Oleuropein, the bitter principle of olives, enhances nitric oxide production by mouse macrophages

Alginate-chitosan-microencapsulated tyrosols/oleuropein-rich olive mill waste extract for lipopolysaccharide-induced skin fibroblast inflammation treatment

The Ca2+ ion-driven emulsification-ionotropic gelation method produced chitosan-alginate microspheres (CAMSs) with a narrow particle size distribution (PSD). Particle size distribution and zeta potential studies, as well as spectral electron microscopy, were used to assess the microspheres' physicochemical properties and morphology. The tyrosols (hydroxytyrosol (HT), tyrosol (TY), and oleuropein (OE) were loaded into these microspheres using a polyphenol extract (PPE) from Koroneki olive mill waste (KOMW). The microencapsulation efficiency and loading capacity of microspheres for PPE were 98.8% and 3.9%, respectively. Three simulated fluids, including gastric (pH = 1.2), intestinal (pH = 6.8), and colonic (pH = 7.4), were used to examine how the pH of the releasing medium affected the ability of CAMSs to release bioactive phenols. At a severely acidic pH (1.2, SGF), PPE release is nearly halted, while at pH 6.8 (SCF), release is at its maximum. Additionally, the PPE-CAMPs have ameliorated the endogenous antioxidant content SOD, GST, GPx with significant values from 0.05 to 0.01 in the treated LPS/human skin fibroblast cells. The anti-inflammatory response was appeared through their attenuations activity for the released cytokines TNF-α, IL6, IL1β, and IL 12 with levels significantly from 0.01 to 0.001. Microencapsulation of PPE by CAMPs significantly improved its antioxidant and anti-inflammatory capabilities.

Alvespimycin Exhibits Potential Anti-TGF-β Signaling in the Setting of a Proteasome Activator in Rats with Bleomycin-Induced Pulmonary Fibrosis: A Promising Novel Approach

Idiopathic pulmonary fibrosis (IPF) is an irreversible and life-threatening lung disease of unknown etiology presenting only a few treatment options. TGF-β signaling orchestrates a cascade of events driving pulmonary fibrosis (PF). Notably, recent research has affirmed the augmentation of TGF-β receptor (TβR) signaling via HSP90 activation. HSP90, a molecular chaperone, adeptly stabilizes and folds TβRs, thus intricately regulating TGF-β1 signaling. Our investigation illuminated the impact of alvespimycin, an HSP90 inhibitor, on TGF-β-mediated transcriptional responses by inducing destabilization of TβRs. This outcome stems from the explicit interaction of TβR subtypes I and II with HSP90, where they are clients of this cellular chaperone. It is worth noting that regulation of proteasome-dependent degradation of TβRs is a critical standpoint in the termination of TGF-β signal transduction. Oleuropein, the principal bioactive compound found in Olea europaea, is acknowledged for its role as a proteasome activator. In this study, our aim was to explore the efficacy of a combined therapy involving oleuropein and alvespimycin for the treatment of PF. We employed a PF rat model that was induced by intratracheal bleomycin infusion. The application of this dual therapy yielded a noteworthy impediment to the undesired activation of TGF-β/mothers against decapentaplegic homologs 2 and 3 (SMAD2/3) signaling. Consequently, this novel combination showcased improvements in both lung tissue structure and function while also effectively restraining key fibrosis markers such as PDGF-BB, TIMP-1, ACTA2, col1a1, and hydroxyproline. On a mechanistic level, our findings unveiled that the antifibrotic impact of this combination therapy likely stemmed from the enhanced degradation of both TβRI and TβRII. In conclusion, the utilization of proteasomal activators in conjunction with HSP90 inhibitors ushers in a promising frontier for the management of PF.

Prevention and Treatment of Retinal Vein Occlusion: The Role of Diet-A Review

Retinal vein occlusion (RVO) is the second most common retinal disorder. In comparison to diabetic retinopathy or age-related macular degeneration, RVO is usually an unexpected event that carries a greater psychological impact. There is strong evidence to suggest that cardiovascular diseases are the most common risk factors in this pathology and it has long been known that a higher consumption of fish, nuts, fruits, and vegetables has a protective effect against these types of conditions. In the last several years, interest in plant-based diets has grown in both the general population and in the scientific community, to the point to which it has become one of the main dietary patterns adopted in Western countries. The aim of this review is to investigate the potential impact of macro- and micronutrients on retinal vein occlusion.

Plausibility of natural immunomodulators in the treatment of COVID-19-A comprehensive analysis and future recommendations

The COVID-19 pandemic has inflicted millions of deaths worldwide. Despite the availability of several vaccines and some special drugs approved for emergency use to prevent or treat this disease still, there is a huge concern regarding their effectiveness, adverse effects, and most importantly, their efficacy against the new variants. A cascade of immune-inflammatory responses is involved with the pathogenesis and severe complications with COVID-19. People with dysfunctional and compromised immune systems display severe complications, including acute respiratory distress syndrome, sepsis, multiple organ failure etc., when they get infected with the SARS-CoV-2 virus. Plant-derived natural immune-suppressant compounds, such as resveratrol, quercetin, curcumin, berberine, luteolin, etc., have been reported to inhibit pro-inflammatory cytokines and chemokines. Therefore, natural products with immunomodulatory and anti-inflammatory potential could be plausible targets to treat this contagious disease. This review aims to delineate the clinical trials status and outcomes of natural compounds with immunomodulatory potential in COVID-19 patients along with the outcomes of their in-vivo studies. In clinical trials several natural immunomodulators resulted in significant improvement of COVID-19 patients by diminishing COVID-19 symptoms such as fever, cough, sore throat, and breathlessness. Most importantly, they reduced the duration of hospitalization and the need for supplemental oxygen therapy, improved clinical outcomes in patients with COVID-19, especially weakness, and eliminated acute lung injury and acute respiratory distress syndrome. This paper also discusses many potent natural immunomodulators yet to undergo clinical trials. In-vivo studies with natural immunomodulators demonstrated reduction of a wide range of proinflammatory cytokines. Natural immunomodulators that were found effective, safe, and well tolerated in small-scale clinical trials are warranted to undergo large-scale trials to be used as drugs to treat COVID-19 infections. Alongside, compounds yet to test clinically must undergo clinical trials to find their effectiveness and safety in the treatment of COVID-19 patients.

