Antioxidant and antigrowth action of peracetylated oleuropein in thyroid cancer cells

Anticancer Effects of Secoiridoids-A Scoping Review of the Molecular Mechanisms behind the Chemopreventive Effects of the Olive Tree Components Oleocanthal, Oleacein, and Oleuropein

The olive tree (Olea europaea) and olive oil hold significant cultural and historical importance in Europe. The health benefits associated with olive oil consumption have been well documented. This paper explores the mechanisms of the anti-cancer effects of olive oil and olive leaf, focusing on their key bioactive compounds, namely oleocanthal, oleacein, and oleuropein. The chemopreventive potential of oleocanthal, oleacein, and oleuropein is comprehensively examined through this systematic review. We conducted a systematic literature search to identify eligible articles from Scopus, PubMed, and Web of Science databases published up to 10 October 2023. Among 4037 identified articles, there were 88 eligible articles describing mechanisms of chemopreventive effects of oleocanthal, oleacein, and oleuropein. These compounds have the ability to inhibit cell proliferation, induce cell death (apoptosis, autophagy, and necrosis), inhibit angiogenesis, suppress tumor metastasis, and modulate cancer-associated signalling pathways. Additionally, oleocanthal and oleuropein were also reported to disrupt redox hemostasis. This review provides insights into the chemopreventive mechanisms of O. europaea-derived secoiridoids, shedding light on their role in chemoprevention. The bioactivities summarized in the paper support the epidemiological evidence demonstrating a negative correlation between olive oil consumption and cancer risk. Furthermore, the mapped and summarized secondary signalling pathways may provide information to elucidate new synergies with other chemopreventive agents to complement chemotherapies and develop novel nutrition-based anti-cancer approaches.

Anti-Tumor Efficacy of Oleuropein-Loaded ZnO/Au Mesoporous Silica Nanoparticle in 5-FU-Resistant Colorectal Cancer Cells

Purpose

5-fluorouracil (5-FU) is a first-line chemotherapeutic agent used to treat colorectal cancer (CRC). However, 5-FU induces drug resistance and activation of cancer stem cells (CSCs). In the present study, we designed a novel biocompatible nanomedicine system with high efficacy and biocompatibility by synthesizing mesoporous silica nanoparticle (MSN)-structured ZnO and gold ions. Oleuropein (OLP) is a phenolic compound derived from olive leaves that exerts anti-cancer effects. Therefore, we synthesized OLP-loaded ZnO/Au MSNs (ZnO/Au/OLP MSNs) and examined their anti-cancer effects on 5-FU-resistant CRC cells.

Methods

ZnO/Au MSNs were synthesized and functionalized, and their physical and chemical compositions were characterized using UV-visible spectroscopy, dynamic light scattering, and transmission electron microscopy (TEM). Their effects were assessed in terms of cellular proliferation capacity, migration and invasion ability, colony-forming ability, spheroid-forming ability, reactive oxygen species (ROS) production, and mitochondrial membrane depolarization.

Results

ZnO/Au MSNs were mostly composed of various ions containing ZnO and gold ions, had a spheroid phenotype, and exhibited no cytotoxicity. ZnO/Au/OLP MSNs reduced cell viability and CSC formation and induced apoptosis of 5-FU-resistant CRC cells via necrosis via ROS accumulation and DNA fragmentation.

Conclusion

ZnO/Au/OLP MSNs exhibited anti-cancer activity by upregulating necrosis. These results revealed that ZnO/Au/OLP MSNs are a novel drug delivery system for 5-FU CRC therapy.

Olea europaea L-derived secoiridoids: Beneficial health effects and potential therapeutic approaches

Over the years, health challenges have become increasingly complex and global and, at the beginning of the 21st century, chronic diseases, including cardiovascular, neurological, and chronic respiratory diseases, as well as cancer and diabetes, have been identified by World Health Organization as one of the biggest threats to human health. Recently, antimicrobial resistance has also emerged as a growing problem of public health for the management of infectious diseases. In this scenario, the exploration of natural products as supplementation or alternative therapeutic options is acquiring great importance, and, among them, the olive tree, Olea europaea L, specifically leaves, fruits, and oil, has been increasingly investigated for its health promoting properties. Traditionally, these properties have been largely attributed to the high concentration of monounsaturated fatty acids, although, in recent years, beneficial effects have also been associated to other components, particularly polyphenols. Among them, the most interesting group is represented by Olea europaea L secoiridoids, comprising oleuropein, oleocanthal, oleacein, and ligstroside, which display anti-inflammatory, antioxidant, cardioprotective, neuroprotective and anticancer activities. This review provides an overview of the multiple health beneficial effects, the molecular mechanisms, and the potential applications of secoiridoids from Olea europaea L.

Iridoid Derivatives as Anticancer Agents: An Updated Review from 1970-2022

The rise of cancer cases has coincided with the urgent need for the development of potent chemical entities and/or modification of existing commodities to improve their efficacy. Increasing evidence suggests that cancer remains one of the leading causes of death globally, with colon cancer cases alone likely to rise exponentially by 2030. The exponential rise in cancer prevalence is largely attributable to the growing change toward a sedentary lifestyle and modern diets, which include genetically modified foods. At present, the prominent treatments for cancer are chemotherapy, surgery, and radiation. Despite slowing cancer progression, these treatments are known to have devastating side effects that may deteriorate the health of the patient, thus, have a low risk-benefit ratio. In addition, many cancer drugs have low bioavailability, thereby limiting their therapeutic effects in cancer patients. Moreover, the drastic rise in the resistance of neoplastic cells to chemotherapeutic agents is rendering the use of some drugs ineffective, thereby signaling the need for more anticancer chemical entities. As a result, the use of natural derivatives as anticancer agents is gaining considerable attention. Iridoids have the potential to form conjugates with other anticancer, antidiabetic, antileishmanial, and antimalarial drugs, which synergistically have the potential to increase their effects. Published studies have identified the role of iridoids, which, if fully explored, may result in cheaper and less toxic alternative/adjuvant cancer drugs. The subject of this article is natural and synthetic iridoid derivatives and their potential therapeutic roles as anticancer agents.

