(2α,3β)-2,3-Dihydroxyolean-12-en-28-oic acid, a new natural triterpene fromOlea europea, induces caspase dependent apoptosis selectively in colon adenocarcinoma cells

Bioactivities and Structure-Activity Relationships of Maslinic Acid Derivatives: A Review

Maslinic acid has a variety of biological activities, such as anti-tumor, hypoglycemic, anti-inflammatory, and anti-parasitic. In order to enhance the biological activity of maslinic acid, scholars have carried out a lot of structural modifications, and found some more valuable maslinic acid derivatives. In this paper, the structural modification, biological activity, and structure-activity relationship of maslinic acid were reviewed, providing references for the development of maslinic acid.

Natural products and mitochondrial allies in colorectal cancer therapy

Colorectal cancer (CRC) is a globally prevalent malignancy with a high potential for metastasis. Existing cancer treatments have limitations, including drug resistance and adverse effects. Researchers are striving to develop effective therapies to address these challenges. Impressively, contemporary research has discovered that many natural products derived from foods, plants, insects, and marine invertebrates can suppress the progression, metastasis, and invasion of CRC. In this review, we conducted a comprehensive search of the CNKI, PubMed, Embase, and Web of Science databases from inception to April 2023 to evaluate the efficacy of natural products targeting mitochondria to fight against CRC. Mitochondria are intracellular energy factories involved in cell differentiation, signal transduction, cell cycle regulation, apoptosis, and tumorigenesis. The identified natural products have been classified and summarized based on their mechanisms of action. These findings indicate that natural products can induce apoptosis in colorectal cancer cells by inhibiting the mitochondrial respiratory chain, ROS elevation, disruption of mitochondrial membrane potential, the release of pro-apoptotic factors, modulation of the Bcl-2 protein family to facilitate cytochrome c release, induction of apoptotic vesicle activity by activating the caspase protein family, and selective targeting of mitochondrial division. Furthermore, diverse apoptotic signaling pathways targeting mitochondria, such as the MAPK, p53, STAT3, JNK and AKT pathway, have been triggered by natural products. Natural products such as diosgenin, allopurinol, and clausenidin have demonstrated low toxicity, high efficacy, and multi-targeted properties. Mitochondria-targeting natural products have great potential for overcoming the challenges of CRC therapy.

Low and high doses of oral maslinic acid protect against Parkinson's disease via distinct gut microbiota-related mechanisms

The use of oral agents that can modify the gut microbiota (GM) could be a novel preventative or therapeutic option for Parkinson's disease (PD). Maslinic acid (MA), a pentacyclic triterpene acid with GM-dependent biological activities when it is taken orally, has not yet been reported to be effective against PD. The present study found both low and high dose MA treatment significantly prevented dopaminergic neuronal loss in a classical chronic PD mouse model by ameliorating motor functions and improving tyrosine hydroxylase expressions in the substantia nigra pars compacta (SNpc) and increasing dopamine and its metabolite homovanillic acid levels in the striatum. However, the effects of MA in PD mice were not dose-responsive, since similar beneficial effects for low and high doses of MA were observed. Further mechanism studies indicated that low dose MA administration favored probiotic bacterial growth in PD mice, which helped to increase striatal serotonin, 5-hydroxyindole acetic acid, and γ-aminobutyric acid levels. High dose MA treatment did not influence GM composition in PD mice but significantly inhibited neuroinflammation as indicated by reduced levels of tumor necrosis factor alpha and interleukin 1β in the SNpc; moreover, these effects were mainly mediated by microbially-derived acetic acid in the colon. In conclusion, oral MA at different doses protected against PD via distinct mechanisms related to GM. Nevertheless, our study lacked in-depth investigations of the underlying mechanisms involved; future studies will be designed to further delineate the signaling pathways involved in the interactive actions between different doses of MA and GM.

Synthesis of Tricyclic Pterolobirin H Analogue: Evaluation of Anticancer and Anti-Inflammatory Activities and Molecular Docking Investigations

Pterolobirin H (3), a cassane diterpene isolated from the roots of Pterolobium macropterum, exhibits important anti-inflammatory and anticancer properties. However, its relatively complex tetracyclic structure makes it difficult to obtain by chemical synthesis, thus limiting the studies of its biological activities. Therefore, we present here a short route to obtain a rational simplification of pterolobirin H (3) and some intermediates. The anti-inflammatory activity of these compounds was assayed in LPS-stimulated RAW 264.7 macrophages. All compounds showed potent inhibition of NO production, with percentages between 54 to 100% at sub-cytotoxic concentrations. The highest anti-inflammatory effect was shown for compounds 15 and 16. The simplified analog 16 revealed potential NO inhibition properties, being 2.34 higher than that of natural cassane pterolobirin H (3). On the other hand, hydroxyphenol 15 was also demonstrated to be the strongest NO inhibitor in RAW 264.7 macrophages (IC50 NO = 0.62 ± 0.21 μg/mL), with an IC50NO value 28.3 times lower than that of pterolobirin H (3). Moreover, the anticancer potential of these compounds was evaluated in three cancer cell lines: HT29 colon cancer cells, Hep-G2 hepatoma cells, and B16-F10 murine melanoma cells. Intermediate 15 was the most active against all the selected tumor cell lines. Compound 15 revealed the highest cytotoxic effect with the lowest IC50 value (IC50 = 2.45 ± 0.29 μg/mL in HT29 cells) and displayed an important apoptotic effect through an extrinsic pathway, as evidenced in the flow cytometry analysis. Furthermore, the Hoechst staining assay showed that analog 15 triggered morphological changes, including nuclear fragmentation and chromatin condensation, in treated HT29 cells. Finally, the in silico studies demonstrated that cassane analogs exhibit promising binding affinities and docking performance with iNOS and caspase 8, which confirms the obtained experimental results.

Maslinic acid exerts anticancer effects by targeting cancer hallmarks

BACKGROUND

Natural products have long been regarded as a source of anticancer compounds with low toxicity. Evidence revealed that maslinic acid (MA), a widely distributed pentacyclic triterpene in common foodstuffs, exhibited pronounced inhibitory effects against various cancer cell lines. Most cancer cells thrive by acquiring cancer hallmarks, as coined by Hanahan and Weinberg in 2000 and 2011.

PURPOSE

This represents the first systematic review concerning the anticancer properties of MA as these cancer hallmarks are targeted. It aims to summarize the antineoplastic activities of MA, discuss the diverse mechanisms of action based on the effects of MA exerted on each hallmark.

METHODS

A comprehensive literature search was conducted using the search terms "maslinic," "cancer," "tumor," and "neoplasm," to retrieve articles from the databases MEDLINE, EMBASE, Web of Science, and Scopus published up to September 2022. Study selection was conducted by three reviewers independently from title and abstract screening until full-text evaluation. Data extraction was done by one reviewer and counterchecked by the second reviewer.

RESULTS

Of the 330 articles assessed, 40 papers met the inclusion criteria and revealed that MA inhibited 16 different cancer cell types. MA impacted every cancer hallmark by targeting multiple pathways.

CONCLUSION

This review provides insights regarding the inhibitory effects of MA against various cancers and its remarkable biological properties as a pleiotropic bioactive compound, which encourage further investigations.

