with supplementation with natural products may confer benefits to cancer patients, by mitigating the side effects of chemotherapy and complementing standard treatments. However, further research is warranted to validate these clinical findings.

Natural products in anti-tuberculosis host-directed therapy

Given that the disease progression of tuberculosis (TB) is primarily related to the host's immune status, it has been gradually realized that chemotherapy that targets the bacteria may never, on its own, wholly eradicate Mycobacterium tuberculosis, the causative agent of TB. The concept of host-directed therapy (HDT) with immune adjuvants has emerged. HDT could potentially interfere with infection and colonization by the pathogens, enhance the protective immune responses of hosts, suppress the overwhelming inflammatory responses, and help to attain a state of homeostasis that favors treatment efficacy. However, the HDT drugs currently being assessed in combination with anti-TB chemotherapy still face the dilemmas arising from side effects and high costs. Natural products are well suited to compensate for these shortcomings by having gentle modulatory effects on the host immune responses with less immunopathological damage at a lower cost. In this review, we first summarize the profiles of anti-TB immunology and the characteristics of HDT. Then, we focus on the rationale and challenges of developing and implementing natural products-based HDT. A succinct report of the medications currently being evaluated in clinical trials and preclinical studies is provided. This review aims to promote target-based screening and accelerate novel TB drug discovery.

Identification of N-(3-(methyl(3-(orotic amido)propyl)amino)propyl) oleanolamide as a novel topoisomerase I catalytic inhibitor by rational design, molecular dynamics simulation, and biological evaluation

DNA topoisomerase I (TOP1) catalytic inhibitors are a promising class of antitumor agents. Oleanolic acid derivatives are potential TOP1 catalytic inhibitors. However, their inhibitory activity still needs to be enhanced, and the stability and hotspot residue sites of their interaction with TOP1 remain to be elucidated. Herein, a novel oleanolic acid derivative, OA4 (N-(3-(methyl(3-(orotic amido)propyl)amino)propyl)oleanolamide), was identified by rational design. Subsequently, molecular dynamics simulations were performed to explore the stability and conformational dynamics of the TOP1-OA4 complex. The molecular mechanics/generalized Born surface area method calculated the binding free energy and predicted Arg488, Ile535, and His632 to be hotspot residues. Biological experiments verified that OA4 is a nonintercalative TOP1 catalytic inhibitor. OA4 exhibits better proliferation inhibitory activity against tumor cells than normal cells. Furthermore, OA4 can induce apoptosis and effectively suppress the proliferation and migration of cancer cells. This work provides new insights for the development of novel TOP1 catalytic inhibitors.

Synthesis, Biological Activity, ADME and Molecular Docking Studies of Novel Ursolic Acid Derivatives as Potent Anticancer Agents

A series of new ursolic acid (UA) derivatives substituted with various amino acids (AAs) or dipeptides (DP) at the C-3 position of the steroid skeleton was designed and synthesized. The compounds were obtained by the esterification of UA with the corresponding AAs. The cytotoxic activity of the synthesized conjugates was determined using the hormone-dependent breast cancer cell line MCF-7 and the triple-negative breast cancer cell line MDA. Three derivatives (l-seryloxy-, l-prolyloxy- and l-alanyl-l-isoleucyloxy-) showed micromolar IC₅₀ values and reduced the concentrations of matrix metalloproteinases 2 and 9. Further studies revealed that for two compounds (l-seryloxy- and l-alanyl-l-isoleucyloxy-), a possible mechanism of their antiproliferative action is the activation of caspase-7 and the proapoptotic Bax protein in the apoptotic pathway. The third compound (l-prolyloxy- derivative) showed a different mechanism of action as it induced autophagy as measured by an increase in the concentrations of three autophagy markers: LC3A, LC3B, and beclin-1. This derivative also showed statistically significant inhibition of the proinflammatory cytokines TNF-α and IL-6. Finally, for all synthesized compounds, we computationally predicted their ADME properties as well as performed molecular docking to the estrogen receptor to assess their potential for further development as anticancer agents.

Phytochemicals: A potential next generation agent for radioprotection

BACKGROUND

Radiation hazards are accountable for extensive damage in the biological system and acts as a public health burden. Owing to the rapid increasing in radiation technology, both Ionizing radiation (IR) from natural and man made source poses detrimental outcome to public health. IR releases free radicals which induces oxidative stress and deleterious biological damage by modulating radiation induced signalling intermediates. The efficacy of existing therapeutic approach and treatment strategy are limited owing to their toxicity and associated side effects. Indian system of traditional medicine is enriched with prospective phytochemicals with potential radioprotection ability.

PURPOSE

The present review elucidated and summarized the potential role of plant derived novel chemical compound with prospective radioprotective potential.

METHOD

So far as the traditional system of Indian medicine is concerned, plant kingdom is enriched with potential bioactive molecules with diverse pharmacological activities. We reviewed several compounds mostly secondary metabolites from plant origin using various search engines.

RESULTS

Both compounds from land plants and marine source exhibited antioxidant antiinflammatory, free radical scavenging ability. These compounds have tremendous potential in fine-tuning of several signalling intermediates, which are actively participated in the progression and development of a pathological condition associated with radiation stress.

CONCLUSION

Development and explore of an operational radioprotective agent from originated from plant source that can be used as a novel molecular tool to eliminate the widespread damage caused by space exploration, ionizing radiation, nuclear war and radiotherapy has been significantly appreciated. Through extensive literature search we highlighted several compounds from both land plant and marine origin can be implemented for a better therapeutic potential against radiation induced injury. Furthermore, extensive clinical trials must be carried out in near future for better therapeutic modality and clinical efficacy.

Delivery of Ursolic Acid by Polyhydroxybutyrate Nanoparticles for Cancer Therapy: in silico and in vitro Studies

Ursolic acid (UA), a pentacyclic triterpenoid and a phytochemical, is a potent inhibitory agent against proliferation of various tumors. Polyhydroxybutyrate nanoparticles (PHB NPs) are preferred in therapeutics due to their drug-stabilizing property and enhanced biological activity. In this study, PHB NPs were utilized to deliver and enhance the bioavailability of UA against cancer cells (HeLa). Further, molecular docking and dynamic studies were conducted to calculate the binding affinity and stability of UA at the active site of target protein (epidermal growth factor receptor-EGFR). The PHB NPs revealed the average size as 150-200 nm in TEM, which were used in subsequent experiments. The cytoplasmic uptake of nanoparticles was confirmed by florescent microscopy. The encapsulation potential of PHB NPs with UA was assessed by UV-visible spectrophotometer as 54%. Besides, the drug release behavior, cytotoxicity and the regulation of apoptosis were investigated in vitro. The cytotoxicity results revealed that the maximum efficiency of drug delivery was at 96th hour.

