Cardioprotective and neuroprotective roles of oleuropein in olive

Multiple-heated cooking oil promotes early hepatic and renal senescence in adult male rats: the potential regenerative capacity of oleuropein

For economic purposes, cooking oil is repeatedly heated in food preparation, which imposes serious health threats. This study investigated the detrimental effects of multiple-heated cooking oil (MHO) on hepatic and renal tissues with particular focusing on cellular senescence (CS), and the potential regenerative capacity of oleuropein (OLE). Adult male rats were fed MHO-enriched diet for 8 weeks and OLE (50 mg/kg, PO) was administered daily for the last four weeks. Liver and kidney functions and oxidative stress markers were measured. Cell cycle markers p53, p21, cyclin D, and proliferating cell nuclear antigen (PCNA) were evaluated in hepatic and renal tissues. Tumor necrosis factor-α (TNF-α) and Bax were assessed by immunohistochemistry. General histology and collagen deposition were also examined. MHO disturbed hepatic and renal structures and functions. MHO-fed rats showed increased oxidative stress, TNF-α, Bax, and fibrosis in liver and kidney tissues. MHO also enhanced the renal and hepatic expression of p53, p21, cyclin D and PCNA. On the contrary, OLE mitigated MHO-induced oxidative stress, inflammatory burden, apoptotic and fibrotic changes. OLE also suppressed CS and preserved kidney and liver functions. Collectively, OLE displays marked regenerative capacity against MHO-induced hepatic and renal CS, via its potent antioxidant and anti-inflammatory effects.

Antimicrobial and anti-biofilm properties of oleuropein against Escherichia coli and fluconazole-resistant isolates of Candida albicans and Candida glabrata

BACKGROUND

Side effects associated with antimicrobial drugs, as well as their high cost, have prompted a search for low-cost herbal medicinal substances with fewer side effects. These substances can be used as supplements to medicine or to strengthen their effects. The current study investigated the effect of oleuropein on the inhibition of fungal and bacterial biofilm in-vitro and at the molecular level.

MATERIALS AND METHODS

In this experimental study, antimicrobial properties were evaluated using microbroth dilution method. The effect of oleuropein on the formation and eradication of biofilm was assessed on 96-well flat bottom microtiter plates and their effects were observed through scanning electron microscopy (SEM). Its effect on key genes (Hwp1, Als3, Epa1, Epa6, LuxS, Pfs) involved in biofilm formation was investigated using the quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) method.

RESULTS

The minimum inhibitory concentration (MIC) and minimum fungicidal/bactericidal concentration (MFC/MBC) for oleuropein were found to be 65 mg/ml and 130 mg/ml, respectively. Oleuropein significantly inhibited biofilm formation at MIC/2 (32.5 mg/ml), MIC/4 (16.25 mg/ml), MIC/8 (8.125 mg/ml) and MIC/16 (4.062 mg/ml) (p < 0.0001). The anti-biofilm effect of oleuropein was confirmed by SEM. RT-qPCR indicated significant down regulation of expression genes involved in biofilm formation in Candida albicans (Hwp1, Als3) and Candida glabrata (Epa1, Epa6) as well as Escherichia coli (LuxS, Pfs) genes after culture with a MIC/2 of oleuropein (p < 0.0001).

CONCLUSIONS

The results indicate that oleuropein has antifungal and antibacterial properties that enable it to inhibit or destroy the formation of fungal and bacterial biofilm.

Olive leaf extract effect on cardiometabolic risk factors: a systematic review and meta-analysis of randomized clinical trials

CONTEXT

Olive leaf extract (OLE) is rich in phenolic compounds, which are known for their health benefits. Cardiovascular diseases, primarily coronary heart disease and stroke, are leading causes of mortality globally.

OBJECTIVE

This systematic review aimed to assess the impact of OLE on cardiometabolic risk factors in adults. The selection of studies was based on intervention and outcomes, using relevant search descriptors.

DATA SOURCES

The databases PubMed, EMBASE, and Web of Science were systematically searched for pertinent studies published up to August 2021.

DATA EXTRACTION

Only randomized clinical trials, either cross-over or parallel, involving adult individuals aged ≥18 years, were considered. Additionally, trials that had a comparative or placebo group and used pure OLEs for oral treatment were included.

DATA ANALYSIS

Twelve randomized clinical trials (RCTs) met the inclusion criteria. These trials had follow-up periods ranging from 2 days to 12 weeks and involved 703 patients aged 18 years-79 years. The outcomes demonstrated a positive correlation between the intervention group and glucose metabolism (4 RCTs), blood pressure (2 RCTs), lipid profile (2 RCTs), and inflammatory markers (2 RCTs). The RoB2 tool and the GRADE system were used to evaluate the risk of bias and the quality of evidence in the studies.

CONCLUSIONS

In the meta-analysis, fasting glycemia, as evaluated in studies using a low dose of OLE, showed a significant result favoring the control group. To obtain more consistent results, further clinical studies in humans, using similar methodologies, are required.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020200877.

Effect of Geographical Location on the Phenolic and Mineral Composition of Chetoui Olive Leaves

In this study, we investigated the influence of pedological parameters and variation of altitude on the mineral nutrients, phenolic compounds, and antioxidant activities of olive leaves. Samples of the Chetoui cultivar were collected from eight geographical locations with different altitudes. Levels of phenolic compounds varied according to the altitude. Classification of the locations revealed that altitude 1 (>500 m) was characterized by high levels of secoiridoids and simple phenols, while altitude 2 (500-300 m) and altitude 3 (<300 m) were higher in flavonoids. Levels of Mn, Ca and B in the leaves and level of Zn in the soil were significantly correlated with the abundance of oleuropein and luteolin-7-O glucoside, the most important phenols in Chetoui olive leaves. The results suggest that, in addition to pedological criteria, environmental conditions also influence the formation of phenolic compounds.

Phenolic Compounds from Virgin Olive Oil: Approaches for Their Synthesis and Analogues

Virgin olive oil (VOO) is the main fat consumed by populations in the Mediterranean basin, and phenolic compounds, minor components of this fat, are known to be responsible for diverse health benefits when consumed in a regular diet. According to numerous investigations, these benefits are mostly related to phenols such as tyrosol and hydroxytyrosol and secoiridoid derivatives such as ligstroside, oleuropein, oleocanthal and oleacein. These compounds are present in low concentrations, and for some of them, standards are not commercially available, hampering studies on the mechanisms underlying their biological activity. In order to contribute to a better knowledge of the bioactivity of these compounds and their metabolites, they must be available with high purity and in sufficient amounts for the assays. Chemical synthesis has been considered a convenient way to obtain these compounds. This Review will focus on the synthesis of representative VOO compounds, namely, ligstroside, oleuropein, oleocanthal, oleacein and analogues.

Valorizing the usage of olive leaves, bioactive compounds, biological activities, and food applications: A comprehensive review

Olive oil production is a significant source of economic profit for Mediterranean nations, accounting for around 98 percent of global output. Olive oil usage has increased dramatically in recent years, owing to its organoleptic characteristics and rising knowledge of its health advantages. The culture of olive trees and the manufacture of industrial and table olive oil produces enormous volumes of solid waste and dark liquid effluents, involving olive leaves, pomace, and olive oil mill wastewaters. These by-products cause an economic issue for manufacturers and pose major environmental concerns. As a result, partial reuse, like other agronomical production wastes, is a goal to be achieved. Because these by-products are high in bioactive chemicals, which, if isolated, might denote components with significant added value for the food, cosmetic, and nutraceutical sectors, indeed, they include significant amounts of beneficial organic acids, carbohydrates, proteins, fibers, and phenolic materials, which are distributed differently between the various wastes depending on the olive oil production method and table olive agronomical techniques. However, the extraction and recovery of bioactive materials from chosen by-products is a significant problem of their reasonable value, and rigorous detection and quantification are required. The primary aims of this review in this context are to outline the vital bioactive chemicals in olive by-products, evaluate the main developments in extraction, purification, and identification, and study their uses in food packaging systems and safety problems.