Maslinic Acid: A New Compound for the Treatment of Multiple Organ Diseases

Maslinic acid (MA) is a pentacyclic triterpene acid, which exists in many plants, including olive, and is highly safe for human beings. In recent years, it has been reported that MA has anti-inflammatory, antioxidant, anti-tumor, hypoglycemic, neuroprotective and other biological activities. More and more experimental data has shown that MA has a good therapeutic effect on multiple organ diseases, indicating that it has great clinical application potential. In this paper, the extraction, purification, identification and analysis, biological activity, pharmacokinetics in vivo and molecular mechanism of MA in treating various organ diseases are reviewed. It is hoped to provide a new idea for MA to treat various organ diseases.

Semisynthesis and Evaluation of Anti-Inflammatory Activity of the Cassane-Type Diterpenoid Taepeenin F and of Some Synthetic Intermediates

A new strategy for the semisynthesis of the aromatic cassane-type diterpene taepeenin F (6) is reported. The introduction of the methyl group at C-14, characteristic of the target compound, was achieved via dienone 13, easily prepared from abietic acid (10), the major compound in renewable rosin. Biological assays of selected compounds are reported. The antiproliferative activity against HT29, B16-F10, and HepG2 tumor cell lines has been investigated. Salicylaldehyde 21 was the most active compound (IC₅₀ = 7.72 μM). Products 16 and 21 displayed apoptotic effects in B16-F10 cells, with total apoptosis rates of 46 and 38.4%, respectively. This apoptotic process involves a significant arrest of the B16-F10 cell cycle, blocking the G0/G1 phase. Dienone 16 did not cause any loss of the mitochondrial membrane potential (MMP), while salicylaldehyde 21 caused a partial loss of the MMP. The anti-inflammatory activity of the selected compounds was investigated with the LPS-stimulated RAW 264.7 macrophages. All compounds showed potent NO inhibition, with percentages between 80 and 99% at subcytotoxic concentrations. Dienone 16 inhibited LPS-induced differentiation of RAW 264.7 cells, by increasing the proportion of cells in the S phase. In addition, salicylaldehyde 21 had effects on the cell cycle, recovering the cells from the G0/G1 full arrest produced in response to LPS action.

Involvement of the PI3K/AKT Intracellular Signaling Pathway in the AntiCancer Activity of Hydroxytyrosol, a Polyphenol from Olea europaea, in Hematological Cells and Implication of HSP60 Levels in Its Anti-Inflammatory Activity

Hydroxytyrosol (HT), the main representative of polyphenols of olive oil, has been described as one of the most powerful natural antioxidants, also showing anti-inflammatory, antimicrobial, cardioprotective and anticancer activity in different type of cancers, but has been little studied in hematological neoplasms. The objective of this work was to evaluate the anticancer potential of HT in acute human leukemia T cells (Jurkat and HL60) and the anti-inflammatory potential in murine macrophages (Raw264.7). For this, cytotoxicity tests were performed for HT, showing IC₅₀ values, at 24 h, for Jurkat, HL60 and Raw264.7 cells, of 27.3 µg·mL⁻¹, 109.8 µg·mL⁻¹ and 45.7 µg·mL⁻¹, respectively. At the same time, HT caused cell arrest in G₀/G₁ phase in both Jurkat and HL60 cells by increasing G₀/G₁ phase and significantly decreasing S phase. Apoptosis and cell cycle assays revealed an antiproliferative effect of HT, decreasing the percentage of dividing cells and increasing apoptosis. Furthermore, HT inhibited the PI3K signaling pathway and, consequently, the MAPK pathway was activated. Inflammation tests revealed that HT acts as an anti-inflammatory agent, reducing NO levels in Raw264.7 cells previously stimulated by lipopolysaccharide (LPS). These processes were confirmed by the changes in the expression of the main markers of inflammation and cancer. In conclusion, HT has an anticancer and anti-inflammatory effect in the cell lines studied, which were Raw264.7, Jurkat, and HL60, and could be used as a natural drug in the treatment of liquid cancers, leukemias, myelomas and lymphomas.

Biological Effects of Maslinic Acid on Human Epithelial Cells Used in Tissue Engineering

In the present work, we evaluated the potential of maslinic acid (MA) to improve currently available keratinocyte culture methods for use in skin tissue engineering. Results showed that MA can increase cell proliferation and WST-1 activity of human keratinocytes after 24, 48, and 72 h, especially at the concentration of 5 μg/ml, without affecting cell viability. This effect was associated to a significant increase of KI-67 protein expression and upregulation of several genes associated to cell proliferation (PCNA) and differentiation (cytokeratins, intercellular junctions and basement membrane related genes). When human keratinocytes were isolated from skin biopsies, we found that MA at the concentration of 5 μg/ml significantly increased the efficiency of the explant and the cell dissociation methods. These results revealed the positive effects of MA to optimize human keratinocyte culture protocols for use in skin tissue engineering.

Nutraceutical Role of Polyphenols and Triterpenes Present in the Extracts of Fruits and Leaves of Olea europaea as Antioxidants, Anti-Infectives and Anticancer Agents on Healthy Growth

There is currently a worldwide consensus and recognition of the undoubted health benefits of the so-called Mediterranean diet, with its intake being associated with a lower risk of mortality. The most important characteristics of this type of diet are based on the consumption of significant amounts of fruit, vegetables, legumes, and nuts, which provide, in addition to some active ingredients, fiber and a proportion of vegetable protein, together with extra virgin olive oil (EVOO) as the main sources of vegetable fat. Fish and meat from poultry and other small farm animals are the main sources of protein. One of the main components, as already mentioned, is EVOO, which is rich in monounsaturated fatty acids and to a lesser extent in polyunsaturated fatty acids. The intake of this type of nutrient also provides an important set of phytochemicals whose health potential is widely spread and agreed upon. These phytochemicals include significant amounts of anthocyanins, stilbenes, flavonoids, phenolic acids, and terpenes of varying complexities. Therefore, the inclusion in the diet of this type of molecules, with a proven healthy effect, provides an unquestionable preventive and/or curative activity on an important group of pathologies related to cardiovascular, infectious, and cancerous diseases, as well as those related to the metabolic syndrome. The aim of this review is therefore to shed light on the nutraceutical role of two of the main phytochemicals present in Olea europaea fruit and leaf extracts, polyphenols, and triterpenes, on healthy animal growth. Their immunomodulatory, anti-infective, antioxidant, anti-aging, and anti-carcinogenic capabilities show them to be potential nutraceuticals, providing healthy growth.

Oleanolic Acid Induces Autophagy and Apoptosis via the AMPK-mTOR Signaling Pathway in Colon Cancer

Aims

The purpose of this study was to explore the biological functions of the mTOR and AMPK signaling pathways in colon cancer (CC). The potential molecular mechanisms by which oleanolic acid (OA) induces autophagy and apoptosis were also investigated.

Methods

The biological functions of mTOR were analyzed by GeneCards, the Search Tool for the Retrieval of Interacting Genes (STRING), and the Database for Annotation, Visualization and Integrated Discovery (DAVID). Least absolute shrinkage and selection operator (LASSO) regression analysis was used to obtain prognostic and survival data of CC patients from the Gene Expression Omnibus (GEO) database. The effects of OA on the CC cell lines HCT-116 and SW-480 were analyzed by CCK-8, colony formation assay, and high-content system (HCS) array scan. The apoptosis rate of SW-480 and HCT-116 cells was detected by flow cytometry. The mRNA and protein expression levels in HCT-116 and SW-480 cells and NCM-460 normal colonic epithelial cells were detected by RT-PCR and Western blotting.