Systematic Review of Potential Anticancerous Activities of Erythrina senegalensis DC (Fabaceae)

The objective of this study was to carry out a systematic review of the substances isolated from the African medicinal plant Erythrina senegalensis, focusing on compounds harboring activities against cancer models detailed in depth herein at both in vitro and in vivo preclinical levels. The review was conducted through Pubmed and Google Scholar. Nineteen out of the forty-two secondary metabolites isolated to date from E. senegalensis displayed interesting in vitro and/or in vivo antitumor activities. They belonged to alkaloid (Erysodine), triterpenes (Erythrodiol, maniladiol, oleanolic acid), prenylated isoflavonoids (senegalensin, erysenegalensein E, erysenegalensein M, alpinumisoflavone, derrone, warangalone), flavonoids (erythrisenegalone, senegalensein, lupinifolin, carpachromene) and pterocarpans (erybraedine A, erybraedine C, phaseollin). Among the isoflavonoids called "erysenegalensein", only erysenealenseins E and M have been tested for their anticancerous properties and turned out to be cytotoxic. Although the stem bark is the most frequently used part of the plant, all pterocarpans were isolated from roots and all alkaloids from seeds. The mechanisms of action of its metabolites include apoptosis, pyroptosis, autophagy and mitophagy via the modulation of cytoplasmic proteins, miRNA and enzymes involved in critical pathways deregulated in cancer. Alpinumisoflavone and oleanolic acid were studied in a broad spectrum of cancer models both in vitro and in preclinical models in vivo with promising results. Other metabolites, including carpachromen, phaseollin, erybraedin A, erysenegalensein M and maniladiol need to be further investigated, as they display potent in vitro effects.

Advances in production and structural derivatization of the promising molecule ursolic acid

Ursolic acid (UA) is a ursane-type pentacyclic triterpenoid compound, naturally produced in plants via specialized metabolism and exhibits vast range of remarkable physiological activities and pharmacological manifestations. Owing to significant safety and efficacy in different medical conditions, UA may serve as a backbone to produce its derivatives with novel therapeutic functions. This review aims to provide ideas for exploring more diverse structures to improve UA pharmacological activity and increasing its biological yield to meet the industrial requirements by systematically reviewing the current research progress of UA. We first provides an overview of the pharmacological activities, acquisition methods and structural modifications of UA. Among them, we focused on the synthetic modifications of UA to yield valuable derivatives with enhanced therapeutic potential. Furthermore, harnessing the essential advances for green synthesis of UA and its derivatives by advent of metabolic engineering and synthetic biology are of great concern. In this regard, all pivotal advances for enhancing the production of UA have been discussed. In combination with the advantages of UA biosynthesis and transformation strategy, large-scale microbial production of UA is a promising platform for further exploration.

Could Polyphenols Really Be a Good Radioprotective Strategy?

Currently, radiotherapy is one of the most effective strategies to treat cancer. However, deleterious toxicity against normal cells indicate for the need to selectively protect them. Reactive oxygen and nitrogen species reinforce ionizing radiation cytotoxicity, and compounds able to scavenge these species or enhance antioxidant enzymes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) should be properly investigated. Antioxidant plant-derived compounds, such as phenols and polyphenols, could represent a valuable alternative to synthetic compounds to be used as radio-protective agents. In fact, their dose-dependent antioxidant/pro-oxidant efficacy could provide a high degree of protection to normal tissues, with little or no protection to tumor cells. The present review provides an update of the current scientific knowledge of polyphenols in pure forms or in plant extracts with good evidence concerning their possible radiomodulating action. Indeed, with few exceptions, to date, the fragmentary data available mostly derive from in vitro studies, which do not find comfort in preclinical and/or clinical studies. On the contrary, when preclinical studies are reported, especially regarding the bioactivity of a plant extract, its chemical composition is not taken into account, avoiding any standardization and compromising data reproducibility.

Structure determination of oleanolic and ursolic acids: a combined density functional theory/vibrational spectroscopy methodology

Raw samples of oleanolic and ursolic acids, a class of terpenoid acids mainly found in the leaf and fruit cuticles of some plant species, can be defined as a blend of clusters of different conformers aggregated in dimers and tetramers by means of hydrogen bonds and stabilized by non-electrostatic interactions.

Bioactive Herbal Extracts of Traditional Chinese Medicine Applied with the Biomaterials: For the Current Applications and Advances in the Musculoskeletal System

Traditional Chinese medicine (TCM) has demonstrated superior therapeutic effect for musculoskeletal diseases for thousands of years. Recently, the herbal extracts of TCM have received rapid advances in musculoskeletal tissue engineering (MTE). A literature review collecting both English and Chinese references on bioactive herbal extracts of TCM in biomaterial-based approaches was performed. This review provides an up-to-date overview of application of TCMs in the field of MTE, involving regulation of multiple signaling pathways in osteogenesis, angiogenesis, anti-inflammation, and chondrogenesis. Meanwhile, we highlight the potential advantages of TCM, opening the possibility of its extensive application in MTE. Overall, the superiority of traditional Chinese medicine turns it into an attractive candidate for coupling with advanced additive manufacturing technology.

Design, modification of phyllanthone derivatives as anti-diabetic and cytotoxic agents

Twelve benzylidene derivatives, one Baeyer-Villiger oxidative, six imine derivatives were successfully designed and synthesised from phyllanthone. In the search for potential new anti-diabetic agents, phyllanthone along with its benzylidene and oxidation analogues were evaluated for enzyme inhibition against α-glucosidase. In the benzylidene series, most analogues displayed stronger activity than the mother compound. Compound 1c revealed the strongest activity, outperforming the acarbose positive control with an IC₅₀ value of 19.59 µM. Phyllanthone and its derivatives were then tested for cytotoxic activity against the K562 cell line. The imine analogues displayed the most powerful cytotoxic activity with 3cand 3d having IC₅₀ values of 57.55 and 68.02 µM, respectively.