Oleuropein reduces LPS-induced inflammation via stimulating M2 macrophage polarization

Oleuropein (OLEU) is the most prevalent phenolic component in olive varieties, and it has been considered for its powerful antioxidant properties in therapeutic applications. OLEU has anti-inflammatory properties and performs this property by suppressing inflammatory cells' function and reducing oxidative stress caused by various factors. This study investigated the ability of OLEU to polarize LPS-stimulated murine macrophage (MQ) cell RAW 264.7 into M1/M2 macrophages. As a first step, the cytotoxicity effects of OLEU were evaluated on LPS-stimulated RAW 264.7 cells using the thiazolyl blue (MTT) colorimetric test. Then, cytokines production, gene expression (Real-Time PCR), and functions (Nitrite oxide assay and phagocytosis assay) of OLEU-treated LPS-stimulated RAW 264.7 cells were evaluated. Our findings demonstrated that OLEU could reduce nitrite oxide (NO) production in LPS-stimulated RAW 264.7 cells by downregulating the inducible nitric oxide synthase gene expression. Furthermore, OLEU therapy decreases the expression of M1-associated pro-inflammatory cytokines production (IL-12, IFN-γ, and TNF-α) and genes expression (iNOS, TNF-α) while increasing the M2-associated anti-inflammatory gene expression and cytokines production (IL-10, and TGF-β). Based on the result, OLEU may be considered a potential therapeutic approach for inflammatory diseases due to its possible effects on oxidative stress-related factors, cytokine expression and production, and phagocytosis.

Protective Effect of Olive Oil Microconstituents in Atherosclerosis: Emphasis on PAF Implicated Atherosclerosis Theory

Atherosclerosis is a progressive vascular multifactorial process. The mechanisms underlining the initiating event of atheromatous plaque formation are inflammation and oxidation. Among the modifiable risk factors for cardiovascular diseases, diet and especially the Mediterranean diet (MedDiet), has been widely recognized as one of the healthiest dietary patterns. Olive oil (OO), the main source of the fatty components of the MedDiet is superior to the other "Mono-unsaturated fatty acids containing oils" due to the existence of specific microconstituents. In this review, the effects of OO microconstituents in atherosclerosis, based on data from in vitro and in vivo studies with special attention on their inhibitory activity against PAF (Platelet-Activating Factor) actions, are presented and critically discussed. In conclusion, we propose that the anti-atherogenic effect of OO is attributed to the synergistic action of its microconstituents, mainly polar lipids that act as PAF inhibitors, specific polyphenols and α-tocopherol that also exert anti-PAF activity. This beneficial effect, also mediated through anti-PAF action, can occur from microconstituents extracted from olive pomace, a toxic by-product of the OO production process that constitutes a significant ecological problem. Daily intake of moderate amounts of OO consumed in the context of a balanced diet is significant for healthy adults.

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.

Cardiac hypertrophy and fibrosis were attenuated by olive leaf extract treatment in a rat model of diabetes

The key role of fibrosis and hypertrophy processes in developing diabetes-induced heart injury has been demonstrated. Considering the known hypoglycemic effects of olive leaf extract (OLE), we decided to investigate its potential effect and associated mechanisms on cardiac fibrosis and myocardial hypertrophy in streptozotocin (STZ)-induced diabetic rats. Eight groups were included in this study: control, diabetic, diabetic-OLEs (100, 200 and 400 mg/kg), diabetic-metformin (300 mg/kg), diabetic-valsartan (30 mg/kg), and diabetic-metformin/valsartan (300/30 mg/kg). After a treatment period of 6 weeks, echocardiography was used to assess cardiac function. Heart-to-body weight ratio (HW/BW) and fasting blood sugar (FBS) were measured. Myocardial histology was examined by Masson's trichrome staining. Gene expressions of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), β-myosin heavy chain (β-MHC), TGF-β1, TGF-β3, angiotensin II type 1 receptor (AT1), alpha-smooth muscle actin (α-SMA), and collagen were evaluated by the quantitative real-time PCR in heart tissue. A reduction in the FBS level and HW/BW ratio in the extract groups was obvious. The improvement of left ventricular dysfunction, cardiac myocytes hypertrophy, and myocardial interstitial fibrosis was also observed in treated groups. A lowering trend in the expression of all hypertrophic and fibrotic indicator genes was evident in the myocardium of OLE treated rats. Our data indicated that OLE could attenuate fibrosis and reduce myocardial hypertrophy markers, thus improving the cardiac function and structure in the STZ-induced diabetic rats. PRACTICAL APPLICATIONS: This study demonstrates that olive leaf extract in addition to lowering blood glucose levels and the heart-to-body weight ratio (HW/BW) may also improve cardiac function and reduce cardiac hypertrophy and fibrosis in cardiac tissue, which leads to inhibition of diabetic heart damage. Thus it is possible that including olive leaf extracts in the diets of individuals with diabetes may assist in lowering cardiovascular disease risk factors.

Olive oil intake and cancer risk: A systematic review and meta-analysis

BACKGROUND

Research evidence has established the beneficial effects of diet in cancer prevention; various epidemiological studies have suggested that olive oil component could play a role in decreasing cancer risk. This systematic review and meta-analysis aims to investigate the association between olive oil consumption, cancer risk and prognosis.

METHODS

A systematic search was conducted in PubMed, EMBASE and Google Scholar databases (end-of-search: May 10, 2020). Pooled relative risk (RR) and 95% confidence intervals (95% CIs) were estimated with random-effects (DerSimonian-Laird) models. Subgroup analyses, sensitivity analyses and meta-regression analysis were also performed.

RESULTS

45 studies were included in the meta-analysis; 37 were case-control (17,369 cases and 28,294 controls) and 8 were cohort studies (12,461 incident cases in a total cohort of 929,771 subjects). Highest olive oil consumption was associated with 31% lower likelihood of any cancer (pooled RR = 0.69, 95%CI: 0.62-0.77), breast (RR = 0.67, 95%CI: 0.52-0.86), gastrointestinal (RR = 0.77, 95%CI: 0.66-0.89), upper aerodigestive (RR = 0.74, 95%CI: 0.60-0.91) and urinary tract cancer (RR = 0.46, 95%CI: 0.29-0.72). Significant overall effects spanned both Mediterranean and non-Mediterranean participants, studies presenting a multivariate and a univariate analysis and all subgroups by study quality.