Foods of the Mediterranean diet: tomato, olives, chili pepper, wheat flour and wheat germ

Mediterranean people, which follows a diet rich in minimally-processed plant-based foods, are believed to live longer and healthier lives than many other populations in the Western world. Epidemiological and clinical data suggest that the Mediterranean diet has beneficial effects for several chronic diseases, such as cardiovascular diseases, obesity, cancer and diabetes. Although the mechanisms of action of the Mediterranean diet are not completely clear, the synergistic effects of a number of its components and their bioactive phytochemicals exert antioxidant, anti-inflammatory, anti-microbial and anti-cancer effects. The Mediterranean diet includes daily consumption of whole cereals, fruit, vegetables and legumes in moderate proportions, weekly consumption of white meat in low to moderate proportions and occasionally sweets and chocolates in small amounts. Since olive oil is the main lipids source, it has special significance for health. Healthy fruit and vegetables, rich in phytochemicals, are a major proportion of this diet and contribute to the overall nutritional value and bioactivity of its components. Here we review the nutritional and health benefits of wheat germ, tomatoes, olives and chili pepper, items at the base of Mediterranean diet food pyramid that provides beneficial molecules, such as polyphenols, vitamins and flavonoids, and exert anti-inflammatory, anti-microbial and anti-oxidative actions.

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.

Secondary Metabolites of Osmanthus fragrans: Metabolism and Medicinal Value

Osmanthus fragrans (scientific name: Osmanthus fragrans (Thunb.) Lour.) is a species of the Osmanthus genus in the family Oleaceae, and it has a long history of cultivation in China. O. fragrans is edible and is well known for conferring a natural fragrance to desserts. This flowering plant has long been cultivated for ornamental purposes. Most contemporary literature related to O. fragrans focuses on its edible value and new species discovery, but the functional use of O. fragrans is often neglected. O, fragrans has many properties that are beneficial to human health, and its roots, stems, leaves, flowers and fruits have medicinal value. These characteristics are recorded in the classics of traditional Chinese medicine. Studies on the metabolites and medicinal value of O. fragrans published in recent years were used in this study to evaluate the medicinal value of O. fragrans. Using keywords such as metabolites and Osmanthus fragrans, a systematic and nonexhaustive search of articles, papers and books related to the medicinal use of Osmanthus fragrans metabolites was conducted. Fifteen metabolites were identified through this literature search and classified into three categories according to their properties and structure: flavonoids, terpenes and phenolic acids. It was found that the pharmacological activities of these secondary metabolites mainly include antioxidant, anticancer, anti-inflammatory and antibacterial activities and that these metabolites can be used to treat many human diseases, such as cancer, skin diseases, cardiovascular diseases, and neurological diseases. Most of the reports that are currently available and concern the secondary metabolites of Osmanthus fragrans have limitations. Some reports introduce only the general classification of compounds in Osmanthus fragrans, and some reports introduce only a single compound. In contrast, the introduction section of this paper includes both the category and the functional value of each compound. While reviewing the data for this study, the authors found that the specific action sites of these compounds and their mechanisms of action in plants are relatively weak, and in the future, additional research should be conducted to investigate this topic further.

A Nutraceutical Product Based on a Mixture of Algae and Extra Virgin Olive Oils and Olive Leaf Extract Attenuates Sepsis-Induced Cardiovascular and Muscle Alterations in Rats

Nutraceuticals are products of natural origin widely used for the treatment and/or prevention of some chronic diseases that are highly prevalent in Western countries, such as obesity or type II diabetes, among others. However, its possible use in the prevention of acute diseases that can put life at risk has been poorly studied. Sepsis is an acute condition that causes cardiovascular and skeletal muscle damage due to a systemic inflammatory state. The aim of this work was to evaluate the possible beneficial effect of a new nutraceutical based on a mixture of algae oil (AO) and extra virgin olive oil (EVOO) supplemented with an olive leaf extract (OLE) in the prevention of cardiovascular alterations and skeletal muscle disorders induced by sepsis in rats. For this purpose, male Wistar rats were treated with the nutraceutical or with water p.o. for 3 weeks and after the treatment they were injected with 1mg/kg LPS twice (12 and 4 h before sacrifice). Pretreatment with the nutraceutical prevented the LPS-induced decrease in cardiac contractility before and after the hearts were subjected to ischemia-reperfusion. At the vascular level, supplementation with the nutraceutical did not prevent hypotension in septic animals, but it attenuated endothelial dysfunction and the increased response of aortic rings to the vasoconstrictors norepinephrine and angiotensin-II induced by LPS. The beneficial effects on cardiovascular function were associated with an increased expression of the antioxidant enzymes SOD-1 and GSR in cardiac tissue and SOD-1 and Alox-5 in arterial tissue. In skeletal muscle, nutraceutical pretreatment prevented LPS-induced muscle proteolysis and autophagy and significantly increased protein synthesis as demonstrated by decreased expression of MURF-1, atrogin-1, LC3b and increased MCH-I and MCH -IIa in gastrocnemius muscle. These effects were associated with a decrease in the expression of TNFα, HDAC4 and myogenin. In conclusion, treatment with a new nutraceutical based on a mixture of AO and EVOO supplemented with OLE is useful to prevent cardiovascular and muscular changes induced by sepsis in rats. Thus, supplementation with this nutraceutical may constitute an interesting strategy to reduce the severity and mortality risk in septic patients.

Biochemical Characterization of Six Traditional Olive Cultivars: A Comparative Study

Olives are an essential ingredient in Turkish food culture. Turkey has grown to become one of the top five producers of olives and olive oils in the world. Olive trees in general are found in the coastal parts of the country. The fruits of six traditional cultivars of olive (Gemlik, Domat, Memecik, Ayvalik, Cilli, and Adana Topagi), grown in Adana, were characterized based on their fruit skin color, the amount of chlorophylls, fatty acids, antioxidant activity, and total phenolic compounds, as well as volatile compounds. The international cultivar Manzanilla, grown in the same orchards as the traditional cultivars, was also included in the study to make a comparison. Compared to the Manzanilla cultivar, Memecik showed the highest amount of total phenolic content and antioxidant activity with the highest level of lightness, blueness/yellowness, and color intensity. Ayvalik presented the highest level of greenness/redness. Although the highest fruit lightness and darkness were found in the Cilli cultivar, with the highest amount of chlorophyll a (2.63 mgL−1), there was more chlorophyll b in Adana Topagi fruits (3.34 mgL−1). The highest percentage of fatty acids was found in the Gemlik cultivar of 66.81%, among which oleic acid was the major component. The total aldehydes ranged between 33.43% and 50.60%. Compared to Manzanilla and the traditional cultivars, the Domat cultivar had the highest amount of hexanal of 44.42%. Adana Topagi had the highest amount of alcohols (61.34%) and acids (1.31%). Memecik registered the highest amount of ketones (17.86%) and terpenes (20.34%). Among all cultivars, Manzanilla displayed the highest amount of esters (2.30%). In this study, traditional cultivars were found to be the richest in health-promoting chemicals. Furthermore, a significant variability among the cultivars was revealed, implying that metabolic fingerprinting approaches could be used to differentiate cultivars once more research into the effects of the growing conditions and environmental factors on the chemical profiles of each cultivar is carried out.