Oleanolic Acid Mitigates 6-Hydroxydopamine Neurotoxicity by Attenuating Intracellular ROS in PC12 Cells and Striatal Microglial Activation in Rat Brains

Oleanolic acid (OA), a biologically active pentacyclic triterpenoid compound, has been implicated in a number of clinical benefits including antioxidant, and anti-inflammatory properties. OA has been previously shown to ameliorate the toxic effects of 6-hydroxydopamine (6-OHDA), however, the mechanism by which this effect is exhibited is not clearly understood. In the present study, we investigated the role of OA in attenuation of microglial activation in 6-OHDA induced Parkinsonian rat model. We also explored the ability of OA to attenuate 6-OHDA-induced intracellular reactive oxygen species (ROS), and thus prevent cell death in PC12 cells. We accessed the utility of immunohistochemistry to assess striatal microglial activation, where shape descriptors such as area, perimeter, Feret's diameter, aspect ratio and solidity were determined using the Fiji ImageJ software. Intracellular ROS and cell viability were assessed in PC12 cells using the OxiSelect^TM Intracellular ROS Assay Kit and MTT assay, respectively. We found that microglial activation was decreased in rats pre-treated with OA prior to 6-OHDA insult as well as in rats treated with OA 1 day post 6-OHDA exposure when compared to untreated rats, as determined by shape descriptors. This finding was in correlation with significantly improved motor symptoms and increased striatal dopamine in treated rats as compared to non-treated rats. Flow cytometry assessment of PC12 cells revealed a decreased amount of intracellular ROS in cells pre-treated with OA 6 h prior to 6-OHDA exposure and cells treated with OA 1 h post 6-OHDA exposure, suggesting that OA provides neuroprotection in PC12 cells by removing intracellular ROS, thereby reducing oxidative stress. Our finding suggest that OA exhibits its neuroprotective effect by attenuating striatal microglial activation, which results in neuroinflammation that is implicated in Parkinson's disease pathology. Further studies detailing the mechanism by which OA interacts with microglia may be useful in understanding the role of OA in attenuating neuroinflammation.

Imprinted Oxide and MIP/Oxide Hybrid Nanomaterials for Chemical Sensors †

The oxides of transition, post-transition and rare-earth metals have a long history of robust and fast responsive recognition elements for electronic, optical, and gravimetric devices. A wide range of applications successfully utilized pristine or doped metal oxides and polymer-oxide hybrids as nanostructured recognition elements for the detection of biologically relevant molecules, harmful organic substances, and drugs as well as for the investigative process control applications. An overview of the selected recognition applications of molecularly imprinted sol-gel phases, metal oxides and hybrid nanomaterials composed of molecularly imprinted polymers (MIP) and metal oxides is presented herein. The formation and fabrication processes for imprinted sol-gel layers, metal oxides, MIP-coated oxide nanoparticles and other MIP/oxide nanohybrids are discussed along with their applications in monitoring bioorganic analytes and processes. The sensor characteristics such as dynamic detection range and limit of detection are compared as the performance criterion and the miniaturization and commercialization possibilities are critically discussed.

Efficacy of ursolic acid against Echinococcus granulosus in vitro and in a murine infection model

BACKGROUND

Cystic echinococcosis is a global public health problem; however, the drugs (albendazole and mebendazole) currently recommended by WHO for its treatment, have limited efficacy. Therefore, novel drugs are required to provide more choices for the treatment of this disease.

METHODS

The anthelmintic effects of ursolic acid (UA) were tested on Echinococcus granulosus protoscoleces, germinal cells and metacestodes in vitro. The in vivo efficacy of UA was investigated in mice following secondary infection with E. granulosus. Furthermore, the corresponding ultrastructural damage induced by UA was evaluated by electron microscopy.

RESULTS

In vitro, 45.95 ± 5.30% of protoscoleces were killed by UA at 40 μg/ml, while the growth of more than 90% of germinal cells was inhibited by UA at 10 to 40 μg/ml. The same effect was observed in metacestodes 7 days after treatment with UA at 10, 20 and 40 μg/ml, and more than 50% of metacestodes showed loss of integrity at the end of the experiment. In vivo, metacestode weight was significantly reduced following oral administration of UA at 200 and 100 mg/kg (39.5 and 38.3%, respectively). Additionally, ultrastructural damage, such as alternations in germinal cell morphology and formation of vacuoles and lipid granules were observed in parasites treated with UA in vitro, while detachment of the germinal layer from the laminated layer was also seen in metacestodes in vivo.

CONCLUSIONS

UA was demonstrated to exert parasiticidal activity against E. granulosus in vitro and in vivo, thus implicating UA as a potential anti-echinococcosis agent.

Recent developments on the extraction and application of ursolic acid. A review

Ursolic acid (UA) is a pentacyclic triterpenoid widely found in herbs, leaves, flowers and fruits; update information on the major natural sources or agro-industrial wastes is presented. Traditional (maceration, Soxhlet and heat reflux) and modern (microwave-, ultrasound-, accelerated solvent- and supercritical fluid) extraction and purification technologies of UA, as well as some patented process, are summarized. The great interest in this bioactive compound is related to the beneficial effects in human health due to antioxidant, antimicrobial, anti-inflammatory, hepatoprotective, immunomodulatory, anti-tumor, chemopreventive, cardioprotective, antihyperlipidemic and hypoglycemic activities, and others. UA may augment the resistance of the skin barrier to irritants, prevent dry skin and could be suitable to develop antiaging products. The development of nanocrystals and nanoparticle-based drugs could reduce the side effects of high doses of UA in organisms, and increase its limited solubility and poor bioavailability of UA which limit the potential of this bioactive and the further applications. Commercial patented applications in relation to cosmetical and pharmaceutical uses of UA and its derivatives are surveyed.

Polymeric nanoparticles developed by vitamin E-modified aliphatic polycarbonate polymer to promote oral absorption of oleanolic acid

Oleanolic acid (OA) exhibited good pharmacological activities in the clinical treatment of hypoglycemia, immune regulation, acute jaundice and chronic toxic hepatitis. However, the oral delivery of OA is greatly limited by its inferior water solubility and poor intestinal mucosa permeability. Herein, we developed a novel polymeric nanoparticle (NP) delivery system based on vitamin E modified aliphatic polycarbonate (mPEG-PCC-VE) to facilitate oral absorption of OA. OA encapsulated mPEG-PCC-VE NPs (OA/mPEG-PCC-VE NPs) showed uniform particle size of about 170 nm with high drug loading capability (8.9%). Furthermore, the polymeric mPEG-PCC-VE NPs, with good colloidal stability and pH-sensitive drug release characteristics, significantly enhanced the in vitro dissolution of OA in the alkaline medium. The in situ single pass intestinal perfusion (SPIP) studies performed on rats demonstrated that the OA/mPEG-PCC-VE NPs showed significantly improved permeability in the whole intestinal tract when compared to OA solution, especially for duodenum and colon. As a result, the in vivo pharmacokinetics study indicated that the bioavailability of OA/mPEG-PCC-VE NPs showed 1.5-fold higher than commercially available OA tablets. These results suggest that mPEG-PCC-VE NPs are a promising platform to facilitate the oral delivery of OA.

