Phenolic compounds oleuropein and hydroxytyrosol exert differential effects on glioma development via antioxidant defense systems

Echinochrome exhibits anti-asthmatic activity through the suppression of airway inflammation, oxidative stress, and histopathological alterations in ovalbumin-induced asthma in BALB/c mice

Asthma is a chronic pulmonary disease with marked infiltrating inflammatory cells and reduced respiratory performance. Echinochrome (Ech) is a dark-red pigment isolated from the sea urchin spines, shells, and ova. It has antioxidant, antimicrobial, and anti-inflammatory properties, but whether it can be used in asthma treatment has yet to be investigated. In this research, we aimed to study the inhibitory actions of Ech on allergic asthma symptoms in mice. Mice were divided into 4 groups (n = 8 for each): control, ovalbumin-challenged, and Ech-treated (0.1 and 1 mg/kg). At the end of the experiment, nasal scratching, lung oxidative stress, airway inflammation, and remodeling were assessed. In ovalbumin-challenged BALB/C mice, treatment with Ech significantly decreased nasal scratching, lung oxidative stress, inflammatory cell infiltration, mucus hyperproduction and hyperplasia of goblet cells, IgE levels, and inflammatory cytokines. It also inhibited NF-κB phosphorylation. This is the first study to investigate the immunomodulatory effect of Ech against allergic asthma in mice. According to our findings, we imply that Ech may be utilized as a treatment for allergic asthma.

Gender Differences in Oxidative Stress in Relation to Cancer Susceptibility and Survival

Genetic, developmental, biochemical, and environmental variables interact intricately to produce sex differences. The significance of sex differences in cancer susceptibility is being clarified by numerous studies. Epidemiological research and cancer registries have revealed over the past few years that there are definite sex variations in cancer incidence, progression, and survival. However, oxidative stress and mitochondrial dysfunction also have a significant impact on the response to treatment of neoplastic diseases. Young women may be more protected from cancer than men because most of the proteins implicated in the regulation of redox state and mitochondrial function are under the control of sexual hormones. In this review, we describe how sexual hormones control the activity of antioxidant enzymes and mitochondria, as well as how they affect several neoplastic diseases. The molecular pathways that underlie the gender-related discrepancies in cancer that have been identified may be better understood, which may lead to more effective precision medicine and vital information on treatment options for both males and females with neoplastic illnesses.

Visnagin Attenuates Gestational Diabetes Mellitus in Streptozotocin-induced Diabetic Pregnant Rats via Regulating Dyslipidemia, Oxidative Stress, and Inflammatory Response

Background:

Gestational diabetes mellitus (GDM) is a condition of glucose intolerance and insulin resistance only diagnosed during pregnancy. GDM has exhibited several adverse effects on both mother and offspring. The current research focuses on discovering visnagin’s beneficial properties against the streptozotocin (STZ)-induced GDM in rats via alleviating the inflammation and oxidative stress.

Materials and Methods:

GDM was caused in the pregnant rats by the administration of 25 mg/kg of STZ by the intraperitoneal route and then treated with 20 mg/kg of visnagin for 20 consecutive days. The rats’ body weight was measured, and fasting blood glucose (FBG) status was determined using a standard glucometer. The contents of total cholesterol (TCh), triglycerides (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were assessed using kits. The MDA level, total antioxidant capacity (TAC) status, and activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST) were determined using assay kits. Kits also assessed the contents of TNF-α and IL-1β. The contents of TNF-α and IL-1β effectively improved the body weight and decreased the FBG status in the GDM rats. The visnagin also decreased the TCh, TG, and LDL, and elevated the HDL content. The content of MDA was decreased and the visnagin treatment increased SOD, CAT, GST, and GPx, and the visnagin treatment increased SOD, CAT, GST, and GPx activities SOD, CAT, GST, and GPx activities. The visnagin effectively decreased the STZ-induced histopathological alterations in the pancreas.

Conclusion:

Altogether, our investigation results suggest a beneficial role visnagin against STZ-induced GDM in rats via inhibiting the inflammatory responses. Hence, it can be a talented therapeutic candidate for the successful management of GDM.