Effect of Supplementation with Olive Leaf Extract Enriched with Oleuropein on the Metabolome and Redox Status of Athletes’ Blood and Urine—A Metabolomic Approach

Oleuropein (OE) is a secoiridoid glycoside occurring mostly in the Oleaceae family and presenting several pharmacological properties, including hypolipidemic and antioxidant properties. Based on these, several dietary supplements containing olive leaf extracts enriched with OE are commercially available in many countries. The current study aimed to examine the effect of supplementation with such an extract on the serum and urine metabolome of young healthy male athletes. For this purpose, applying a randomized, balanced, double-blind study, nine young, healthy males (physical education students) received either a commercially prepared extract or placebo for one week, followed by a two-week washout period; then, they were subsequently dosed with the alternate scheme (crossover design). Urine and serum samples were analyzed using UHPLC-HRMS, followed by evaluation with several multivariate methods of data analysis. The data were interpreted using a multilevel metabolomic approach (multilevel-sPLSDA) as it was found to be the most efficient approach for the study design. Metabolic pathway analysis of the most affected metabolites revealed that tryptophan and acylcarnitine’s biochemistries were most influenced. Furthermore, several metabolites connected to indole metabolism were detected, which may indicate enhanced serotonin turnover. Phenylethylamine and related metabolites, as well as estrone, were connected to enhanced performance. In addition, possible changes to the lipidemic profile and the blood and urine redox statuses were investigated.

Olea europaea L. (olive) leaf extract ameliorates learning and memory deficits in streptozotocin-induced diabetic rats

Objective

The aim of the present study was to assess olive leaf extract (OLE) effects on learning and memory deficits in a model of diabetes induced by streptozotocin (STZ) in rats.

Materials and methods

The rats were divided as: (1) control rats, (2) diabetic rats, and (3-6) diabetic rats treated by 100, 200, and 400 mg/kg of OLE or metformin. Using the passive avoidance test (PA), we investigated fear learning and memory behaviors. In cortical and hippocampus tissues, total levels of malondialdehyde (MDA) and thiol were measured along with the activity of catalase (CAT) and superoxide dismutase (SOD).

Results

Learning and memory behavior impairment were significantly developed in diabetic rats as shown by the impairment of the PA task compared to the control group (p<0.001). In addition, elevated levels of MDA and reduced overall concentrations of thiol, CAT and SOD activity were obvious in diabetic rats' cortex and hippocampus tissues (p<0.01-p<0.001). Meanwhile, OLE in a dose-dependent manner, improved memory deficit and cognitive performance that was attributed to a reduction of lipid peroxidation and elevation of total thiol concentration, and CAT and SOD activity levels in the brain tissues (p<0.05-p<0.001).

Conclusion

OLE could be effective in improving cognitive impairment in STZ-induced diabetes by oxidative stress depression.

Modulation of Hair Growth Promoting Effect by Natural Products

A large number of people suffer from alopecia or hair loss worldwide. Drug-based therapies using minoxidil and finasteride for the treatment of alopecia are available, but they have shown various side effects in patients. Thus, the use of new therapeutic approaches using bioactive products to reduce the risk of anti-hair-loss medications has been emphasized. Natural products have been used since ancient times and have been proven safe, with few side effects. Several studies have demonstrated the use of plants and their extracts to promote hair growth. Moreover, commercial products based on these natural ingredients have been developed for the treatment of alopecia. Several clinical, animal, and cell-based studies have been conducted to determine the anti-alopecia effects of plant-derived biochemicals. This review is a collective study of phytochemicals with anti-alopecia effects, focusing mainly on the mechanisms underlying their hair-growth-promoting effects.

Quality assessment of leaf extracts of 12 olive cultivars and impact of seasonal variation based on UV spectroscopy and phytochemcial content using multivariate analyses

INTRODUCTION

Recently, focus has been made on the health-oriented uses of olive leaves, a byproduct of olive production, as a potential source of antioxidants. Oleuropein is one of the phenolic components in olive leaves known for its high antioxidant value.

OBJECTIVE

The main aim of the current study was constructing a model for the quality assessment of olive leaves and their potential phytochemical content and hence biological value as well. The phytochemical variation in olive leaves in both flowering (spring) and fruiting seasons (autumn) was also investigated.

METHODS

In this study, the leaves of 12 different olive cultivars from different geographical origins growing in Egypt were assessed for their oleuropein content, total flavonoid (TF) content and total polyphenol (Pph) content in spring and autumn via ultraviolet (UV) spectroscopy and high-performance liquid chromatography (HPLC) coupled to multivariate data analyses. The antioxidant activity of olive leaf extracts was assessed using 2,2'-diphenyl-1-picrylhydrazyl (DPPH) assay.

RESULTS

Higher levels of oleuropein, TF and Pph content were found in spring with the highest oleuropein content in the Spanish cultivar; Manzanillo, followed by the Italian cultivar Coratina and the Egyptian Agizi Okasi (218.94, 151.58 and 122.18 mg/100 g of dried leaf extract, respectively). UV spectra was also measured and the collected data were coupled to multivariate analyses showing clustering of cultivars with common geographical origin.

CONCLUSION

Our findings emphasised the influence of collection time and type of cultivar on the chemical profile of olive leaves. The model presented herein, serves for the quality assessment of olive leaves based on their phytochemical profile.

Oleuropein Enhances Stress Resistance and Extends Lifespan via Insulin/IGF-1 and SKN-1/Nrf2 Signaling Pathway in Caenorhabditis elegans

Oleuropein (OLE) is a secoiridoid glycoside that mainly exists in olives with multifaceted health benefits. The present study aimed to investigate the stress resistance and lifespan extension effects of OLE in Caenorhabditis elegans. The results showed that OLE could significantly prolong the lifespan of C. elegans by 22.29%. Treatment with OLE also significantly increased the survival rates of worms against lethal heat shock and oxidative stress. Meanwhile, OLE supplementation increased the expression and activity of antioxidant enzymes and suppressed the generation of malondialdehyde in nematodes. In addition, the results from mutants implied that OLE might mediate longevity and stress resistance via DAF-16/FoxO, which played a vital role in the insulin/IGF-1 signaling (IIS) pathway. To further identify the molecular targets of OLE, mRNA level and loss-of-function mutants of IIS-associated genes were investigated. The data revealed that OLE activated IIS by down-regulating the upstream components, daf-2 and age-1. Furthermore, another stress response and longevity pathway in parallel to DAF-16, SKN-1/Nrf2, was also shown to involve in OLE-induced beneficial effects. Collectively, these results provide the theoretical basis that OLE could enhance the stress resistance and increase the lifespan of C. elegans through the IIS and SKN-1/Nrf2 signaling pathways.

Oleuropein and Verbascoside - Their Inhibition Effects on Carbonic Anhydrase and Molecular Docking Studies

Recently, carbonic anhydrase (CA, E.C.4.2.1.1) inhibitors from natural product have paved the way for novel drug design in the treatment and prevention of some global diseases such as glaucoma, diabetes, and cancer. For this purpose, the inhibition effects of oleuropein and verbascoside from olive (Olea europaea L.) oil on human carbonic anhydrase I, and II (hCA I, and II) isoenzymes were evaluated in the current study. The inhibition effects of both natural compounds were determined by the esterase activity (in vitro). IC₅₀ value of oleuropein and verbascoside was calculated as 1.57 and 1.73 µM for hCA I isoenzyme, respectively. At the same manner, K _i values were determined as 1.25 ± 0.42 and 2.00 ± 0.42 µM, respectively. Then, IC₅₀ value of each compound for hCA II isoenzyme was calculated as 2.23 and 1.90 µM, respectively. Similarly, K _i values were determined as 2.37 ± 0.87 µM and 1.49 ± 0.33 µM, respectively. Also, the inhibitory effects and potent binding mechanisms of oleuropein and verbascoside on hCA I, and II isoenzymes were realized by molecular docking studies. Consequently, both natural phenolic compounds demonstrated the potent inhibition profiles against the both isoenzymes. Therefore, we believe that these results may break new ground in the drug development for the treatment of some global disorders.