CONCLUSIONS

Olive oil consumption seems to exert beneficial actions in terms of cancer prevention. Additional prospective cohort studies on various cancer types and survivors, as well as large randomized trials, seem desirable.

Green Synthesis of Silver Nanoparticles Using Olea europaea Leaf Extract for Their Enhanced Antibacterial, Antioxidant, Cytotoxic and Biocompatibility Applications

Herein, we report the green synthesis of silver nanoparticles (OE-Ag NPs) by ecofriendly green processes using biological molecules of Olea europaea leaf extract. Green synthesized OE-Ag NPs were successfully characterized using different spectroscopic techniques. Antibacterial activity of OE-Ag NPs was assessed against four different bacteriological strains using the dilution serial method. The cytotoxic potential was determined against MCF-7 carcinoma cells using MTT assay in terms of cell viability percentage. Antioxidant properties were evaluated in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging. Biocompatibility was further examined by incubating the synthesized NPs with hMSC cells for 24 h. The results were demonstrated that synthesized OE-Ag NPs presented excellent log10 reduction in the growth of all the tested bacterial strains, which as statistically equivalent (p > 0.05) to the standard antibiotic drug. Moreover, they also demonstrated excellent cytotoxic efficacy against the MCF-7 carcinoma cells compared to plant lead extract and Com-Ag NPs. Green synthesized OE-Ag NPs appeared more biocompatible to hMSC and 293T cells compared to Com-Ag NPs. Excellent biological results of the OE-Ag NPs might be attributed to the synergetic effect of NPs' properties and the adsorbed secondary metabolites of plant leaf extract. Hence, this study suggests that synthesized OE-Ag NPs can be a potential contender for their various biological and nutraceutical applications. Moreover, this study will open a new avenue to produce biocompatible nanoparticles with additional biological functionalities from the plants.

Oleuropin controls miR-194/XIST/PD-L1 loop in triple negative breast cancer: New role of nutri-epigenetics in immune-oncology

Oleuropein, the main secoiridoid glucoside found in Olea europaea L., has attracted scientific community as a potential anticancer agent. Immunotherapy and RNA interference revolutionized cancer treatment. Success of PD-L1/PD-1 antibodies encouraged the investigation of PD-1/PD-L1 regulation by non-coding RNAs. This study aimed to verify the cytotoxic effect of oleuropein on MDA-MB-231 cell line and to unravel novel ceRNA interaction between miR-194-5p and XIST in breast cancer and their immunomodulatory effect on PD-L1 expression to propose a promising prophylactic and preventive role of Oleuropin in diet. For the first time, miR-194/Lnc-RNA XIST/PD-L1 triad was investigated in breast cancer, where miR-194 and PD-L1 levels were significantly upregulated in 21 BC-biopsies, yet XIST was downregulated. Ectopic expression of miR-194 enhanced cell function and viability with concomitant increase in PD-L1 expression yet XIST expression decreased, in contrast to miR-194 antagomirs that yielded opposite results. XIST knock-out elevated miR194-5p and PD-L1 levels. miR-194-5p mimics and XIST siRNAs co-transfection induced PD-L1 expression, while miR-194-5p mimics and TSIX siRNAs co-transfection showed opposite effect. Oleuropein showed anti-carcinogenic impact by decreasing miR-194 and PD-L1 levels while increasing XIST level. In conclusion, our study highlighted novel ceRNA interaction controlling PD-L1 expression in BC. Oleuropein is a promising nutraceutical for cancer therapy. Therefore, oleuropin represents a new nutri-epigenetic in immune-oncology that controls miR-194/XIST/PD-L1 loop in triple negative breast cancer.

Effect of fortified feed with olive leaves extract on the haematological and biochemical parameters of Oreochromis niloticus (Nile tilapia)

Olive leaves have been used traditionally to improve the immunity against several infections. Current study aimed to examine the effect of fortified feed with olive leaves extract on haematological and biochemical parameters of Oreochromis niloticus. Total 400 healthy fish were divided randomly into four groups and were cultured for two months in glass tanks of 250 L water capacity in triplicate. Fortified feed was prepared with various extract, 1%, 1.5% and 2% concentration in diet, while, control-group diet was without extraction. Results showed that all the haematological parameters including WBC, RBC, Hb, PCV and plasma protein were significantly increased while the biochemical parameters such as globulin albumen ratio increased in fish which fed on 1% of extract, but the level of cholesterol and triglycerides was decreasing by increasing the concentration of extract. It was concluded that olive leaves extract can be used to enhance the immunity, growth and health of fish.

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.

Antioxidant Effects of Oleuropein on Hydrogen Peroxide-Induced Neuronal Stress- An In Vitro Study

Background

Persistent oxidative stress can lead to chronic inflammation and mediate most chronic diseases including neurological disorders. Oleuropein has been shown to be a potent antioxidant molecule in olive oil leaf having antioxidative properties.

Objective

The aim of this study was to investigate the protective effects of oleuropein against oxidative stress in human glioblastoma cells.

Methods

Human glioblastoma cells (U87) were pretreated with oleuropein (OP) essential oil 10 µM. After 30 minutes, 100 µM H₂O₂ was added to the cells for three hours. Cell survival was quantified by colorimetric MTT assay. Glutathione level, total oxidant capacity, total antioxidant capacity and nitric oxide levels were determined by using specific spectrophotometric methods. The relative gene expression level of iNOS was performed by qRT-PCR method.

Results

According to viability results, the effective concentration of H₂O₂ (100µM) significantly decreased cell viability and oleuropein pretreatment significantly prevented the cell losses. Oleuropein regenerated total antioxidant capacity and glutathione levels decreased by H₂O₂ exposure. In addition, nitric oxide and total oxidant capacity levels were also decreased after administration of oleuropein in treated cells.

Conclusion

Oleuropein was found to have potent antioxidative properties in human glioblastoma cells. However, further studies and validations are needed in order to understand the exact neuroprotective mechanism of oleuropein.