Results

mTOR was highly expressed in CC patients and acted as an oncogene. The AMPK signaling pathway mediated by mTOR predicted the poor prognosis of CC patients. OA effectively inhibited the proliferation and viability of CC cells. Furthermore, the apoptosis rate of CC cells was clearly increased following OA administration. Regarding the molecular mechanism of OA, the results indicated that mTOR and the antiapoptosis gene Bcl-2 were downregulated by OA. In addition, regulator genes of autophagy and apoptosis, including BAX, caspase-9, caspase-8, and caspase-3, were significantly upregulated by OA. Moreover, OA upregulated AMPK and its downstream proteins, including TSC2, BAX, Beclin 1, LC3B-II, and ULK1, to induce autophagy and apoptosis in CC cells.

Conclusion

The findings from this study demonstrate that OA could effectively inhibit the proliferation and viability of CC cells. The anti-CC activity of OA is closely related to the activation of the AMPK-mTOR signaling pathway. Activation of AMPK and inhibition of mTOR are involved in the induction of autophagy and apoptosis by OA. OA induced autophagy and apoptosis mainly in an AMPK activation-dependent manner in CC cells.

Access to New Cytotoxic Triterpene and Steroidal Acid-TEMPO Conjugates by Ugi Multicomponent-Reactions

Multicomponent reactions, especially the Ugi-four component reaction (U-4CR), provide powerful protocols to efficiently access compounds having potent biological and pharmacological effects. Thus, a diverse library of betulinic acid (BA), fusidic acid (FA), cholic acid (CA) conjugates with TEMPO (nitroxide) have been prepared using this approach, which also makes them applicable in electron paramagnetic resonance (EPR) spectroscopy. Moreover, convertible amide modified spin-labelled fusidic acid derivatives were selected for post-Ugi modification utilizing a wide range of reaction conditions which kept the paramagnetic center intact. The nitroxide labelled betulinic acid analogue 6 possesses cytotoxic effects towards two investigated cell lines: prostate cancer PC3 (IC₅₀ 7.4 ± 0.7 μM) and colon cancer HT29 (IC₅₀ 9.0 ± 0.4 μM). Notably, spin-labelled fusidic acid derivative 8 acts strongly against these two cancer cell lines (PC3: IC₅₀ 6.0 ± 1.1 μM; HT29: IC₅₀ 7.4 ± 0.6 μM). Additionally, another fusidic acid analogue 9 was also found to be active towards HT29 with IC₅₀ 7.0 ± 0.3 μM (CV). Studies on the mode of action revealed that compound 8 increased the level of caspase-3 significantly which clearly indicates induction of apoptosis by activation of the caspase pathway. Furthermore, the exclusive mitochondria targeting of compound 18 was successfully achieved, since mitochondria are the major source of ROS generation.

Chemical analysis, biological and therapeutic activities of Olea europaea L. extracts

The Olea europaea L. is a very well-known and widely used plant, especially for its nutritional qualities. Its extracts from leaves and fruits are widely used in contrasting and preventing various pathologies. In this review, the collected data highlight important chemical analyses and biological effects of this plant extracts. It exhibits cholesterol-lowering, hypoglycemic, cytotoxic, antibacterial, neuroprotective, antioxidant, anti-inflammatory and hypotensive activities. The results show that extracts from O. europaea could be used as a food additive in the supplementary treatment of many diseases.

Antiulcer Potential of Olea europea L. cv. Arbequina Leaf Extract Supported by Metabolic Profiling and Molecular Docking

Gastric ulceration is among the most serious humanpublic health problems. Olea europea L. cv. Arbequina is one of the numerous olive varieties which have scarcely been studied. The reported antioxidant and anti-inflammatory potential of the olive plant make it a potential prophylactic natural product against gastric ulcers. Consequently, the main goal of this study is to investigate the gastroprotective effect of Olea europea L. cv. Arbequina leaf extract. LC-HRMS-based metabolic profiling of the alcoholic extract of Olea europea L. cv. Arbequina led to the dereplication of 18 putative compounds (1-18). In vivo indomethacin-induced gastric ulcer in a rat model was established and the Olea europea extract was tested at a dose of 300 mg kg-1 compared to cimetidine (100 mg kg-1). The assessment of gastric mucosal lesions and histopathology of gastric tissue was done. It has been proved that Olea europea significantly decreased the ulcer index and protected the mucosa from lesions. The antioxidant potential of the extract was evaluated using three in vitro assays, H2O2 scavenging, xanthine oxidase inhibitory, and superoxide radical scavenging activities and showed promising activities. Moreover, an in silico based study was performed on the putatively dereplicated compounds, which highlighted that 3-hydroxy tyrosol (4) and oleacein (18) can target the 5-lipoxygenase enzyme (5-LOX) as a protective mechanism against the pathogenesis of ulceration. Upon experimental validation, both compounds 3-hydroxy tyrosol (HT) and oleacein (OC) (4 and 18, respectively) exhibited a significant in vitro 5-LOX inhibitory activity with IC50 values of 8.6 and 5.8 µg/mL, respectively. The present study suggested a possible implication of O. europea leaves as a potential candidate having gastroprotective, antioxidant, and 5-LOX inhibitory activity for the management of gastric ulcers.

An overview on ethnobotanico-pharmacological studies carried out in Morocco, from 1991 to 2015: Systematic review (part 1)

ETHNOPHARMACOLOGICAL RELEVANCE

The full bibliometric records of data retrieved from ethnobotanical field studies carried out in Morocco (1991-2015) was quali-quantitatively analysed. Despite the importance of traditional medicinal uses in Morocco, any comments about the methodologies and approaches adopted by reviewed studies have been undertaken. Include more data about the importance of traditional medicinal uses in Morocco.

AIM OF THE STUDY

Three key points were targeted in this review: (i) to contribute to original compilation of medicinal plants traditionally used by people at whole Morocco, by gathering and documenting the current status of these ancestral medical practices, (ii) to provide a novel insight into the relationship between local and biomedical disease concepts in Moroccan society, taking into account health-related beliefs, and their influences on medicinal plant uses, (iii) to figurout the weaknesses and the strengths of the conceptual approches and methods adopted by researchers in ethnobotanical field works.

MATERIALS AND METHODS

With the help of a computerized database querying, we conducted an extensive literature search respecting our integration criteria. We performed this bibliographic research by using the following search engines available over the Web: Google Scholar, PUBMED, Sciencedirect, Current Content Connect, SCOPUS, SPRINGER LINK, GLOBAL PLANTS, Cochrane Library and SCIRUS. The scientific names listed in the present paper have been validated according to the "The Plant List" and the African Plants Database in order to standardize ethnobotanical data on an international level. For the analysis of data gathered, quali-quantitative analyses have been performed.

RESULTS

A total of 905 medicinal plant species belonging to 116 families and 726 genera have been selected from 63 published articles. The dominant families were ASTERACEAE (111 species) followed by the FABACEAE (77 species), LAMIACEAE (75 species) and APIACEAE (46 species). The plant species listed are used to cure several public ailments. The digestive ailments represented the most important category (494 species) followed by dermatological diseases (407 species), diabetes (315 species) and urinary diseases (277 species). We assigned the importance of the plant species by several measures (including Frequency Cited (FC), Number of Uses (NU), Number of Respondents (NR) and Index of Performance (IP). The ICF (Informant Consensus Factor) calculated was important in all categories of diseases averaging 47%.

CONCLUSION

The results obtained, which cover the whole country, delineate the profile of rich wealth of indigenous knowledge on traditional uses of medicinal plants heald by Moroccan society. The total number of 905 plant species listed in this paper, are currently being utilized as medicines and the number is expected to grow as infrastructure allows greater access to unexplored parts of the country. Furthermore, the know how, regarding the plants used, is consistent because the ICF has recorded important values for most diseases treated. Furthermore, in the present paper, we suggested, for authors, some useful recommendations for ethnobotanical field works such as the respect of ethnobotanical standards including checklist of plants with international data base, the deposited voucher specimens, sampling and collection methods.