The Double-Edged Sword of Oleuropein in Ovarian Cancer Cells: From Antioxidant Functions to Cytotoxic Effects

Oleuropein plays a key role as a pro-oxidant as well as an antioxidant in cancer. In this study, the activity of oleuropein, in an in vitro model of ovarian (OCCs) and breast cancer cells (BCCs) was investigated. Cell viability and cell death were analyzed. Oxidative stress was measured by CM-H2DCFDA flow cytometry assay. Mitochondrial dysfunction was evaluated based on mitochondrial reactive oxygen species (ROS) and GPX4 protein levels. Further, the effects on iron metabolism were analyzed by measuring the intracellular labile iron pool (LIP). We confirmed that high doses of oleuropein show anti-proliferative and pro-apoptotic activity on HEY and MCF-7 cells. Moreover, our results indicate that low doses of oleuropein impair cell viability without affecting the mortality of cells, and also decrease the LIP and ROS levels, keeping them unchanged in MCF-7 cells. For the first time, our data show that low doses of oleuropein reduce erastin-mediated cell death. Interestingly, oleuropein decreases the levels of intracellular ROS and LIP in OCCs treated with erastin. Noteworthily, we observed an increased amount of ROS scavenging enzyme GPX4 together with a consistent reduction in mitochondrial ROS, confirming a reduction in oxidative stress in this model.

Potential Properties of Natural Nutraceuticals and Antioxidants in Age-Related Eye Disorders

Eye health is crucial, and the onset of diseases can reduce vision and affect the quality of life of patients. The main causes of progressive and irreversible vision loss include various pathologies, such as cataracts, ocular atrophy, corneal opacity, age-related macular degeneration, uncorrected refractive error, posterior capsular opacification, uveitis, glaucoma, diabetic retinopathy, retinal detachment, undetermined disease and other disorders involving oxidative stress and inflammation. The eyes are constantly exposed to the external environment and, for this reason, must be protected from damage from the outside. Many drugs, including cortisonics and antinflammatory drugs have widely been used to counteract eye disorders. However, recent advances have been obtained via supplementation with natural antioxidants and nutraceuticals for patients. In particular, evidence has accumulated that polyphenols (mostly deriving from Citrus Bergamia) represent a reliable source of antioxidants able to counteract oxidative stress accompanying early stages of eye diseases. Luteolin in particular has been found to protect photoreceptors, thereby improving vision in many disease states. Moreover, a consistent anti-inflammatory response was found to occur when curcumin is used alone or in combination with other nutraceuticals. Additionally, Coenzyme Q10 has been demonstrated to produce a consistent effect in reducing ocular pressure, thereby leading to protection in patients undergoing glaucoma. Finally, both grape seed extract, rich in anthocyanosides, and polynsatured fatty acids seem to contribute to the prevention of retinal disorders. Thus, a combination of nutraceuticals and antioxidants may represent the right solution for a multi-action activity in eye protection, in association with current drug therapies, and this will be of potential interest in early stages of eye disorders.

A Comprehensive Review on the Anti-Cancer Effects of Oleuropein

In Mediterranean cuisine and culture, olive oil and olive fruits play a significant role. Many people believe that those who consume olive oil and its fruit live longer and have a decreased risk of illness. Olive leaves were used to treat a range of diseases in ancient times, including malaria fever and lower earaches. Although it was not understood at the time what key components were responsible for these effects because they had not yet been discovered, Oleuropein is now recognized as one of the primary elements in immature olive fruits and leaves. Later research was carried out to determine the effects of this molecule, and it was determined that it functions as an antioxidant. Oleuropein consumption has aided in cancer treatment over the years, and this was assumed to be owing to its antioxidant properties. Oleuropein’s effects on cancer, however, go beyond that; it is now known that Oleuropein functions as both an anti-proliferative and an apoptotic promoter in many cancer cells. The kinetics and dosages of Oleuropein and the mechanisms behind its involvement and effects in cancer are explored in this review. Finally, the effects of Oleuropein in combination with anticancer medicines are investigated.

The Cross-Talk between Polyphenols and the Target Enzymes Related to Oxidative Stress-Induced Thyroid Cancer

The most serious hallmark step of carcinogenesis is oxidative stress, which induces cell DNA damage. Although in normal conditions ROS are important second messengers, in pathological conditions such as cancer, due to imbalanced redox enzyme expression, oxidative stress can occur. Recent studies with firmly established evidence suggest an interdependence between oxidative stress and thyroid cancer based on thyroid hormone synthesis. Indeed, a reduced antioxidant defense system might play a part in several steps of progression in thyroid cancer. Based on studies that have been conducted previously, future drug designs for targeting enzymatic ROS sources, as a single agent or in combination, have to be tested. Polyphenols represent the potential for modulating biological events in thyroid cancer, including antioxidative activity. Targeting enzymatic ROS sources, without affecting the physiological redox state, might be an important purpose. As regards the underlying chemopreventive mechanisms of natural compounds that have been discussed in other cancer models, the confirmation of the influence of polyphenols on thyroid cancer is inconclusive and rarely available. Therefore, there is a need for further scientific investigations into the features of the antioxidative effects of polyphenols on thyroid cancer. The current review illustrates the association between some polyphenols and the key enzymes that take place in oxidation reactions in developing thyroid cancer cells. This review gives the main points of the enzymatic ROS sources act and redox signaling in normal physiological or pathological contexts and supplies a survey of the currently available modulators of TPO, LOX, NOX, DUOX, Nrf2, and LPO derived from polyphenols.

The Employment of Genera Vaccinium, Citrus, Olea, and Cynara Polyphenols for the Reduction of Selected Anti-Cancer Drug Side Effects

Cancer is one of the most widespread diseases globally and one of the leading causes of death. Known cancer treatments are chemotherapy, surgery, radiation therapy, targeted hormonal therapy, or a combination of these methods. Antitumor drugs, with different mechanisms, interfere with cancer growth by destroying cancer cells. However, anticancer drugs are dangerous, as they significantly affect both cancer cells and healthy cells. In addition, there may be the onset of systemic side effects perceived and mutagenicity, teratogenicity, and further carcinogenicity. Many polyphenolic extracts, taken on top of common anti-tumor drugs, can participate in the anti-proliferative effect of drugs and significantly reduce the side effects developed. This review aims to discuss the current scientific knowledge of the protective effects of polyphenols of the genera Vaccinium, Citrus, Olea, and Cynara on the side effects induced by four known chemotherapy, Cisplatin, Doxorubicin, Tamoxifen, and Paclitaxel. In particular, the summarized data will help to understand whether polyphenols can be used as adjuvants in cancer therapy, although further clinical trials will provide crucial information.