Potential Protective Effects of Ursolic Acid against Gamma Irradiation-Induced Damage Are Mediated through the Modulation of Diverse Inflammatory Mediators

This study was aimed to evaluate the possible protective effects of ursolic acid (UA) against gamma radiation induced damage both in vitro as well as in vivo. It was observed that the exposure to gamma radiation dose- and time-dependently caused a significant decrease in the cell viability, while the treatment of UA attenuated this cytotoxicity. The production of free radicals including reactive oxygen species (ROS) and NO increased significantly post-irradiation and further induced lipid peroxidation and oxidative DNA damage in cells. These deleterious effects could also be effectively blocked by UA treatment. In addition, UA also reversed gamma irradiation induced inflammatory responses, as indicated by the decreased production of TNF-α, IL-6, and IL-1β. NF-κB signaling pathway has been reported to be a key mediator involved in gamma radiation-induced cellular damage. Our results further demonstrated that gamma radiation dose- and time-dependently enhanced NF-κB DNA binding activity, which was significantly attenuated upon UA treatment. The post-irradiation increase in the expression of both phospho-p65, and phospho-IκBα was also blocked by UA. Moreover, the treatment of UA was found to significantly prolong overall survival in mice exposed to whole body gamma irradiation, and reduce the excessive inflammatory responses. Given its radioprotective efficacy as described here, UA as an antioxidant and NF-κB pathway blocker, may function as an important pharmacological agent in protecting against gamma irradiation-induced injury.

Ursolic acid nanoparticles inhibit cervical cancer growth in vitro and in vivo via apoptosis induction

Cervical cancer is a cause of cancer death, making it one of the most common causes of death among women globally. Previously, a variety of studies have revealed the molecular mechanisms by which cervical cancer develops. However, there are still limitations in treatment for cervical cancer. Ursolic acid is a naturally derived pentacyclic triterpene acid, exhibiting broad anticancer effects. Nanoparticulate drug delivery systems have been known to better the bioavailability of drugs on intranasal administration compared with only drug solutions. Administration of ursolic acid nanoparticles is thought to be sufficient to lead to considerable suppression of cervical cancer progression. We loaded gold-ursolic acid into poly(DL-lactide-co-glycolide) nanoparticles to cervical cancer cell lines due to the properties of ursolic acid in altering cellular processes and the easier absorbance of nanoparticles. In addition, in this study, ursolic acid nanoparticles were administered to cervical cancer cells to find effective treatments for cervical cancer inhibition. In the present study, ELISA, western blotting, flow cytometry and immunohistochemistry assays were carried out to calculate the molecular mechanism by which ursolic acid nanoparticles modulated cervical cancer progression. Data indicated that ursolic acid nanoparticles, indeed, significantly suppress cervial cancer cell proliferation, invasion and migration compared to the control group, and apoptosis was induced by ursolic acid nanoparticles in cervical cancer cells through activating caspases, p53 and suppressing anti-apoptosis-related signals. Furthermore, tumor size was reduced by treatment of ursolic acid nanoparticles in in vivo experiments. In conclusion, this study suggests that ursolic acid nanoparticles inhibited cervical cancer cell proliferation via apoptosis induction, which could be a potential target for future therapeutic strategy clinically.

Ursolic Acid Loaded PLGA Nanoparticles: in vitro and in vivo Evaluation to Explore Tumor Targeting Ability on B16F10 Melanoma Cell Lines

PURPOSE

Ursolic acid (UA), a pentacyclic triterpenoid extracted from plants, shows promising inhibitory effect in different tumor bearing cell lines. In the present study we fabricated UA loaded PLGA nanoparticles (UA-NPs) as the drug carrier and thoroughly evaluated in vitro and in vivo the differential tumor targeting effects of UA and UA-NPs in B16F10 melanoma cells.

METHODS

Ursolic acid loaded PLGA nanoparticles were prepared by emulsion solvent evaporation technique and evaluated for particle size, polydispersity, zeta potential and drug release potency. MTT assay as well as flow cytometric and confocal microscopic analyses were done in B16F10 mouse melanoma cell lines. Formulations were labeled with technetium-99m to evaluate the biodistribution and perform scintigraphic imaging studies following intravenous administration in tumor bearing mice model.

RESULTS

Single emulsification technique produced smooth spherical nanoparticles of small size with relatively narrow size distribution (154 ± 4.56 nm). On B16F10 cell line, the formulation showed higher cytotoxicity compared to the free drug due to increased in vitro cellular uptake. The formulation was successfully radiolabeled and remained substantially (>90%) stable when incubated (37°C, 6 h) separately in normal saline or freshly collected rat serum or histidine solution. The radiolabeled UA-NPs exhibited slower blood clearance and comparatively high uptake in tumor region as evidenced by biodistribution and scintigraphic studies.

CONCLUSIONS

The in vitro and in vivo studies have proved the tumor targeting potential of UA-NPs in B16F10 melanoma cell lines.

In vitro effectiveness of triterpenoids and their synergistic effect with antibiotics against Staphylococcus aureus strains

OBJECTIVES

The aim of this study is to evaluate the effect of four triterpenoids such as oleanolic acid, ursolic acid, cycloastragenol, and beta-boswellic acid alone and in combination with antibiotics against Staphylococcus aureus strains.

MATERIALS AND METHODS

Sixteen clinical strains of S. aureus from infected wounds were isolated. Eight were methicillin-sensitive S. aureus (MSSA), and the other eight were methicillin-resistant S. aureus (MRSA). The activity was also seen in reference S. aureus American Type Culture Collection™ strains. The activity of all the triterpenoids and antibiotics against S. aureus was evaluated by broth microdilution method. The effectiveness was judged by comparing the minimum inhibitory concentrations (MICs) of the compounds with antibiotics. The combination of antibiotics with compounds was evaluated by their fractional inhibitory concentrations (FIC).

RESULTS

Against both clinical and reference MSSA strains, none of the compounds exhibited comparable activity to antibiotics vancomycin or cefradine except for ursolic acid (MIC 7.8 μg/ml). Against MRSA, all compounds (MIC 16-128 μg/ml) showed lesser activity than vancomycin (MIC 5.8 μg/ml). Among triterpenoid-antibiotic combinations, the most effective were ursolic acid and vancomycin against clinical strain MSSA (FICS 0.17). However, overall, different combinations between triterpenoids and antibiotics showed 95%-46% (P < 0.05) reduction in MICs of antibiotics compared to when antibiotics were used alone. Cefradine, a drug not suitable for treating MRSA (MIC = 45 μg/ml), showed a remarkable decrease in its MIC (87% P< 0.01) when it was used in combination with oleanolic acid or ursolic acid in both clinical and reference strains.

CONCLUSION

The tested triterpenoids are relatively weaker than antibiotics. However, when used in combination with antibiotics, they showed remarkable synergistic effect and thus can help in prolonging the viability of these antibiotics against S. aureus infections. Furthermore, reduction in MIC of cefradine with oleanolic acid indicates their potential use against MRSA.

