Oleuropein prevents oxidative myocardial injury induced by ischemia and reperfusion

Pretreatment with oleuropein protects the neonatal brain from hypoxia-ischemia by inhibiting apoptosis and neuroinflammation

Hypoxic-ischemic (HI) encephalopathy is a cerebrovascular injury caused by oxygen deprivation to the brain and remains a major cause of neonatal mortality and morbidity worldwide. Therapeutic hypothermia is the current standard of care but it does not provide complete neuroprotection. Our aim was to investigate the neuroprotective effect of oleuropein (Ole) in a neonatal (seven-day-old) mouse model of HI. Ole, a secoiridoid found in olive leaves, has previously shown to reduce damage against cerebral and other ischemia/reperfusion injuries. Here, we administered Ole as a pretreatment prior to HI induction at 20 or 100 mg/kg. A week after HI, Ole significantly reduced the infarct area and the histological damage as well as white matter injury, by preserving myelination, microglial activation and the astroglial reactive response. Twenty-four hours after HI, Ole reduced the overexpression of caspase-3 and the proinflammatory cytokines IL-6 and TNF-α. Moreover, using UPLC-MS/MS we found that maternal supplementation with Ole during pregnancy and/or lactation led to the accumulation of its metabolite hydroxytyrosol in the brains of the offspring. Overall, our results indicate that pretreatment with Ole confers neuroprotection and can prevent HI-induced brain damage by modulating apoptosis and neuroinflammation.

Cardioprotective effect of oleuropein in a cisplatin-induced cardiotoxicity model in rats

This study investigated the cardioprotective effect of oleuropein against cisplatin-induced cardiac damage in terms of inflammatory, oxidative stress and cardiac parameters. In this study, 40 female Wistar albino rats were divided into four groups: control, cisplatin, oleuropein and cisplatin+oleuropein. To establish the experimental model, oleuropein (200 mg/kg) was administered for 14 days and cisplatin (7 mg/kg) was administered as a single dose on the seventh day. Cisplatin increased MDA cardiac parameters (CK, CK-MB and cTnI) and inflammatory cytokines (TNF-α, IL-1β and IL-6) in cardiac tissue and decreased GSH, GSH-Px and catalase levels. On the other hand, oleuropein improved cardiac parameters and decreased inflammatory cytokine and oxidative stress levels in cardiac tissue.

Dexmedetomidine attenuates myocardial ischemia-reperfusion injury in hyperlipidemic rats by inhibiting inflammation, oxidative stress and NF-κB

The present study was conducted to determine the protective effect of Dexmedetomidine (DEX) in myocardial ischemia-reperfusion injury in hyperlipidemic rats. Towards this, the effect of DEX was first evaluated on the infarct size and the histopathology of cardiac tissues using TTC and H and E staining, and it was found that DEX significantly improved the infarct size and architecture of the myocardial tissues following the I/R injury. DEX also showed significant improvement in various examined hemodynamic parameters (e.g., LVSP, and ± dp/dtmax ) in a dose-dependent manner. The lipid profile (LDL, VLDL, TC, TG, and HDL level) of the rats were also found significantly improved in DEX-treated rats. The level of various pro-inflammatory cytokines (IL-1β, IL-6, IL-10, IL-17, and TNF-α), cardiac injury (CK, CK-MB, Troponin I AST, ALT, and LDH), and oxidative stress (MDA, SOD, and GSH) biomarkers were also found to be restored near to the normal in DEX-treated group. It has been found that DEX also significantly reduces apoptosis of rat cardiomyocytes. In western blot analysis, DEX showed a significant reduction in the activation of NF-κB. In conclusion, our study demonstrated the protective effect of Dexmedetomidine in myocardial ischemia-reperfusion injury in hyperlipidemic rats possibly via amelioration of oxidative stress, and inflammation apoptosis.

Oleuropein: Chemistry, extraction techniques and nutraceutical perspectives-An update

Olive family (Oleaceae) contains several species among which Olea europaea L. is mostly used for production of olive oils. Various parts of olive tree are rich source of diverse bioactive compounds such as Apigenin, elenolic acid, Hydroxytyrosol, Ligstroside, Oleoside, Oleuropein, Oleuropein aglycone, Tyrosol, etc. Among these, oleuropein, a secoiridoid is predominantly found in olive leaves and young olive fruits of different species of Oleaceae family. Scientists have adopted numerous extraction methods (conventional & latest) to increase the yield of oleuropein. Among these techniques, maceration, soxhlet, microwave-assisted, ultrasonication, and supercritical fluid methods are most commonly employed for extraction of oleuropein. Evidently, this review emphasizes on various in-vitro and in-vivo studies focusing on nutraceutical properties of oleuropein. Available literature highlights the pharmaceutical potential of oleuropein against various diseases such as obesity, diabetes, cardiovascular complications, neurodegenerative diseases, cancer, inflammation, microbial infections, and oxidation. This review will benefit the scientific community as it narrates comprehensive literature regarding absorption, metabolism, bioavailability, extraction techniques, and nutraceutical perspectives associated with oleuropein.

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.

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.

Syringa microphylla Diels: A comprehensive review of its phytochemical, pharmacological, pharmacokinetic, and toxicological characteristics and an investigation into its potential health benefits

BACKGROUND

Syringa microphylla Diels is a plant in the family Syringa Linn. For hundreds of years, its flowers and leaves have been used as a folk medicine for the treatment of cough, inflammation, colds, sore throat, acute hepatitis, chronic hepatitis, early liver cirrhosis, fatty liver, and oesophageal cancer.

