Search Results (52)

The olive tree (Olea europaea L.) has been cultivated for millennia, with olive oil representing both a cornerstone of the Mediterranean diet and a major agricultural commodity. Its composition, rich in monounsaturated fatty acids, polyphenols, tocopherols and squalene, supports well-documented cardioprotective, antioxidant and anti-inflammatory benefits. Olive oil production generates substantial secondary streams, including pomace, leaves, pits and mill wastewater, which are rich in phenols, triterpenes and fibers. This review consolidates recent advances in their phytochemical characterization, innovative extraction technologies and health-promoting effects, while highlighting the economic and regulatory prospects for industrial adoption. Comparative analysis shows that olive leaves can produce up to 16,674.0–50,594.3 mg/kg total phenolics; oleuropein 4570.0–27,547.7 mg/kg, pomace retains 2.24 g GAE/100 g dried matrix (DM)total phenolics; oil 13.66% DM; protein 6.64% DM, and wastewater contains high concentration of phenolics content of olives. Innovative extraction techniques, such as ultrasound and microwave-assisted methods, allow for a recovery, while reducing solvent use and energy input. The analysis highlights opportunities for integrating these by-products into circular bioeconomy models, supporting the development of functional foods, nutraceutical applications and sustainable waste management. Future research should address techno-economic feasibility, regulatory harmonization and large-scale clinical validation to accelerate market translation. Full article

Olive leaves (Olea europaea) are the most abundant agricultural by-product of olive tree cultivation, generating substantial waste each year. Their disposal is deemed an environmental challenge, particularly in Mediterranean countries that dominate the olive oil sector, yet their rich bioactive profile makes them promising candidates for functional food development. This study aimed to determine the total antioxidant capacity (TAC) and total phenolic content (TPC) of olive leaf powder extracts using different extraction solvents and methods to identify the most efficient strategy for possible incorporation into functional food systems. Extractions were performed with distilled water, 70% ethanol, 80% methanol, and 50% acetone using three methods: stirring, soaking, and ultrasound-assisted extraction (UAE). TAC and TPC were quantified using the FRAP and Folin–Ciocalteu assays, respectively. Among solvents, acetone consistently yielded the highest values across most methods (TAC: 19.02 mmol Fe²⁺/L, TPC: 1289.95 mg GA/L), while ethanol also showed strong extraction performance (TAC: 15.35 mmol Fe²⁺/L; TPC: 1214.76 mg GA/L), offering a safer and more scalable option for food applications. Method-wise, UAE achieved the greatest phenolic recovery, while both UAE and stirring proved effective for antioxidant extraction. Overall, these findings provide quantitative evidence supporting possible incorporation of olive leaf powder as a valuable ingredient in functional foods and other sustainable applications, while also contributing to the circular economy through the sustainable valorization of agricultural waste. Full article

Olive tree branches (OB) and leaves (OL) from the Viseu region (Portugal) were studied for their chemical composition and liquefaction behavior using polyalcohols. Chemical analysis revealed that OL contained higher ash content (4.08%) and extractives, indicating more bioactive compounds, while OB had greater α-cellulose (30.47%) and hemicellulose (27.88%). Lignin content was higher in OL (21.64%) than OB (16.40%). Liquefaction experiments showed that increasing the temperature from 140 °C to 180 °C improved conversion, with OB showing a larger increase (52.5% to 80.9%) compared to OL (66% to 72%). OB reached peak conversion faster, and the optimal particle size for OB was 40–60 mesh, while OL performed better at finer sizes. OL benefited more from higher solvent ratios, whereas OB achieved high conversion with less solvent. FTIR analysis confirmed that acid-catalyzed liquefaction breaks down lignocellulosic structures, depolymerizes cellulose and hemicellulose, and modifies lignin, forming hydroxyl, aliphatic, and carbonyl groups. These changes reflect progressive biomass degradation and the incorporation of polyalcohol components, converting solid biomass into a reactive, polyol-rich liquid. The study highlights the distinct chemical and processing characteristics of olive branches and leaves, informing their potential industrial applications. Full article