Temporal gene expression profiling of maslinic acid-treated Raji cells

Maslinic acid is a novel phytochemical reported to target multiple signaling pathways. A complete gene expression profile was therefore constructed to illustrate the anti-tumourigenesis effects of maslinic acid in Raji cells across five time-points. Microarray analysis was used to identify genes that were differentially expressed in maslinic acid treated Raji cells at 0, 4, 8, 12, 24 and 48 h. Extracted RNA was hybridized using the AffymetrixGeneChip to obtain expression profiles. A total of 109 genes were found to be significantly expressed over a period of 48 hours. By 12 hours, maslinic acid regulates the majority of genes involved in the cell cycle, p53 and NF-κB signaling pathways. At the same time, XAF1, APAF1, SESN3, and TP53BP2 were evidently up-regulated, while oncogenes, FAIM, CD27, and RRM2B, were down-regulated by at least 2-fold. In conclusion, maslinic acid shows an hourly progression of gene expression in Raji cells.

A Diamine-PEGylated Oleanolic Acid Derivative Induced Efficient Apoptosis through a Death Receptor and Mitochondrial Apoptotic Pathway in HepG2 Human Hepatoma Cells

Hepatocellular carcinoma (HCC) is the most common type of liver cancer. Our recent studies have shown that the diamine-(PEG)ylated oleanolic acid (OADP) has strong anti-tumor effects in HCCs. In this study, we evaluated the anti-tumor mechanisms of OADP in the HepG2 HCC cell line. The cytotoxicity results showed that HepG2 cell viability was markedly reduced, with a very low 50% of cell growth inhibitory concentration (IC₅₀, 0.14 µg/mL). We then investigated the anti-tumor mechanisms of OADP in HepG2 cells. The flow-cytometry analysis was used to evaluate cell apoptosis, indicating that 74–95% of cells were apoptotic. OADP caused cell cycle arrest in the G0/G1 phase and the loss of the mitochondrial membrane potential (MMP). Western blot analysis was performed to assess the expression levels of key proteins associated with the underlying molecular mechanism. The results showed the clear upregulation of caspase-8, caspase-9, caspase-3, Bak, p21, and p53, accompanied by the downregulation of Bcl-2. Similar results were obtained by the cotreatment with OADP and the c-Jun N-terminal kinase (JNK) inhibitor SP600125. Agents such as OADP, which are capable of activating extrinsic and intrinsic apoptotic pathways, may represent potential HCC cancer therapies.

Maslinic acid differentially exploits the MAPK pathway in estrogen-positive and triple-negative breast cancer to induce mitochondrion-mediated, caspase-independent apoptosis

Breast cancer accounts for 1.4 million new cases every year. Triple-negative breast cancer (TNBC) is one the leading cause of mortality in developing countries and is associated with early age onset (under 40 years old). Chemotherapy has a poor success rate in patients with TNBC as compared to other types of breast cancers. It is due to the lack of expression of three validated molecular markers for breast cancer, the estrogen and progesterone receptors, and the amplification of HER-2/Neu. Therefore, a clear need exists for a greater understanding of TNBC at all levels and for the development of better therapies. We have studied the anti-tumor effects of a potential drug, maslinic acid, which can be extracted from olive oil industry waste. This natural product showed inhibitory effect at concentrations ranging from 30 to 50 µM within 24 h. It exhibited divergent effects in cell cycle progression for the MCF7 (estrogen positive) cell line when compared with TNBCs like MDA-MB-231 and MDA-MB-468. Also, maslinic acid treatment altered the mitochondrial membrane electrochemical potential and the reactive oxygen species (ROS) levels to cause a caspase-independent programmed cell death. In silico approaches and immunoblotting suggested the involvement of the MAPK pathway explaining the variability in cell cycle progression along with the apoptotic cell death caused by maslinic acid.

Unveiling the Differential Antioxidant Activity of Maslinic Acid in Murine Melanoma Cells and in Rat Embryonic Healthy Cells Following Treatment with Hydrogen Peroxide

Maslinic acid (MA) is a natural triterpene from Olea europaea L. with multiple biological properties. The aim of the present study was to examine MA’s effect on cell viability (by the MTT assay), reactive oxygen species (ROS levels, by flow cytometry) and key antioxidant enzyme activities (by spectrophotometry) in murine skin melanoma (B16F10) cells compared to those on healthy cells (A10). MA induced cytotoxic effects in cancer cells (IC₅₀ 42 µM), whereas no effect was found in A10 cells treated with MA (up to 210 µM). In order to produce a stress situation in cells, 0.15 mM H₂O₂ was added. Under stressful conditions, MA protected both cell lines against oxidative damage, decreasing intracellular ROS, which were higher in B16F10 than in A10 cells. The treatment with H₂O₂ and without MA produced different responses in antioxidant enzyme activities depending on the cell line. In A10 cells, all the enzymes were up-regulated, but in B16F10 cells, only superoxide dismutase, glutathione S-transferase and glutathione peroxidase increased their activities. MA restored the enzyme activities to levels similar to those in the control group in both cell lines, highlighting that in A10 cells, the highest MA doses induced values lower than control. Overall, these findings demonstrate the great antioxidant capacity of MA.

Synthesis and Cytotoxic Activity of Novel C-23-Modified Asiatic Acid Derivatives

We selectively oxidized the C-23 hydroxyl group in an asiatic acid (AA) derivative and then, for the first time with AA, modification of the C-23 carboxyl group was conducted to synthesize a series of new AA derivatives. The evaluation of their cytotoxic activities against two human cancer cell lines (SKOV-3 and HCT116) using the MTT assay in vitro revealed a distinctive structure activity relationship (SAR) associated with the intramolecular hydrogen bonding of the amide moiety at C-23. According to the established SAR, the cytotoxic activities of four promising compounds were then evaluated against MCF-7, A549, A2780, HepG2 and HL-60 cancer cell lines. Compound 10 had the best cytotoxic activity among all tested derivatives in the HL-60 cell line, giving IC₅₀ = 0.47 μM, while showing no cytotoxic effect against human normal cells (HUVEC).

Maslinic acid induces anticancer effects in human neuroblastoma cells mediated via apoptosis induction and caspase activation, inhibition of cell migration and invasion and targeting MAPK/ERK signaling pathway

Maslinic acid is an active member of pentacyclic triterpenes predominantly found in dietary plants including hawthorn berries and olive fruit skins. It has been reported to show immense pharmacological and biological importance including anticancer property. This research was initiated to explore the anticancer potential of maslinic acid against human neuroblastoma. The effects of maslinic acid on cellular apoptosis, ROS generation, cell migration and invasion, caspase activation and targeting MAPK/ERK signaling pathway were investigated. The proliferation percentage was calculated by performing of MTT assay. AO/EB and annexin V/PI staining assays along with western blotting were used to monitor the apoptosis and expressions of apoptosis connected proteins. Spectrofluorometry was used for ROS monitoring. To assess the anti-metastatic effects of maslinic acid on neuroblastoma cells, transwell chambers assays for migration as well as invasion were executed. Western blotting was implemented to establish the expressions of MAPK/ERK signaling pathway connected proteins. Results evidenced remarkable anticancer potential of maslinic acid against human neuroblastoma. It induced dose as well as time reliant anti-proliferative effects against SHSY-5Y cells selectively. The underlying mechanism of cancer suppressive effects of maslinic acid was found to mediate via caspase-dependent apoptosis. Further, ROS production amplified terrifically with exposure of SHSY-5Y to higher maslinic acid doses. Cell migration and invasion in SHSY-5Y cells were both reduced remarkably by maslinic acid. Finally, the activity of proteins associated with MAPK/ERK signaling pathway was found to be significantly reduced with increasing maslinic acid doses. In conclusion, it was observed that maslinic acid possesses a great anti-neuroblastoma potential and could be considered for its chemotherapy provided further investigations are recommended.