Neuroprotective Effect of Terpenoids Recovered from Olive Oil By-Products

The neuroprotective potential of 32 natural extracts obtained from olive oil by-products was investigated. The online coupling of supercritical fluid extraction (SFE) and dynamic adsorption/desorption allowed the selective enrichment of olive leaves extracts in different terpenoids’ families. Seven commercial adsorbents based on silica gel, zeolite, aluminum oxide, and sea sand were used with SFE at three different extraction times to evaluate their selectivity towards different terpene families. Collected fractions were analyzed by gas chromatography coupled to quadrupole-time-of-flight mass spectrometry (GC-QTOF-MS) to quantify the recoveries of monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), and triterpenes (C30). A systematic analysis of the neuroprotective activity of the natural extracts was then carried out. Thus, a set of in vitro bioactivity assays including enzymatic (acetylcholinesterase (AChE), butyrylcholinesterase (BChE)), and anti-inflammatory (lipoxidase (LOX)), as well as antioxidant (ABTS), and reactive oxygen and nitrogen species (ROS and RNS, respectively) activity tests were applied to screen for the neuroprotective potential of these extracts. Statistical analysis showed that olive leaves adsorbates from SS exhibited the highest biological activity potential in terms of neuroprotective effect. Blood–brain barrier permeation and cytotoxicity in HK-2 cells and human THP-1 monocytes were studied for the selected olive leaves fraction corroborating its potential.

Bioactive Compounds in Waste By-Products from Olive Oil Production: Applications and Structural Characterization by Mass Spectrometry Techniques

In recent years, a remarkable increase in olive oil consumption has occurred worldwide, favoured by its organoleptic properties and the growing awareness of its health benefits. Currently, olive oil production represents an important economic income for Mediterranean countries, where roughly 98% of the world production is located. Both the cultivation of olive trees and the production of industrial and table olive oil generate huge amounts of solid wastes and dark liquid effluents, including olive leaves and pomace and olive oil mill wastewaters. Besides representing an economic problem for producers, these by-products also pose serious environmental concerns, thus their partial reuse, like that of all agronomical production residues, represents a goal to pursue. This aspect is particularly important since the cited by-products are rich in bioactive compounds, which, once extracted, may represent ingredients with remarkable added value for food, cosmetic and nutraceutical industries. Indeed, they contain considerable amounts of valuable organic acids, carbohydrates, proteins, fibers, and above all, phenolic compounds, that are variably distributed among the different wastes, depending on the employed production process of olive oils and table olives and agronomical practices. Yet, extraction and recovery of bioactive components from selected by-products constitute a critical issue for their rational valorization and detailed identification and quantification are mandatory. The most used analytical methods adopted to identify and quantify bioactive compounds in olive oil by-products are based on the coupling between gas- (GC) or liquid chromatography (LC) and mass spectrometry (MS), with MS being the most useful and successful detection tool for providing structural information. Without derivatization, LC-MS with electrospray (ESI) or atmospheric pressure chemical (APCI) ionization sources has become one of the most relevant and versatile instrumental platforms for identifying phenolic bioactive compounds. In this review, the major LC-MS accomplishments reported in the literature over the last two decades to investigate olive oil processing by-products, specifically olive leaves and pomace and olive oil mill wastewaters, are described, focusing on phenolics and related compounds.

Olive leaf extract effect on cardiometabolic profile among adults with prehypertension and hypertension: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to determine the effectiveness of olive leaf extract on cardiometabolic profiles among prehypertensive and hypertensive groups.

METHODOLOGY

The Cochrane central register of controlled trials, Medline (1966 to April week 1, 2020), Embase (1966 to April week 1, 2020) and trial registries for relevant randomized clinical trials were used. Published and unpublished randomized clinical trials were reviewed and evaluated. Random effects models were used to estimate the continuous outcomes and mean differences (MDs); both with 95% confidence intervals (CIs). The primary outcomes were changes in systolic and diastolic BP. The secondary outcomes were changes in lipid profile, glucose metabolism, inflammatory markers for CVD, kidney and liver functions safety parameters. We assessed the data for risk of bias, heterogeneity, sensitivity, reporting bias and quality of evidence.

RESULTS

Five trials were included involving 325 patients aged 18-80 years. Two trials involved high-income countries and three trials involved moderate-income countries. The analysis performed was based on three comparisons. No significant changes were found between systolic or diastolic blood pressure (BP) for the first comparison, 1,000 mg per day for a combined formulation of olive leaf extract versus a placebo. The second comparison, 500 mg per day of olive leaf extract versus placebo or no treatment, showed a significant reduction in systolic BP over a period of at least 8 weeks of follow up (MD -5.78 mmHg, 95% CI [-10.27 to -1.30]) and no significant changes on diastolic BP. The third comparison, 1,000 mg per day of olive leaf extract versus placebo shows no significant difference but an almost similar reduction in systolic BP (-11.5 mmHg in olive leaf extract and -13.7 mmHg in placebo, MD 2.2 mmHg, 95% CI [-0.43-4.83]) and diastolic BP (-4.8 mmHg in olive leaf extract and -6.4 mmHg in placebo, MD 1.60 mmHg, 95% CI [-0.13-3.33]). For secondary outcomes, 1,000 mg per day of olive leaf extract versus captopril showed a reduction in LDL (MD -6.00 mg/dl, 95% CI [-11.5 to -0.50]). The 500 mg per day olive leaf extract versus placebo showed a reduction in inflammatory markers for CVD IL-6 (MD -6.83 ng/L, 95% CI [-13.15 to -0.51]), IL-8 (MD -8.24 ng/L, 95% CI [-16.00 to -0.48) and TNF-alpha (MD -7.40 ng/L, 95% CI [-13.23 to -1.57]).

CONCLUSIONS

The results from this review suggest the reduction of systolic BP, LDL and inflammatory biomarkers, but it may not provide a robust conclusion regarding the effects of olive leaf extract on cardiometabolic profile due to the limited number of participants in the included trials.

REVIEW REGISTRATIONS

PROSPERO CDR 42020181212.

Olive Tree in Circular Economy as a Source of Secondary Metabolites Active for Human and Animal Health Beyond Oxidative Stress and Inflammation

Extra-virgin olive oil (EVOO) contains many bioactive compounds with multiple biological activities that make it one of the most important functional foods. Both the constituents of the lipid fraction and that of the unsaponifiable fraction show a clear action in reducing oxidative stress by acting on various body components, at concentrations established by the European Food Safety Authority's claims. In addition to the main product obtained by the mechanical pressing of the fruit, i.e., the EVOO, the residual by-products of the process also contain significant amounts of antioxidant molecules, thus potentially making the Olea europea L. an excellent example of the circular economy. In fact, the olive mill wastewaters, the leaves, the pomace, and the pits discharged from the EVOO production process are partially recycled in the nutraceutical and cosmeceutical fields also because of their antioxidant effect. This work presents an overview of the biological activities of these by-products, as shown by in vitro and in vivo assays, and also from clinical trials, as well as their main formulations currently available on the market.

Attitudes Toward Psychological Disorders and Alternative Medicine in Saudi Participants

Background: This study was designed to investigate Saudis' attitudes toward mental distress and psychotropic medication, attribution of causes, expected side effects, and to analyze participants' expectations toward alternative or complementary medicine using aromatic and medicinal plants, through a survey. Method: The study included 674 participants (citizens and residents in Saudi Arabia) who were randomly contacted via email and social media and gave their consent to complete a questionnaire dealing with 39 items that can be clustered in six parts. Descriptive statistics and Chi-square for cross-tabulation were generated using SPSS. Results: Among the 664 participants, 73.4% believed that there are some positive and negative outcomes of psychotropic medication. Participants (72.0%) think that the most important reason leading to psychological disorders is mainly due to the loss of a relative or beloved person, and 73.9% considered psychic session as one of the possible treatments of psychological disorders. Surprisingly, only 18.8% of the participants agreed that medicinal and aromatic plants could be a possible treatment of the psychological disorder. Participants (82%) consider that physicians are the most trustful and preferred source of information about alternative and complementary medicine.