Prophylactic role of olive fruit extract against cigarette smoke-induced oxidative stress in Sprague-Dawley rats

Cigarette smoke exposure increases the production of free radicals leading to initiation of several pathological conditions by triggering the oxidative stress and inflammatory cascade. Olive fruit owing to its unique phytochemical composition possesses antioxidant, immune modulatory, and anti-inflammatory potential. Considering the compositional alterations in olive fruits during ripening, the current experimental trail was designed to investigate the prophylactic role of green and black olives against the oxidative stress induced by cigarette smoke exposure in rats. Purposely, rats were divided into five different groups: NC (negative control; normal diet), PC [positive control; normal diet + smoke exposure (SE)], drug (normal diet + SE + citalopram), GO (normal diet + SE + green olive extract), and BO (normal diet + SE + black olive extract). Rats of all groups were exposed to cigarette smoke except "NC" and were sacrificed for collection of blood and organs after 28 days of experimental trial. The percent reduction in total oxidative stress by citalopram and green and black olive extracts in serum was 29.72, 58.69, and 57.97%, respectively, while the total antioxidant capacity increased by 30.78, 53.94, and 43.98%, accordingly in comparison to PC. Moreover, malondialdehyde (MDA) was reduced by 29.63, 42.59, and 45.70% in drug, GO, and BO groups, respectively. Likewise, green and black olive extracts reduced the leakage of hepatic enzymes in sera, alkaline phosphatase (ALP) by 23.44 and 25.80% and 35.62 and 37.61%, alanine transaminase (ALT) by 42.68 and 24.39% and 51.04 and 35.41%, and aspartate transaminase (AST) by 31.51 and 16.07% and 40.50 and 27.09% from PC and drug group, respectively. Additionally, olive extracts also maintained the antioxidant pool, i.e., superoxide dismutase, catalase, and glutathione in serum. Furthermore, histological examination revealed that olive extracts prevented the cigarette smoke-induced necrosis, pyknotic alterations, and congestion in the lung, hepatic, and renal parenchyma. Besides, gene expression analysis revealed that olive extracts and citalopram decreased the brain and lung damage caused by stress-induced upregulation of NRF-2 and MAPK signaling pathways. Hence, it can be concluded that olives (both green and black) can act as promising antioxidant in alleviating the cigarette smoke-induced oxidative stress.

Tyrosol improves ovalbumin (OVA)-induced asthma in rat model through prevention of airway inflammation

Asthma is an inflammatory disease that affects many people around the world, especially persons at paediatric age group. The effectiveness of tyrosol, a natural phenolic compound, was examined in the asthma model induced by ovalbumin (OVA). For this purpose, four groups, each consisting of eight rats, were arranged. For 21 days, physiological saline solution was treated to the control group and OVA was treated to the groups of OVA, OVA + dexamethasone (Dexa) and OVA + tyrosol groups, intraperitoneally and through inhalation. Additionally, 0.25 mg/kg Dexa was treated to the OVA + Dexa group and 20 mg/kg tyrosol to the OVA + tyrosol group by oral gavage. Serum, blood, bronchoalveolar lavage fluid (BALF) and lung tissues of the rats were examined. It was observed that MDA level decreased, GSH level and GPx activity increased, and there was no change in CAT activity in lung tissues of the tyrosol treatment groups. It was also observed that NF-κB, TNF-α, IL-4, IL-5, IL-13, IFN-γ and IgE levels decreased compared to the OVA group in lung tissue and serum samples except for serum NF-κB and IL-4. However, no effect on IL-1 β level was observed. In addition, it was determined that tyrosol treatment increased the IL-10 level on both tissue samples. The results of the histopathological investigation of lung tissue showed that tyrosol significantly ameliorated OVA-induced histopathological lesions. Additionally, PAS staining showed that mucus hypersecretion was significantly reduced with the use of tyrosol. In addition, it was determined that the number of eosinophils decreased significantly in blood and BALF samples. The obtained results showed that tyrosol possessed antioxidant and anti-inflammatory features on OVA-induced rats and preserved tissue architecture.

Safety and Efficacy Assessments to Take Antioxidants in Glioblastoma Therapy: From In Vitro Experiences to Animal and Clinical Studies

Glioblastoma (GBM) is considered one of the most common malignant brain tumors, occurring as over 15% of all primary central nervous system and brain neoplasms. The unique and standard treatment option towards GBM involves the combination of surgical resection followed by radiotherapy (RT) and chemotherapy (CT). However, due to the aggressive nature and heterogeneity of GBMs, they remained difficult to treat. Recent findings from preclinical studies have revealed that disruption of the redox balance via using either oxidative or anti-oxidative agents in GBM presented an effective and promising therapeutic approach. A limited number of clinical trials substantially encouraged their concomitant use with RT or CT. Thus, treatment of GBMs may benefit from natural or synthetic antioxidative compounds as novel therapeutics. Despite the presence of variegated in vitro and in vivo studies focusing on safety and efficacy issues of these promising therapeutics, nowadays their translation to clinics is far from applicability due to several challenges. In this review, we briefly introduce the enzymatic and non-enzymatic antioxidant defense systems as well as potential signaling pathways related to the pathogenesis of GBM with a special interest in antioxidant mechanisms. In addition, we describe the advantages and limitations of antioxidant supplementation in GBM cases or disease models as well as growing challenges for GBM therapies with antioxidants in the future.