The cytotoxicity of oleanane derived aminocarboxamides depends on their aminoalkyl substituents

Several oligo-methylene diamine derived carboxamides of oleanolic and maslinic acid have been prepared, and substitutions of the terminal primary amine as well as variations of the length of alkyl chain of the diamine moiety were made. Biological evaluation of their cytotoxic activity was performed using photometric sulforhodamin B assays employing a panel of different human cancer cell lines. These experiments showed most of the carboxamides to be cytotoxic with EC₅₀ values below 10 µM. Prolongation of the alkyl chain length initially reduced EC₅₀ values to a minimum, but a decrease in cytotoxicity was observed for longer alkyl chains. Variation of substituents at the terminal nitrogen atom, however, did not influence EC₅₀ values at all. Noteworthy results were obtained particularly for compounds 4, 6 and 23 as indicated by EC₅₀ values lower than 2 µM, and in case of a maslinic derivative 23 even an increased tumor/non-tumor cell selectivity was observed. These compounds were further investigated using fluorescence microscopy and flow cytometry analysis, which revealed 6 to show indications of apoptosis.

Maslinic acid alleviates ischemia/reperfusion-induced inflammation by downregulation of NFκB-mediated adhesion molecule expression

Ischemia/reperfusion (I/R)-induced inflammation is associated with enhanced leukocyte rolling, adhesion and transmigration within the microcirculation. These steps are mediated by hypoxia-triggered signaling pathways, which upregulate adhesion molecule expression on endothelial cells and pericytes. We analyzed whether these cellular events are affected by maslinic acid (MA). Mitochondrial activity and viability of MA-exposed endothelial cells and pericytes were assessed by water-soluble tetrazolium (WST)-1 and lactate dehydrogenase (LDH) assays as well as Annexin V/propidium iodide (PI) stainings. Effects of MA on hypoxia and reoxygenation-induced expression of E-selectin, intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 were determined by flow cytometry. The subcellular localization of the NFκB subunit p65 was analyzed by immunofluorescence and Western blot. I/R-induced leukocytic inflammation was studied in MA- and vehicle-treated mouse dorsal skinfold chambers by intravital fluorescence microscopy and immunohistochemistry. MA did not affect viability, but suppressed the mitochondrial activity of endothelial cells. Furthermore, MA reduced adhesion molecule expression on endothelial cells and pericytes due to an inhibitory action on NFκB signaling. Numbers of adherent and transmigrated leukocytes were lower in post-ischemic tissue of MA-treated mice when compared to vehicle-treated controls. In addition, MA affected reactive oxygen species (ROS) formation, resulting in a diminished oxidative DNA damage. Hence, MA represents an attractive compound for the establishment of novel therapeutic approaches against I/R-induced inflammation.

Biological Evaluation and Docking Studies of Synthetic Oleanane-type Triterpenoids

Saponins are potential wide-spectrum antitumor drugs, and copper(I) catalyzed azide-alkyne 1,3-dipolar cycloaddition is a suitable approach to synthesizing saponin-like compounds by regioselective glycosylation of the C2/C3 hydroxyl and C28 carboxylic groups of triterpene aglycones maslinic acid (MA) and oleanolic acid (OA). Biological studies on the T-84 human colon carcinoma cell line support the role of the hydroxyl groups at C2/C3, the influence of the aglycone, and the bulky nature of the substituents in C28. OA bearing a α-d-mannose moiety at C28 (compound 18) focused our interest because the estimated inhibitory concentration 50 was similar to that reported for ginsenoside Rh2 against colon cancer cells and it inhibits the G₁-S phase transition affecting the cell viability and apoptosis. Considering that triterpenoids from natural sources have been identified as inhibitors of nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling, docking studies were conducted to evaluate whether NF-κB may be a potential target. Results are consistent with the biological study and predict a similar binding mode of MA and compound 18 to the p52 subunit from NF-κB but not for OA. The fact that the binding site is shared by the NF-κB inhibitor 6,6-dimethyl-2-(phenylimino)-6,7-dihydrobenzo[d][1,3]oxathiol-4(5H)-one supports the result and points to NF-κB as a potential target of both MA and compound 18.

Simultaneous downregulation of miR-21 and miR-155 through oleuropein for breast cancer prevention and therapy

Breast cancer (BC) is the leading cause of cancer mortality in women worldwide. It recently was proven that miRNAs play a critical role in BC development. The use of natural agents for control of cancer by modulating miRNAs is promising. Oleuropein is a natural polyphenolic agent with anti-neoplastic properties and is well tolerated by humans. This study was undertaken to determine the therapeutic effects of oleuropein through modulation of master oncomiRs (miR-21 and miR-155) in BC cells. The present study provides the first link between miRNA and oleuropein as a mechanism in BC. MCF-7 cells were tested with and without oleuropein and the cell viability, apoptosis, and migration were examined. The effect of oleuropein on miR-21 and miR-155 expression was assessed through qRT-PCR. It was found that oleuropein induced apoptosis and retarded cell migration and invasion in a dose-dependent manner in the human MCF7 BC cell line. It was observed that oleuropein significantly decreased expression of both miR-21 and miR-155 over time in a dose-dependent manner. These results demonstrate that oleuropein is a potential therapeutic and preventive agent for BC. Oleuropein exhibits an anti-cancer effect by modulation of tumor suppressor gene expression, which is targeted by oncomiRs.

Antioxidant and antiproliferative potentials of methanol extract of Xylopia aethiopica (Dunal) A. Rich in PC-3 and LNCaP cells

BACKGROUND

Our previous studies showed that fruit methanol extract from Xylopia aethiopica (MEXA) exhibited antiproliferative activity in human cervical cancer cells via the induction of apoptosis. The present study was designed to assess the antiproliferative, antiangiogenic and antioxidant effects of MEXA on prostate cancer (PCa) cells (PC-3 and LNCaP).

METHODS

PC-3 and LNCaP cells were cultured and treated with MEXA (10, 50 and 100 μg/mL). The sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate (XTT) and lactate dehydrogenase (LDH) assays were used to evaluate cell viability and cytotoxicity, respectively. DNA fragmentation was determined by cell death detection ELISA plus, and angiogenesis was assessed by chicken chorioallantoic membrane (CAM) assay. The antioxidant activities of MEXA were determined by DPPH and hydroxyl (OH) radicals' scavenging methods as well as through the inhibition of lipid peroxidation (LPO) in rats' liver homogenate.

RESULTS

MEXA at 100, 250 and 500 μg/mL scavenged DPPH by 48%, 62%, 70% and OH radical by 39%, 58%, 67%, respectively. MEXA significantly (p<0.05) inhibited LPO in a concentration-dependent manner. In addition, MEXA had antiproliferative effects on PC-3 and LNCaP with IC50 of 62.1 and 73.6 μg/mL, respectively, at 96 h. The LDH assay showed that MEXA had low toxicity in vitro at its IC50 values. The extent of DNA fragmentation by MEXA showed higher values in PC-3 and LNCaP, suggesting the possible induction of apoptosis. In contrast, MEXA did not affect the network of vessels in CAM, thus lacking anti-angiogenic property.