An updated review on the potential antineoplastic actions of oleuropein

Oleuropein is an ester of elenolic acid and hydroxytyrosol (3, 4-dihydroxyphenylethanol). It is a phenolic compound and the most luxuriant in olives. The detailed information related to the anticancer effects of oleuropein was collected from the internet database PubMed/Medline, ResearchGate, Web of Science, Wiley Online Library, and Cnki using appropriate keywords until the end of October 2021. Oleuropein has been shown to have antioxidant, anticancer, antiinflammatory, cardioprotective, neuroprotective, and hepatoprotective effects. Previous studies also revealed that oleuropein could effectively inhibit the malignant progression of esophageal cancer, gastric cancer, breast cancer, lung cancer, liver cancer, pancreatic cancer, ovarian cancer, prostate cancer, and cervical cancer. Recently, the role of oleuropein in inhibiting tumor cell proliferation, invasion, and migration and inducing tumor cell apoptosis has gained extensive attention. In this review, we have summarized the latest research progress related to the antioncogenic mechanisms and the potential role of oleuropein in targeting different human malignancies. Based on these findings, it can be concluded that oleuropein can function as a promising chemopreventive and chemotherapeutic agent against cancer, but its more detailed anticancer effects and underlying mechanisms need to be further validated in future preclinical as well as clinical studies.

Nutraceuticals and Cancer: Potential for Natural Polyphenols

Cancer is one of the leading causes of death globally, associated with multifactorial pathophysiological components. In particular, genetic mutations, infection or inflammation, unhealthy eating habits, exposition to radiation, work stress, and/or intake of toxins have been found to contribute to the development and progression of cancer disease states. Early detection of cancer and proper treatment have been found to enhance the chances of survival and healing, but the side effects of anticancer drugs still produce detrimental responses that counteract the benefits of treatment in terms of hospitalization and survival. Recently, several natural bioactive compounds were found to possess anticancer properties, capable of killing transformed or cancerous cells without being toxic to their normal counterparts. This effect occurs when natural products are associated with conventional treatments, thereby suggesting that nutraceutical supplementation may contribute to successful anticancer therapy. This review aims to discuss the current literature on four natural bioactive extracts mostly characterized by a specific polyphenolic profile. In particular, several activities have been reported to contribute to nutraceutical support in anticancer treatment: (1) inhibition of cell proliferation, (2) antioxidant activity, and (3) anti-inflammatory activity. On the other hand, owing to their attenuation of the toxic effect of current anticancer therapies, natural antioxidants may contribute to improving the compliance of patients undergoing anticancer treatment. Thus, nutraceutical supplementation, along with current anticancer drug treatment, may be considered for better responses and compliance in patients with cancer. It should be noted, however, that when data from studies with bioactive plant preparations are discussed, it is appropriate to ensure that experiments have been conducted in accordance with accepted pharmacological research practices so as not to disclose information that is only partially correct.

Assessment of the Efficacy of Olive Leaf (Olea europaea L.) Extracts in the Treatment of Colorectal Cancer and Prostate Cancer Using In Vitro Cell Models

Cancer is one of the most serious public health issues worldwide, ranking second only to cardiovascular diseases as a cause of death. Numerous plant extracts have extraordinary health benefits and have been used for centuries to treat a variety of ailments with few side effects. Olive leaves have a long history of medicinal and therapeutic use. In this study, the anti-cancer properties of an olive leaf extract were investigated in vitro using colorectal and prostate cancer cell lines (HT29 and PC3, respectively). A high-performance liquid chromatography analysis showed that the olive leaf extract contained a high chlorogenic acid content. Accordingly, chlorogenic acid may be related to the observed effects of the aqueous extract on cancer cells, including increased inhibition of cancer cell growth, migration, DNA fragmentation, cell cycle arrest at the S phase, reactive oxygen species (ROS) production, and altered gene expression. The effects of the extracts were greater in HT29 than in PC3 cells. These results suggest that chlorogenic acid, the main constituent in the olive extract, is a promising new anti-cancer agent. Further analyses should focus on its in vivo effects on colorectal tumor models, both alone and in combination with established agents.

Phytochemicals in thyroid cancer: analysis of the preclinical studies

PURPOSE

In the search for novel effective compounds to use in thyroid cancer (TC) unresponsive to current treatment, attention has recently focused on plant-derived compounds with anticancer activity. In this review, we discuss the preclinical studies demonstrating phytochemical activity against thyroid cancer cells.

RESULTS/CONCLUSIONS

In particular, we describe their antiproliferative properties or ability to re-induce iodine retention, thus supporting their potential use as single agents or adjuvants in radioiodine-resistant thyroid cancer treatment.

Quercetin Protects Human Thyroid Cells against Cadmium Toxicity

Various natural compounds have been successfully tested for preventing or counteracting the toxic effects of exposure to heavy metals. In this study, we analyzed the effects of cadmium chloride (CdCl₂) on immortalized, non-tumorigenic thyroid cells Nthy-ori-3-1. We investigated the molecular mechanism underlying its toxic action as well as the potential protective effect of quercetin against CdCl₂-induced damage. CdCl₂ suppressed cell growth in a dose- and time-dependent manner (IC50 value ~10 μM) associated with a decrease in levels of phospho-ERK. In addition, CdCl₂ elicited an increase in reactive oxygen species (ROS) production and lipid peroxidation. A significant increase in GRP78, an endoplasmic reticulum (ER) stress-related protein, was also observed. Supplementation of quercetin counteracted the growth-inhibiting action of CdCl₂ by recovering ERK protein phosphorylation levels, attenuating ROS overproduction, decreasing MDA content and reducing the expression of GRP78 in cells exposed to CdCl₂. Thus, in addition to revealing the molecular effects involved in cadmium-induced toxicity, the present study demonstrated, for the first time, a protective effect of quercetin against cadmium-induced damages to normal thyroid cells.

Thyroid-Modulating Activities of Olive and Its Polyphenols: A Systematic Review

Olive oil, which is commonly used in the Mediterranean diet, is known for its health benefits related to the reduction of the risks of cancer, coronary heart disease, hypertension, and neurodegenerative disease. These unique properties are attributed to the phytochemicals with potent antioxidant activities in olive oil. Olive leaf also harbours similar bioactive compounds. Several studies have reported the effects of olive phenolics, olive oil, and leaf extract in the modulation of thyroid activities. A systematic review of the literature was conducted to identify relevant studies on the effects of olive derivatives on thyroid function. A comprehensive search was conducted in October 2020 using the PubMed, Scopus, and Web of Science databases. Cellular, animal, and human studies reporting the effects of olive derivatives, including olive phenolics, olive oil, and leaf extracts on thyroid function were considered. The literature search found 445 articles on this topic, but only nine articles were included based on the inclusion and exclusion criteria. All included articles were animal studies involving the administration of olive oil, olive leaf extract, or olive pomace residues orally. These olive derivatives were consistently demonstrated to have thyroid-stimulating activities in euthyroid or hypothyroid animals, but their mechanisms of action are unknown. Despite the positive results, validation of the beneficial health effects of olive derivatives in the human population is lacking. In conclusion, olive derivatives, especially olive oil and leaf extract, could stimulate thyroid function. Olive pomace residue is not suitable for pharmaceutical or health supplementation purposes. Therapeutic applications of olive oil and leaf extract, especially in individuals with hypothyroidism, require further validation through human studies.