PURPOSE

For the first time, we have comprehensively reviewed information on Syringa microphylla Diels that is not included in the Pharmacopoeia, clarified the pharmacological mechanisms of Syringa microphylla Diels and its active ingredients from a molecular biology perspective, compiled in vivo and in vitro animal experimental data and clinical data, and summarized the toxicology and pharmacokinetics of Syringa microphylla Diels. The progress in toxicology research is expected to provide a theoretical basis for the development of new drugs from Syringa microphylla Diels, a natural source of compounds that are potentially beneficial to human health.

METHODS

The PubMed, Google Scholar, China National Knowledge Infrastructure, Web of Science, SciFinder Scholar and Thomson Reuters databases were utilized to conduct a comprehensive search of published literature as of July 2021 to find original literature related to Syringa microphylla Diels and its active ingredients.

RESULTS

To date, 72 compounds have been isolated and identified from Syringa microphylla Diels, and oleuropein, verbascoside, isoacteoside, echinacoside, forsythoside B, and eleutheroside B are the main active components. These compounds have antioxidant, antibacterial, anti-inflammatory, and neuroprotective effects, and their safety and effectiveness have been demonstrated in long-term traditional applications. Molecular pharmacology experiments have indicated that the active ingredients of Syringa microphylla Diels exert their pharmacological effects in various ways, primarily by reducing oxidative stress damage via Nrf2/ARE pathway regulation, regulating inflammatory factors and inducing apoptosis through the MAPK and NF-κB pathways.

CONCLUSION

This comprehensive review of Syringa microphylla Diels provides new insights into the correlations among molecular mechanisms, the importance of toxicology and pharmacokinetics, and potential ways to address the limitations of current research. As Syringa microphylla Diels is a natural low-toxicity botanical medicine, it is worthy of development and utilization and is an excellent choice for treating various diseases.

Effects of oleuropein on rat's atria and thoracic aorta: a study of antihypertensive mechanisms

Oleuropein (OLE) is the main bioactive ingredient in the leaves of the olive plant Olea europaea L. (Oleaceae), which has proven beneficial due to the antiinflammatory, antiatherogenic, anticancer, antimicrobial, and antiviral effects. This study aimed to investigate the antihypertensive and vasodilator potential of OLE by analyzing its acute effects on spontaneous atrial contractions and vasomotor responses of the isolated thoracic aorta in rats. We showed that the application of OLE induces negative chronotropic and inotropic effects on the heart. OLE also causes mild aortic vasodilation given that the maximal reduction in tension of intact aortic rings precontracted with phenylephrine was approximately 30%. This vasodilation is likely dependent on the nitric oxide released from the endothelium based on the effect obtained on denuded and phenylephrine precontracted aortic rings and responses reordered following vasoconstriction induced by high concentrations of K⁺ and heparin. Our findings provide a basis for further testing of OLE cardiovascular effects, which may lead to subsequent clinical research for its application in the treatment of hypertension and heart disease.

The effect of nutraceuticals on multiple signaling pathways in cardiac fibrosis injury and repair

Cardiac fibrosis is one of the most common pathological conditions caused by different heart diseases, including myocardial infarction and diabetic cardiomyopathy. Cardiovascular disease is one of the major causes of mortality worldwide. Cardiac fibrosis is caused by different processes, including inflammatory reactions and oxidative stress. The process of fibrosis begins by changing the balance between production and destruction of extracellular matrix components and stimulating the proliferation and differentiation of cardiac fibroblasts. Many studies have focused on finding drugs with less adverse effects for the treatment of cardiovascular disease. Some studies show that nutraceuticals are effective in preventing and treating diseases, including cardiovascular disease, and that they can reduce the risk. However, big clinical studies to prove the therapeutic properties of all these substances and their adverse effects are lacking so far. Therefore, in this review, we tried to summarize the knowledge on pathways and mechanisms of several nutraceuticals which have shown their usefulness in the prevention of cardiac fibrosis.

Effect of oleuropein on oxidative stress, inflammation and apoptosis induced by ischemia-reperfusion injury in rat kidney

AIMS

This study aimed to evaluate the effect of oleuropein (OLE), the main phenolic compound present in olive leaves, on kidney ischemia-reperfusion injury (IRI) and to explore the underlying protective mechanism.

MAIN METHODS

Rat kidneys were subjected to 60 min of bilateral warm ischemia followed by 120 min of reperfusion. OLE was administered orally 48 h, 24 h and 30 min prior to ischemia at doses of 10, 50 and 100 mg/kg body weight. The creatinine, urea, uric acid concentrations and lactate dehydrogenase (LDH) activity in plasma were evaluated. Oxidative stress and inflammation parameters were also assessed. Renal expression of AMP-activated protein kinase (p-AMPK), endothelial nitric oxide synthase (eNOS), mitogen-activated protein kinases (MAPK), inflammatory proteins and apoptotic proteins were evaluated using Western blot.

KEY FINDINGS

Our results showed that OLE at 50 mg/kg reduced kidney IRI as revealed by a significant decrease of plasmatic creatinine, urea, uric acid concentrations and LDH activity. In parallel, OLE up-regulated antioxidant capacities. Moreover, OLE diminished the level of CRP and the expression of cyclooxygenase 2 (COX-2). Finally, OLE enhanced AMPK phosphorylation as well as eNOS expression whereas MAPK, and cleaved caspase-3 implicated in cellular apoptosis were attenuated in the ischemic kidneys.

SIGNIFICANCE

In conclusion, this study shows that OLE could be used as therapeutic agent to reduce IRI through its anti-oxidative, anti-inflammatory and anti-apoptotic properties.