Effects of Olive (Olea europaea L.) Leaves with Antioxidant and Antimicrobial Activities on In Vitro Ruminal Fermentation and Methane Emission

Simple Summary

Olives are cultivated mostly in the Mediterranean as well as in Asia Minor, Korea, Japan, and China. Olive oil is currently used as a food ingredient in human diet, and its consumption is gradually expanding in various countries. Therefore, olive cultivation and oil extraction produce a significant amount of byproducts; providing these byproducts as feed to livestock has been attempted for a long period. Economic, environmental, and nutritional considerations make the use of olive byproducts efficient and cost-effective as feed for ruminants. Among the olive byproducts, olive leaves (OLs) contain higher levels of polyphenols than olive fruits, and have a very high feed value. In this study, it was confirmed that methane production decreased during 12 h of in vitro fermentation, and the number of fat-utilizing microorganisms increased in the 5% OLs group. OLs were found to show antioxidant and antimicrobial activity. Moreover, the proportion of cellulose-degrading bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens increased in the 5% OLs group at 12 h and decreased at 24 h. Olive leaves are believed to be very useful as feed additives and supplements for ruminants.

Abstract

We evaluated whether olive leaves (OLs) are effective as feed additives and supplements for ruminants and the potential methane reduction effects during in vitro fermentation. Two Hanwoo cows (460 ± 20 kg) equipped with cannula were fed Timothy hay and corn-based feed 3% of the body weight at a ratio of 6:4 (8:30 a.m. and 5:00 p.m.). Ruminal fluid from the cows was collected and mixed before morning feeding. In vitro batch fermentation was monitored after 12 and 24 h of incubation at 39 °C, and OLs were used as supplements to achieve the concentration of 5% in the basal diet. At 12 h of fermentation, methane production decreased in the 5% OLs group compared to that in the control group, but not at 24 h. The proportion of cellulose-degrading bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens, tended to increase in the 5% OLs group at 12 h. The amount of ammonia produced was the same as the polymerase chain reaction result for Prevotella ruminicola. At 12 h, the proportion of Prevotella ruminicola was significantly higher in the 5% OLs group. OLs may be used incorporated with protein byproducts or other methane-reducing agents in animal feed.

Gender differences in the antioxidant response of oral administration of hydroxytyrosol and oleuropein against N-ethyl-N-nitrosourea (ENU)-induced glioma

Brain tumorigenesis has been associated not only with oxidative stress, but also with a reduced response of non-enzyme and enzyme antioxidant defense systems. In fact, the imbalance between free-radical production and the efficiency of the antioxidant defense systems triggers the process because the central nervous system (CNS) is very sensitive to free-radical damage. Phenolic compounds, mainly oleuropein and its major metabolite hydroxytyrosol, derived from olives and virgin olive oil, have been shown to exert important anticancer activities both in vitro and in vivo due to their antioxidant properties. The present study analyzes the effects of the oral administration of oleuropein, hydroxytyrosol and the mixture of both phenolic compounds in rats with transplacental N-ethyl-N-nitrosourea (ENU)-induced brain tumors to analyze their potential effect against brain tumorigenesis through the modification of redox system components. Oxidative stress parameters, non-enzyme and enzyme antioxidant defense systems and blood chemistry were assayed in the different experimental groups. The treatment with oleuropein, hydroxytyrosol and/or the mixture of both phenolic compounds promotes a limited beneficial effect as anticancer compounds in our ENU-induced animal model of brain tumor. These effects occur via redox control mechanisms involving endogenous enzymatic and non-enzymatic antioxidant defense systems, and are highly dependent on the gender of the animals.