Potential Uses of Olive Oil Secoiridoids for the Prevention and Treatment of Cancer: A Narrative Review of Preclinical Studies

The Mediterranean diet (MD) is a combination of foods mainly rich in antioxidants and anti-inflammatory nutrients that have been shown to have many health-enhancing effects. Extra-virgin olive oil (EVOO) is an important component of the MD. The importance of EVOO can be attributed to phenolic compounds, represented by phenolic alcohols, hydroxytyrosol, and tyrosol, and to secoiridoids, which include oleocanthal, oleacein, oleuropein, and ligstroside (along with the aglycone and glycosidic derivatives of the latter two). Each secoiridoid has been studied and characterized, and their effects on human health have been documented by several studies. Secoiridoids have antioxidant, anti-inflammatory, and anti-proliferative properties and, therefore, exhibit anti-cancer activity. This review summarizes the most recent findings regarding the pharmacological properties, molecular targets, and action mechanisms of secoiridoids, focusing attention on their preventive and anti-cancer activities. It provides a critical analysis of preclinical, in vitro and in vivo, studies of these natural bioactive compounds used as agents against various human cancers. The prospects for their possible use in human cancer prevention and treatment is also discussed.

Endothelial Dysfunction and Extra-Articular Neurological Manifestations in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory autoimmune disease that affects about 1% of the global population, with a female–male ratio of 3:1. RA preferably affects the joints, with consequent joint swelling and deformities followed by ankylosis. However, evidence has accumulated showing that patients suffering from RA can also develop extra-articular manifestations, including cardiovascular disease states, neuropathies, and multiorgan dysfunction. In particular, peripheral nerve disorders showed a consistent impact in the course of the disease (prevalence about 20%) mostly associated to vasculitis of the nerve vessels leading to vascular ischemia, axonal degeneration, and neuronal demyelination. The pathophysiological basis of this RA-associated microvascular disease, which leads to impairment of assonal functionality, is still to be better clarified. However, endothelial dysfunction and alterations of the so-called brain-nerve barrier (BNB) seem to play a fundamental role. This review aims to assess the potential mechanisms underlying the impairment of endothelial cell functionality in the development of RA and to identify the role of dysfunctional endothelium as a causative mechanism of extra-articular manifestation of RA. On the other hand, the potential impact of lifestyle and nutritional interventions targeting the maintenance of endothelial cell integrity in patients with RA will be discussed as a potential option when approaching therapeutic solutions in the course of the disease.

Semi-synthesis as a tool for broadening the health applications of bioactive olive secoiridoids: a critical review

Covering: 2005 up to 2020Olive bioactive secoiridoids are recognized as natural antioxidants with multiple beneficial effects on human health. Nevertheless, the study of their biological activity has also disclosed some critical aspects associated with their application. Firstly, only a few of them can be extracted in large amounts from their natural matrix, namely olive leaves, drupes, oil and olive mill wastewater. Secondly, their application as preventive agents and drugs is limited by their low membrane permeability. Thirdly, the study of their biological fate after administration is complicated by the absence of pure analytical standards. Accordingly, efficient synthetic methods to obtain natural and non-natural bioactive phenol derivatives have been developed. Among them, semi-synthetic protocols represent efficient and economical alternatives to total synthesis, combining efficient extraction protocols with efficient catalytic conversions to achieve reasonable amounts of active molecules. The aim of this review is to summarize the semi-synthetic protocols published in the last fifteen years, covering 2005 up to 2020, which can produce natural olive bioactive phenols scarcely available by extractive procedures, and new biophenol derivatives with enhanced biological activity. Moreover, the semi-synthetic protocols to produce olive bioactive phenol derivatives as analytical standards are also discussed. A critical analysis of the advantages offered by semi-synthesis compared to classical extraction methods or total synthesis protocols is also performed.

Gene Expression Alterations Associated with Oleuropein-Induced Antiproliferative Effects and S-Phase Cell Cycle Arrest in Triple-Negative Breast Cancer Cells

It is known that the Mediterranean diet is effective in reducing the risk of several chronic diseases, including cancer. A critical component of the Mediterranean diet is olive oil, and the relationship between olive oil consumption and the reduced risk of cancer has been established. Oleuropein (OL) is the most prominent polyphenol component of olive fruits and leaves. This compound has been shown to have potent properties in various types of cancers, including breast cancer. In the present study, the molecular mechanism of OL was examined in two racially different triple-negative breast cancer (TNBC) cell lines-African American (AA, MDA-MB-468) and Caucasian American (CA, MDA-MB-231). The data obtained showed that OL effectively inhibits cell growth in both cell lines, concomitant with S-phase cell cycle arrest-mediated apoptosis. The results also showed that OL-treated MDA-MB-468 cells were two-fold more sensitive to OL antiproliferative effect than MDA-MB-231 cells were. At lower concentrations, OL modified the expression of many apoptosis-involved genes. OL was more effective in MDA-MB-468, compared to MDA-MB-231 cells, in terms of the number and the fold-change of the altered genes. In MDA-MB-468 cells, OL induced a noticeable transcription activation in fourteen genes, including two members of the caspase family: caspase 1 (CASP1) and caspase 14 (CASP14); two members of the TNF receptor superfamily: Fas-associated via death domain (FADD) and TNF receptor superfamily 21 (TNFRSF21); six other proapoptotic genes: growth arrest and DNA damage-inducible 45 alpha (GADD45A), cytochrome c somatic (CYCS), BCL-2 interacting protein 2 (BNIP2), BCL-2 interacting protein 3 (BNIP3), BH3 interacting domain death agonist (BID), and B-cell lymphoma/leukemia 10 (BCL10); and the CASP8 and FADD-like apoptosis regulator (CFLAR) gene. Moreover, in MDA-MB-468 cells, OL induced a significant upregulation in two antiapoptotic genes: bifunctional apoptosis regulator (BFAR) and B-Raf proto-oncogene (BRAF) and a baculoviral inhibitor of apoptosis (IAP) repeat-containing 3 (BIRC3). On the contrary, in MDA-MB-231 cells, OL showed mixed impacts on gene expression. OL significantly upregulated the mRNA expression of four genes: BIRC3, receptor-interacting serine/threonine kinase 2 (RIPK2), TNF receptor superfamily 10A (TNFRSF10A), and caspase 4 (CASP4). Additionally, another four genes were repressed, including caspase 6 (CASP6), pyrin domain (PYD), and caspase recruitment domain (CARD)-containing (PAYCARD), baculoviral IAP repeat-containing 5 (BIRC5), and the most downregulated TNF receptor superfamily member 11B (TNFRSF11B, 16.34-fold). In conclusion, the data obtained indicate that the two cell lines were markedly different in the anticancer effect and mechanisms of oleuropein's ability to alter apoptosis-related gene expressions. The results obtained from this study should also guide the potential utilization of oleuropein as an adjunct therapy for TNBC to increase chemotherapy effectiveness and prevent cancer progression.