Protective effect of oleuropein on ketamine-induced cardiotoxicity in rats

The antioxidant and cardioprotective effects of oleuropein have been reported in several studies; however, its effect on ketamine cardiotoxicity has not been known yet. The aim of this study was to investigate the effects of oleuropein in ketamine-induced cardiotoxicity model in rats. A total of 28 male Wistar Albino rats were included in the study and they were randomly divided into four groups, each having seven rats. Group 1 (control): rats were given 1 mL of DMSO by oral gavage method for 7 days. Group 2 (ketamine): on the seventh day of the study, 60 mg/kg ketamine was administered intraperitoneally. Then, 60 mg/kg ketamine was administered intraperitoneally every 10 min for 3 h. Group 3 (oleuropein): rats were given 200 mg/kg/day oleuropein by oral gavage method for 7 days. Group 4 (oleuropein + ketamine): rats were given 1 × 200 mg/kg oleuropein by oral gavage method for 7 days. Furthermore, 60 mg/kg ketamine was administered intraperitoneally on the seventh day of the experiment. Then, 60 mg/kg ketamine was administered intraperitoneally every 10 min for 3 h. Serum cardiac marker (TnI, CK-MB and CK) levels were measured. Histopathological analysis was performed on a portion of the cardiac tissue. Cardiac tissue oxidative stress and antioxidant markers (MDA, GSH, GSH.Px and CAT), TNF-α, IL-6, NF-κB, COX-2 and Nrf-2 gene expressions, and protein conversion levels of related genes were determined. Data obtained showed that ketamine administration increased MDA (p < 0.001), TNF-α (p < 0.01), IL-6 (p < 0.01), COX-2 (p < 0.001) and NF-κB (p < 0.001) levels, as well as serum TnI (p < 0.001), CK-MB (p < 0.001) and CK (p < 0.01) levels whereas decreased GSH (p < 0.05) and Nrf-2 (p < 0.05) levels, as well as GSH-Px (p < 0.001) and CAT (p < 0.05) enzyme activities. Oleuropein administration was observed to decrease MDA, TNF-α, IL-6, COX-2, NF-κB, TnI, CK-MB and CK levels close to the control group and to increase GSH levels and GSH-Px and CAT enzyme activities close to the control group. This study showed that oleuropein administration reversed the increased oxidative stress and inflammation as a result of the use of ketamine and had protective effects on the heart.

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

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

Oleuropein, a Bioactive Compound from Olea europaea L., as a Potential Preventive and Therapeutic Agent in Non-Communicable Diseases

Growing scientific literature data suggest that the intake of natural bioactive compounds plays a critical role in preventing or reducing the occurrence of human chronic non-communicable diseases (NCDs). Oleuropein, the main phenolic component of Olea europaea L., has attracted scientific attention for its several health beneficial properties such as antioxidant, anti-inflammatory, cardio- and neuro-protective, and anti-cancer. This article is a narrative review focused on the current literature concerning the effect of oleuropein in NCDs, such as neuro- and cardiovascular diseases, diabetes mellitus, chronic kidney diseases, and cancer, by its putative antioxidant and anti-inflammatory activity, but also for its other peculiar actions such as an autophagy inducer and amyloid fibril growth inhibitor and, finally, for its anti-cancer effect. Despite the increasing number of published studies, looking at the beneficial effects of oleuropein, there is limited clinical evidence focused on the benefits of this polyphenol as a nutraceutical product in humans, and many problems are still to be resolved about its bioavailability, bioaccessibility, and dosage. Thus, future clinical randomized trials are needed to establish the relation between the beneficial effects and the mechanisms of action occurring in the human body in response to the intake of oleuropein.

Water Stress, Irrigation and Concentrations of Pentacyclic Triterpenes and Phenols in Olea europaea L. cv. Picual Olive Trees

Pentacyclic triterpenes and phenols are two types of bioactive molecules found in olive trees that have important activities related to health and disease prevention. Triterpenes, including oleanolic acid, maslinic acid, erythrodiol and uvaol, show antitumoral activities, and phenols such as oleuropein, tyrosol, and hydroxytyrosol are natural antioxidants. The concentration of these metabolites is considered a marker of the quality of olives and olive oil. In recent years, a lack of rain water has caused important economic losses relating to olive trees grown in Jaén, Spain. In this work, we investigated the effect of water stress by drought on the concentration of pentacyclic triterpenes and phenols in the fruits, leaves, stems and roots of cv. Picual olive trees, by comparing the concentration found in water-stressed versus irrigated plants. We used HPLC-UV/Vis and HPLC-MS to identify and determine the concentration of each individual compound. Our results showed that important changes in the concentration of these compounds are produced in response to water stress in different organs. The total content of most of these compounds in the fruits was significantly reduced, affecting their quality and production.

Effect of oleuropein on morphine-induced hippocampus neurotoxicity and memory impairments in rats

Oleuropein, as an olive leaf extract antioxidant polyphenol, has been reported to be a free radical scavenger. This study was done to investigate the effects of oleuropein, against morphine-induced hippocampus neurotoxicity and memory impairment in rats. The Morris water maze (MWM) test was used to assess the effect of oleuropein (5, 15, and 30 mg/kg, i.p., co-administrated with morphine) on spatial learning and memory of male Wistar rats which were treated with morphine sulfate (45 mg/kg, s.c., 4 weeks). In order to evaluate the cleaved caspase-3, Bax, and Bcl2 protein expression (as biochemical markers of apoptosis) in CA1 area of hippocampus tissue, the western blot test was used. Also, to evaluate the oxidative stress status of hippocampus CA1 area tissue, the malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity were assessed. The data showed that oleuropein treatment (15 and 30 mg/kg) improves the spatial learning and memory impairments in morphine-treated animals. Also, oleuropein treatment decreased the apoptosis and oxidative stress levels in the hippocampus CA1 area of morphine-treated rats. Oleuropein can prevent the spatial learning and memory impairments in morphine-treated rats. Molecular mechanisms underlying the observed effects could be at least partially related to the inhibition of neuronal apoptosis and oxidative stress in the hippocampus CA1 area of morphine-treated rats.