One of the most persistent and damaging diseases in olive trees is olive knot disease. This disease is caused by an infection by the Gram-negative phytopathogenic bacterium Pseudomonas savastanoi pv. savastanoi that is notoriously difficult to control. The increasing demand for eco-friendly and sustainable agricultural solutions has driven research into plant-based agents. This study investigated the antibacterial properties of essential oils (EOs) and their constituents, olive mill wastewater (OMWW), the phenolic compound hydroxytyrosol (HTyr), and algae and garlic extracts, as well as copper-based and plant-stimulating commercial products against P. savastanoi pv. savastanoi, a significant olive tree pathogen. Antibacterial activity was determined using the Kirby–Bauer disc diffusion and broth microdilution methods. The EOs derived from Thymus vulgaris (thyme) and Origanum compactum (oregano), and their key components thymol and carvacrol, exhibited the strongest antibacterial efficacy. Conversely, the OMWW, plant-stimulating products, and algae and garlic extracts showed limited to no antibacterial activity in vitro, with their antibacterial properties determined using the disc diffusion method. While the EOs were highly effective in vitro, regardless of the testing method, their efficacy in bacterial growth inhibition was strain- and concentration-dependent, possibly highlighting some metabolic or genetic variability in the target pathogen, even though the MIC values against all tested strains of P. savastanoi pv. savastanoi were equal. Bacterial membrane disruption and the consequent leakage of metabolites were determined as the modes of action of carvacrol and oregano EO. Carvacrol also promoted plant growth in lettuce without significant phytotoxic effects, although minor necrotic lesions were observed in young olive leaves at higher concentrations, presenting these agents as potential next-generation green bactericides. Full article

Soil salinisation is threatening crop sustainability worldwide, mainly due to anthropogenic climate change. Molecular mechanisms developed to counteract salinity have been intensely studied in model plants. Nevertheless, the economically relevant olive tree (Olea europaea subsp. europaea L.), being highly exposed to soil salinisation, deserves a specific review to extract the recent genomic advances that support the known morphological and biochemical mechanisms that make it a relative salt-tolerant crop. A comprehensive list of 98 olive cultivars classified by salt tolerance is provided, together with the list of available olive tree genomes and genes known to be involved in salt response. Na⁺ and Cl^– exclusion in leaves and retention in roots seem to be the most prominent adaptations, but cell wall thickening and antioxidant changes are also required for a tolerant response. Several post-translational modifications of proteins are emerging as key factors, together with microbiota amendments, making treatments with biostimulants and chemical compounds a promising approach to enable cultivation in already salinised soils. Low and high-throughput transcriptomics and metagenomics results obtained from salt-sensitive and -tolerant cultivars, and the future advantages of engineering specific metacaspases involved in programmed cell death and autophagy pathways to rapidly raise salt-tolerant cultivars or rootstocks are also discussed. The overview of bioinformatic tools focused on olive tree, combined with machine learning approaches for studying plant stress from a multi-omics perspective, indicates that the development of salt-tolerant cultivars or rootstocks adapted to soil salinisation is progressing. This could pave the way for ‘smart oliviculture’, promoting more productive and sustainable practices under salt stress. Full article

Current research strongly suggests that phenolic compounds in extra virgin olive oil (EVOO) are potent preventive and therapeutic agents against metabolic diseases associated with inflammation and oxidative stress. Oleocanthal (OC) and oleacein (OA) are two of the most abundant and promising EVOO phenolics. To fully establish their health-promoting efficacy, additional animal studies and human clinical trials must be conducted, but the sourcing of both compounds at gram scale, reasonable cost, and ease of access remains a challenge. Here, we describe an extraction procedure to obtain OC and OA from the common privet (Ligustrum vulgare), a fast-growing, semi-evergreen shrub. We show that, compared to the olive tree, in addition to its broader geographical distribution, L. vulgare offers the benefit of yielding both OA and OC from its leaves. We also demonstrate the necessity of providing adapted enzymatic conditions during leaf treatment to optimize OC and OA concentrations in the final extracts. Full article