Effects of oleuropein on tumor cell growth and bone remodelling: Potential clinical implications for the prevention and treatment of malignant bone diseases

Oleuropein (Ole) is the main bioactive phenolic compound present in olive leaves, fruits and olive oil. This molecule has been shown to exert beneficial effects on several human pathological conditions. In particular, recent preclinical and observational studies have provided evidence that Ole exhibits chemo-preventive effects on different types of human tumors. Studies undertaken to elucidate the specific mechanisms underlying these effects have shown that this molecule may thwart several key steps of malignant progression, including tumor cell proliferation, survival, angiogenesis, invasion and metastasis, by modulating the expression and activity of several growth factors, cytokines, adhesion molecules and enzymes involved in these processes. Interestingly, experimental observations have highlighted the fact that most of these signalling molecules also appear to be actively involved in the homing and growth of disseminating cancer cells in bones and, ultimately, in the development of metastatic bone diseases. These findings, and the experimental and clinical data reporting the preventive activity of Ole on various pathological conditions associated with a bone loss, are indicative of a potential therapeutic role of this molecule in the prevention and treatment of cancer-related bone diseases. This paper provides a current overview regarding the molecular mechanisms and the experimental findings underpinning a possible clinical role of Ole in the prevention and development of cancer-related bone diseases.

Low Doses of Methylmercury Induce the Proliferation of Thyroid Cells In Vitro Through Modulation of ERK Pathway

Exposure to environmental endocrine disruptors has been associated with an increased frequency of thyroid pathology. In this study, we evaluated the effects of various concentrations of methylmercury (MeHg) on immortalized, non-tumorigenic thyroid cells (Nthy-ori-3-1). Exposure to MeHg at 2.5 and 5 µM for 24 h caused a reduction in cell viability with a decrease of the cell population in sub-G0 phase, as detected by MTT and flow cytometry. Conversely, MeHg at the lower concentration of 0.1 µM increased the cell viability with a rise of G2/M phase. An immunoblot analysis showed higher expression levels of phospho-ERK and not of phospho-Akt. Further enhancement of the cell growth rate was observed after a prolonged exposure of the cells up to 18 days to MeHg 0.1 µM. The present findings demonstrate the toxicity of high concentrations of MeHg on thyroid cells, while showing that treatment with lower doses of Hg, as may occur after prolonged exposure to this environmental contaminant, exerts a promoting effect on thyroid cell proliferation, by acting on the ERK-mediated pro-oncogenic signal transduction pathway.

Potential Protective Role Exerted by Secoiridoids from Olea europaea L. in Cancer, Cardiovascular, Neurodegenerative, Aging-Related, and Immunoinflammatory Diseases

Iridoids, which have beneficial health properties, include a wide group of cyclopentane [c] pyran monoterpenoids present in plants and insects. The cleavage of the cyclopentane ring leads to secoiridoids. Mainly, secoiridoids have shown a variety of pharmacological effects including anti-diabetic, antioxidant, anti-inflammatory, immunosuppressive, neuroprotective, anti-cancer, and anti-obesity, which increase the interest of studying these types of bioactive compounds in depth. Secoiridoids are thoroughly distributed in several families of plants such as Oleaceae, Valerianaceae, Gentianaceae and Pedialaceae, among others. Specifically, Olea europaea L. (Oleaceae) is rich in oleuropein (OL), dimethyl-OL, and ligstroside secoiridoids, and their hydrolysis derivatives are mostly OL-aglycone, oleocanthal (OLE), oleacein (OLA), elenolate, oleoside-11-methyl ester, elenoic acid, hydroxytyrosol (HTy), and tyrosol (Ty). These compounds have proved their efficacy in the management of diabetes, cardiovascular and neurodegenerative disorders, cancer, and viral and microbial infections. Particularly, the antioxidant, anti-inflammatory, and immunomodulatory properties of secoiridoids from the olive tree (Olea europaea L. (Oleaceae)) have been suggested as a potential application in a large number of inflammatory and reactive oxygen species (ROS)-mediated diseases. Thus, the purpose of this review is to summarize recent advances in the protective role of secoiridoids derived from the olive tree (preclinical studies and clinical trials) in diseases with an important pathogenic contribution of oxidative and peroxidative stress and damage, focusing on their plausible mechanisms of the action involved.

Oleuropein and its peracetylated derivative negatively regulate osteoclastogenesis by controlling the expression of genes involved in osteoclast differentiation and function

OL and Per-OL impair transcriptional gene circuits able to support osteoclastogenesis from human blood monocytes.

Anticancer effects of olive oil polyphenols and their combinations with anticancer drugs

Cancer presents one of the leading causes of death in the world. Current treatment includes the administration of one or more anticancer drugs, commonly known as chemotherapy. The biggest issue concerning the chemotherapeutics is their toxicity on normal cells and persisting side effects. One approach to the issue is chemoprevention and the other one is the discovery of more effective drugs or drug combinations, including combinations with polyphenols. Olive oil polyphenols (OOPs), especially hydroxytyrosol (HTyr), tyrosol (Tyr) and their derivatives oleuropein (Ole), oleacein and oleocanthal (Oc) express anticancer activity on different cancer models. Recent studies report that phenolic extract of virgin olive oil may be more effective than the individual phenolic compounds. Also, there is a growing body of evidence about the combined treatment of OOPs with various anticancer drugs, such as cisplatin, tamoxifen, doxorubicin and others. These novel approaches may present an advanced strategy in the prevention and treatment of cancer.