Dual prophylactic/therapeutic potential of date seed, and nigella and olive oils-based nutraceutical formulation in rats with experimentally-induced Alzheimer's disease: A mechanistic insight

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with a multifactorial etiology and significantly increasing incidence during the last decade. Hence, developing an effective therapy is crucial for public health. The current study aimed to examine the dual prophylactic/therapeutic potential of a nutraceutical formula based on aqueous extract of roasted date seeds, and nigella and virgin-olive oils against experimentally-induced Alzheimer's disease in rats. Alzheimer's disease-like pathology was induced in male Wistar rats using oral CuSO₄ (200 mg/Kg/day for two months). The nutraceutical formula was given orally to experimental animals (10 mL/kg/d) for 14 days before (as prophylaxis) and after Alzheimer's disease induction and its therapeutic effect in both cases is tested in comparison to donepezil (0.5 mg/kg/d). The nutraceutical formula was found to ameliorate the CuSO₄-induced neuronal damage and regenerate the affected hippocampus tissue and significantly improvemed in learning ability. The formula was also effective in decreasing brain amyloid-β, tau protein, TNF-α level, iNOS level in hippocampus, oxidative stress level, and inhibiting acetylcholinesterase activity and expression in brain and hippocampus, respectively. Further, an increase in GSH levels, activities of SOD, and GST and levels of hippocampus ADAM 17 and brain phospholipids was observed. In conclusion, the studied nutraceutical formula is proved to be effective in ameliorating Alzheimer's neurodegenerative progression with added-prophylactic potential.

Invasive and non-invasive therapies for Alzheimer's disease and other amyloidosis

Advancements in medical science have facilitated in extending human lives. The increased life expectancy, though, has come at a cost. The cases of an aging population suffering from degenerative diseases like Alzheimer's disease (AD) are presently at its all-time high. Amyloidosis disorders such as AD are triggered by an abnormal transition of soluble proteins into their highly ordered aggregated forms. The landscape of amyloidosis treatment remains unchanged, and there is no cure for such disorders. However, an increased understanding of the mechanism of amyloid self-assembly has given hope for a possible therapeutic solution. In this review, we will discuss the current state of molecular and non-molecular options for therapeutic intervention of amyloidosis. We highlight the efficacy of non-invasive physical therapies as possible alternatives to their molecular counterparts. Graphical abstract.

Syringoleosides A-H, Secoiridoids from Syringa dilatata Flowers and Their Inhibition of NO Production in LPS-Induced RAW 264.7 Cells

Repeated column chromatography of Syringa dilatata flowers, a native shrub to Korea, led to the isolation of eight new oleoside-type secoiridoids, syringoleosides A-H (1-8), as well as five known secoiridoids (9-13). The new chemical structures were identified through spectroscopic data analysis, as well as the application of chemical methods. Compounds 1, 2, 6, 7, 11, and 13 showed suppression effects on NO production in LPS-induced RAW 264.7 cells, with IC₅₀ values ranging from 32.5 ± 9.8 to 65.7 ± 11.0 μM, and no visible toxicity. The content of the major secoiridoids in S. dilatata flowers, compounds 1, 4, 5, 8, 9, 12, and 13, were determined through HPLC analysis.

Olive Tree Leaves—A Source of Valuable Active Compounds

The agricultural and processing activities of olive crops generate a substantial amount of food by-products, particularly olive leaves, which are mostly underexploited, representing a significant threat to the environment. Olive leaves are endowed with endogenous bioactive compounds. Their beneficial/health-promoting potential, together with environmental protection and circular economy, merit their exploitation to recover and reuse natural components that are potentially safer alternatives to synthetic counterparts. These biomass residues have great potential for extended industrial applications in food/dietary systems but have had limited commercial uses so far. In this regard, many researchers have endeavoured to determine a green/sustainable means to replace the conventional/inefficient methods currently used. This is not an easy task as a sustainable bio-processing approach entails careful designing to maximise the liberation of compounds with minimum use of (i) processing time, (ii) toxic solvent (iii) fossil fuel energy, and (iv) overall cost. Thus, it is necessary to device viable strategies to (i) optimise the extraction of valuable biomolecules from olive leaves and enable their conversion into high added-value products, and (ii) minimise generation of agro-industrial waste streams. This review provides an insight to the principal bioactive components naturally present in olive leaves, and an overview of the existing/proposed methods associated with their analysis, extraction, applications, and stability.

Thermochemical Conversion of Olive Oil Industry Waste: Circular Economy through Energy Recovery

The demand for new sources of energy is one of the main quests for humans. At the same time, there is a growing need to eliminate or recover a set of industrial or agroforestry waste sources. In this context, several options may be of interest, especially given the amounts produced and environmental impacts caused. Olive pomace can be considered one of these options. Portugal, as one of the most prominent producers of olive oil, therefore, also faces the problem of dealing with the waste of the olive oil industry. Olive pomace energy recovery is a subject referenced in many different studies and reports since long ago. However, traditional forms of recovery, such as direct combustion, did not prove to be the best solution, mainly due to its fuel properties and other characteristics, which cause difficulties in its storage and transportation as well. Torrefaction and pyrolysis can contribute to a volume reduction, optimizing storage and transportation. In this preliminary study, were carried out torrefaction and pyrolysis tests on olive pomace samples, processed at 300 °C, 400 °C, and 500 °C, followed by laboratory characterization of the materials. It was verified an improvement in the energy content of the materials, demonstrating that there is potential for the use of these thermochemical conversion technologies for the energy recovery of olive pomace.

Is Extra Virgin Olive Oil an Ally for Women's and Men's Cardiovascular Health?

Noncommunicable diseases are long-lasting and slowly progressive and are the leading causes of death and disability. They include cardiovascular diseases (CVD) and diabetes mellitus (DM) that are rising worldwide, with CVD being the leading cause of death in developed countries. Thus, there is a need to find new preventive and therapeutic approaches. Polyphenols seem to have cardioprotective properties; among them, polyphenols and/or minor polar compounds of extra virgin olive oil (EVOO) are attracting special interest. In consideration of numerous sex differences present in CVD and DM, in this narrative review, we applied "gender glasses." Globally, it emerges that olive oil and its derivatives exert some anti-inflammatory and antioxidant effects, modulate glucose metabolism, and ameliorate endothelial dysfunction. However, as in prescription drugs, also in this case there is an important gender bias because the majority of the preclinical studies are performed on male animals, and the sex of donors of cells is not often known; thus a sex/gender bias characterizes preclinical research. There are numerous clinical studies that seem to suggest the benefits of EVOO and its derivatives in CVD; however, these studies have numerous limitations, presenting also a considerable heterogeneity across the interventions. Among limitations, one of the most relevant in the era of personalized medicine, is the non-attention versus women that are few and, also when they are enrolled, sex analysis is lacking. Therefore, in our opinion, it is time to perform more long, extensive and lessheterogeneous trials enrolling both women and men.