The olive tree is currently cultivated worldwide, with higher incidence in Mediterranean Basin. Its climate is highly favorable to the synthesis of phenolic compounds, stored in olive leaves; their consumption has been linked to a lower incidence of cancer and cardiovascular disorders for which the research interest upon this feature has increased in last decade. This study aimed (i) to review evidence about the importance of olive leaf extract (OLE) on human health and the physiological effect of its major compounds; (ii) to update the state of the art of studies conducted on the health and technological usage of olive leaf extract; (iii) to report potential uses of OLE in pharmaceuticals, food production, and cosmetics; and (iv) to prospect the future of clinical applications of OLE from diverse cultivars, especially in metabolic inflammatory conditions such as polycystic ovary syndrome (PCOS). Overall, cultivars richer in TPC, including TFC, αT, omega-3 and omega-9, present a main research target for supplementation alone or in conjunction with vitaminic compounds, due to their nutraceutical value in metabolic disorders, chronic inflammatory diseases, and anti-aging treatments, whereas cultivars with less water content might be useful as substrates for food preservation. With regard to future prospects, it would be of great interest to clarify the specific mechanisms underlying the beneficial effects of OLE on neuro-immune and cardiovascular health to design safer and healthier nature-based medicine for a wide array of costly and highly prevalent chronic diseases, such as inflammatory and metabolic-related syndromes, namely, PCOS. Full article

Background: Extra virgin olive oil is a fundamental component of the Mediterranean diet. It contains several molecules that sustain human well-being by modulating cellular metabolism and exerting antioxidant, anti-inflammatory, and anti-ageing effects to protect normal tissues, and it can exert anti-angiogenic and pro-apoptotic effects on cancer cells. Metabolites found in different parts of the olive tree, including leaves, also possess properties that might help in cancer prevention and promote wellness in aging. Olive mill wastewater (OMWW), a liquid residue produced during olive oil extraction, represents an environmental issue. However, it is rich in phytochemicals with potential beneficial properties. Dietary supplements based on OMWW can be produced for nutritional supplementation with advantages to the ecology. Purpose: This work aims to measure hematochemical, anthropometric, and metabolomic parameters in volunteers taking an OMWW dietary supplement, Oliphenolia^® (OMWW-OL). Methods: The supplementation of OMWW-OL 25 mL twice daily for 30 days was tested on a pilot cohort of volunteers with characteristics close to metabolic syndrome. Hematochemical, anthropometric, serum biomarkers and serum metabolomic parameters were analyzed before the intervention, at 30 days, and 30 days after stopping consumption. Results: A total of 29 volunteers were enrolled, and 23 completed the study. The participants’ parameters at baseline were measured, and then twice daily at 30 days of treatment and 30 days after assumption discontinuation. Although treatment was with an olive derivative, their weight did not increase. Their body mass index, instead of augmenting, slightly decreased, particularly in the women. Also, hydration increased, especially in the women, while blood pressure, glycemia, and insulin decreased. Cholesterol, high-density lipoproteins, and triglycerides were stable, and LDL levels decreased, while vitamin D levels, alongside calcium, perceptibly increased. Albumin also increased. All the values were in support of an equilibrium, with no damaging effects. By mass spectrometry analysis, we also found favorable changes in the vitamin D/histamine and homocysteine/methionine ratios, an increase in a new metabolite of unknown formula, and the vitamin D/unknown metabolite ratio. Conclusions: Supplementation of OMWW-OL has no detrimental effects and might imply the beneficial modulation of several biological parameters. Although this is a small pilot study, with limited potency, it preliminarily suggests that the OMWW extract use could be potentially valuable for people at risk of metabolic syndrome. Some of these parameters could also be relevant in supporting healthy ageing and in cancer prevention. Full article

Olive trees not only produce olives but also generate a substantial amount of waste and by-products, including leaves, pomace (the solid remains after pressing olives for oil), and wastewater from the olive oil-making process. The waste products, particularly the leaves, contain bioactive compounds, especially phenolic compounds, known for their health benefits, such as high antioxidant potential and the ability to reduce inflammation. These compounds have shown promise in preventing and treating cancer. This review, based on in vitro evidence, provides a detailed description and discussion of the mechanisms through which these compounds from olive leaves can prevent development, the ways they might act against cancer cells, and their potential to increase the sensitivity of tumor cells to conventional anticancer therapy. The possible synergistic effects of these compounds suggest that olive leaf extracts may offer a promising approach for cancer treatment, compared with isolated compounds, thus providing novel possibilities for cancer therapy. Full article