Traditional uses, phytochemistry and pharmacology of genus Syringa: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Genus Syringa, which belongs to Oleaceae family, contains 21 accepted species mainly distributed in Southeast Europe, Japan, China, Himalayas, etc. The various parts of Syringa species have been used as traditional Chinese herbal medicines for treatment of cough, myocardial ischemia, acute icteric hepatitis, diarrhea, conjunctivitis, bronchitis and other ailments.

AIM OF THE STUDY

A more comprehensive and in-depth review about the phytochemistry, pharmacology, traditional medicinal uses and clinical applications as well as toxicology of Syringa have summarized and hope to provide a relatively novel angle for further clinical applicantion on genus.

MATERIALS AND METHODS

The literatures about Syringa were collected via a series of scientific search engines including Web of Science, PubMed, Elsevier, Google Scholar, SciFinder and CNKI.

RESULTS

The phytochemical studies revealed that about 302 compounds include phenylpropanoids, iridoids, phenylethanols, flavonoids, triterpenes and other minor compounds have been isolated and identified from Syringa species. Phenylpropanoids and iridoids are the main constituents among these compounds and may be responsible for the activities directly or indirectly. As traditional medicine, Syringa applied to treat cough, diarrhea, acute icteric hepatitis, vomit, abdominal pain, bronchitis and other ailments. Most of traditional uses are related the biological activities and confirmed by modern studies. Pharmacological researches in vitro and in vivo revealed that the extracts and pure compounds possessed significantly hepatoprotective, anti-inflammatory, antimicrobial, antioxidant, antitumor, antiviral, cardioprotective, immunomodulatory and other activities.

CONCLUSIONS

The phytochemistry, pharmacology, traditional uses and clinical applications described in this article demonstrated that Syringa species possessed a huge number of activities and these findings will promote the further action mechanisms studies. However, fewer preclinical and clinical studies are focued on the pharmacokinetics of crudes extracts and conpounds from Syringa. The explored of new agents with Syringa species as ingredients may be limited. It points to the further in-depth investigations on pharmacokinetics as well as toxicological are essential in future for assessment the effectiveness and safety of drug.

The Impact of Olive Oil Compounds on the Metabolic Reprogramming of Cutaneous Melanoma Cell Models

Cutaneous melanoma is the deadliest type of skin cancer, characterized by a high molecular and metabolic heterogeneity which contributes to therapy resistance. Despite advances in treatment, more efficient therapies are needed. Olive oil compounds have been described as having anti-cancer properties. Here, we clarified the cytotoxic potential of oleic acid, homovanillyl alcohol, and hydroxytyrosol on melanoma cells. Metabolic viability was determined 48 h post treatment of A375 and MNT1 cells. Metabolic gene expression was assessed by qRT-PCR and Mitogen-Activated Protein Kinase (MAPK) activation by Western blot. Hydroxytyrosol treatment (100 and 200 µM) significantly reduced A375 cell viability (p = 0.0249; p < 0.0001) which, based on the expression analysis performed, is more compatible with a predominant glycolytic profile and c-Jun N-terminal kinase (JNK) activation. By contrast, hydroxytyrosol had no effect on MNT1 cell viability, which demonstrates an enhanced oxidative metabolism and extracellular signal-regulated kinase (ERK) activation. This compound triggered cell detoxification and the use of alternative energy sources in A375 cells, inhibiting JNK and ERK pathways. Despite oleic acid and homovanillyl alcohol demonstrating no effect on melanoma cell viability, they influenced the MNT1 glycolytic rate and A375 detoxification mechanisms, respectively. Both compounds suppressed ERK activation in MNT1 cells. The distinct cell responses to olive oil compounds depend on the metabolic and molecular mechanisms preferentially activated. Hydroxytyrosol may have a cytotoxic potential in melanoma cells with predominant glycolytic metabolism and JNK activation.

Therapeutic and Preventive Effects of Olea europaea Extract on Indomethacin-Induced Small Intestinal Injury Model in Rats

Background

Olea europaea (known as olive fruit) has anti-inflammatory and antioxidant activities and many potential health benefits including gastric inflammation reduction has been shown previously. This study aimed to investigate the preventive and therapeutic effects of O. europaea extract on the early histological changes in indomethacin-induced small intestinal injury model with the plasma D-lactate concentration being measured as a tool for determination of intestinal permeability.

Methods

In this experimental study, two separate protective and therapeutic protocols were designed. In both experiments, male Wistar rats were randomly divided into 4 groups and either pretreated with 0, 100, 200, or 400 mg/kg/day of O. europaea extract or received the treatment after administration of indomethacin. Their small intestines were examined to compare the histological changes. The intestinal injury severity was evaluated according to the presence of eosinophils, plasma cell infiltration, edema, congestion, and hyperplasia of the crypt using a histological scoring system. Also, measured were the presence of neutrophils, decreased villus length-to-crypt depth ratio, and destructed villus architecture. The plasma concentration of D-lactate was measured as well.

Results

The therapeutic use of O. europaea decreased the eosinophil, edema, congestion, and crypt hyperplasia scores compared to the control group. Although no significant difference was seen between groups of the preventive experiment in plasma cell infiltration score, villus length-to-crypt depth ratio, neutrophil infiltration, and percentage of destructed villus architecture, treatment with O. europaea caused a reduction in edema, eosinophil, congestion, and crypt hyperplasia score. In both experiments, no significant difference was seen between groups for villus length-to-crypt depth ratio, neutrophil infiltration, and percentage of destructed villus architecture. Plasma D-lactate concentration was decreased in all O. europaea-treated groups compared to the control group in the therapeutic and preventive experiments (p < 0.01, one-way ANOVA followed by the Dunnett test).

Conclusion

O. europaea extract can be used to decrease some side effects of indomethacin on intestinal tissue and enhances the gastrointestinal function. O. europaea extract could be considered as a potential herbal supplement in the treatment of intestinal morphological injuries.

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.

Oleuropein Improved Post Cerebral Stroke Cognitive Function by Promoting Histone Acetylation and Phosphorylation of cAMP Response Element-Binding Protein in MCAO Rats

Background:

Post-stroke cognitive impairment (PSCI) is commonest clinical disorder in which peripheral cholinergic activity is important. Oleuropein (OLP) is polyphenol is present in olive oil. Here we evaluated the effect of OLP in cognitive dysfunction rats in post cerebral stroke model.

Methods:

The post cerebral stroke cognitive dysfunction PSD rat model was created by occlusion of transient middle cerebral artery. The rats were divided into 6 groups named, Sham + Vehicle, Sham + OLP (50 mg/kg), PSD rats + Vehicle, PSD rats + OLP (20, 50 or 100 mg/kg). The spatial learning was assessed by Morris water maze (MWM). The expression of choline acetyltransferase (ChAT), acetylcholine (ACH), extent of histone acetylation and phosphorylation of cAMP response element-binding protein (CREB) were evaluated by Western blot assay and immunofluorescence staining.

Results:

Treatment of OLP at various doses showed higher number of spontaneous and rewarded alterations and lesser percentage bias compared to vehicle treated PSD rats. OLP resulted in decreased levels of ChAT and ACH, whereas the degree of histone acetylation and phosphorylation of CREB improved in dose dependent pattern.

Conclusion:

treatment of OLP improved PSCI via increasing the phosphorylation of CREB and histone acetylation, thus attenuating cholinergic activity.