Journal of Food Quality Evaluation of Effect of Extraction Solvent on Selected Properties of Olive Leaf Extract

The quest for natural preservatives and functional foods with health benefits has seen an increasing demand for natural products having therapeutic value. Herein, we investigated the influence of ethanol, methanol, acetone (50%, 70%, and 90% v/v), and distilled water on selected properties of olive leaf extract and determined the yield, total phenolic content (TPC), antioxidant activity, and antimicrobial activity. Extracts were analyzed for their oleuropein, hydroxytyrosol, and tyrosol contents by high-performance liquid chromatography (HPLC). The highest extraction yield of 20.41% was obtained when using 90 vol% methanol, while the highest total polyphenol contents of 232 and 231 mggallic-acid-equivalent/100 g were obtained for 90 vol% methanol and 90 vol% ethanol, respectively. Antioxidant activity was determined using the α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging assay, by determining the ferric reducing antioxidant power (FRAP), and using the Fe2+-chelating activity assay, which provided the highest values when 90 vol% methanol was used (33.84%, 0.75, and 12.91%, respectively). HPLC analysis showed that the highest oleuropein contents corresponded to the extracts obtained using 90 and 70 vol% methanol (26.10 ± 0.20 and 24.92 ± 1.22 g/L, respectively), and the highest antimicrobial activity was observed for 90 vol% methanol and distilled water. Olive leaf extracts using 90 vol% methanol had high levels of polyphenols and were highly antioxidant and antimicrobial. The results of this study facilitate the commercial applications of natural extracts with antioxidant and antibacterial activities and are expected to establish a foundation for further optimization studies.

Gender Differences in the Antioxidant Response to Oxidative Stress in Experimental Brain Tumors

Background:

Brain tumorigenesis is related to oxidative stress and a decreased response of antioxidant defense systems. As it is well known that gender differences exist in the incidence and survival rates of brain tumors, it is important to recognize and understand the ways in which their biology can differ.

Objective:

To analyze gender differences in redox status in animals with chemically-induced brain tumors.

Methods:

Oxidative stress parameters, non-enzyme and enzyme antioxidant defense systems are assayed in animals with brain tumors induced by transplacental N-ethyl-N-nitrosourea (ENU) administration. Both tissue and plasma were analyzed to know if key changes in redox imbalance involved in brain tumor development were reflected systemically and could be used as biomarkers of the disease.

Results:

Several oxidative stress parameters were modified in tumor tissue of male and female animals, changes that were not reflected at plasma level. Regarding antioxidant defense system, only glutathione (GSH) levels were decreased in both brain tumor tissue and plasma. Superoxide dismutase (SOD) and catalase (CAT) activities were decreased in brain tumor tissue of male and female animals, but plasma levels were only altered in male animals. However, different protein and mRNA expression patterns were found for both enzymes. On the contrary, glutathione peroxidase (GPx) activity showed increased levels in brain tumor tissue without gender differences, being protein and gene expression also increased in both males and female animals. However, these changes in GPx were not reflected at plasma level.

Conclusion:

We conclude that brain tumorigenesis was related to oxidative stress and changes in brain enzyme and non-enzyme antioxidant defense systems with gender differences, whereas plasma did not reflect the main redox changes that occur at the brain level.

The hopeful anticancer role of oleuropein in breast cancer through histone deacetylase modulation

Breast cancer (BC) is one of the most common cancers among women worldwide. Genetic, epigenetic, and environmental factors play a crucial role in BC development. Because epigenetic imbalance occurs earlier than expression in carcinogenesis and is reversible, epigenetic reprogramming strategies could be more useful for cancer prevention and therapy. There is evidence indicating that the use of herbal compounds with low toxicity can offer a real benefit in the prevention or treatment of cancer. Oleuropein (OLE), as a natural polyphenol, has shown the anticancer property in cancers. In this study, we investigated for the first time the link between histone deacetylase (HDAC) and OLE to have an anticancer effect in BC. The potential apoptotic and anti-invasive effects of OLE were tested using MCF-7 cells. Transcript expression of HDAC1 and HDAC4 genes after treatment was determined using quantitative reverse transcription polymerase chain reaction. OLE obviously reduced invasiveness and cell viability and simultaneously induced cell apoptosis in MCF-7 cancer cells. Dose-dependent reduction of HDAC4 was observed, whereas apparent changes could not be observed in HDAC1 expression. The current research indicated that OLE can inhibit proliferation and invasion of cells by inducing apoptosis likely through modulation of an important epigenetic factor, HDAC4, in MCF-7 cells. OLE has the potential to be a therapeutic drug for BC prevention and treatment.

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.