The olive tree is crucial to the Mediterranean agricultural economy but faces significant threats from climate change and soil-borne pathogens like Verticillium dahliae. This study assesses the dual role of an onion extract formulation, rich in organosulfur compounds, as both biostimulant and antifungal agent. Research was conducted across three settings: a controlled climatic chamber with non-stressed olive trees; an experimental farm with olive trees under abiotic stress; and two commercial olive orchards affected by V. dahliae. Results showed that in the climatic chamber, onion extract significantly reduced MDA levels in olive leaves, with a more pronounced reduction observed when the extract was applied by irrigation compared to foliar spray. The treatment also increased root length by up to 37.1% compared to controls. In field trials, irrigation with onion extract increased the number of new shoots by 148% and the length of shoots by 53.5%. In commercial orchards, treated trees exhibited reduced MDA levels, lower V. dahliae density, and a 26.7% increase in fruit fat content. These findings suggest that the onion extract effectively reduces oxidative stress and pathogen colonization, while enhancing plant development and fruit fat content. This supports the use of the onion extract formulation as a promising, sustainable alternative to chemical treatments for improving olive crop resilience. Full article

Olea europaea L. is the most valuable species of the Olea type, and its products offer a wide range of therapeutical uses. The olive tree has been extensively studied for its nourishing qualities, and the “Mediterranean diet”, which includes virgin olive oil as a key dietary component, is strongly associated with a reduced risk of cardiovascular disease and various malignancies. Olive leaves, a by-product in the olive harvesting process, are valued as a resource for developing novel phytomedicines. For this purpose, two ethanolic extracts obtained from Olivae folium from Spain (OFS) and Greece (OFG) were investigated. Our findings contribute to a wider characterization of olive leaves. Both extracts displayed important amounts of phenolic compounds and pentacyclic triterpenes, OFG having higher concentrations of both polyphenols, such as oleuropein and lutein, as well as triterpenes, such as oleanolic acid and maslinic acid. The antioxidant capacity is similar for the two extracts, albeit slightly higher for OFG, possibly due to metal polyphenol complexes with antioxidant activity. The extracts elicited an antimicrobial effect at higher doses, especially against Gram-positive bacteria, such as Streptococcus pyogenes. The extract with lower inorganic content and higher content of polyphenols and triterpenic acids induced a strong anti-radical capacity, a selective cytotoxic effect, as well as antimigratory potential on A375 melanoma cells and antiangiogenic potential on the CAM. No irritability and a good tolerability were noted after evaluating the extracts on the in vivo Hen’s Egg Test−Chorioallantoic Membrane (HET-CAM). Therefore, the present data are suggestive for the possible use of the two types of olive leaf products as high-antioxidant extracts, potentially impacting the healthcare system through their use as antimicrobial agents and as anticancer and anti-invasion treatments for melanoma. Full article

An eco-friendly approach towards the recovery of value-added extracts from olive tree leaves with the aid of supercritical CO₂ at 30 MPa was carried out. The impact of extraction temperature (35–90 °C) and presence of co-solvents (ethanol, water, and aqueous ethanol) on the total phenolic, flavonoid, and pigment content, as well as oleuropein, hydroxytyrosol, tyrosol, and α-tocopherol content was determined. In addition, the antioxidant activity of extracts from tree leaves using DPPH, ABTS, and CUPRAC assays was investigated. The results of the study showed that the most effective supercritical CO₂ extraction was at 90 °C with an addition of ethanol, which enabled the separation of extract with the highest content of tested compounds. Some of the highest recorded values were for oleuropein 1.9 mg/g, for carotenoids 5.3 mg/g, and for α-tocopherol 2.0 mg/g. Our results are expected to contribute to the efforts towards the valorization of olive leaves as a sustainable source of valuable compounds, and boost local economies as well as the interest of pharmaceutical, food, and cosmetic industries for novel food by-product applications. Full article