Hydroxytyrosol, Tyrosol and Derivatives and Their Potential Effects on Human Health

The Mediterranean diet and olive oil as its quintessential part are almost synonymous with a healthy way of eating and living nowadays. This kind of diet has been highly appreciated and is widely recognized for being associated with many favorable effects, such as reduced incidence of different chronic diseases and prolonged longevity. Although olive oil polyphenols present a minor fraction in the composition of olive oil, they seem to be of great importance when it comes to the health benefits, and interest in their biological and potential therapeutic effects is huge. There is a growing body of in vitro and in vivo studies, as well as intervention-based clinical trials, revealing new aspects of already known and many new, previously unknown activities and health effects of these compounds. This review summarizes recent findings regarding biological activities, metabolism and bioavailability of the major olive oil phenolic compounds—hydroxytyrosol, tyrosol, oleuropein, oleocanthal and oleacein—the most important being their antiatherogenic, cardioprotective, anticancer, neuroprotective and endocrine effects. The evidence presented in the review concludes that these phenolic compounds have great pharmacological potential, however, further studies are still required.

Gastroprotective effects of oleuropein and thymol on indomethacin-induced gastric ulcer in Sprague-Dawley rats

Ethnopharmacological studies demonstrated that thymol (Thym) and oleuropein (Ole) have therapeutic potential for gastric ulcers. The molecular mechanism underlying the gastroprotective effects of these compounds have not been elucidated yet especially for their individual and combination use at high dose. Therefore, this study was conducted to explore their gastroprotective mechanisms on indomethacin (Indo)-induced gastric ulcer model. Ole (50,100, 250, and 500 mg/kg) and Thym (50,100, 200, and 500 mg/kg) were orally administered to the rats 10 min before the induction of ulcer with Indo. The combination of 500 mg/kg doses of Ole and Thym were applied. The gastric mucosa was evaluated histopathologically. Moreover, TAC/TOS, tumor necrosis factor-alpha (TNF-α), prostaglandin E₂ (PGE₂), endothelial nitric oxide synthase (eNOS), and caspase-3 levels were assessed by ELISA and the caspase-3 and TNF-α expressions were quantified by qRT-PCR. Indo-induced histopathological changes while Ole and Thym pretreatment prevented these effects. Unlike the 500 mg/kg dose of Ole treatment, the 500 mg/kg dose of Thym administration enhanced these damages. The decreased TAC, PGE₂ levels and increased TOS, eNOS, TNF-α, caspase-3 levels were obtained in Indo group. However, these changes were reversed by Ole and Thym groups except the 500 mg/kg dose of Thym and the combination treatment groups. Similar trends were observed in the caspase-3 and TNF-α expression levels. These results demonstrated that enhanced inflammation, oxidant/antioxidant imbalance, and apoptotic activities were occurred in Indo, 500 mg/kg dose of Thym and the combination treatment groups while not in the other groups. The findings demonstrated the gastroprotective ability of Ole and low doses of Thym in gastric ulcer models.

Oleuropein Aglycone Protects against MAO-A-Induced Autophagy Impairment and Cardiomyocyte Death through Activation of TFEB

Age-associated diseases such as neurodegenerative and cardiovascular disorders are characterized by increased oxidative stress associated with autophagy dysfunction. Oleuropein aglycone (OA), the main polyphenol found in olive oil, was recently characterized as an autophagy inducer and a promising agent against neurodegeneration. It is presently unknown whether OA can have beneficial effects in a model of cardiac stress characterized by autophagy dysfunction. Here, we explored the effects of OA in cardiomyocytes with overexpression of monoamine oxidase-A (MAO-A). This enzyme, by degrading catecholamine and serotonin, produces hydrogen peroxide (H₂O₂), which causes oxidative stress, autophagic flux blockade, and cell necrosis. We observed that OA treatment counteracted the cytotoxic effects of MAO-A through autophagy activation, as displayed by the increase of autophagic vacuoles and autophagy-specific markers (Beclin1 and LC3-II). Moreover, the decrease in autophagosomes and the increase in autolysosomes, indicative of autophagosome-lysosome fusion, suggested a restoration of the defective autophagic flux. Most interestingly, we found that the ability of OA to confer cardioprotection through autophagy induction involved nuclear translocation and activation of the transcriptional factor EB (TFEB). Our data provide strong evidence of the beneficial effects of OA, suggesting its potential use as a nutraceutical agent against age-related pathologies involving autophagy dysfunction, including cardiovascular diseases.

Cardioprotection and natural polyphenols: an update of clinical and experimental studies

Mechanisms involved in ischemia–reperfusion injury.

Critical Review on the Significance of Olive Phytochemicals in Plant Physiology and Human Health

Olive oil displays remarkable organoleptic and nutritional features, which turn it into a foodstuff appreciated by consumers, and a basic component of the Mediterranean diet. Indeed, the noticed benefits of including olive oil in the diet have been assigned to the presence of diverse bioactive compounds with different molecular structures. These compounds confer a wide range of biological properties to this food matrix, including the prevention of distinct human diseases as well as the modulation of their severity. The most relevant bioactive compounds present in olive oil correspond to benzoic and cinnamic acids, phenolic alcohols and secoiridoids, and also flavonoids. Over the last decades, several studies, devoted to gaining a further insight into the relative contribution of the separate groups and individual compounds for their biological activities, have been conducted, providing relevant information on structure-activity relationships. Therefore, this paper critically reviews the health benefits evidenced by distinct phenolic compounds found in olive oils, thus contributing to clarify the relationship between their chemical structures and biological functions, further supporting their interest as essential ingredients of wholesome foods.