CONCLUSIONS

These findings suggest that MEXA induces antiproliferative activity in PCa cells through a mechanism that involves apoptosis. Therefore, MEXA may be a potential therapeutic agent for PCa.

Phenolic extract from oleaster (Olea europaea var. Sylvestris) leaves reduces colon cancer growth and induces caspase-dependent apoptosis in colon cancer cells via the mitochondrial apoptotic pathway

Dietary polyphenols, derived from natural products, have received a great interest for their chemopreventive properties against cancer. In this study, we investigated the effects of phenolic extract of the oleaster leaves (PEOL) on tumor growth in mouse model and on cell death in colon cancer cell lines. We assessed the effect of oleaster leaf infusion on HCT116 (human colon cancer cell line) xenograft growth in athymic nude mice. We observed that oleaster leaf polyphenol-rich infusion limited HCT116 tumor growth in vivo. Investigations of PEOL on two human CRC cell lines showed that PEOL induced apoptosis in HCT116 and HCT8 cells. We demonstrated an activation of caspase-3, -7 and -9 by PEOL and that pre-treatment with the pan-caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (z-VAD-fmk), prevented PEOL-induced cell death. We observed an involvement of the mitochondrial pathway in PEOL-induced apoptosis evidenced by reactive oxygen species (ROS) production, a decrease of mitochondrial membrane potential, and cytochrome c release. Increase in intracellular Ca2+ concentration induced by PEOL represents the early event involved in mitochondrial dysfunction, ROS-induced endoplasmic reticulum (ER) stress and apoptosis induced by PEOL, as ruthenium red, an inhibitor of mitochondrial calcium uptake inhibited apoptotic effect of PEOL, BAPTA/AM inhibited PEOL-induced ROS generation and finally, N-acetyl-L-cysteine reversed ER stress and apoptotic effect of PEOL. These results demonstrate that polyphenols from oleaster leaves might have a strong potential as chemopreventive agent in colorectal cancer.

Evaluation of pentacyclic triterpenes found in Perilla frutescens for inhibition of skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate

A series of pentacyclic tritperpenes found in Perilla frutescens (P. frutescens), including ursolic acid (UA), oleanolic acid (OA), corosolic acid (CA), 3-epi-corosolic acid (3-epiCA), maslinic acid (MA), and 3-epi-maslinic acid (3-epiMA) were evaluated for their effects on epidermal cell signaling, proliferation, and skin inflammation in relation to their ability to inhibit skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) and compared to UA as the prototype compound. All compounds were given topically 30 min prior to each TPA application and significantly inhibited skin tumor promotion. 3-epiCA and MA were significantly more effective than UA at inhibiting tumor development. All of these compounds significantly inhibited epidermal proliferation induced by TPA, however, CA, 3-epiCA and MA were more effective than UA. All compounds also reduced skin inflammation (assessed by infiltration of mast cells and T-cells) and inflammatory gene expression induced by TPA, however, 3-epiCA and MA were again more effective than UA. The greater ability of 3-epiCA and MA to inhibit skin tumor promotion was associated with greater reduction of Cox-2 and Twist1 proteins and inhibition of activation (i.e., phosphorylation) of IGF-1R, STAT3 and Src. Further study of these compounds, especially 3-epiCA and MA, for chemopreventive activity in other cancer model systems is warranted.

Target molecules in 3T3-L1 adipocytes differentiation are regulated by maslinic acid, a natural triterpene from Olea europaea

BACKGROUND

Metabolic syndrome is a set of pathologies among which stand out the obesity, which is related to the lipid droplet accumulation and changes to cellular morphology regulated by several molecules and transcription factors. Maslinic acid (MA) is a natural product with demonstrated pharmacological functions including anti-inflammation, anti-tumor and anti-oxidation, among others.

PURPOSE

Here we report the effects of MA on the adipogenesis process in 3T3-L1 cells.

METHODS

Cell viability, glucose uptake, cytoplasmic triglyceride droplets, triglycerides quantification, gene transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte fatty acid-binding protein (aP2) and intracellular Ca²⁺ levels were determined in pre-adipocytes and adipocytes of 3T3-L1 cells.

RESULTS

MA increased glucose uptake. MA also decreased lipid droplets and triglyceride levels, which is in concordance with the down-regulation of PPARγ and aP2. Finally, MA increased the intracellular Ca²⁺ concentration, which could also be involved in the demonstrated antiadipogenic effect of this triterpene.

CONCLUSION

MA has been demonstrated as potential antiadipogenic compound in 3T3-L1 cells.

NADPH production, a growth marker, is stimulated by maslinic acid in gilthead sea bream by increased NADP-IDH and ME expression

NADPH plays a central role in reductive biosynthesis of membrane lipids, maintenance of cell integrity, protein synthesis and redox balance maintenance. Hence, NADPH is involved in the growth and proliferation processes. In addition, it has been shown that changes in nutritional conditions produced changes in NADPH levels and growth rate. Maslinic acid (MA), a pentacyclic triterpene of natural origin, is able to stimulate NADPH production, through regulation of the two oxidative phase dehydrogenases of the pentose phosphate pathway. Our main objective was to study the effects of MA on the kinetic behaviour and on the molecular expression of two NADPH-generating systems, NADP-dependent isocitrate dehydrogenase (NADP-IDH) and malic enzyme (ME), in the liver and white muscle of gilthead sea bream (Sparus aurata). Four groups of 12g of a mean body mass were fed for 210days in a fish farm, with diets containing 0 (control), and 0.1g of MA per kg of diet. Two groups were fed ad libitum (C-AL and MA-AL) and another's two, with restricted diet of 1% of fish weight (C-R and MA-R). Results showed that MA significantly increased the main kinetic parameter of the NADPH-forming enzymes (NADP-IDH and ME). In this sense, specific activity, maximum velocity, catalytic efficiency and activity ratio values were higher in MA conditions than control groups. Moreover, these changes were observed in both feeding regimen, AL and R. Meanwhile, the Michaelis constant changed mainly in groups fed with the MA and restricted diet, these changes are related to the best substrate affinity by enzyme. Moreover, in the Western-blot result, we found that MA increased both protein levels studied, this behaviour being consistent with the regulation of the number of enzyme molecules. All results, indicate that MA, independently of the fed regimen, could potentially be a nutritional additive for fish as it improved the metabolic state of fish, as consequence of increased activity and expression of NADP-IDH and ME enzymes.

Effects of an extract of Celtis aetnensis (Tornab.) Strobl twigs on human colon cancer cell cultures

Cancers of the digestive tract, in particular colorectal cancer (CRC), are among those most responsive to dietary modification. Research has shown that approximately 75% of all sporadic cases of CRC are directly influenced by diet. Many natural compounds have been investigated for their potential usefulness as cancer chemopreventive agents as they have been thought to suppress carcinogenesis mainly during the initiation phase due to their radical scavenger activity. Since there is an increasing interest in the in vivo protective effects of natural compounds contained in plants against oxidative damage involved in several human diseases such as cancer, the aim of the present research was to test the effects of a Celtis aetnensis (Tornab.) Strobl twig extract on a human colon carcinoma cell line (Caco2). In order to elucidate the mechanisms of action of this extract, LDH release, GSH content, ROS levels, caspase-3 and γ-GCS expression were also evaluated. The results revealed that the Celtis aetnensis extract reduced the cell viability of the Caco2 cells inducing apoptosis at the lowest concentration and necrosis at higher dosages. In addition, this extract caused an increase in the levels of ROS, a decrease in RSH levels and in the expression of HO-1. The expression of γ-GCS was not modified in the Celtis aetnensis-treated Caco-2 cells. These results suggest an interference of this extract on the oxidant/antioxidant cell balance with consequent cell damage. The present study supports the growing body of data suggesting the bioactivities of Celtis aetnensis (Tornab.) Strobl and its potential impact on cancer therapy and on human health.