Identification of a novel oxidative stress induced cell death by Sorafenib and oleanolic acid in human hepatocellular carcinoma cells

The lack of effective chemotherapies in hepatocellular carcinoma (HCC) is still an unsolved problem and underlines the need for new strategies in liver cancer treatment. In this study, we present a novel approach to improve the efficacy of Sorafenib, today's only routinely used chemotherapeutic drug for HCC, in combination with triterpenoid oleanolic acid (OA). Our data show that cotreatment with subtoxic concentrations of Sorafenib and OA leads to highly synergistic induction of cell death. Importantly, Sorafenib/OA cotreatment triggers cell damage in a sustained manner and suppresses long-term clonogenic survival. Sorafenib/OA cotreatment induces DNA fragmentation and caspase-3/7 cleavage and the addition of the pan-caspase inhibitor zVAD.fmk shows the requirement of caspase activation for Sorafenib/OA-triggered cell death. Furthermore, Sorafenib/OA co-treatment stimulates a significant increase in reactive oxygen species (ROS) levels. Most importantly, the accumulation of intracellular ROS is required for cell death induction, since the addition of ROS scavengers (i.e. α-tocopherol, MnTBAP) that prevent the increase of intracellular ROS levels completely rescues cells from Sorafenib/OA-triggered cell death. In conclusion, OA represents a novel approach to increase the sensitivity of HCC cells to Sorafenib via oxidative stress.

Pharmacological screening of Monotheca buxifolia (Falc.) A. DC. for antinociceptive, anti-inflammatory and antipyretic activities

Background

Medicinal plants have proven their importance as a valuable source of molecules with therapeutic potential. Monotheca buxifolia (Falc.) A. DC. (family: Sapotaceae) is traditionally used as a hematinic, laxative, digestive, anthelmintic, antipyretic, and in the treatment of gastro-urinary disorders. To provide scientific evidence for its folkloric use, the present study investigated Monotheca buxifolia fruit hydro-ethanolic extract (MBHE) for its prospective antinociceptive, anti-inflammatory and antipyretic activities. MBHE was eluted through column chromatography to isolate the bioactive secondary metabolites which may probably involve in its beneficial properties.

Methods

The phytochemical constituents in MBHE was elucidated using UV, IR, ¹H-NMR, ¹³C NMR, 2D-NMR spectra in combination with EIMS and FAB-MS spectrometric techniques and comparison with literature data of related compounds. The antinociceptive activity of MBHE was evaluated in the acetic acid induced abdominal constriction assay; the anti-inflammatory potential was assessed in the carrageenan induced paw edema, while the antipyretic effect was tested against brewer’s yeast induced pyrexia in BALB/c mice at doses of 50, 100 and 150 mg/kg.

Results

Elution of MBHE along with various characterization techniques led to the isolation of oleanolic acid and isoquercetin. Significant attenuation of chemical induced nociception was observed with MBHE at tested doses of 50 mg/kg (P < 0.01, 68.87 %), 100 mg/kg (P < 0.01, 68.87 %) and 150 mg/kg (P < 0.001, 83.02 %). During a duration of 1–5 h in the carrageenan induced paw edema assay, significant ameliorative effect (P < 0.01, P < 0.001) was demonstrated by MBHE at 50 mg/kg (22.94–20 %), 100 mg/kg (33.23–21.13 %) and 150 mg/kg (38.23–25 %). MBHE also significantly alleviated the brewer’s yeast induced pyrexic response when tested at doses of 50 mg/kg (P < 0.05 in 2nd h), 100 mg/kg (P < 0.05, P < 0.01 and P < 0.001 in 1–5 h) and 150 mg/kg (P < 0.01 and P < 0.001 in 1–5 h).

Conclusion

These findings suggest that Monotheca buxifolia possess pain, inflammation and pyrexia ameliorating properties, probably mediated by the presence of oleanolic acid and isoquercetin contents, though the involvement of other important phytochemicals constituents cannot be ignored.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1257-z) contains supplementary material, which is available to authorized users.

Chemical Composition and Bioactivities of Two Common Chaenomeles Fruits in China: Chaenomeles speciosa and Chaenomeles sinensis

Contents of total flavonoids, total phenolics, total triterpenes, total condensed tannin and total saponins in peels, flesh and endocarps of Chaenomeles speciosa (CSP) and Chaenomeles sinensis (CSS) were determined by colorimetric method, while 5 phenolics (vanillic, gallic, chlorogenic, ferulic and p-coumaric acids), 2 triterpenes (oleanolic and ursolic acids), and 3 flavonoids (rutin, catechin and epicatechin) were identified and quantified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and HPLC, and antioxidant and α-glucosidase inhibitory activities of them also were evaluated as well as their digestive characteristics. In the correlation analysis, total phenolics, vanillic acid, catechin, ursolic acid and oleanolic acid all contribute to DPPH(·) scavenge capacity, gallic acid contributes to total ferric reducing antioxidant power, while total triterpenes, total saponins, chlorogenic acid and ferullic acid contribute to α-glucosidase inhibitory activity. In the principal component analysis, endocarps of CSP and CSS both show better quality than their peels and flesh, respectively. In vitro digestion can increase contents of total flavonoids, total condensed tannin and total saponins, while contents of total phenolics and total triterpenes decreased greatly. Our study would contribute to the full use of discarded parts of the 2 Chaenomeles and be helpful to establish a good foundation for further research of CSP and CSS.

Effect of a controlled-release drug delivery system made of oleanolic acid formulated into multivesicular liposomes on hepatocellular carcinoma in vitro and in vivo

The aim of the present study was to develop a novel dosage form of multivesicular liposomes for oleanolic acid (OA) to overcome its poor solubility, prolong therapeutic drug levels in the blood, and enhance the antitumor effect on hepatocellular carcinoma. OA-encapsulated multivesicular liposomes (OA-MVLs) were prepared by a double-emulsion method, and the formulation was optimized by the central composite design. The morphology, particle size, and drug-loading efficiency of OA-MVLs were investigated. Furthermore, OA-MVLs were also characterized both in vitro and in vivo. The results showed that OA-MVLs were spherical particles with an average particle size of 11.57 μm and an encapsulation efficiency of 82.3%±0.61%. OA-MVLs exhibited a sustained-release pattern in vitro, which was fitted to Ritger–Peppas equation. OA-MVLs inhibited the growth of human HepG2 cells which was confirmed by the MTT assay and fluorescence microscopy detection. The in vivo release of OA from OA-MVLs exhibited a sustained manner, indicating a longer circulation time compared to OA solution. The in vivo toxicity study indicated that medium-dose OA-MVLs exerted no toxic effect on the hosts. Importantly, OA-MVLs suppressed the growth of murine H22 hepatoma and prolonged the survival of tumor-bearing mice. In conclusion, the poorly soluble OA could be encapsulated into MVLs to form a novel controlled-release drug delivery system. The present study may hold promise for OA-MVLs as a new dosage form for sustained-release drug delivery in cancer therapy.