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.

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.

Protective Effects Induced by Two Polyphenolic Liquid Complexes from Olive (Olea europaea, mainly Cultivar Coratina) Pressing Juice in Rat Isolated Tissues Challenged with LPS

MOMAST^(®) HY100 and MOMAST^(®) HP30 are polyphenolic liquid complexes from olive pressing juice with a total polyphenolic content of 100 g/kg (at least 50% as hydroxytyrosol) and 36 g/kg (at least 30% as hydroxytyrosol), respectively. We investigated the potential protective role of MOMAST^(®) HY100 and MOMAST^(®) HP30 on isolated rat colon, liver, heart, and prefrontal cortex specimens treated with Escherichia coli lipopolysaccharide (LPS), a validated ex vivo model of inflammation, by measuring the production of prostaglandin (PG)E₂, 8-iso-PGF_2α, lactate dehydrogenase (LDH), as well as cyclooxygenase (COX)-2, tumor necrosis factor α (TNFα), and inducible nitric oxide synthase (iNOS) mRNA levels. MOMAST^(®) HY100 decreased LPS-stimulated PGE₂ and LDH levels in all tested tissues. Following treatment with MOMAST^(®) HY100, we found a significant reduction in iNOS levels in prefrontal cortex and heart specimens, COX-2 and TNFα mRNA levels in heart specimens, and 8-iso-PGF_2α levels in liver specimens. On the other hand, MOMAST^(®) HP30 was found to blunt COX-2, TNFα, and iNOS mRNA levels, as well as 8-iso-PGF_2α in cortex, liver, and colon specimens. MOMAST^(®) HP30 was also found to decrease PGE₂ levels in liver specimens, while it decreased iNOS mRNA, LDH, and 8-iso-PGF_2α levels in heart specimens. Both MOMAST^(®) HY100 and MOMAST^(®) HP30 exhibited protective effects on multiple inflammatory and oxidative stress pathways.

Are plants used in the Eastern Cape province for cosmetics fully commercialized?

Plants have been used for years for various cosmetic purposes. In the Eastern Cape province of South Africa, a large proportion of the population reliant (to some extent) on botanical resources for beauty and health. Despite the use of these botanical resources for various cosmetic purposes, only a few have been fully commercialized or used as ingredients in cosmetic formulation. The present study aimed to review plant species that are fully explored commercially for cosmetic products in the Eastern Cape province. A survey of cosmetic products with plant-based ingredients was done covering the major supermarkets (SPAR, Shoprite, and Pick n Pay), cosmetic shops (Clicks), and pharmacies in the Eastern Cape province, and electronic databases including Embase, Google Scholar, Medline, PubMed, Scopus, SciFinder^®, Springer, Science Direct, and Web of Science were used as data sources for ethnobotanical information. Surprisingly, out of 150 plant species used by both Xhosa men and women for various cosmeceutical purposes, only six plant species have been used commercially with regard to cosmeceutical application. These plants species belong to five major plant families, namely Lamiaceae (two species), Asphodelaceae (one species) Cucurbitaceae (one species), Oleaceae (one species), and Verbenaceae (one species). The findings revealed that the use of Eastern Cape plants for cosmetic purposes has not been fully explored commercially. Thus, there is a need for cosmeceutical industries to explore these species commercially in order to develop new possible cosmetic products for local and international markets.

Bioactive potential of fruit and vegetable wastes

Fruits and vegetables are essential for human nutrition, delivering a substantial proportion of vitamins, minerals, and fibers in our daily diet. Unfortunately, half the fruits and vegetables produced worldwide end up as wastes, generating environmental issues caused mainly by microbial degradation. Most wastes are generated by industrial processing, the so-called by-products. These by-products still contain many bioactive compounds post-processing, such as macronutrients (proteins and carbohydrates) and phytochemicals (polyphenols and carotenoids). Recently, the recovery of these bioactive compounds from industry by-products has received significant attention, mainly due to their possible health benefits for humans. This chapter focuses on the bioactive potential of fruit and vegetable by-products with possible applications in the food industry (functional foods) and in the health sector (nutraceuticals).

Dietary supplementation of olive leaf extract increases haematological, serum biochemical parameters and immune related genes expression level in common carp (Cyprinus carpio) juveniles

The present study investigated the effects of dietary olive leaf (Olea europea L.) extract (OLE) on some blood parameters and immune (TNF-α, IL-1ß and IL-8) related genes in different tissues (head kidney, liver and spleen) and resistance of common carp, Cyprinus carpio to Edwardsiella tarda. Five diets were prepared for fed fish (mean body weight 15.90 ± 0.93 g) with different rates of OLE (0.0%, 0.1%, 0.25%, 0.50% and 1.0%). A control diet was prepared non-supplemented with OLE. Increased haematocrit ratio, serum myeloperoxidase activity, immune response gene levels (IL-1β in head kidney tissue and TNF-α in spleen tissue) and survival rate against E. tarda particularly in the 0.1% OLE treatment group. In conclusion, results of the present study show that feeding common carp with a diet containing 1 g/kg OLE over a period of 60 days might be adequate to improve fish immune parameters, and survival rate against E. tarda. Therefore, OLE can be used as a dietary additive to prevent E. tarda in common carp.