Inhibition of Human Group IIA-Secreted Phospholipase A2 and THP-1 Monocyte Recruitment by Maslinic Acid

Maslinic acid is a natural pentacyclic triterpenoid which has anti-inflammatory properties. A recent study showed that secretory phospholipase A2 (sPLA2) may be a potential binding target of maslinic acid. The human group IIA (hGIIA)-sPLA2 is found in human sera and their levels are correlated with severity of inflammation. This study aims to determine whether maslinic acid interacts with hGIIA-sPLA2 and inhibits inflammatory response induced by this enzyme. It is shown that maslinic acid enhanced intrinsic fluorescence of hGIIA-sPLA2 and inhibited its enzyme activity in a concentration-dependent manner. Molecular docking revealed that maslinic acid binds to calcium binding and interfacial phospholipid binding site, suggesting that it inhibit access of catalytic calcium ion for enzymatic reaction and block binding of the enzyme to membrane phospholipid. The hGIIA-sPLA2 enzyme is also responsible in mediating monocyte recruitment and differentiation. Results showed that maslinic acid inhibit hGIIA-sPLA2-induced THP-1 cell differentiation and migration, and the effect observed is specific to hGIIA-sPLA2 as cells treated with maslinic acid alone did not significantly affect the number of adherent and migrated cells. Considering that hGIIA-sPLA2 enzyme is known to hydrolyze glyceroacylphospholipids present in lipoproteins and cell membranes, maslinic acid may bind and inhibit hGIIA-sPLA2 enzymatic activity, thereby reduces the release of fatty acids and lysophospholipids which stimulates monocyte migration and differentiation. This study is the first to report on the molecular interaction between maslinic acid and inflammatory target hGIIA-sPLA2 as well as its effect towards hGIIA-sPLA2-induced THP-1 monocyte adhesive and migratory capabilities, an important immune-inflammation process in atherosclerosis.

Maslinic Acid, a Natural Triterpene, Induces a Death Receptor-Mediated Apoptotic Mechanism in Caco-2 p53-Deficient Colon Adenocarcinoma Cells

Maslinic acid (MA) is a natural triterpene present in high concentrations in the waxy skin of olives. We have previously reported that MA induces apoptotic cell death via the mitochondrial apoptotic pathway in HT29 colon cancer cells. Here, we show that MA induces apoptosis in Caco-2 colon cancer cells via the extrinsic apoptotic pathway in a dose-dependent manner. MA triggered a series of effects associated with apoptosis, including the cleavage of caspases -8 and -3, and increased the levels of t-Bid within a few hours of its addition to the culture medium. MA had no effect on the expression of the Bax protein, release of cytochrome-c or on the mitochondrial membrane potential. This suggests that MA triggered the extrinsic apoptotic pathway in this cell type, as opposed to the intrinsic pathway found in the HT29 colon-cancer cell line. Our results suggest that the apoptotic mechanism induced in Caco-2 may be different from that found in HT29 colon-cancer cells, and that in Caco-2 cells MA seems to work independently of p53. Natural antitumoral agents capable of activating both the extrinsic and intrinsic apoptotic pathways could be of great use in treating colon-cancer of whatever origin.

The oleanolic acid derivative, 3-O-succinyl-28-O-benzyl oleanolate, induces apoptosis in B16–F10 melanoma cells via the mitochondrial apoptotic pathway

Antiproliferative and proapoptotic effects of 3-O-succinyl-28-O-benzyl oleanolate on B16–F10 skin-melanoma cells.

Synthesis of oxygenated oleanolic and ursolic acid derivatives with anti-inflammatory properties

The scalable syntheses of four oxygenated triterpenes have been implemented to access substantial quantities of maslinic acid, 3-epi-maslinic acid, corosolic acid, and 3-epi-corosolic acid. Semi-syntheses proceed starting from the natural products oleanolic acid and ursolic acid. Proceeding over five steps, each of the four compounds can be synthesized on the gram scale. Divergent diastereoselective reductions of α-hydroxy ketones provided access to the four targeted diol containing compounds from two precursors of the oleanane or ursane lineage. These compounds were subsequently evaluated for their ability to inhibit inflammatory gene expression in a mouse model of chemically induced skin inflammation. All compounds possessed the ability to inhibit the expression of one or more inflammatory genes induced by 12-O-tetradecanoylphorbol-13 acetate in mouse skin, however, three of the compounds, corosolic acid, 3-epi-corosolic acid and maslinic acid were more effective than the others. The availability of gram quantities will allow further testing of these compounds for potential anti-inflammatory activities as well as cancer chemopreventive activity.

A New HPLC-MS Method for Measuring Maslinic Acid and Oleanolic Acid in HT29 and HepG2 Human Cancer Cells

Maslinic acid (MA) and oleanolic acid (OA), the main triterpenic acids present in olive, have important properties for health and disease prevention. MA selectively inhibits cell proliferation of the HT29 human colon-cancer cell line by inducing selective apoptosis. For measuring the MA and OA concentration inside the cell and in the culture medium, a new HPLC-MS procedure has been developed. With this method, a determination of the amount of MA and OA incorporated into HT29 and HepG2 human cancer-cell lines incubated with different concentrations of MA corresponding to 50% growth inhibitory concentration (IC₅₀), IC_50/2, IC_50/4, and IC_50/8 has been made. The results demonstrate that this method is appropriate for determining the MA and OA concentration in different types of cultured cells and reveals the specific dynamics of entry of MA into HT29 and HepG2 cells.

A Natural Triterpene Derivative from Euphorbia kansui Inhibits Cell Proliferation and Induces Apoptosis against Rat Intestinal Epithelioid Cell Line in Vitro

Kansenone is a triterpene from the root of the traditional Chinese medicine, Euphorbia kansui. However, kansenone exerts serious toxicity, but the exact mechanism was not clear. In this work, the effects of kansenone on cell proliferation, cell cycle, cell damage, and cell apoptosis were investigated. The suppression of cell proliferation was assessed via the colorimetric MTT assay, and cell morphology was visualized via inverted microscopy after IEC-6 cells were incubated with different concentrations of kansenone. Reactive oxygen species (ROS), superoxide dismutase (SOD) and malondialdehyde (MDA) content were detected for evaluating cell damage. RNase/propidium iodide (PI) labeling for evaluation of cell cycle distribution was performed by flow cytometry analysis. Annexin V-fluorescein isothiocyanate (FITC)/PI and Hoechst 33342/Annexin V-FITC/PI staining assay for cell apoptosis detection were performed using confocal laser scanning microscopy and high content screening. Moreover, apoptosis induction was further confirmed by transmission electron microscope (TEM) and JC-1 mitochondrial membrane potential, western blot and RT-PCR analysis. The results demonstrated that kansenone exerted high cytotoxicity, induced cell arrest at G0/G1 phase, and caused mitochondria damage. In addition, kansenone could up-regulate the apoptotic proteins Bax, AIF, Apaf-1, cytochrome c, caspase-3, caspase-9, caspase-8, FasR, FasL, NF-κB, and TNFR1 mRNA expression levels, and down-regulate the anti-apoptotic Bcl-2 family proteins, revealing that kansenone induces apoptosis through both the death receptor and mitochondrial pathways.