Oleuropein Is Responsible for the Major Anti-Inflammatory Effects of Olive Leaf Extract

Olive leaves are rich in polyphenolic compounds that are known to have antioxidant, antimicrobial, and anti-inflammatory activities. Therefore, olive leaf extract (OLE) is considered as a natural supplement. In this study we evaluated the antibacterial and the anti-inflammatory effect of OLE and its individual phenolic components in vitro. Polymorphonuclear cells (PMNCs) were isolated from the whole blood using Histopaque solution and cultured in RPMI-enriched medium. Tumor necrosis factor α (TNFα) level was determined by ELISA after 24 h of lipopolysaccharide stimulation. The antibacterial activity of OLE was determined by well diffusion assay. We found a significant decrease in TNFα secretion level in PMNCs culture treated with OLE. Oleuropein is the only OLE component that has shown anti-inflammatory effects at a concentration of 20 μg/mL. Furthermore, OLE exhibited antibacterial activity against some gram positive bacterial strains; however, gram negative bacterial strains were resistant to OLE. Downregulation of TNFα secretion in PMNCs culture in response to OLE treatment indicates that this polyphenol-rich extract has an anti-inflammatory effect, and oleuropein is the major OLE component responsible for this effect. The antibacterial activity of OLE is limited to gram positive bacteria.

Dietary Polyphenols in the Prevention of Stroke

Polyphenols have an important protective role against a number of diseases, such as atherosclerosis, brain dysfunction, stroke, cardiovascular diseases, and cancer. Cardiovascular diseases are the number one cause of death worldwide: more people die annually from cardiovascular diseases than from any other cause. The most important behavioural risk factors of heart disease and stroke are unhealthy diet, physical inactivity, tobacco use, and excess alcohol intake. The dietary consumption of polyphenols has shown to be inversely associated with morbidity and mortality by cardio- and cerebrovascular diseases. It is well-known that the protective effects of polyphenols in vivo depend on the grade how they are extracted from food and on their intestinal absorption, metabolism, and biological action with target tissues. The aim of this review was to summarise the relation between polyphenols of different plant sources and stroke in human intervention studies, animal models, and in vitro studies.

Encapsulation of Olive Leaves Extracts in Biodegradable PLA Nanoparticles for Use in Cosmetic Formulation

The aim of the current work was to encapsulate olive leaves extract in biodegradable poly(lactic acid) nanoparticles, characterize the nanoparticles and define the experimental parameters that affect the encapsulation procedure. Moreover, the loaded nanoparticles were incorporated in a cosmetic formulation and the stability of the formulation was studied for a three-month period of study. Poly(lactic acid) nanoparticles were prepared by the nanoprecipitation method. Characterization of the nanoparticles was performed using a variety of techniques: size, polydispersity index and ζ-potential were measured by Dynamic Light Scattering; morphology was studied using Scanning Electron Microscopy; thermal properties were investigated using Differential Scanning Calorimetry; whereas FT-IR spectroscopy provided a better insight on the encapsulation of the extract. Encapsulation Efficiency was determined indirectly, using UV-Vis spectroscopy. The loaded nanoparticles exhibited anionic ζ-potential, a mean particle size of 246.3 ± 5.3 nm (Pdi: 0.21 ± 0.01) and equal to 49.2%, while olive leaves extract release from the nanoparticles was found to present a burst effect at the first 2 hours. Furthermore, the stability studies of the loaded nanoparticles’ cosmetic formulation showed increased stability compared to the pure extract, in respect to viscosity, pH, organoleptic characteristics, emulsions phases and grid.

Oleuropein prevents the development of experimental autoimmune myocarditis in rats

Oleuropein (OLE) is a natural secoiridoid that is derived from Olea europaea. OLE possesses cardioprotective effects in experimental models of hypertension, myocardial infarction, atherosclerosis and hyperlipidaemia. In the present study, the effects of OLE on experimental autoimmune myocarditis (EAM) were evaluated. EAM in rats were induced by subcutaneous injections of porcine cardiac myosin. Cardiac function parameters, myocardial pathology, myocardial inflammatory cell infiltration and nuclear factor kappa-B (NF-κB) expression were measured. Our data showed that the postmyocarditis rats exhibited increased left ventricular end systolic diameters, left ventricular end diastolic diameters, left ventricular end-diastolic pressures (LVEDP), and decreased ejection fractions. However, OLE significantly suppressed these changes in EAM rats. Histological analysis revealed that myosin induced miliary foci of discolouration on endocardial surfaces and extensive myocardial injuries with inflammatory cell infiltration were significantly improved by OLE therapy. A definitive positive correlation between the histological scores and LVEDP was observed. Moreover, OLE inhibited CD4⁺, CD8⁺ cells and macrophage infiltration in myocardium and decreased the serum production of tumour necrosis factor-a (TNF-a), interleukin-1β (IL-1β) and IL-6 in EAM rats. Expectedly, the myocardial levels of NF-κB p65, p-IκBa, IKKa were significantly attenuated by OLE, indicating the inhibitory effects of OLE on the NF-κB pathway. Furthermore, OLE decreased the myocardial expressions of phosphorylated-p38 MAPK, phosphorylated-ERK, and did not change the levels of p38 MAPK and ERK in EAM rats. Collectively, our results suggest that OLE effectively prevents the development of myocarditis, at least in part, by inhibiting the MAPKs and NF-κB mediated inflammatory responses.