Solid inclusion complexes of oleanolic acid with amino-appended β-cyclodextrins (ACDs): Preparation, characterization, water solubility and anticancer activity

Oleanolic acid (OA) is a pentacyclic triterpenoid acid of natural abundance in plants which possesses important biological activities. However, its medicinal applications were severely impeded by the poor water solubility and resultant low bioavailability and potency. In this work, studies on solid inclusion complexes of OA with a series of amino-appended β-cyclodextrins (ACDs) were conducted in order to address this issue. These complexes were prepared by suspension method and were well characterized by NMR, SEM, XRD, TG, DSC and Zeta potential measurement. The 2:1 inclusion mode of ACDs/OA complexes was elucidated by elaborate 2D NMR (ROESY). Besides, water solubility of OA was dramatically promoted by inclusion complexation with ACDs. Moreover, in vitro anticancer activities of OA against human cancer cell lines HepG2, HT29 and HCT116 were significantly enhanced after formation of inclusion complexes, while the apoptotic response results indicated their induction of apoptosis of cancer cells. This could provide a novel approach to development of novel pharmaceutical formulations of OA.

Ursolic acid inhibits the growth of human pancreatic cancer and enhances the antitumor potential of gemcitabine in an orthotopic mouse model through suppression of the inflammatory microenvironment

The development of chemoresistance in human pancreatic cancer is one reason for the poor survival rate for patients with this cancer. Because multiple gene products are linked with chemoresistance, we investigated the ability of ursolic acid (UA) to sensitize pancreatic cancer cells to gemcitabine, a standard drug used for the treatment of pancreatic cancer. These investigations were done in AsPC-1, MIA PaCa-2, and Panc-28 cells and in nude mice orthotopically implanted with Panc-28 cells. In vitro, UA inhibited proliferation, induced apoptosis, suppressed NF-κB activation and its regulated proliferative, metastatic, and angiogenic proteins. UA (20 μM) also enhanced gemcitabine (200 nM)-induced apoptosis and suppressed the expression of NF-κB-regulated proteins. In the nude mouse model, oral administration of UA (250 mg/kg) suppressed tumor growth and enhanced the effect of gemcitabine (25 mg/kg). Furthermore, the combination of UA and gemcitabine suppressed the metastasis of cancer cells to distant organs such as liver and spleen. Immunohistochemical analysis showed that biomarkers of proliferation (Ki-67) and microvessel density (CD31) were suppressed by the combination of UA and gemcitabine. UA inhibited the activation of NF-κB and STAT3 and the expression of tumorigenic proteins regulated by these inflammatory transcription factors in tumor tissue. Furthermore, the combination of two agents decreased the expression of miR-29a, closely linked with tumorigenesis, in the tumor tissue. UA was found to be bioavailable in animal serum and tumor tissue. These results suggest that UA can inhibit the growth of human pancreatic tumors and sensitize them to gemcitabine by suppressing inflammatory biomarkers linked to proliferation, invasion, angiogenesis, and metastasis.

Ursolic Acid--A Pentacyclic Triterpenoid with a Wide Spectrum of Pharmacological Activities

Ursolic acid (UA) is a natural terpene compound exhibiting many pharmaceutical properties. In this review the current state of knowledge about the health-promoting properties of this widespread, biologically active compound, as well as information about its occurrence and biosynthesis are presented. Particular attention has been paid to the application of ursolic acid as an anti-cancer agent; it is worth noticing that clinical tests suggesting the possibility of practical use of UA have already been conducted. Amongst other pharmacological properties of UA one can mention protective effect on lungs, kidneys, liver and brain, anti-inflammatory properties, anabolic effects on skeletal muscles and the ability to suppress bone density loss leading to osteoporosis. Ursolic acid also exhibits anti-microbial features against numerous strains of bacteria, HIV and HCV viruses and Plasmodium protozoa causing malaria.

Synthesis and antitumor activity evaluation of novel ursolic acid derivatives

Eleven novel ursolic acid (UA) derivatives were designed and synthesized with modification at positions of C-2, C-3, and C-28 of UA. Their structures were confirmed by MS, (1)H NMR, and elemental analysis. Their in vitro cytotoxicities against various cancer cell lines (HeLa, HepG2, and BGC-823) were evaluated by MTT assay. The results indicated that all compounds could inhibit cell proliferation of HeLa, HepG2, and BGC-823 cells. Among them, compounds I3 and I4 showed more potent cytotoxicity on these three tumor cells than gefitinib (positive control), worthy to be studied further.

Simultaneous determination of 3-O-acetyloleanolic acid and oleanolic acid in rat plasma using liquid chromatography coupled to tandem mass spectrometry

3-O-Acetyloleanolic acid (OAA) is a triterpenoid compound, and exerts an apoptosis in cancer cell lines, an inhibition of both atopic and allergic contact dermatitis in murine model, and a suppression of inflammatory bone loss in mice. OAA can be converted into oleanolic acid (OA) by hydrolysis in vivo, and OA exhibits several pharmacological effects as well. A liquid chromatographic method using tandem mass spectrometry (MS/MS) was developed for the simultaneous determination of OAA and OA in rat plasma. After liquid-liquid extraction with ethylacetate, both substances were chromatographed on a reversed phase column with a mobile phase of 0.1% formic acid aqueous solution and acetonitrile (1:9, v/v). The accuracy and precision of the assay were in accordance with FDA regulations for the validation of bioanalytical methods. This analytical method was successfully applied to monitor plasma concentrations of both substances over time following an intravenous administration of OAA in rats.

Smac mimetic and oleanolic acid synergize to induce cell death in human hepatocellular carcinoma cells

Chemotherapy resistance of hepatocellular carcinoma (HCC) is still a major unsolved problem highlighting the need to develop novel therapeutic strategies. Here, we identify a novel synergistic induction of cell death by the combination of the Smac mimetic BV6, which antagonizes Inhibitor of apoptosis (IAP) proteins, and the triterpenoid oleanolic acid (OA) in human HCC cells. Importantly, BV6 and OA also cooperate to suppress long-term clonogenic survival as well as tumor growth in a preclinical in vivo model of HCC underscoring the clinical relevance of our findings. In contrast, BV6/OA cotreatment does not exert cytotoxic effects against normal primary hepatocytes, pointing to some tumor selectivity. Mechanistic studies show that BV6/OA cotreatment leads to DNA fragmentation and caspase-3 cleavage, while supply of the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk) revealed a cell type-dependent requirement of caspases for BV6/OA-induced cell death. The receptor interacting protein (RIP)1 kinase Inhibitor Necrostatin-1 (Nec-1) or genetic knockdown of RIP1 fails to rescue BV6/OA-mediated cell death, indicating that BV6/OA cotreatment does not primarily engage necroptotic cell death. Notably, the addition of several reactive oxygen species (ROS) scavengers significantly decreases BV6/OA-triggered cell death, indicating that ROS production contributes to BV6/OA-induced cell death. In conclusion, cotreatment of Smac mimetic and OA represents a novel approach for the induction of cell death in HCC and implicates further studies.