Oleuropein-Induced Apoptosis Is Mediated by Mitochondrial Glyoxalase 2 in NSCLC A549 Cells: A Mechanistic Inside and a Possible Novel Nonenzymatic Role for an Ancient Enzyme

Oleuropein (OP) is a bioactive compound derived from plants of the genus Oleaceae exhibiting antitumor properties in several human cancers, including non-small-cell lung cancer (NSCLC). Recent evidence suggests that OP has proapoptotic effects on NSCLC cells via the mitochondrial apoptotic pathway. However, the exact molecular mechanisms behind the apoptogenic action of OP in NSCLC are still largely unknown. Glyoxalase 2 (Glo2) is an ancient enzyme belonging to the glyoxalase system involved in the detoxification of glycolysis-derived methylglyoxal. However, emerging evidence suggests that Glo2 may have also nonenzymatic roles in some malignant cells. In the present study, we evaluated whether and how Glo2 participated in the proapoptotic effects of OP in NSCLC A549 cells. Our results indicate that OP is able to induce apoptosis in A549 cells through the upregulation of mitochondrial Glo2 (mGlo2), mediated by the superoxide anion and Akt signaling pathway. Moreover, our data shows that the proapoptotic role of mGlo2, observed following OP exposure, occurs via the interaction of mGlo2 with the proapoptotic Bax protein. Conversely, OP does not alter the behavior of nonmalignant human BEAS-2B cells or mGlo2 expression, thus suggesting a specific anticancer role for this bioactive compound in NSCLC. Our data identify a novel pathway through which OP exerts a proapoptotic effect in NSCLC and suggest, for the first time, a novel, nonenzymatic antiapoptotic role for this ancient enzyme in NSCLC.

Antiproliferative Effects of Cynaropicrin on Anaplastic Thyroid Cancer Cells

BACKGROUND

The sesquiterpene lactone cynaropicrin, a major constituent of the artichoke leaves extracts, has shown several biologic activities in many preclinical experimental models, including anti-proliferative effects.

OBJECTIVE

Herein we evaluated the effects of cynaropicrin on the growth of three human anaplastic thyroid carcinoma cell lines, investigating the molecular mechanism underlying its action.

METHOD

MTT assay was used to evaluate the viability of CAL-62, 8505C and SW1736 cells, and flow cytometry to analyse cell cycle distribution. Western blot was performed to detect the levels of STAT3 phosphorylation and NFkB activation. Antioxidant effects were analyzed by measuring the reactive oxygen species and malonyldialdehyde dosage was used to check the presence of lipid peroxidation.

RESULTS

Viability of CAL-62, 8505C and SW1736 cells was significantly reduced by cynaropicrin in a dose- and time-dependent way, with an EC50 of about 5 µM observed after 48 h of treatment with the compound. Cellular growth inhibition was accompanied both by an arrest of the cell cycle, mainly in the G2/M phase, and the presence of a significant percentage of necrotic cells. After 48 h of treatment with 10 µM of cynaropicrin, a reduced nuclear expression of NFkB and STAT3 phosphorylation were also revealed. Moreover, we observed an increase in lipid peroxidation, without any significant effect on the reactive oxygen species production.

CONCLUSION

These results demonstrate that cynaropicrin reduces the viability and promotes cytotoxic effects in anaplastic thyroid cancer cells associated with reduced NFkB expression, STAT3 phosphorylation and increased lipid peroxidation. Further characterization of the properties of this natural compound may open the way for using cynaropicrin as an adjuvant in the treatment of thyroid cancer.

The Oleaceae family: A source of secoiridoids with multiple biological activities

In the quest to search and discover bioactive compounds from nature, terpenoids have emerged as one of the most interesting and researched classes of compounds. Secoiridoid, a type of the terpenoid, has also been extensively studied, especially their chemical structures and pharmacological effects. Oleaceae is a family of woody dicotyledonous plants with broad economic and medicinal values. This family contains a large number of flavonoids, monoterpenoids, iridoids, secoiridoids and phenylethyl alcohols, of which the secoiridoids have various biological activities. The purpose of this review is to summarize the phytochemical and pharmacological of the secoiridoids (glycosides, aglycones, derivatives and dimers) in the Oleaceae family from 1987 to 2018. This review will also serve as a reference for further studies.

Secoiridoids of olive and derivatives as potential coadjuvant drugs in cancer: A critical analysis of experimental studies

Phenolic secoiridoids from olive, including oleocanthal, oleuropein and related derivatives, are bioactive natural products with documented anticancer activities, that have mainly been attributed to their antioxidant, anti-inflammatory and antiproliferative effects. This review summarizes the results of the preclinical studies on the natural secoiridoids of olive used as single agents or in combination with other chemotherapeutics against cancer cells. The molecular targets of their action are described. A critical analysis of the importance of the experimental studies in view of the possible use in humans is also discussed.

Phenolic Compounds Isolated from Olive Oil as Nutraceutical Tools for the Prevention and Management of Cancer and Cardiovascular Diseases

Non-communicable diseases (NCDs) have become the largest contributor to worldwide morbidity and mortality. Among them, cancer and cardiovascular diseases (CVDs) are responsible for a 47% of worldwide mortality. In general, preventive approaches modifying lifestyle are more cost-effective than treatments after disease onset. In this sense, a healthy diet could help a range of NCDs, such as cancer and CVDs. Traditional Mediterranean Diet (MD) is associated by the low-prevalence of certain types of cancers and CVDs, where olive oil plays an important role. In fact, different epidemiological studies suggest that olive oil consumption prevents some cancers, as well as coronary heart diseases and stroke incidence and mortality. Historically, the beneficial health effects of virgin olive oil (VOO) intake were first attributed to the high concentration of monounsaturated fatty acids. Nowadays, many studies indicate that phenolic compounds contained in olive oil have positive effects on different biomarkers related to health. Among them, phenolic compounds would be partially responsible for health benefits. The present work aims to explore, in studies published during the last five years, the effects of the main phenolic compounds isolated from olive oil on different cancer or CVD aspects, in order to clarify which compounds have more potential to be used as nutraceuticals with preventive or even therapeutic properties.