Oleuropein Protects Cardiomyocyte against Apoptosis via Activating the Reperfusion Injury Salvage Kinase Pathway In Vitro

Oleuropein, the main glycoside present in olives, has been reported to have cardioprotective effect, but the exact mechanism has not been clearly elucidated. This study attempted to clarify the cardioprotective effect of oleuropein against simulated ischemia/reperfusion- (SI/R-) induced cardiomyocyte injury in vitro and further explore the underlying mechanism. Here we confirmed that oleuropein reduced the cell injury in neonatal rat cardiomyocyte induced by SI/R evidenced by decreasing MTT dye reduction and LDH activity in the culture medium. Meanwhile, the compound also inhibited reactive oxygen species excessive generation and stabilized mitochondrial membrane potential after SI/R. The flow cytometry assessment results indicated the inhibition of cellular apoptosis with oleuropein treatment. Furthermore, western blot analysis showed that oleuropein attenuated the expression of Cyt-C, c-caspase-3, and c-caspase-9, increased the Bcl-2/Bax ratio, and enhanced the phosphorylation of ERK1/2 and Akt after SI/R. However, the phosphorylation enhancement was partially abolished in the presence of LY294002 (PI3K inhibitor) and U0126 (ERK inhibitor). All these findings indicate that oleuropein has the protective potential against SI/R-induced injury and its protective effect may be partly due to the attenuation of apoptosis via the activation of the PI3K/Akt and ERK1/2 signaling pathways.

Oleuropein attenuates cognitive dysfunction and oxidative stress induced by some anesthetic drugs in the hippocampal area of rats

The present study was designed to evaluate the antioxidant effects of oleuropein against oxidative stress in the hippocampal area of rats. We used seven experimental groups as follows: Control, Propofol, Propofol-Ketamine (Pro.-Ket.), Xylazine-Ketamine (Xyl.-Ket.), and three oleuropein-pretreated groups (Ole.-Pro., Ole.-Pro.-Ket. and Ole.-Xyl.-Ket.). The oleuropein-pretreated groups received oleuropein (15 mg/kg body weight as orally) for 10 consecutive days. Propofol 100 mg/kg, xylazine 3 mg/kg, and ketamine 75 mg/kg once as ip was used on the 11th day of treatment. Spatial memory impairment and antioxidant status of hippocampus were measured via Morris water maze, lipid peroxidation marker, and antioxidant enzyme activities. Spatial memory impairment and lipid peroxidation significantly increased in Xyl.-Ket.-treated rats in comparison to the control, propofol, Ole.-Pro. and Ole.-Pro.-Ket. groups. Oleuropein pretreatment significantly reversed spatial memory impairment and lipid peroxidation in the Ole.-Xyl.-Ket. group as compared to the Xyl.-Ket.-treated rats. There was no significant difference between the control and the propofol group in lipid peroxidation and spatial memory status. Superoxide dismutase and catalase activities both significantly decreased in Xyl.-Ket.-treated rats when compared to the control, propofol, Ole.-Pro., Ole.-Pro.-Ket., and Ole.-Xyl.-Ket. groups. In contrast, glutathione peroxidase activity in Xyl.-Ket.-treated rats significantly increased as compared to the control, propofol, Pro.-Ket., Ole.-Pro., and Ole.-Pro.-Ket. groups. We concluded that xylazine in combination with ketamine is an oxidative anesthetic drug and oleuropein pretreatment attenuates cognitive dysfunction and oxidative stress induced by anesthesia in the hippocampal area of rats. We also confirmed the antioxidant properties of propofol as a promising antioxidant anesthetic agent.

Effect of oleuropein on myocardial dysfunction and oxidative stress induced by ischemic-reperfusion injury in isolated rat heart

Background

Studies have reported antioxidant effect of oleuropein in isolated rat heart.

Objective

This study was conducted to investigate whether perfusion of isolated rat heart with oleuropein, before induction of ischemia or at the onset of reperfusion, had any effect on the hemodynamic parameters, infarct size and biochemical factors following ischemic – reperfusion injury.

Materials and methods

Forty-eight male Wistar rats were divided into 6 groups: the control groups (Con-P and Con-T groups), O10-P and O50-P groups perfused with 10 and 50 μg/g heart oleuropein 5 min before the induction of ischemia and O10-T and O50-T groups perfused with 10 and 50 μg/g heart oleuropein at the beginning of the reperfusion, respectively. All hearts were subjected to 30 min global ischemia and 90 min reperfusion. Hemodynamic parameters were monitored throughout the experiment. The creatine kinase (CK) and malondialdehyde (MDA) level of coronary outflow were assayed and the infarct size measured at the end of reperfusion.

Results

We found hemodynamic parameters namely heart rate, left ventricular end diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), ±dp/dt and coronary outflow significantly improved in all groups that received oleuropein compared to the control groups. Also, the infarct size was smaller and the coronary outflow levels of CK and MDA were lower in the oleuropein groups compared to the control groups.

Conclusions

The findings suggest that perfusion of isolated rat heart with oleuropein would lead to improved myocardial dysfunction following ischemic-reperfusion injury. Our findings confirm the antioxidant potential of oleuropein.

Oxidative Stability of Edible Vegetable Oils Enriched in Polyphenols with Olive Leaf Extract

Commercially available oils (olive oil, sunflower oil, palm oil, and a vegetable shortening) were enriched in polyphenols, by adding olive leaf extract. Addition of the extract was performed in such way that the oils were enriched with 200 mg/kg polyphenols. Total polyphenols of both enriched and commercial oils were estimated by the Folin—Ciocalteau assay, while identification and quantification of individual simple phenolic compounds was performed by GC/MS and of oleuropein by HPLC analysis. The enrichment resulted in the supplementation of the commercial oils mainly with oleuropein, hydroxytyrosol, and quercetin. Antioxidant capacity and oxidative stability of the enriched oils and the commercial ones were assessed by the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging assay and the Rancimat method, respectively. Both antioxidant capacity and oxidative stability were substantially improved for all the oils studied after supplementation. By the procedure adopted, oils rich in polyphenols, mainly in oleuropein, can be produced with olive leaf extract supplementation.