Design and optimization of oleanolic/ursolic acid-loaded nanoplatforms for ocular anti-inflammatory applications

Oleanolic acid (OA) and ursolic acid (UA) are ubiquitous pentacyclic triterpenes compounds in plants with great interest as anti-inflammatory therapeutics. The aim of this study was the design and optimization of polymeric nanoparticles (NPs) loaded with natural and synthetic mixtures (NM, SM) of these drugs for ophthalmic administration. A 2(3) + star central rotatable composite design was employed to perform the experiments. Results showed optimal and stable formulations with suitable physicochemical properties (mean diameter<225 nm), homogeneous distribution (polydispersity index∼0.1), negatively charged surface (∼-27 mV) and high entrapment efficiency (∼77%). Release and corneal permeation studies showed that NM release was faster than SM. Amounts of drug retained in the corneal tissue were also higher for NM. In vitro and in vivo tests showed no signs of irritation or toxicity and successful in vivo anti-inflammatory efficacy for both formulations, being NM-OA/UA NPs the most effective. From the clinical editor: Oleanolic acid (OA) and ursolic acid (UA) are compounds found in plants with anti-inflammatory properties. The authors in this paper designed nanoparticles (NPs) using poly(dl-lactide-coglycolide) acid (PLGA) loaded with these compounds for ophthalmic administration. Both in vitro and in vivo experiments showed no toxicity and significant anti-inflammatory efficacy. This may provide new drugs for ocular anti-inflammatory treatment.

Quantitative determination of three pentacyclic triterpenes from five Swertia L. species endemic to Western Ghats, India, using RP-HPLC analysis

Aim of this study was to identify pentacyclic triterpenoids betulinic acid (BA), oleanolic acid (OA) and ursolic acid (UA) from five Swertia species endemic to Western Ghats, which are used as substitutes as well as adulterants to Swertia chirayita. Our results indicate that the concentration of active compound vary largely among and within the species from different localities. OA was found in a higher amount in all species compared to BA and UA. From the results, it was clear that BA, OA and UA are present in the endemic species collected from Western Ghats, thus advocating the use of these species as alternate sources to S. chirayita. This in due course may release pressure of exploitation from natural resources of S. chirayita and help to bring it out from an endangered category from conservation point of view.

Caveolin-1 plays a key role in the oleanolic acid-induced apoptosis of HL-60 cells

Our previous study found that caveolin-1 (CAV-1) protein expression is upregulated during oleanolic acid (OA)-induced inhibition of proliferation and promotion of apoptosis in HL-60 cells. CAV-1 is the main structural protein component of caveolae, playing important roles in tumorigenesis and tumor development. It has been shown that cav-1 expression is lower in leukemia cancer cell lines SUP-B15, HL-60, THP-1 and K562 and in chronic lymphocytic leukemia primary (CLP) cells when compared with normal white blood cells, with the lowest cav-1 expression level found in HL-60 cells. To study the effects of cav-1 in HL-60 cells and the effects of cav-1 overexpression on OA drug efficacy, cav-1 was overexpressed in HL-60 cells using lentiviral-mediated transfection combined with OA treatment. The results showed that cav-1 overexpression inhibited HL-60 cell proliferation, promoted apoptosis, arrested the cell cycle in the G1 phase and inhibited activation of the PI3K/AKT/mTOR signaling pathway. Overexpression of CAV-1 also increased HL-60 cell sensitivity to OA. To further verify whether OA affects HL-60 cells via the activation of downstream signaling pathways by CAV-1, cav-1 gene expression was silenced using RNAi, and the cells were treated with OA to examine its efficacy. The results showed that after cav-1 silencing, OA had little effect on cell activity, apoptosis, the cell cycle and phosphorylation of HL-60 cells. This study is the first to show that CAV-1 plays a crucial role in the effects of OA on HL-60 cells.

Dietary oleanolic acid mediates circadian clock gene expression in liver independently of diet and animal model but requires apolipoprotein A1

Oleanolic acid is a triterpene widely distributed throughout the plant kingdom and present in virgin olive oil at a concentration of 57 mg/kg. To test the hypotheses that its long-term administration could modify hepatic gene expression in several animal models and that this could be influenced by the presence of APOA1-containing high-density lipoproteins (HDLs), diets including 0.01% oleanolic acid were provided to Apoe- and Apoa1-deficient mice and F344 rats. Hepatic transcriptome was analyzed in Apoe-deficient mice fed long-term semipurified Western diets differing in the oleanolic acid content. Gene expression changes, confirmed by reverse transcriptase quantitative polymerase chain reaction, were sought for their implication in hepatic steatosis. To establish the effect of oleanolic acid independently of diet and animal model, male rats were fed chow diet with or without oleanolic acid, and to test the influence of HDL, Apoa1-deficient mice consuming the latter diet were used. In Apoe-deficient mice, oleanolic acid intake increased hepatic area occupied by lipid droplets with no change in oxidative stress. Bmal1 and the other core component of the circadian clock, Clock, together with Elovl3, Tubb2a and Cldn1 expressions, were significantly increased, while Amy2a5, Usp2, Per3 and Thrsp were significantly decreased in mice receiving the compound. Bmal1 and Cldn1 expressions were positively associated with lipid droplets. Increased Clock and Bmal1 expressions were also observed in rats, but not in Apoa1-deficient mice. The core liver clock components Clock-Bmal1 are a target of oleanolic acid in two animal models independently of the diets provided, and this compound requires APOA1-HDL for its hepatic action.

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.

Oleanolic acid inhibits proliferation and induces apoptosis in NB4 cells by targeting PML/RARα

Oleanolic acid (OA), a naturally occurring pentacyclic triterpenoid contained in a variety of plant species, exhibits broad biological properties, including anticancer effects. Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia. APL has a unique and specific chromosomal aberration, t(15;17), which results in the formation of a fusion gene and protein PML/RARα, which is not only necessary for the diagnosis of APL, but is also critical for APL pathogenesis. In the present study, the cytotoxic effect of OA on NB4 cells was investigated. Cell viability was assessed via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression levels of bax and bcl-2 mRNA were determined by quantitative PCR. Apoptosis was analyzed using DNA fragment analysis and cell cycle distributions were analyzed by flow cytometry. The activity of caspase-3 and caspase-9 was determined by colorimetric assays. The expression of the PML/RARα fusion protein was analyzed by western blotting. The MTT assay showed that OA inhibited the proliferation of the NB4 cells. The expression levels of pro-apoptotic bax mRNA were increased and the levels of anti-apoptotic bcl-2 mRNA were decreased following the treatment of the NB4 cells with OA at 80 μmol/l. Treatment of the NB4 cells with OA at 80 μmol/l induced apoptosis and G₁ phase arrest, while caspase-9 and caspase-3 activity was significantly increased. Furthermore, the expression of the PML/RARα fusion protein was decreased. Together, these data suggest that OA exerts a cytotoxic effect that inhibits proliferation and induces apoptosis in NB4 cells by targeting PML/RARα, making it a potent therapeutic agent against leukemia.