Endophytic Fungus Isolated From Achyrocline satureioides Exhibits Selective Antiglioma Activity-The Role of Sch-642305

Glioblastoma is the most devastating primary brain tumor. Current treatment is palliative, making necessary the development of new therapeutic strategies to offer alternatives to patients. Therefore, endophytes represent an interesting source of natural metabolites with anticancer potential. These microorganisms reside in tissues of living plants and act to improve their growth. Evidence revealed that several medicinal plants are colonized by endophytic fungi producer of antitumor metabolites. Achyrocline satureioides is a Brazilian medicinal plant characterized by its properties against gastrointestinal disturbances, anticancer and antioxidant effects. However, there are no reports describing the endophytic composition of A. satureioides. The present study proposes the isolation of endophytic fungus from A. satureioides, extract preparation, phytochemical characterization and evaluation of its antiglioma potential. Our data showed that crude extracts of endophyte decreased glioma viability with IC50 values of 1.60-1.63 μg/mL to eDCM (dichloromethane extract) and 37.30-55.12 μg/mL to eEtAc (ethyl acetate extract), respectively. Crude extracts induced cell death by apoptosis with modulation of redox status. In order to bioprospect anticancer metabolites, endophytic fungus extracts were subjected to guided fractionation and purification yielded five fractions of each extract. Six of ten fractions showed selective antiproliferative activity against glioma cells, with IC50 values ranged from 0.95 to 131.3 μg/mL. F3DCM (from eDCM) and F3EtAc (from eEtAc) fractions promoted C6 glioma toxicity with IC50 of 1.0 and 27.05 μg/mL, respectively. F3EtAc fraction induced late apoptosis and arrest in G2/M stage, while F3DCM promoted apoptosis with arrest in Sub-G1 phase. Moreover, F3DCM increased antioxidant defense and decreased ROS production. Additionally, F3DCM showed no cytotoxic activity against astrocytes, revealing selective effect. Based on promising potential of F3DCM, we identified the production of Sch-642305, a lactone, which showed antiproliferative properties with IC50 values of 1.1 and 7.6 μg/mL to C6 and U138MG gliomas, respectively. Sch-642305 promoted arrest on cell cycle in G2/M inducing apoptosis. Furthermore, this lactone decreased glioma cell migration and modulated redox status, increasing superoxide dismutase and catalase activities and enhancing sulfhydryl content, consequently suppressing reactive species of oxygen generation. Taken together, these results indicate that metabolites produced by endophytic fungus isolated from A. satureioides have therapeutic potential as antiglioma agent.

Olive tree (Olea europaea L.) leaf as a waste by-product of table olive and olive oil industry: a review

Research into finding new uses for by-products of table olive and olive oil industry are of great value not only to the economy but also to the environment where olives are grown and to the human health. Since leaves represent around 10% of the total weight of olives arriving at the mill, it is worth obtaining high added-value compounds from those materials for the preparation of dietary supplements, nutraceuticals, functional food ingredients or cosmeceuticals. In this review article, olive tree (Olea europaea L.) leaf is reviewed as being a potential inexpensive, renewable and abundant source of biophenols. The importance of this agricultural and industrial waste is emphasised by means of describing its availability, nutritional and therapeutic effects and studies conducted on this field. © 2017 Society of Chemical Industry.

Anti-Inflammatory and Antitumor Effects of Hydroxytyrosol but Not Oleuropein on Experimental Glioma In Vivo. A Putative Role for the Renin-Angiotensin System

Functional roles of the angiotensin peptides of the renin-angiotensin system (RAS) cascade can be analyzed through their corresponding proteolytic regulatory enzymes aspartyl aminopeptidase (ASAP), aminopeptidase A (APA), aminopeptidase B (APB), aminopeptidase N (APN) and insulin-regulated aminopeptidase (IRAP). These enzyme activities generate active or inactive angiotensin peptides that alter the ratios between their bioactive forms, regulating several important processes such as the regulation of cardiovascular functions, body water regulation, normal memory consolidation and retrieval, but also cell growth, differentiation and apoptosis or the inflammatory response. We have previously described that the treatment with hydroxytyrosol but not with oleuropein or with the mixture of both compounds led to the significant inhibition of tumor growth in an in vivo glioma model by mechanisms not only related to redox balance. Using this glioma model, here we analyze the effects of the phenolic compounds oleuropein and hydroxytyrosol in circulating RAS-regulating ASAP, APA, APN, APB and IRAP specific activities and the pro-inflammatory cytokines IL-6 and TNFα to understand the relationship between the antitumor and anti-inflammatory effects of hydroxytyrosol, but not oleuropein, and the components of the RAS. We found that oleuropein increased all the activities analyzed and promoted a pro-inflammatory status, whereas hydroxytyrosol only modified ASAP and IRAP activities and promotes an anti-inflammatory status. When administrated together, oleuropein overrode the effects of hydroxytyrosol. Our results suggest a role for angiotensin III and angiotensin 1-7 in both tumor growth inhibition and anti-inflammatory response promoted by hydroxytyrosol.

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.

Anti-cancer properties of olive oil secoiridoid phenols: a systematic review of in vivo studies

Olive oil phenolic alcohols and their secoiridoid derivatives may prevent cancer.