This study aspires to evaluate the antibacterial and inhibitory effects of carbohydrate digestive enzymes in tree leaves that are widely distributed in the Mediterranean region. Leaves were sequentially extracted with solvents of increasing polarity. The results demonstrated a wide range of phenolic (3.5–770.7 mg gallic acid equivalent g⁻¹) and flavonoid (0.2–321.3 mg catechin equivalent g⁻¹) contents in leaf extracts. The minimum inhibitory and bactericidal concentration of leaf extracts was determined for six bacteria using the broth microdilution method. The polar extracts of carob, lentisk, and white mulberry leaves exerted strong antibacterial potency against Gram-positive bacteria, while the susceptibility of Escherichia coli on relative apolar extracts of carob, fig, and olive leaves was also observed. In parallel, the inhibitory effects of leaf extracts on carbohydrate digestive enzymes were evaluated. A robust inhibition of α-glucosidase was found for carob and lentisk leaf extracts, followed by extracts produced by white mulberry and olive leaves. Carob and lentisk leaves also act as a-amylase inhibitors at high concentrations. Overall, this study provides valuable data for the nutraceutical value of the “forgotten” treasure of Mediterranean tree leaves and assesses these plants as potential sources of antibacterial and carbohydrate digestive enzyme inhibitory agents for drug discovery. Full article

Alzheimer’s disease manifests as a complex pathological condition, with neuroinflammation, oxidative stress and cholinergic dysfunction being a few of the many pathological changes. Due to the complexity of the disease, current therapeutic strategies aim at a multitargeted approach, often relying on a combination of substances with versatile and complementary effects. In the present study, a unique combination of α-lipoic acid, citicoline, extracts of leaves from olive tree and green tea, vitamin D3, selenium and an immune-supporting complex was tested in scopolamine-induced dementia in rats. Using behavioral and biochemical methods, we assessed the effects of the combination on learning and memory, and elucidated the mechanisms of these effects. Our results showed that, compared to its components, the experimental combination was most efficient in improving short- and long-term memory as assessed by the step-through method as well as spatial memory as assessed by T-maze and Barnes maze underlined by decreases in AChE activity (p < 0.05) and LPO (p < 0.001), increases in SOD activity in the cortex (p < 0.05) and increases in catalase (p < 0.05) and GPx (p < 0.01) activities and BDNF (p < 0.001) and pCREB (p < 0.05) levels in the hippocampus. No significant histopathological changes or blood parameter changes were detected, making the experimental combination an effective and safe candidate in a multitargeted treatment of AD. Full article

Artificial intelligence has many applications in various industries, including agriculture. It can help overcome challenges by providing efficient solutions, especially in the early stages of development. When working with tree leaves to identify the type of disease, diseases often show up through changes in leaf color. Therefore, it is crucial to improve the color brightness before using them in intelligent agricultural systems. Color improvement should achieve a balance where no new colors appear, as this could interfere with accurate identification and diagnosis of the disease. This is considered one of the challenges in this field. This work proposes an effective model for olive disease diagnosis, consisting of five modules: image enhancement, feature extraction, clustering, and deep neural network. In image enhancement, noise reduction, balanced colors, and CLAHE are applied to LAB color space channels to improve image quality and visual stimulus. In feature extraction, raw images of olive leaves are processed through triple convolutional layers, max pooling operations, and flattening in the CNN convolutional phase. The classification process starts by dividing the data into clusters based on density, followed by the use of a deep neural network. The proposed model was tested on over 3200 olive leaf images and compared with two deep learning algorithms (VGG16 and Alexnet). The results of accuracy and loss rate show that the proposed model achieves (98%, 0.193), while VGG16 and Alexnet reach (96%, 0.432) and (95%, 1.74), respectively. The proposed model demonstrates a robust and effective approach for olive disease diagnosis that combines image enhancement techniques and deep learning-based classification to achieve accurate and reliable results. Full article