Nutraceutical Properties of Olive Oil Polyphenols. An Itinerary from Cultured Cells through Animal Models to Humans

The increasing interest in the Mediterranean diet hinges on its healthy and anti-ageing properties. The composition of fatty acids, vitamins and polyphenols in olive oil, a key component of this diet, is considered a key feature of its healthy properties. Therefore, it is of significance that the Rod of Asclepius lying on a world map surrounded by olive tree branches has been chosen by the World Health Organization as a symbol of both peace and well-being. This review travels through most of the current and past research, recapitulating the biochemical and physiological correlations of the beneficial properties of olive tree (Olea europaea) polyphenols and their derivatives found in olive oil. The factors influencing the content and beneficial properties of olive oil polyphenols will also be taken into account together with their bioavailability. Finally, the data on the clinical and epidemiological relevance of olive oil and its polyphenols for longevity and against age- and lifestyle-associated pathologies such as cancer, cardiovascular, metabolic and neurodegenerative diseases are reviewed.

Computer-aided discovery of biological activity spectra for anti-aging and anti-cancer olive oil oleuropeins

Aging is associated with common conditions, including cancer, diabetes, cardiovascular disease, and Alzheimer's disease. The type of multi-targeted pharmacological approach necessary to address a complex multifaceteddisease such as aging might take advantage of pleiotropic natural polyphenols affecting a wide variety of biological processes. We have recently postulated that the secoiridoids oleuropein aglycone (OA) and decarboxymethyl oleuropein aglycone (DOA), two complex polyphenols present in health-promoting extra virgin olive oil (EVOO), might constitute anew family of plant-produced gerosuppressant agents. This paper describes an analysis of the biological activity spectra (BAS) of OA and DOA using PASS (Prediction of Activity Spectra for Substances) software. PASS can predict thousands of biological activities, as the BAS of a compound is an intrinsic property that is largely dependent on the compound's structure and reflects pharmacological effects, physiological and biochemical mechanisms of action, and specific toxicities. Using Pharmaexpert, a tool that analyzes the PASS-predicted BAS of substances based on thousands of “mechanism-effect” and “effect-mechanism” relationships, we illuminate hypothesis-generating pharmacological effects, mechanisms of action, and targets that might underlie the anti-aging/anti-cancer activities of the gerosuppressant EVOO oleuropeins.

Prophylactic and Therapeutic Effects of Oleuropein on Reperfusion-Induced Arrhythmia in Anesthetized Rat

Background:

This study was conducted to reveal that whether i.v. injection of oleuropein, the most potent polyphenolic antioxidant in olive leaf, has any effect on the magnitude of reperfusion arrhythmia in anesthetized rats or not.

Methods:

Eighty male Wistar rats were divided into 8 groups of 10 each: groups 1 and 5 were assigned as the prophylactic and treatment control groups, groups 2 and 6 as the prophylactic and treatment groups with lidocaine (10 mg/kg), groups 3 and 4 as the prophylactic groups with 10 and 50 mg/kg oleuropein (i.v.), and groups 7 and 8 as the treatment groups with 10 and 50 mg/kg oleuropein (i.v.), respectively. Reperfusion injury was induced by 5-min regional ischemia and 15-min reperfusion of left anterior descending coronary artery. Heart rate, blood pressure, and electrocardiogram were monitored throughout the procedure.

Results:

blood pressure was significantly decreased by infusion of 50 mg/kg oleuropein in groups 4 and 8, but unlike the lidocaine as a standard anti-arrhythmic drug in groups 2 and 5 had not significant effect on heart rate. The onset of arrhythmia in groups received oleuropein (groups 3, 4, 7, and 8) was significantly delayed. The mortality rate due to irreversible ventricular fibrillation was also significantly reduced in groups 3, 4, 7, and 8. The effect of lidocaine in groups 2 and 5 was more potent than that in oleuropein group.

Conclusion:

These findings indicate that i.v. injection of oleuropein possibly through its antioxidant activity reduces the magnitude of reperfusion-induced arrhythmia.

Oleuropein offers cardioprotection in rats with simultaneous type 2 diabetes and renal hypertension

Objectives:

The study aimed at examining the role of oxidative stress in cadioprotective effects of oleuropein in a rat model of simultaneous type 2 diabetes and renal hypertension.

Materials and Methods:

Five groups of male Sprague-Dawley rats including a control group, a diabetic-hypertensive group receiving vehicle, and three diabetic-hypertensive groups receiving oleuropein at 20, 40, or 60 mg/kg/day were used. Blood pressure and glucose, serum malondialdehyde, and erythrocyte superoxide dismutase were measured, and animal's hearts with ischemia/reperfusion injuries were used using Langendorff technique.

Results:

Blood pressure, blood glucose, serum malondialdehyde, infarct size, coronary effluent creatine kinase-MB, and coronary resistance of diabetic-hypertensive group were significantly higher than those of the control group, while those of the oleuropein-receiving groups were significantly lower than those of the diabetic hypertensive group receiving the vehicle. Erythrocyte superoxide dismutase, left ventricular developed pressure, and rate of rise and rate of decrease of ventricular pressure of diabetic-hypertensive group were significantly lower than those of the control group. These parameters as well as heart rate of oleuropein-receiving groups were significantly higher than those of the diabetic-hypertensive group.

Conclusion:

The findings indicate that oleuropein offered cardioprotection, which might be partly mediated by its antioxidant properties.

Effects of the olive-derived polyphenol oleuropein on human health

The use of the products derived from the olive tree on human health dates back centuries. In several civilizations, the olive tree had and still has a very strong cultural and religious symbolism. Notably, the official seal and emblem of the World Health Organization features the rod of Asclepius over a world map surrounded by olive tree branches, chosen as a symbol of peace and health. Recently, accumulating experimental, clinical and epidemiological data have provided support to the traditional beliefs of the beneficial effect provided by olive derivates. In particular, the polyphenols present in olive leaves, olives, virgin (unrefined) olive oil and olive mill waste are potent antioxidant and radical scavengers with anti-tumor and anti-inflammatory properties. Here, we review the positive impact on human health of oleuropein, the most prevalent polyphenol present in olives. In addition, we provide data collected in our laboratory on the role of oleuropein in counteracting lipid accumulation in a mouse model of non-alcoholic fatty liver disease.