Evolution of Phenotypic Traits and Main Functional Components in the Fruit of 'Chenggu-32' Olives (Olea europaea L.) Cultivated in Longnan (China)

China has taken olive cultivation as a significant part of its agricultural development. Longnan city of Gansu province was marked into the world olive distribution map by International Olive Oil Council in 1998. However, so far, little research has been done on the growth and development stages of Chinese olives. The objective of this study was to investigate the dynamics changes of several quality characteristics of olive oil at different sampling times. Olive fruit of 'Chenggu-32' grown in Longnan were harvested at twenty-four time periods and used for determination of phenotypic traits and oil quality characteristics: total polyphenols and flavonoids contents, as well as fatty acid composition by using Gas Chromatography-Mass Spectrometer (GC-MS) and analysed by using Principal Components Analysis (PCA). Towards maturation, fruit moisture content decreased while oil content increased. Levels of both total flavonoids and total polyphenols contents slightly decreased first then increased. The ratio of unsaturated to saturated fatty acids was close to three. The ratio of monounsaturated fatty acids (MUFA)/ polyunsaturated fatty acids (PUFA) was from 2.28 to 4.05. The oleic acid (C18:1)/linoleic acid (C18:2) ratio was varied between 5.23 and 10.67 according to different sampling dates. The olive oil had lower oleic acid (C18:1) levels, higher linoleic acid (C18:2), linolenic acid (C18:3), and palmitic acid (C16:0) levels compared to Codex values (2017) in some periods, which is the characteristics fatty acid composition of 'Chenggu-32' variety in Longnan, China.

Olive Leaves and Hibiscus Flowers Extracts-Based Preparation Protect Brain from Oxidative Stress-Induced Injury

Oxidative stress (OS) arising from tissue redox imbalance, critically contributes to the development of neurodegenerative disorders. Thus, natural compounds, owing to their antioxidant properties, have promising therapeutic potential. Pres phytum (PRES) is a nutraceutical product composed of leaves- and flowers-extracts of Olea europaea L. and Hibiscus sabdariffa L., respectively, the composition of which has been characterized by HPLC coupled to a UV-Vis and QqQ-Ms detector. As PRES possess antioxidant, antiapoptotic and anti-inflammatory properties, the aim of this study was to assess its neuroprotective effects in human neuroblastoma SH-SY5Y cells and in rat brain slices subjected to OS. PRES (1–50 µg/mL) reverted the decrease in viability as well as the increase in sub-diploid-, DAPI-and annexin V-positive-cells, reduced ROS formation, recovered the mitochondrial potential and caspase-3 and 9 activity changes caused by OS. PRES (50–100 µg/mL) neuroprotective effects occurred also in rat brain slices subjected to H₂O₂ challenge. Finally, as the neuroprotective potential of PRES is strictly related to its penetration into the brain and a relatively good pharmacokinetic profile, an in-silico prediction of its components drug-like properties was carried out. The present results suggest the possibility of PRES as a nutraceutical, which could help in preventing neurodegenerative diseases.

Effects of Emulsion Formulations of Oleuropein Isolated from Ethanol Extract of Olive Leaf in Diabetic Rats

This study was designed to investigate the effects of emulsion formulations of oleuropein isolated from ethanol extract of olive leaf in streptozotocin-diabetic rats. The rats were treated with the administration of the emulsion containing oleuropein at a low (150 mg/kg b.wt.) and high (225 mg/kg b.wt.) dose for 30 days. At the end of the study, blood samples were drawn from the heart of the rats to determine blood glucose, alanine transaminase, and aspartate transaminase levels. In addition, their liver tissues were dissected to determine the levels of glutathione and thiobarbituric acid-reactive substances, and superoxide dismutase activity. According to the results for both dose treatments, a statistically significant increase in superoxide dismutase activities and glutathione levels of the treated diabetic rats was observed when compared with those of the diabetic control rats. On the other hand, a statistically significant decrease in the levels of thiobarbituric acid-reactive substances, aspartate transaminase and alanine transaminase of the treated diabetic rats was determined. It should be highlighted that the administrations at the high dose were more effective compared to that of the low dose. Furthermore, a substantial decrease in the blood glucose levels of the diabetic rats exposed to the high dose was observed.

Senolytic activity of small molecular polyphenols from olive restores chondrocyte redifferentiation and promotes a pro-regenerative environment in osteoarthritis

Articular cartilage and synovial tissue from patients with osteoarthritis (OA) show an overactivity of connexin43 (Cx43) and accumulation of senescent cells associated with disrupted tissue regeneration and disease progression. The aim of this study was to determine the effect of oleuropein on Cx43 and cellular senescence for tissue engineering and regenerative medicine strategies for OA treatment. Oleuropein regulates Cx43 promoter activity and enhances the propensity of hMSCs to differentiate into chondrocytes and bone cells, reducing adipogenesis. This small molecule reduce Cx43 levels and decrease Twist-1 activity in osteoarthritic chondrocytes (OACs), leading to redifferentiation, restoring the synthesis of cartilage ECM components (Col2A1 and proteoglycans), and reducing the inflammatory and catabolic factors mediated by NF-kB (IL-1ß, IL-6, COX-2 and MMP-3), in addition to lowering cellular senescence in OACs, synovial and bone cells. Our in vitro results demonstrate the use of olive-derived polyphenols, such as oleuropein, as potentially effective therapeutic agents to improve chondrogenesis of hMSCs, to induce chondrocyte re-differentiation in OACs and clearing out senescent cells in joint tissues in order to prevent or stop the progression of the disease.

A Box-Behnken Design for Optimal Green Extraction of Compounds from Olive Leaves That Potentially Activate the AMPK Pathway

Olive leaves contain bioactive compounds that have been shown to activate AMP-activated protein kinase (AMPK), which decreases intracellular lipid accumulation. Microwave-assisted extraction (MAE) is a green extraction technique that is frequently used in the recovery of phenolic compounds from plants. Thus, in this study, a Box-Behnken design was used to optimize MAE conditions such as temperature, percentage of ethanol and extraction time to obtain the maximum content of total compounds and compounds that activate AMPK. To this end, all extracts were characterized by High-Performance Liquid Chromatography Coupled to Electrospray Ionization Time-of-Flight Mass Spectrometry (HPLC-ESI-TOF-MS). The optimum conditions to obtain the highest content of total compounds were 123 °C, 100% of ethanol/water (v/v) and 23 min, whereas the optimum conditions for the highest amount of compounds that activate AMPK were 111 °C, 42% of ethanol/water (v/v) and 23 min. Thus, a multi-analysis by desirability was carried out to establish MAE optimal conditions for both responses. The optimum conditions were 111 °C, 100% EtOH and 23 min with a desirability of 0.97, which means that the responses are close to their individual optimal values. As a result, the olive leaf extract obtained at these optimal MAE conditions has great potential to be effective in the treatment of obesity.

Olive oil limited motor disruption and neuronal damage in parkinsonism induced by MPTP administration

Some vegetable oils show beneficial effects in modulating neurodegeneration; in this work, we evaluated the therapeutic potential of corn and olive oils against neurodegenerative processes using the acute parkinsonism murine model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in C57BL6 mice. The effects of corn and olive oils were quantified by the performance of mice in the open field and rotarod, and grasp strength tests and neuronal survival in the substantia nigra and striatum were determined by immunohistochemistry. Extra-virgin olive oil decreased the toxicity induced by MPTP administration judged by the performance in the behavioral motor tests and the number of total neurons in the analyzed brain regions. In contrast, corn oil only produced discrete changes in the behavioral and histological evaluations. Despite the numerous benefits of olive oil, its active substances that confer desirable effects and their mechanism of action remain unclear. Our observations can help to understand the ameliorative effects of some natural oils on neurodegeneration induced by some toxins, particularly the attenuation of neural damage related to toxin-induced parkinsonism or other pathologies that comprise neuronal death and motor disruption.

Potential role of phytochemicals in brain plasticity: Focus on polyunsaturated fatty acids

PURPOSE

Functional foods are thought to strongly influence the structure and function of the brain. Previous studies have reported that brain-boosting diets may enhance neuroprotective functions. Certain foods are particularly rich in nutrients like phytochemicals that are known to support brain plasticity; such foods are commonly referred to as brain foods.