Maslinic Acid, a Triterpene from Olive, Affects the Antioxidant and Mitochondrial Status of B16F10 Melanoma Cells Grown under Stressful Conditions

Maslinic acid (MA) is a natural compound whose structure corresponds to a pentacyclic triterpene. It is abundant in the cuticular lipid layer of olives. MA has many biological and therapeutic properties related to health, including antitumor, anti-inflammatory, antimicrobial, antiparasitic, antihypertensive, and antioxidant activities. However, no studies have been performed to understand the molecular mechanism induced by this compound in melanoma cancer. The objective of this study was to examine the effect of MA in melanoma (B16F10) cells grown in the presence or absence of fetal bovine serum (FBS). We performed cell proliferation measurements, and the reactive oxygen species (ROS) measurements using dihydrorhodamine 123 (DHR 123) and activities of catalase, glucose 6-phosphate dehydrogenase, glutathione S-transferase, and superoxide dismutase. These changes were corroborated by expression assays. FBS absence reduced cell viability decreasing IC50 values of MA. The DHR 123 data showed an increase in the ROS level in the absence of FBS. Furthermore, MA had an antioxidant effect at lower assayed levels measured as DHR and antioxidant defense. However, at higher dosages MA induced cellular damage by apoptosis as seen in the results obtained.

Traditional Uses, Phytochemistry, and Pharmacology of Olea europaea (Olive)

Aim of the Review. To grasp the fragmented information available on the botany, traditional uses, phytochemistry, pharmacology, and toxicology of Olea europaea to explore its therapeutic potential and future research opportunities. Material and Methods. All the available information on O. europaea was collected via electronic search (using Pubmed, Scirus, Google Scholar, and Web of Science) and a library search. Results. Ethnomedical uses of O. europaea are recorded throughout the world where it has been used to treat various ailments. Phytochemical research had led to the isolation of flavonoids, secoiridoids, iridoids, flavanones, biophenols, triterpenes, benzoic acid derivatives, isochromans, and other classes of secondary metabolites from O. europaea. The plant materials and isolated components have shown a wide spectrum of in vitro and in vivo pharmacological activities like antidiabetic, anticonvulsant, antioxidant, anti-inflammatory, immunomodulatory, analgesic, antimicrobial, antiviral, antihypertensive, anticancer, antihyperglycemic, antinociceptive, gastroprotective, and wound healing activities. Conclusions. O. europaea emerged as a good source of traditional medicine for the treatment of various ailments. The outcomes of phytochemical and pharmacological studies reported in this review will further expand its existing therapeutic potential and provide a convincing support to its future clinical use in modern medicine.

Solid-phase library synthesis of bi-functional derivatives of oleanolic and maslinic acids and their cytotoxicity on three cancer cell lines

A wide set of 264 compounds has been semisynthesized with high yields and purities. These compounds have been obtained through easy synthetic processes based on a solid-phase combinatorial methodology. All the members of this library have one central core of a natural pentacyclic triterpene (oleanolic or maslinic acid) and differ by 6 amino acids, coupled with the carboxyl group at C-28 of the triterpenoid skeleton, and by 10 different acyl groups attached to the hydroxyl groups of the A-ring of these molecules. According to the literature on the outstanding and promising pharmacological activities of other similar terpene derivatives, some of these compounds have been tested for their cytotoxic effects on the proliferation of three cancer cell lines: B16-F10, HT29, and Hep G2. In general, we have found that around 70% of the compounds tested show cytotoxicity in all three of the cell lines selected; around 60% of the cytotoxic compounds are more effective than their corresponding precursors, that is, oleanolic (OA) or maslinic (MA) acids; and nearly 50% of the cytotoxic derivatives have IC50 values between 2- to 320-fold lower than their corresponding precursor (OA or MA).

Maslinic acid, a natural phytoalexin-type triterpene from olives--a promising nutraceutical?

Maslinic acid is a pentacyclic triterpene found in a variety of natural sources, ranging from herbal remedies used in traditional Asian medicine to edible vegetables and fruits present in the Mediterranean diet. In recent years, several studies have proved that maslinic acid exerts a wide range of biological activities, i.e. antitumor, antidiabetic, antioxidant, cardioprotective, neuroprotective, antiparasitic and growth-stimulating. Experimental models used for the assessment of maslinic acid effects include established cell lines, which have been often used to elucidate the underlying mechanisms of action, and also animal models of different disorders, which have confirmed the effects of the triterpene in vivo. Overall, and supported by the lack of adverse effects in mice, the results provide evidence of the potential of maslinic acid as a nutraceutical, not only for health promotion, but also as a therapeutic adjuvant in the treatment of several disorders.

The natural triterpene 3β,6β,16β-trihydroxy-lup-20(29)-ene obtained from the flowers of Combretum leprosum induces apoptosis in MCF-7 breast cancer cells

Background

The 3β, 6β, 16β-trihydroxylup-20(29)-ene (TTHL) is a pentacyclic triterpene obtained from the medicinal plant Combretum leprosum Mart. In folk medicine, this plant is popularly known as mofumbo, cipoaba or mufumbo, and is used to treat several diseases associated with inflammation and pain.

Methods

We investigated the antitumor efficacy of TTHL isolated from C. leprosum. The TTHL cytotoxic effect was investigated in MRC5, MCF-7, HepG2, T24, HCT116, HT29, and CACO-2 cells after 24, 48, 72 and 120 h of treatment. The mechanisms of cell death and DNA damage induction were investigated by flow cytometry and comet assay, respectively.

Results

The results indicated that TTHL induced a time- and concentration-dependent growth inhibition in all human cancer cell lines. The cytotoxicity was more pronounced in MCF-7 breast cancer cells, with an IC50 of 0.30 μg/mL at 120 h. We therefore evaluated the cell death mechanism induced by TTHL (IC20, IC50, and IC80) in MCF-7 cells at 24 h. We found that the treatment with IC50 and IC80 TTHL for 24 h induced apoptosis in 14% (IC50) and 52% (IC80) of MCF-7 cells. The apoptosis induced by TTHL was accompanied by increased levels of both cleaved caspase-9 and intracellular ROS. In order to further understand the biological mechanism of TTHL-induced cytotoxicity, we have also investigated its effect on different Saccharomyces cerevisiae yeast strains. The mutant strains sod1Δ, sod2Δ, and sod1Δsod2Δ, which are deficient in superoxide dismutase antioxidant defenses, were hypersensitive to TTHL, suggesting that its capacity to disturb cellular redox balance plays a role in drug toxicity. Moreover, TTHL induced mutagenicity in the yeast strain XV185-14c.

Conclusions

Taken together, the results suggest that TTHL forms covalent adducts with cellular macromolecules, potentially disrupting cellular function and triggering apoptosis.

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6882-14-280) contains supplementary material, which is available to authorized users.

Membrane damaging activity of a maslinic acid analog

Close inspection of human ovarian cancer cells A2780 in the course of an antitumor screening using maslinic acid analogs revealed for one of the compounds, 4-oxa-4-phenyl-butyl 2,3-dihydroxy-olean-12-en-28-oate (1), an unusual behavior. During the incubation of the cells with 1, at the perimeter of the cells or close by crystals were formed consisting of cholesterol and excess 1. Compound 1 was incorporated into the cell's membrane followed by an extrusion of cholesterol from the lipid rafts. As a consequence of the alterations of the cell membrane, a volume decrease was initiated that triggered apoptosis; this extends previous models on apoptosis initiating mechanisms.