Pro-Apoptotic and Anti-Angiogenesis Effects of Olive Leaf Extract on Spontaneous Mouse Mammary Tumor Model by Balancing Vascular Endothelial Growth Factor and Endostatin Levels

It has been proven that olive associated products such as olive leaf extract (OLE) causes significant reduction in cancer cells viability and proliferation. Female BALB/c adult mice were divided into four groups. Three days prior to oral treatments, tumors were transplanted. First group were treated with distilled water and other three groups were received, respectively, 75, 150, and 225 mg/kg/day of OLE for three weeks. For assessment of anti-angiogenesis and pro-apoptotic effect of OLE on tumor tissue, tumor volume, cell mitosis and apoptosis, and also vascular endothelial growth factor (VEGF) and endostatin levels were assessed. OLE treatment with 150 and 225 mg/kg/day lead to significant reduction in tumor volume and cell mitosis compared with the control group, while the same doses significantly increase tumor cell apoptosis. OLE treatment with 150 mg/kg/day increase endostatin levels, while the same dose did not significantly decrease VEGF levels. The VEGF level is significantly reduced by the treatment with OLE 225 mg/kg/day for three weeks. Although, further studies are needed to clarify anti-angiogenesis and anti-apoptotic mechanism of OLE, consumption of OLE polyphenols after tumor transplantation reduced spontaneous mouse mammary tumor growth.

The in vitro Immunomodulatory Activity of Oleuropein, a Secoiridoid Glycoside from Olea europaea L

Oleuropein, a secoiridoid glycoside, is a potential antioxidant and antimicrobial agent. The aim of the present study was to investigate the in vitro effects of oleuropein and Olea europaea extracts on unstimulated lymphocytes. Oleuropein did not produce any significant cytotoxic effects on lymphocytes. On the contrary, it had a stimulatory effect, and was capable of inducing and maintaining high proliferation rates in lymphocytes. The stimulatory effects of oleuropein and extracts were concentration-dependent with a range of median stimulatory concentration 1 mM at 48 h. The cytotoxicity effect of oleuropein and extracts increased with time resulting in a greater cytotoxic effect on already-stimulated lymphocytes at 96 h even though dose dependence was not demonstrated. Morphological observations showed that oleuropein and extracts induced blastogenesis similar to that of phytohaemagglutinin (PHA). In fact, from lymphocyte activation studies, oleuropein exhibited a high degree of lymphocyte aggregation, which is an indicator of cell activation and proliferation.

The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial

Upper respiratory illness (URI) has a major impact on both training and competition in an athletic setting. High school athletes are a sub-category who have reported higher illness rates than professional and sub-elite high school athletes of the same sport. Olive leaf extract (OLE) is an over-the-counter supplement that contains polyphenols, notably oleuropein and hydroxytyrosol, that have antiviral, antibacterial, anti-inflammatory and antioxidant properties that may reduce URI rates. Thirty-two high school students who play sport for the elite team at their school were recruited to a randomised controlled trial and allocated to a daily placebo or OLE (extent equivalent to 20 g of olive leaf, containing 100 mg oleuropein) supplementation for nine weeks during their competitive season. Twice weekly measures of wellbeing, training load and respiratory illness (sporting upper respiratory illness (SUPPRESS) questionnaire) were recorded at trainings, meetings or games. There was no significant difference in illness incidence (odds ratio (OR): 1.02 (95% confidence interval (CI) 0.21–4.44)), but there was a significant 28% reduction in sick days (OR: 0.72 (95% CI 0.56–0.93) p-value = 0.02) when supplemented with OLE. The dietary intakes of the athletes were sub-optimal with regard to immune support. OLE supplementation over a season did not significantly reduce URI incidence, but did decrease duration in high school athletes, potentially aiding return to play.

Isolation of an antiviral compound from Tunisian olive twig cultivars

(1) Many studies demonstrated that olive oil and the leaves have several biological activities, but the works on olive twigs remain very limited. In this report, we investigated for anti-coxsackievirus B-3 (CVB-3) and anti-herpes virus type 2 (HSV-2) activities of olive twigs from two Tunisian varieties: Chemlali (CM) and Chétoui (CT). Extraction from the olive twigs was carried out using successively hexane, dichloromethane, ethyl acetate and methanol. The obtained extracts were evaluated for their anti-CVB-3 and anti-HSV-2 activities by MTT and plaque reduction assays, respectively. Only hexane extracts exhibited significant activity with a selectivity index of 6.32±0.67 and 5.24±0.82 for CM and CT, respectively. The active compound was isolated through bio-guided assays using Thin Layer Chromatography (TLC) and identified as 2,4-di-tert-butylphenol (2,4-DTBP) by gas chromatography coupled with mass spectrometry (GC-MS). This work is the first study that demonstrated an antiviral activity of both olive twigs and DTBP.

Potential Health Benefits of Olive Oil and Plant Polyphenols

Beneficial effects of natural plant polyphenols on the human body have been evaluated in a number of scientific research projects. Bioactive polyphenols are natural compounds of various chemical structures. Their sources are mostly fruits, vegetables, nuts and seeds, roots, bark, leaves of different plants, herbs, whole grain products, processed foods (dark chocolate), as well as tea, coffee, and red wine. Polyphenols are believed to reduce morbidity and/or slow down the development of cardiovascular and neurodegenerative diseases as well as cancer. Biological activity of polyphenols is strongly related to their antioxidant properties. They tend to reduce the pool of reactive oxygen species as well as to neutralize potentially carcinogenic metabolites. A broad spectrum of health-promoting properties of plant polyphenols comprises antioxidant, anti-inflammatory, anti-allergic, anti-atherogenic, anti-thrombotic, and anti-mutagenic effects. Scientific studies present the ability of polyphenols to modulate the human immune system by affecting the proliferation of white blood cells, and also the production of cytokines or other factors that participate in the immunological defense. The aim of the review is to focus on polyphenols of olive oil in context of their biological activities.

NHC catalyzed enantioselective Coates-Claisen rearrangement: a rapid access to the dihydropyran core for oleuropein based secoiridoids

A simple protocol for the synthesis of the dihydropyran core structure of secoiridoids using NHC catalyzed Coates-Claisen rearrangement is described.

Self-assembly of collagen-based biomaterials: preparation, characterizations and biomedical applications

By combining regulatory parameters with characterization methods, researchers can selectively fabricate collagenous biomaterials with various functional responses for biomedical applications.