METHODS

In this review, we briefly explore the scientific evidence supporting the neuroprotective activity of a number of phytochemicals with a focus on phenols and polyunsaturated fatty acids such as flavonoid, olive oil, and omega-3 fatty acid.

RESULTS

The aim of this study was to systematically examine the primary issues related to phytochemicals in the brain. These include (a) the brain-gut-microbiome axis; (b) the effects of phytochemicals on gut microbiome and their potential role in brain plasticity; (c) the role of polyunsaturated fatty acids in brain health; and (d) the effects of nutrition and exercise on brain function.

CONCLUSION

This review provides evidence supporting the view that phytochemicals from medicinal plants play a vital role in maintaining brain plasticity by influencing the brain-gut-microbiome axis. The consumption of brain foods may have neuroprotective effects, thus protecting against neurodegenerative disorders and promoting brain health.

Diet, Lifestyle and Cardiovascular Diseases: Linking Pathophysiology to Cardioprotective Effects of Natural Bioactive Compounds

Heart and blood vessels disorders comprise one of the main causes of death worldwide. Pharmacologically active natural compounds have been used as a complementary therapy in cardiovascular disease around the world in a traditional way. Dietary, natural bioactive compounds, as well as healthy lifestyles, are considered to prevent coronary artery diseases. Pre-clinical and clinical studies reported that consumption of plant-food bioactive derivatives including polyphenolic compounds, peptides, oligosaccharides, vitamins, unsaturated fatty acids possess protective effects on cardiovascular diseases. This review aims to summarize the cardiovascular risk factors, pre-clinical studies and clinical trials related to cardioprotective properties of the plant-food-derived bioactive compounds. Molecular mechanisms by the natural bioactive compounds exert their cardiovascular protective properties have also been highlighted.

Effect Of An Extra-Virgin Olive Oil Intake On The Delay Of Cognitive Decline: Role Of Secoiridoid Oleuropein?

Currently, there is an increase in the number of the world's aging population. This aging process is often connected with cognitive decline of some functions such as memory or speed processing loss. Since Alzheimer's disease cannot be cured yet, considerable efforts are being made to at least delay this cognitive decline among elderly in order to maintain and prolong the quality of their life. This can also be achieved by non-pharmacological approaches such as performing physical activities, cognitive training, or adhering to a Mediterranean Diet (MedDiet). One of the components of MedDiet - extra-virgin olive oil (EVOO) - has considerable health benefits. The purpose of this review is to examine the effect of EVOO intake on the delay of cognitive decline among the elderly. The methodology is based on a literature review of available sources found on the research topic in three acknowledged databases: Web of Science, Scopus, and PubMed. The results of in vitro and in vivo studies indicate that the regular intake of EVOO is associated with enhanced cognitive functions, which means that this oil may have a neuroprotective effect and could positively prevent the development of dementia, especially Alzheimer's dementia. It is believed that secoiridoid oleuropein is responsible for this effectiveness. Furthermore, there is also a need of more randomized controlled studies or longitudinal observational studies to be performed to confirm the efficacy of the beneficial health effect of EVOO on the delay of cognitive decline.

Simultaneous Purification and Separation of Syringoside and Oleuropein from Syringa oblata Lindl. Extract Using Macroporous Resin

This study developed an efficient method to simultaneously separate and purify syringoside and oleuropein from Syringa oblata Lindl. extract using macroporous resins. The adsorption and desorption property of 11 resins were systematically evaluated. Based on the adsorption performance, HPD-100B resin was selected for the separation of syringoside and oleuropein. The HPD-100B resin fitted well to the Langmuir isotherm model (R2 > 0.97), as ascertained by the results of the static adsorption experiment. Kinetic and dynamic adsorption/desorption experiments were conducted using the HPD-100B resin to optimize the separation parameters of syringoside and oleuropein. On the optimal parameters, syringoside and oleuropein were obtained from the 20% and 40% ethanol eluates, respectively. In addition, the adsorption effluent (15–60 BV) contained a large amount of syringoside with less impurities; therefore, this part was also collected for further syringoside separation and enrichment of syringoside. By only one cycle treatment, the syringoside and oleuropein contents in the final products increased by 7.1-fold and 8.2-fold, respectively, compared to the initial extract. The method developed in this study provides a potential basis for the industrial-scale enrichment and separation of syringoside and oleuropein from S. oblata extract.

Vasculoprotective Role of Olive Oil Compounds via Modulation of Oxidative Stress in Atherosclerosis

Existing evidence supports the significant role of oxidative stress in the endothelial injury, and there is a direct link between increased oxidative stress, and the development of endothelial dysfunction. Endothelial dysfunction precedes the development of atherosclerosis and subsequent cardiovascular disease (CVD). The overproduction of reactive oxygen species facilitates the processes, such as oxidative modification of low-density lipoproteins and phospholipids, reduction in the NOS-derived nitric oxide, and the functional disruption of high-density lipids that are profoundly involved in atherogenesis, inflammation, and thrombus formation in vascular cells. Thus, under oxidative stress conditions, endothelial dysfunction was found to be associated with the following endothelial alterations: reduced nitric oxide bioavailability, increased anticoagulant properties, increased platelet aggregation, increased expression of adhesion molecules, chemokines, and cytokines. In this review, we summarized the evidence indicating that endothelial damage triggered by oxidation can be diminished or reversed by the compounds of olive oil, a readily available antioxidant food source. Olive oil bioactive compounds exhibited a potent capability to attenuate oxidative stress and improve endothelial function through their anti-inflammatory, anti-oxidant, and anti-thrombotic properties, therefore reducing the risk and progression of atherosclerosis. Also, their molecular mechanisms of action were explored to establish the potential preventive and/or therapeutic alternatives to the pharmacological remedies available.

Oleuropein inhibits migration ability through suppression of epithelial-mesenchymal transition and synergistically enhances doxorubicin-mediated apoptosis in MCF-7 cells

Distinct metastasis is one of the main causes of breast cancer (BC)-related mortality and epithelial-mesenchymal transition (EMT) is a primary step in metastasis dissemination. On the other hand, doxorubicin (DOX) is an effective chemotherapeutic agent against BC; unfortunately, its clinical use is limited by dose-dependent side effects. Therefore, extensive efforts have been dedicated to suppressing metastasis of BC and also to overcome DOX side effects together with keeping its antitumor efficacy. Studies supported the role of oleuropein (OLEU) in reducing DOX-induced side effects besides its antitumor actions. In this study, the antimigratory effect of OLEU was assessed and real-time PCR (RT-PCR) was used to detect OLEU effect on the expression level of EMT markers, in MCF-7 cells. The cytotoxic effect of OLEU and DOX was assessed by MTT assay, whereas the ratio of apoptosis was investigated by flow cytometry. The results showed that migration ability of MCF-7 cells remarkably decreased in OLEU treated group and RT-PCR results showed that OLEU may exert its antimigratory action by suppressing EMT through downregulation of sirtuin1 (SIRT1). Also, the results indicated that both OLEU and DOX were cytotoxic to MCF-7 cells, whereas DOX-OLEU cotreatment led to additive cytotoxicity and apoptosis rate. This study provides evidence regarding the suppressive role of OLEU on MCF-7 cells migration ability through suppression of EMT, and for the first time, it was proposed that SIRT1 downregulation can be involved in the OLEU antimigratory effect. Also, the findings demonstrated that OLEU can reduce DOX-induced side effects by reducing its effective dose.