Ethnopharmacological and bioactivity guided investigation of five TCM anticancer herbs

ETHNOPHARMACOLOGICAL RELEVANCE

Five herbs, Curcuma longa L. (CL), Scutellaria baicalensis Georgi (SBC), Scutellaria barbata D. Don (SBB), Hedyotis diffusa Willd. (HD) and Solanum nigrum L. (SN), are often prescribed in the polyherbal formulas for cancer treatment by traditional Chinese medicine (TCM) practitioners. The purpose of the present study was to identify important anticancer herbs used in TCM and carry out bioactivity-directed fractionation and isolation (BDFI) using six cancer cell lines as well as peripheral blood mononuclear cells (PBMCs), to identify constituents with anticancer activity but devoid of toxic effects against healthy immune cells.

MATERIALS AND METHODS

Of 243 document anticancer TCM treatments, 199 anticancer TCM herbs were ranked by the number of literature reports for each herb. Five herbs were identified from the top 50 ranked herbs by at least two out of three TCM practitioners as frequently used in the TCM treatment of cancer. BDFI using MTS assay was applied to determine the active anticancer extracts, fractions, and finally discrete compounds.

RESULTS

Five herbs were selected for study of their anticancer activities. The extracts of Curcuma longa L., Scutellaria barbata D. Don, and Hedyotis diffusa showed antiproliferative activity to various extents, extracts of Scutellaria baicalensis Georgi and Solanum nigrum L. showed little anticancer activity. Seven out of the 21 fractions obtained from Hedyotis diffusa Willd. showed anticancer activity. One new compound, ethyl 13(2) (S)-hydroxy-chlorophyllide a(1), along with 10 known compounds, i.e. 2-methyl-3-methoxyanthraquinone (2), 2-hydroxymethylanthraquinone(3), 2-hydroxy-3-methylanthraquinone(4), 2-hydroxymethy-1-hydroxyanthraquinone(5), 1-methoxy-2-hydroxyanthraquinone(6), 2-hydroxy-3-methyl-1-methoxyanthraquinone (7), oleanolic acid (8), ursolic acid (9), stigmasterol (10) and docosanoic acid (11), were isolated and identified. Compounds 2-6, 8 and 9 dose-dependently inhibited the cell viability of cancer cells within a concentration range of 1-200µM. Furthermore, compounds 2, 3, 5 and 9 showed significantly stronger inhibition of tested cancer cell lines than on that of PBMCs.

CONCLUSION

This study identified anticancer herbs, extracts, fractions and eventually compounds from the documented anticancer TCM herbs by using BDFI. It also determined the antiproliferative activity in cancer and healthy immune cells of the isolated compounds from Hedyotis diffusa. The results will be useful in the validation of the clinical application of these herbs and the development of novel anticancer therapeutics.

Radiosensitizing effect of oleanolic acid on tumor cells through the inhibition of GSH synthesis in vitro

Oleanolic acid (OA) is a natural pentacyclic triterpenoid that has been used in traditional medicine as an anticancer and anti-inflammatory agent. The aim of our study was to investigate whether or not OA increases the radiosensivity of tumor cells, and the relative mechanism was also investigated. Clonogenic assay was used to observe the radiosensitivity of C6 and A549 cells following different treatments. The alteration of intracellular DNA damage was determined using a micronucleus (MN) assay. In order to identify the mechanism of OA-mediated radiosensitization of tumor cells, the levels of glutathione (GSH) in irradiated cells following various pretreatments were determined using glutathione reductase/5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) recycling assay. Under the same condition, the activities of γ-glutamylcysteine synthetase (γ-GCS) and GSH synthase (GSS), both key enzymes for GSH synthesis, were detected using appropriate methods. In order to confirm the radiosensitizing effect of OA on cancer cells by attenuating GSH, N-acetylcysteine (NAC) was added to cells in culture for 12 h before irradiation. The results showed that the combined treatment of radiation with OA significantly decreased the clonogenic growth of tumor cells and enhanced the numbers of intracellular MN compared to irradiation alone. Furthermore, it was found that the synthesis of cellular GSH was inhibited concomitantly with the downregulation of γ-GCS activity. Therefore, the utilization of OA as a radiosensitizing agent for irradiation-inducing cell death offers a potential therapeutic approach to treat cancer.

Chemical and preclinical studies on Hedyotis diffusa with anticancer potential

This paper presents the chemical and preclinical anticancer research on Hedyotis diffusa Willd. in detail, one of the most renowned herbs often prescribed in the polyherbal formulas for cancer treatment in traditional Chinese medicine. Anthraquinones, flavonoids, and terpenoids constitute the majority of the 69 compounds that have been isolated and identified from H. diffusa. The anticancer effects of the methanolic, ethanolic, and aqueous extracts in various preclinical cancer models have been described. This review also summarized the anticancer activity of constituents of the herb and the mechanisms of action. All the studies suggest that H. diffusa has enormous potential in the therapy of cancer and warrants further chemical and pharmacological investigation.

Triterpenoids amplify anti-tumoral effects of mistletoe extracts on murine B16.f10 melanoma in vivo

PURPOSE

Mistletoe extracts are often used in complementary cancer therapy although the efficacy of that therapy is controversially discussed. Approved mistletoe extracts contain mainly water soluble compounds of the mistletoe plant, i.e. mistletoe lectins. However, mistletoe also contains water-insoluble triterpenoids (mainly oleanolic acid) that have anti-tumorigenic effects. To overcome their loss in watery extracts we have solubilized mistletoe triterpenoids with cyclodextrins, thus making them available for in vivo cancer experiments.

EXPERIMENTAL DESIGN

B16.F10 subcutaneous melanoma bearing C57BL/6 mice were treated with new mistletoe extracts containing both water soluble compounds and solubilized triterpenoids. Tumor growth and survival was monitored. In addition, histological examinations of the tumor material and tumor surrounding tissue were performed.

RESULTS

Addition of solubilized triterpenoids increased the anti-tumor effects of the mistletoe extracts, resulting in reduced tumor growth and prolonged survival of the mice. Histological examination of the treated tumors showed mainly tumor necrosis and some apoptotic cells with active caspase-3 and TUNEL staining. A significant decrease of CD31-positive tumor blood vessels was observed after treatment with solubilized triterpenoids and different mistletoe extracts.

CONCLUSION

We conclude that the addition of solubilized mistletoe triterpenoids to conventional mistletoe extracts improves the efficacy of mistletoe treatment and may represent a novel treatment option for malignant melanoma.