Biogenic synthesis of copper oxide nanoparticles using olea europaea leaf extract and evaluation of their toxicity activities: An in vivo and in vitro study

Copper oxide nanoparticles (CUNPs) were synthesized using Olea europaea leaf extract as reducing and protecting agent. The formation of nanoparticles was observed through a color change from yellowish to brownish black. The CUNPs were confirmed with UV-Vis spectrophotometer, which revealed a peak absorbance at 289 nm. The synthesized CUNPs were characterized by XRD, FTIR, SEM, and TEM. The XRD pattern revealed that CUNPs were crystalline in nature with a diameter around 20 nm. FTIR spectral analysis showed that CUNPs were capped with plant constituents. From SEM and TEM analyses, the CUNPs were generally found to be spherical in shape, and the size range was 20-50 nm. Free radical scavenging potential of CUNPs against DPPH was confirmed by its stable antioxidant effects. In addition, the toxicity of CUNPs in mice was also assessed by body weight and weights of liver, kidneys, spleen, and thymus. The immune response in mice was signaled through an obvious change in spleen and thymus index, with a decrease of ADA enzyme activity in serum, spleen, and thymus after CUNPs treatment. The CUNPs were found to exert cell growth arrest against AMJ-13 and SKOV-3 cancer cells in a dose-dependent manner and induce cell death by apoptosis. Less significant cytotoxic effect was observed in normal dermal fibroblast cells. These findings suggest that CUNPs may have the potential to be anticancer agents. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:218-230, 2018.

Amyloid beta: structure, biology and structure-based therapeutic development

Amyloid beta peptide (Aβ) is produced through the proteolytic processing of a transmembrane protein, amyloid precursor protein (APP), by β- and γ-secretases. Aβ accumulation in the brain is proposed to be an early toxic event in the pathogenesis of Alzheimer's disease, which is the most common form of dementia associated with plaques and tangles in the brain. Currently, it is unclear what the physiological and pathological forms of Aβ are and by what mechanism Aβ causes dementia. Moreover, there are no efficient drugs to stop or reverse the progression of Alzheimer's disease. In this paper, we review the structures, biological functions, and neurotoxicity role of Aβ. We also discuss the potential receptors that interact with Aβ and mediate Aβ intake, clearance, and metabolism. Additionally, we summarize the therapeutic developments and recent advances of different strategies for treating Alzheimer's disease. Finally, we will report on the progress in searching for novel, potentially effective agents as well as selected promising strategies for the treatment of Alzheimer's disease. These prospects include agents acting on Aβ, its receptors and tau protein, such as small molecules, vaccines and antibodies against Aβ; inhibitors or modulators of β- and γ-secretase; Aβ-degrading proteases; tau protein inhibitors and vaccines; amyloid dyes and microRNAs.

Extração de oleuropeína a partir de folhas de oliveira utilizando solvente hidroalcoólico

Resumo Folhas de oliveira contêm oleuropeína, um composto fenólico conhecido por seu potencial antioxidante, antimicrobiano, anti-inflamatório, entre outros. Este trabalho teve como objetivo estudar a extração da oleuropeína, utilizando solvente hidroalcoólico. Folhas de oliveira (FO) foram maceradas a 25 °C com um solvente (S), formado por uma mistura de etanol e água (70:30 v/v), nas proporções FO:S iguais a 1:8, 1:6 e 1:3, em massa, com ou sem a presença de ácido acético. Observou-se que o maior teor de oleuropeína no extrato liofilizado (18 g/100 g, aproximadamente) foi obtido no procedimento utilizando a razão FO:S = 1:3, com ácido acético. Por fim, foi realizado um teste para verificar o efeito do extrato liofilizado sobre o tempo de indução em amostras de azeite de oliva extravirgem e refinado, verificando-se um aumento de três e duas horas, respectivamente. Concluiu-se que é possível obter extratos de folhas de oliveira utilizando solventes renováveis e que a oleuropeína pode atuar como um antioxidante natural no azeite, melhorando sua estabilidade oxidativa.

Olive Polyphenols and the Metabolic Syndrome

Here, the effects of consuming polyphenol-rich olive products, including olive leaves, their crude extract, and extra virgin olive oil, on aspects of the metabolic syndrome are reviewed. We have sought to summarize the available scientific evidence from dietary intervention trials demonstrating a role for these phytochemicals in ameliorating aberrant glucose metabolism, high blood pressure and elevated blood lipids, and we discuss the potential mechanisms underpinning these observations. Searches for relevant literature published in English were conducted via PubMed and Science Direct. Based on published dietary intervention studies, there is convincing evidence to show that olive polyphenols, independently of olive lipids, reduce risk factors for metabolic syndrome, in particular by improving blood sugar and blood pressure control, and in reducing low density lipoprotein oxidation. There is more limited evidence to suggest that the consumption of olive polyphenols or related products can reduce body weight and visceral fat or impede weight gain, and similarly there are some limited data suggesting improved lipid profiles. There is some mechanistic data to support observations made in human volunteers, but further work is needed in this area. The consumption of olive polyphenols within the context of a healthy pattern of food intake may, in part, explain the reduced risk of metabolic disease associated with adherence to the Mediterranean diet.

Olive (Olea europaea) leaf methanolic extract prevents HCl/ethanol-induced gastritis in rats by attenuating inflammation and augmenting antioxidant enzyme activities

Gastritis is preponderantly characterized by inflammation of the lining epithelial layer and the chronic gastritis is considered as a pre-cancer lesion. For many centuries olive (Olea europaea) leaf has been used for its putative health potential, nonetheless, to date, the gastroprotective effects of olive leaves have not been studied yet. Hence, in this study we investigated whether olive leaf extract (OLE) could protect gastric mucosa against HCl/ethanol-induced gastric mucosal damage in rats. Hcl/ethanol administration caused significant damage to the gastric mucosa, as confirmed by gastric ulcer index and histological evaluation. However, this damage was largely prevented by pre-administering 20mg/kg omeprazole or 100mg/kg OLE. Interestingly, the damage was completely prevented by pre-administering 200 and 300mg/kg OLE. Moreover, OLE attenuated the inflammatory response by decreasing nuclear factor-κB (NF-κB), cycloxygenase-2 (COX-2) and tumor necrosis factor-α (TNF-α) expressions, and down-regulating inducible nitric oxide synthase (iNOS) and interleukin-1β (IL-1β) in gastric mucosa. The gastroprotective mechanism of OLE involved the promotion of enzymatic and nonenzymatic molecules (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione reduced form), promoting nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA expression, halting lipid peroxidation and preventing the overproduction of nitric oxide. Together, our findings clearly demonstrated that OLE could prevent HCl/ethanol-induced gastritis by attenuating inflammation and oxidant/antioxidant imbalance. Indeed, OLE could potentially be useful as a natural therapy for gastritis.