Investigation of antioxidant and antihemolytic activities of Algerian defatted olive fruits (olea europaea L.) at two ripening stages

BACKGROUND: Olive fruits have become extremely valuable because they have important nutrient properties and have shown positive benefits for human health. The chemical composition and organoleptic characteristics may be influenced by genotype and some agronomic factors like olive drupe harvesting date. OBJECTIVE: In this study, the greatest interest is to clarify and to give more information for Algerian Olea europaea L. by investigation of their total phenolic and flavonoid contents, phenolic compounds identification, total antioxidant capacity and antihemolytic activity at two levels of the olive ripening process. METHODS: Colorimetric methods were used to quantify total phenolic and flavonoid contents. The phenolic composition was done by HPLC technique. The antioxidant activity was assessed by measuring radical scavenging activity against 2,2’-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) radical cation (ABTS• +) expressed as Trolox Equivalent Antioxidant Capacity (TEAC), Ferric Reducing Antioxidant Power (FRAP) and antihemolytic activity. RESULTS: The harvesting time effect on HPLC analysis of olive fruits was significant. Interestingly, the phenolic composition of the olive fruits differed greatly between samples. Two compounds usually not described in olive fruit were identified, namely morine dihydrate and coumarin. The amounts of total phenolics varied widely in the investigated extracts and ranged from 495 to 2325 mg GAE/100 g for black olives and from 865 to 2387 mg GAE/100 g for green olives, whereas the flavonoids content expressed as rutin equivalent per 100 gram of defatted dry matter was ranged between 155 and 354 mg/100 g for green olives and between 214 and 260 mg/100 g for black olives. The antioxidant activity of black and green olives ranged from 5.86 and 4.88 to 59.44 and 50.50 mM Trolox equivalents respectively, while ferric reducing antioxidant power (FRAP) was within the range of 0.36 and 0.31 to 4.41 and 3.04 mM Fe(II) respectively. Majority of extracts exhibited a beneficial antihemolytic effect. CONCLUSIONS: Results showed that the level of maturation influences the chemical composition, antioxidant and bioactive properties. Consequently, this allows us to estimate the best and optimal harvest time.

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.

Food pyramid for subjects with chronic pain: foods and dietary constituents as anti-inflammatory and antioxidant agents

Emerging literature suggests that diet constituents may play a modulatory role in chronic pain (CP) through management of inflammation/oxidative stress, resulting in attenuation of pain. We performed a narrative review to evaluate the existing evidence regarding the optimum diet for the management of CP, and we built a food pyramid on this topic. The present review also describes the activities of various natural compounds contained in foods (i.e. phenolic compounds in extra-virgin olive oil (EVO)) listed on our pyramid, which have comparable effects to drug management therapy. This review included 172 eligible studies. The pyramid shows that carbohydrates with low glycaemic index should be consumed every day (three portions), together with fruits and vegetables (five portions), yogurt (125 ml), red wine (125 ml) and EVO; weekly: legumes and fish (four portions); white meat, eggs and fresh cheese (two portions); red or processed meats (once per week); sweets can be consumed occasionally. The food amounts are estimates based on nutritional and practical considerations. At the top of the pyramid there is a pennant: it means that CP subjects may need a specific customised supplementation (vitamin B12, vitamin D, n-3 fatty acids, fibre). The food pyramid proposal will serve to guide dietary intake with to the intent of alleviating pain in CP patients. Moreover, a targeted diet can also help to solve problems related to the drugs used to combat CP, i.e. constipation. However, this paper would be an early hypothetical proposal due to the limitations of the studies.

Oleuropein attenuates hydrogen peroxide-induced autophagic cell death in human adipose-derived stem cells

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with self-renewing properties; thus, transplanting functionally enhanced MSCs might be a promising strategy for cell therapy against ischemic diseases. However, extensive oxidative damage in ischemic tissue affects the cell fate of transplanted MSCs, eventually resulting in cell damage and autophagic cell death. Oleuropein (OLP) is a bioactive compound isolated from olives and olive oil that harbors antioxidant properties. This study aimed to investigate the potential cytoprotective effects of OLP against oxidative stress and autophagic cell death in MSCs. We found that short-term priming with OLP attenuated H₂O₂-induced apoptosis by regulating the pro-apoptotic marker Bax and the anti-apoptotic markers Bcl-2 and Mcl-1. Notably, OLP inhibits H₂O₂ -induced autophagic cell death by modulating autophagy-related death signals, including mTOR (mammalian target of rapamycin), ULK1 (unc-51 like autophagy activating kinase 1), Beclin-1, AMPK (AMP-activated protein kinase), and LC3 (microtubule-associated protein 1a/1b-light chain 3). Our data suggest that OLP might reduce H₂O₂-induced autophagy and cell apoptosis in MSCs by regulating both the AMPK-ULK axis and the Bcl-2-Mcl-1 axis. Consequently, short-term cell priming with OLP might enhance the therapeutic effect of MSCs against ischemic vascular diseases, which provides an important potential improvement for emerging therapeutic strategies.

The neuroprotective effects of hydro-alcoholic extract of olive (Olea europaea L.) leaf on rotenone-induced Parkinson's disease in rat

Parkinson's disease (PD) is an age-related disease in which dopaminergic neurons in the nigrostriatal pathway are destroyed, resulting in movement and behavioral problems. Oxidative stress and the generation of reactive oxygen species play key roles in neurodegenerative diseases, such as PD. Rotenone (ROT) is a common pesticide that induces oxidative stress. Olive leaves extract (OLE) has antioxidant and neuroprotective effects. Thus, the aim of this study was to investigate the neuroprotective effects of OLE on ROT-induced oxidative stress in the midbrain of a rat model of PD. Ninety-six Wistar rats were randomly divided into the following 6 groups (n = 16 rats/group): Control, Sham, ROT, and 3 ROT + OLE (75, 150, and 300 mg/kg/daily) groups. ROT (2.5 mg/kg/48 h) was injected subcutaneously, and vehicle or OLE was orally administered for 30 days. The animals were then sacrificed, and their brains were removed. Biochemical measures, including the levels of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and malondialdehyde (MDA), and the number of tyrosine hydroxylase (TH)-positive neurons were determined, and behavioral (rotarod and hanging) tests were conducted. The balance and muscle strength of the OLE (150 and 300 mg/kg)-treated groups were significantly improved. Treatment with OLE prevented the increases in the levels of MDA, significantly improved the SOD, CAT, and GPx levels in the midbrain, and prevented the depletion of the TH-positive neurons. These findings suggested that OLE has neuroprotective properties and that it might be useful for preventing the death of dopaminergic neurons in patients with PD.

Highly potent antioxidant Olea europaea L. leaf extract affects carotid and renal haemodynamics in experimental hypertension: The role of oleuropein

Haemodynamic alterations in carotid and renal arteries are associated with the severity of target organ damage in patients with hypertension. Dietary habits, such as the Mediterranean diet, regulate blood pressure and oxidative stress, thus reduce the mortality rate due to cardiovascular diseases. In this study, our aim was to evaluate the reducing activity, antioxidant capacity and metal chelating ability of standardized Olea europaea L. leaf extract (OLE), and to test its (5, 25, 50 mg/kg) acute in vivo effects, as well as oleuropein's (OP, 10 mg/kg) on oxidative stress, carotid, renal and systemic haemodynamic parameters (blood pressure, heart rate, cardiac output, peripheral resistance) in spontaneously hypertensive rats (SHR). OLE has a higher antioxidative capacity than BHT, higher reducing ability than vitamin C, and 23 times lower capacity for metal ion chelation than EDTA. All three doses of OLE, and OP, improved oxidative stress in SHR. OLE5 improved carotid and renal haemodynamics, without significant effects on systemic haemodynamics. Two different mechanisms of antihypertensive responses to OLE were observed, OLE25 was most effective in reducing cardiovascular risks by improving systemic and regional (carotid and renal) haemodynamics, peripheral and regional vascular resistance. OLE50 causes the improvement of blood pressure and cardiac performances, but tends to retain elevated vascular resistance, therefore, reducing the inflow of blood into the brain and kidneys of the SHR. The OP did not alter systemic or regional haemodynamics, suggesting others constituents responsible for changes of cardiac function, as well as carotid and renal haemodynamics in response to OLE50.