Antitumor Perspectives of Oleuropein and Its Metabolite Hydroxytyrosol: Recent Updates

Olive fruit is a significant and promising source of potential bioactive compounds such as oleuropein and hydroxytyrosol. Oleuropein is the ester of elenolic acid and 3,4-dihydroxyphenyl ethanol (HT). It is the main glycoside in olives, the degradation of which results in the formation of hydroxytyrosol in olive oil. Both plays a significant role in the reduction of coronary heart diseases and a certain type of cancers. Both olive oil phenols have an effective role counter to cell proliferation, cell growth, migration, invasion, and angiogenesis. They down regulate the expression of BCL-2 and COX-2 proteins, and reduced DNA damage. Hydroxytyrosol and oleuropein inhibited the multiple stages in colon carcinogenesis; initiation, promotion, and metastasis. They also provide protection against various human cancers including colorectal, skin, breast, thyroid, digestive, lung, brain, blood, and cervical. This review article discusses the anticancer perspectives and mechanisms of oleuropein and hydroxytyrosol in cell cultures and animal and human studies.

Synthesis and antioxidant evaluation of lipophilic oleuropein aglycone derivatives

Oleuropein is the most important phenolic compound present in olive cultivars, but it is scarcely present in extra virgin olive oil (EVOO) due to its high hydrophilicity and degradability. Thus, a set of oleuropein aglycone derivatives were synthesized by transacetylation under mild conditions with the aim of circumventing these drawbacks and making the active moiety in oleuropein suitable to be added to food fats. The oleuropein aglycone (closed ring form) is obtained by hydrolyzing oleuropein using Lewis acid catalysis. Then, the permeation profiles as well as the antioxidant capacity of the oleuropein aglycone derivatives were evaluated by ORAC, DPPH assays and by ROS formation using the SH-SY5Y cell line. The biological activities of the obtained compounds exhibited a dependence on their level of lipophilicity.

Oleuropein potentiates anti-tumor activity of cisplatin against HepG2 through affecting proNGF/NGF balance

AIMS

Oleuropein is considered as a new chemotherapeutic agent in human hepatocellular carcinoma (HCC) while, its exact underlying molecular mechanism still not yet explored. In addition, cisplatin is a standard anticancer drug against solid tumors with toxic side effects. Therefore, we conducted this study to assess antitumor activity of oleuropein either alone or in combination with cisplatin against HepG2, human HCC cell lines, via targeting pro-NGF/NGF signaling pathway.

MAIN METHODS

HepG2 cells were treated with cisplatin (20, 50, 100 μM) and oleuropein (100, 200, 300 and 400 μM) as well as some of the cells were treated with 50 μM cisplatin and different concentrations of oleuropein. Gene expressions of nerve growth factor (NGF), matrix metalloproteinase-7 (MMP-7) and caspase-3 were evaluated by real time-PCR. In addition, protein levels of NGF and pro-form of NGF (pro-NGF) were measured by ELISA while, nitric oxide (NO) content was determined colorimetrically.

KEY FINDINGS

Cisplatin treatment showed a significant elevation of NO content and pro-NGF protein level with a marked reduction of NGF protein level in addition to the upregulation of caspase-3 along with downregulation of MMP-7 gene expressions in a dose-dependent manner. However, the combination of 50 μM cisplatin and 200 μM oleuropein showed the most potent effect on the molecular level when compared with oleuropein or cisplatin alone.

SIGNIFICANCE

Our results showed for the first time that the anti-tumor activity of oleuropein against HCC could be attributed to influencing the pro-NGF/NGF balance via affecting MMP-7 activity without affecting the gene expression of NGF. Concurrent treatment with both oleuropein and cisplatin could lead to more effective chemotherapeutic combination against HCC.

Peracetylation as a strategy to improve oleuropein stability and its affinity to fatty foods

Acetylated oleuropein, a safe, biologically active semi-synthetic stable derivative of oleuropein, is proposed as an easy alternative to make oleuropein more bioavailable and suitable to be added to fatty foods.

P38 MAP kinase is involved in oleuropein-induced apoptosis in A549 cells by a mitochondrial apoptotic cascade

Lung cancer is one of malignant tumors that cause great threats to human health, which causes the fastest growing morbidity and mortality. Oleuropein as natural production exerts anticancer effects in several cancer cells. In the study, we investigated apoptotic effect of oleuropein on A549 cells and the underlying mechanisms. Oleuropein markedly decreased cell viability in A549 cells by resulting in G₂/M phase arrest, but failed to decreased cell viability in BEAS-2B cells significantly. Apoptosis by oleuropein was confirmed by apoptotic morphology, accumulation in a sub-G₁ peak, nucleus fragmentation and cleavage of PARP. Dose-dependent elevation in p-p38MAPK and p-ATF-2 was observed whereas apparent changes could not be observed in p-JNK and p-c-Jun, showing activation of p38MAPK but not JNK. Interestingly, ERK1/2 appeared to be constant while p-ERK1/2 was reduced dose-dependently. Oleuropein caused decrease in mitochondrial membrane potential, increase in Bax/Bcl- 2 ratio, release of mitochondrial cytochrome c and activation of caspase-9 and caspase-3, implying that mitochondrial apoptotic pathway was activated. Additionally, oleuropein-induced apoptosis was dramatically attenuated by Z-VAD-FMK (caspase inhibitor). The p38MAPK inhibitor prevented production of apoptotic bodies and reduced expressions of cleaved-PARP, p-P38, p-ATF-2 and release of cytochrome c. Taken together, these results demonstrated p38MAPK signaling pathway mediated oleuropein-induced apoptosis via mitochondrial apoptotic cascade in A549 cells. Oleuropein has the potential to be a therapeutic drug for lung cancer treatment.

Chemical Characterization and Biological Activities of Phenolic-Rich Fraction from Cauline Leaves of Isatis tinctoria L. (Brassicaceae) Growing in Sicily, Italy

The present work focused on the evaluation of the antioxidant and cytotoxic activities of the phenolic-rich fraction (ItJ-EAF) obtained from cauline leaves collected in January from Isatis tinctoria L. (Brassicaceae) growing wild around Acireale (Sicily, Italy). The total phenolic, flavonoid, and condensed tannin contents of the fraction were determined spectrophotometrically, whereas the phenolic profile was assessed by HPLC-PDA/ESI-MS analysis. A total of 20 compounds were positively identified and twelve out of them were never previously reported in I. tinctoria leaves. The fraction exhibited good radical scavenging activity in DPPH test (IC₅₀  = 0.6657 ± 0.0024 mg/ml) and reducing power (3.87 ± 0.71 ASE/ml), whereas, it neither showed chelating activity nor was able to counteract H₂ O₂ induced oxidative stress damage in Escherichia coli. The antiproliferative effect was evaluated in vitro on two human anaplastic thyroid carcinoma cell lines (CAL-62 and 8505C) by MTT assay. At the highest tested concentration ItJ-EAF significantly reduced (80%) the growth of CAL-62 cells. No cytotoxicity against Artemia salina was observed. It can be concluded that I. tinctoria cauline leaves represent a source of phenolic compounds which could be potentially used as chemopreventive or adjuvant agents against cancer.