Exploiting oleuropein for inhibiting collagen fibril formation

Collagen fibrils accumulate in excessive amounts and impair the normal functioning of the organ; therefore it stimulates the interest for identifying the compounds that could prevent the formation of fibrils. Herein, inhibition of self-assembly of collagen using oleuropein has been studied. The changes in the physico-chemical characteristics of collagen on interaction with increasing concentration of oleuropein has been studied using techniques like viscosity, UV-vis, CD and FT-IR. The inhibitory effect of oleuropein on fibril formation of collagen was proved using SEM. Circular dichroism and FT-IR spectra elucidates the alterations in the secondary structure of collagen suggesting non-covalent interactions between oleuropein and collagen. The decreased rate of collagen fibril formation also confirms the inhibition in the self-assembly of collagen. Hence, our study suggests that inhibition of the self-assembly process using oleuropein may unfold new avenues to treat fibrotic diseases.

Microchannels Effective Method for the Extraction of Oleuropein Compared with Conventional Methods

Different methods of oleuropein extraction from olive leaf were investigated, including maceration, soxhlet, ultrasonic-assisted extraction, and microchannel. In current research, a response surface methodology (RSM) was used for prediction of the optimal values of parameters affecting the extraction of oleuropein through two methods of ultrasound and microchannel. Frequency (F), temperature (T), and power of ultrasound (P) were the parameters which were studied in ultrasound method, but in microchannel system effects of pH and temperature (T), volumetric flow rate ratio of two phases (VR), and contact time (CT) of two phases were optimized. UV detector device at 254 nm was used to recognize oleuropein through comparison of the retention time of the extracts with standard compound in chromatogram. The analysis of extracts was performed using HPLC. Optimum conditions for ultrasound were obtained as follows:F=80 kHz,T= 25°C, andP=100 w. Using these optimum conditions, the extraction of oleuropein was 81.29%. Amount of oleuropein extraction by microchannel method in optimum conditions was 96.29%, which was way more than other applied methods. Microchannel system as a continuous method has many advantages including low solvent consumption, being environment friendly, short time for extraction, and high efficiency.

Protective effect of olive and juniper leaves extracts on nephrotoxicity induced by thioacetamide in male mice

This study, for the first time, evaluates the effect of olive and juniper leaves extracts and their combination on thioacetamide (TAA)-induced nephrotoxicity in male mice. The experimental mice were divided into eight groups. Group 1 was served as control. Group 2 was exposed to TAA. Group 3 was treated with TAA and olive leaves extract. Group 4 was subjected to TAA and juniper leaves extract. Group 5 was exposed to TAA and olive and juniper leaves extracts. Groups 6, 7 and 8 were treated with olive, juniper, and olive and juniper leaves extracts respectively. In mice treated with only TAA, significant increases of blood urea nitrogen and uric acid were observed after six weeks. Moreover, levels of serum creatinine, blood urea nitrogen and uric acid were statistically increased in mice administrated with only TAA for twelve weeks. Insignificant alterations in levels of these haematobiochemical parameters were noted in other treated groups after six and twelve weeks. Histopathological evaluations of renal sections from mice treated with only TAA for twelve weeks showed severe damage of the renal corpuscles. Furthermore, the renal sections from mice treated with TAA and olive leaves extract, TAA and juniper leaves extract, TAA and olive and juniper leaves extracts, olive leaves extract, juniper leaves extract, and olive and juniper leaves extracts showed normal structures. In addition, it is conceivable therefore, that these extracts exhibit protective influences against TAA-induced nephrotoxicity, probably mediated through the antioxidative pathway roles.

Nutritionally relevant concentrations of resveratrol and hydroxytyrosol mitigate oxidative burst of human granulocytes and monocytes and the production of pro-inflammatory mediators in LPS-stimulated RAW 264.7 macrophages

The health benefits of bio-active phenolic compounds have been largely investigated in vitro at concentrations which exceed those reachable in vivo. We investigated and compared the anti-inflammatory effects of resveratrol, hydroxytyrosol and oleuropein at physiologically relevant concentrations by using in vitro models of inflammation. Human granulocytes and monocytes were stimulated with phorbol myristate acetate (PMA) and the ability of resveratrol, hydroxytyrosol and oleuropein to inhibit the oxidative burst and CD11b expression was measured. Nitric oxide (NO), prostaglandin E2 (PGE2) levels, COX-2, iNOS, TNFα, IL-1β and miR-146a expression and activation of the transcription factor Nrf2 were evaluated in macrophages RAW 264.7 stimulated with LPS (1μg/ml) for 18h, exposed to resveratrol, hydroxytyrosol and oleuropein (5 and 10μM). Synergistic effects were explored as well, together with the levels of PGE2, COX-2 and IL-1β expression in macrophages after 6h of LPS stimulation. PGE2 and COX-2 expression were also assessed on human monocytes. All the tested compounds inhibited granulocytes oxidative burst in a concentration dependent manner and CD11b expression was also significantly counteracted by resveratrol and hydroxytyrosol. The measurement of oxidative burst in human monocytes produced similar effects being resveratrol more active. Hydroxytyrosol and resveratrol inhibited the production of NO and PGE2 but did not reduce iNOS, TNFα or IL-1β gene expression in LPS-stimulated RAW 264.7 for 18h. Resveratrol slightly decreased COX-2 expression after 18h but not after 6h, but reduced PGE2 levels after 6h. Resveratrol and hydroxytyrosol 10μM induced NRf2 nuclear translocation and reduced miR-146a expression in LPS treated RAW 264.7. Overall, we reported an anti-inflammatory effect of resveratrol and hydroxytyrosol at low, nutritionally relevant concentrations, involving the inhibition of granulocytes and monocytes activation, the modulation of miR-146a expression and the activation of Nrf2. A regular dietary intake of resveratrol and hydroxytyrosol may be a useful complementary strategy to control inflammatory diseases.