Beneficial effects of the olive oil phenolic components oleuropein and hydroxytyrosol: focus on protection against cardiovascular and metabolic diseases

The overall health beneficial action of olive oil phenolic components is well established. Recent studies have elucidated the biological effects of two isolated compounds, namely oleuropein and hydroxytyrosol, with particular attention on their antioxidant activity. Thus, a protective action has been demonstrated in preclinical studies against several diseases, especially cardiovascular and metabolic disorders.

The present review will describe the biological effects of oleuropein and hydroxytyrosol, with particular attention on the molecular mechanism underlying the protective action on cardiovascular and metabolic alterations, as demonstrated by in vitro and in vivo experimental studies performed with the isolated compounds.

The role of structural C--H compared with phenolic OH sites on the antioxidant activity of oleuropein and its derivatives as a great non-flavonoid family of the olive components: a DFT study

Oleuropein and its derivatives are the main phenolic compounds of Olea europaea L. leaf and fruit. The structure-antioxidant activity relationship was considered for studying the radical scavenging activity of this non-flavonoid family of the olive components using density functional theory (DFT). The structure of these compounds were optimized employing the B3LYP/6-31G (d,p) and the role of some structural CH positions was compared with phenolic OH sites on radical scavenging. As a result, a radical unique position (C3) in the oleuropein, characterized by low BDE (Bond Dissociation Enthalpy), reasonable spin density and electron distribution, was identified. The experimental results of the previous publications of oleuropein for NO and OH scavenging confirmed the presence of this unique active site in its molecular structure. According to the results, 2,2-diphenylpicrylhydrazyl (DPPH) cannot find this non-marginal active site. Therefore, DPPH may not be a determinant assay for all antioxidant comparisons. Solvent effects were considered in all calculations using a Polarized Continuum Model (PCM) at the B3LYP/6-31G (d,p) level. Solvation calculations were carried out for benzene (ε=2.3) to simulate the oil environment compared to gas phase.

Diet-induced increase in plasma oxidized LDL promotes early fibrosis in a renal porcine auto-transplantation model

BACKGROUND

In kidney transplantation, the prevalence of hypercholesterolemia as a co-morbidity factor known to affect graft function, is rising due to the increased number of older donors in response to organ shortage as well as to the hyperlipidemic effects of immunosuppressors in recipient. This study aimed to characterize the effects of hypercholesterolemia on renal graft outcome, investigating the role of oxidized low-density lipoprotein (OxLDL).

METHODS

In vivo, we used a porcine preclinical model of renal auto-transplantation modulated by two experimental diets: a normal (n = 6) or a hyperlipidemic diet (n = 5) maintained during the 3 month follow-up after the surgical procedure. Kidney function and OxLDL levels were monitored as well as fibrosis, LOX-1 and TGF beta signaling pathways. In vitro, we used human artery endothelial cells subjected to OxLDL to investigate the TGF beta profibrotic pathway and the role of the scavenger receptor LOX-1.

RESULTS

Hyperlipidemic diet-induced increase in plasma OxLDL levels at the time of surgery correlated with an increase in proteinuria 3 months after transplantation, associated with an early graft fibrosis combined with an activation of renal TGF beta signaling. These data suggest a direct involvement of OxLDL in the hyperlipidemic diet-induced activation of the pro-fibrotic TGF beta pathway which seems to be activated by LOX-1 signaling. These results were supported by studies with endothelial cells incubated in culture medium containing OxLDL promoting TGF beta expression inhibited by LOX-1 antibody.

CONCLUSIONS

These results implicate OxLDL in the hyperlipidemic diet-promoted fibrosis in transplanted kidneys, suggesting LOX-1 as a potential therapeutic target and reinforce the need to control cholesterol levels in kidney transplant recipients.

The effect of olive leaf extract in decreasing the expression of two pro-inflammatory cytokines in patients receiving chemotherapy for cancer. A randomized clinical trial

BACKGROUND

Oral mucositis is the most common side effects of chemotherapy of all cancer with intensive treatments regimen, and is the most common side effects of head and neck radiation therapy. For steam cell transplantation, its also regarded as the most debilitating side effects.

AIMS OF THE STUDY

The objectives of this study were to assess the effect of a mouth rinse containing olive leaf extract (OLE) in preventing severe oral mucositis in patients receiving chemotherapy, and to estimate its effect in decreasing pro-inflammatory cytokine production after chemotherapy.

MATERIALS AND METHODS

This study utilized a placebo-controlled, randomized, double-blind, and cross-over design. Twenty-five patients undergoing intensive chemotherapy were randomly assigned to receive a mouth wash containing OLE, benzydamine hydrochloride, or placebo in 3 different cycles of chemotherapy. Oral mucositis severity was assessed using the World Health Organization criteria and Oral Mycositis Assessment Scale. Patients were evaluated weekly until 15 days after chemotherapy for each cycle. Salivary levels of interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were evaluated by enzyme-linked immunosorbant assay.

RESULTS

Oral mucositis rates and severity after 2 weeks were significantly lower in the OLE and benzydamine groups compared to the placebo group. The IL-1β and TNF-α levels were significantly decreased in the OLE group compared to the other groups.

CONCLUSION

Preliminary findings indicate that OLE is effective in reducing IL-1β and TNF-α levels after chemotherapy and exert a therapeutic effect and prevent development of severe oral mucositis.