Anticancer effects of oleuropein

Cancer cells exhibit enhanced proliferation rate and a resistance to apoptosis. Epidemiological studies suggest that olive oil intake is associated with a reduced risk of cancer. Olive oil, olives, and olive leaves contain many polyphenols, including oleuropein. Recently, several studies have demonstrated that oleuropein inhibits proliferation and induces apoptosis in different cancer cell lines. In addition, anticancer effects of oleuropein have been seen in animal studies. These effects are associated with oleuropein's ability to modulate gene expression and activity of a variety of different signaling proteins that play a role in proliferation and apoptosis. This article summarizes the existing in vitro and in vivo studies focusing on the anticancer effects of oleuropein and its effects on key signaling molecules. © 2017 BioFactors, 43(4):517-528, 2017.

Silencing of hTERT blocks growth and migration of anaplastic thyroid cancer cells

Mutations in the hTERT promoter responsible for constitutive telomerase activity are the most frequent genetic alteration detected in anaplastic thyroid cancer (ATC), and proposed as diagnostic and prognostic biomarker in these tumours. In this study we analyzed hTERT expression in a series of human ATCs and investigated the effects of small-interfering RNA-mediated silencing of hTERT on viability and migration and invasive properties of three human ATC cell lines. Expression of hTERT mRNA resulted increased in 8/10 ATCs compared to normal thyroid tissues. Silencing of hTERT in CAL-62, 8505C and SW1736 cells did not modify telomere length but determined a significant decrease (about 50%) of cell proliferation in all cell lines and a great reduction (about 50%) of migration and invasion capacity. These finding demonstrate that hTERT may be considered as a molecular target for ATC treatment.

Oleuropein and Cancer Chemoprevention: The Link is Hot

Cancer comprises a collection of related diseases characterized by the existence of altered cellular pathways resulting in an abnormal tendency for uncontrolled growth. A broad spectrum, coordinated, and personalized approach focused on targeting diverse oncogenic pathways with low toxicity and economic natural compounds can provide a real benefit as a chemopreventive and/or treatment of this complex disease. Oleuropein, a bioactive phenolic compound mainly present in olive oil and other natural sources, has been reported to modulate several oncogenic signalling pathways. This review presents and critically discusses the available literature about the anticancer and onco-suppressive activity of oleuropein and the underlying molecular mechanisms implicated in the anticarcinogenic and therapeutic effects. The existence of limitations and the promising perspectives of research on this phenolic compound are also critically analyzed and discussed.

High doses of hydroxytyrosol induce apoptosis in papillary and follicular thyroid cancer cells

PURPOSE

Recent evidences indicates that hydroxytyrosol, one of the main olive oil phenols, possess antitumor effects because of its pro-oxidant properties and the capacity to inhibit proliferation and to promote apoptosis in several tumor cell lines, although most of the results were obtained for breast and digestive systems cancers.

METHODS

In this study, we evaluated the activities of hydroxytyrosol against papillary (TPC-1, FB-2) and follicular (WRO) thyroid cancer cell lines.

RESULTS

Cellular viability revealed that high doses of hydroxytyrosol reduced cancer cells viability concomitantly with a reduction of cyclin D1 expression and an up-regulation of cell cycle key modulator p21 levels. In the same experimental conditions, Annexin V-PI staining and DNA laddering revealed that hydroxytyrosol exerts proapoptotic effects on papillary and follicular cancer cells. Furthermore, by Western blot analysis, we observed that hydroxytyrosol treatment reduced thyroid cancer cells viability by promoting apoptotic cell death via intrinsic pathway.

CONCLUSIONS

Collectively, our results demonstrated for the first time that in thyroid cancer cells hydroxytyrosol promoted apoptosis at higher doses with respect to other cancer cells lines. Therefore, further studies will reveal the mechanisms by which thyroid cancer cells are more resistant to the proapoptotic effect exerted by hydroxytyrosol as well as the potential application as novel target therapeutic in thyroid cancer.

Oleuropein protects L-02 cells against H2O2-induced oxidative stress by increasing SOD1, GPx1 and CAT expression

Oleuropein (OL), a natural phenolic compound, comprises the major constituent of Olea europea leaves and unprocessed olives, and OL is considered to be the principal components that confer the characteristic taste and stability of olive oil. Oxidative damage induced by H₂O₂ treatment can irreversibly damage the L-02 cells, resulting in cell death and apoptosis. Whether the effects of oxidative stress could be attenuated in cultured human L-02 cells by incubation with OL is still unknown. In this research, the function of OL in protecting human L-02 cells against H₂O₂ induced cell death and cell apoptosis was investigated, and the mechanism by which OL underlies the effect was also examed. L-02 cells were exposed to 100μM H₂O₂ with or without OL pretreatment at different concentrations. Cell viabilities were monitored by WST-1 assay. ALT, AST and LDH production in culture medium were also determined. ROS levels were detected by L-012 chemiluminescence, and OL increased SOD1, CAT and GPx1 expression in a concentration-dependent manner. Further studies showed that OL also inhibited H₂O₂-induced P38 and JNK phosphorylation but enhanced ERK1/2 phosphorylation in a dose-dependent manner. These findings suggested that OL as a potent antioxidant agent and a natural compound found in several plants, may be exploited as a potentially useful method for hepatopathy prevention.

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

Background: The peracetylation is a simple chemical modification that can be used to enhance the bioavailability of hydrophilic products and to obtain safe and stable pro-drugs.

Results: A totally green, solvent-free and catalyst-free microwave (MW)-assisted method for peracetylation of natural products such as oleuropein, alpha-hederin, quercetin and rutin is presented. By simply tuning the MW heating program, polyols with chemical diverse –OH groups or thermolabile functionalities can be peracetylated to improve the biological activity without degradation of the natural starting molecules. An evaluation of the process greenness was performed.

Conclusion: The method is potentially universally applicable for green acetylation of hydrophilic biological molecules, potentially easily scalable for industrial applications, including pharmaceutical, cosmetic and food industry.