Olive leaf extract inhibits metastatic melanoma spread through suppression of epithelial to mesenchymal transition

Olive leaf extract (OLE) reduces mast cell-mediated allergic inflammation

Mast cell-mediated reactions promote various allergic disease, including anaphylaxis, allergic rhinitis, asthma, and atopic dermatitis. Different data demonstrated an intricate relationship between the use of antihistaminic drugs, the onset of side effects, and the development of resistance, underscoring the importance to find novel therapeutic approaches to treat allergic diseases. Olive leaf extract (OLE), is a by-product of the olive tree rich in bioactive compounds, known for its numerous therapeutic properties, including antioxidant, anti-tumoral and antidiabetic effects. In this study, we investigated the effect of OLE on the mast-cell-mediated allergic inflammation using human mast cells HMC-1.2. OLE reduced histamine and β-Hexosaminidase release from HMC cells activated by phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI) through modulation of calcium signal. Moreover, OLE decreased the PMACI-stimulated gene expression of proinflammatory cytokines such as tumor necrosis factor-a (TNF-α), interleukin-8 (IL-8) and interleukin-6 (IL-6) in human mast cells. This result was confirmed by multiplex assay in which the pre-treatment with OLE reduced the effective secretion of TNF-α, IL-6 and IL-8. These effects were correlated to ROS reduction and modulation of both mitochondrial mass and membrane potential. Finally, the inhibitory effect of OLE was nuclear factor (NF)-kB dependent as demonstrated by both activity assay and Western Blot analysis. Taken together, our results demonstrated that OLE inhibits mast-cell-derived allergic inflammation modulating mast cells degranulation, proinflammatory cytokines release and NF-kB activation. Therefore, OLE could represent a novel potential therapeutic approach for the treatment of mast cell-associated disorders.

Olive Leaves as a Source of Anticancer Compounds: In Vitro Evidence and Mechanisms

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.

Synergistic cytotoxicity of olive leaf extract-loaded lipid nanocarriers combined with Newcastle disease virus against cervical cancer cells

Despite recent medical progress, cervical cancer remains a major global health concern for women. Current standard treatments have limitations such as non-specific toxicity that necessitate development of safer and more effective therapeutic strategies. This research evaluated the combinatorial effects of olive leaf extract (OLE), rich in anti-cancer polyphenols, and the oncolytic Newcastle disease virus (NDV) against human cervical cancer cells. OLE was efficiently encapsulated (>94% loading) within MF59 lipid nanoparticles and nanostructured lipid carriers (NLCs; contains Precirol as NLC-P, contains Lecithin as NLC-L) to enhance stability, bioavailability, and targeted delivery. Physicochemical analysis confirmed successful encapsulation of OLE within nanoparticles smaller than 150 nm. In vitro cytotoxicity assays demonstrated significantly higher toxicity of the OLE-loaded nanoparticle formulations on HeLa cancer cells versus HDF normal cells (P<0.05). MF59 achieved the highest encapsulation efficiency, while NLC-P had the best drug release profile. NDV selectively infected and killed HeLa cells versus HDF cells. Notably, combining NDV with OLE-loaded nanoparticles led to significantly enhanced synergistic cytotoxicity against cancer cells (P<0.05), with NLC-P (OLE) and NDV producing the strongest effects. Apoptosis and cell cycle analyses confirmed the increased anti-cancer activity of the combinatorial treatment, which induced cell cycle arrest. This study provides evidence that co-delivery of OLE-loaded lipid nanoparticles and NDV potentiates anti-cancer activity against cervical cancer cells in vitro through a synergistic mechanism, warranting further development as a promising alternative cervical cancer therapy.

Antioxidant Extracts from Greek and Spanish Olive Leaves: Antimicrobial, Anticancer and Antiangiogenic Effects

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.

Potential Therapeutic Properties of Olea europaea Leaves from Selected Cultivars Based on Their Mineral and Organic Profiles

Olive leaves are consumed as an extract or as a whole herbal powder with several potential therapeutic benefits attributed to polyphenols, tocopherol's isomers, and flavonoids, among others. This study assessed the potential variance in the functional features presented by olive leaves from three different Portuguese cultivars-Cobrançosa, Madural, and Verdeal-randomly mix-cultivated in the geographical area of Vale de Salgueiros. Inorganic analysis determined their mineral profiles while an organic analysis measured their total phenolic and flavonoid content, and scanned their phenolic and tocopherol and fatty acid composition. The extracts' biological activity was tested by determining their antimicrobial and antioxidant power as well as their ability to inhibit acetylcholinesterase, butyrylcholinesterase, MAO-A/B, and angiotensin-I-converting enzyme. The inorganic profiles showed them to be an inexpensive source able to address different mineral deficiencies. All cultivars appear to have potential for use as possible antioxidants and future alternative antibiotics against some multidrug-resistant microorganisms, with caution regarding the arsenic content in the Verdeal cultivar. Madural's extract displayed properties to be considered a natural multitarget treatment for Alzheimer's and Parkinson's diseases, depression, and cardiometabolic and dual activity for blood pressure modulation. This work indicates that randomly cultivating different cultivars significantly modifies the leaves' composition while keeping their multifaceted therapeutic value.

Nutritional Supplements for Skin Health-A Review of What Should Be Chosen and Why

Supplementation of micronutrients is considered to be crucial in the reinforcement of the skin's barrier. In this paper, 14 nutritional compounds commonly used in food or pharmaceutic industries were analyzed in terms of influencing skin conditions. The major objective of this paper was to provide a narrative review of the available literature regarding several chosen compounds that are currently widely recommended as supplements that aim to maintain proper and healthy skin conditions. We conducted a review of the literature from PubMed, Scopus, and Web of Science until September 2023 without any other restrictions regarding the year of the publication. Ultimately, we reviewed 238 articles, including them in this review. Each of the reviewed compounds, including vitamin A, vitamin C, vitamin D, vitamin E, curcumin, chlorella, Omega-3, biotin,Ppolypodium leucotomos, Simmondsia chinesis, gamma oryzanol, olive leaf extract, spirulina, and astaxanthin, was observed to present some possible effects with promising benefits for a skin condition, i.e., photoprotective radiation. Adding them to the diet or daily routine might have a positive influence on some skin inflammatory diseases such as atopic dermatitis or psoriasis. Further, UV radiation protection facilitated by some supplements and their impact on human cells might be helpful during chemotherapy or in preventing melanoma development. Further research is needed because of the lack of clear consensus regarding the doses of the described compounds that could provide desirable effects on the skin.

Oleuropein in olive leaf, branch, and stem extracts: stability and biological activity in human cervical carcinoma and melanoma cells

Olive leaves as a main byproduct of olive oil and fruit industry are a valuable source of phytochemicals such as polyphenols, with multiple biomedical effects. Apart from leaves, olive branches and stems make up a significant amount of olive waste. It is well known that the drying process and long-term storage affect the stability and concentration of polyphenols present in raw materials. For that matter, two different means of storing olive waste, at room temperature and +4 °C, were compared by determining the content of the polyphenol oleuropein (OLE) in olive leaf, branch, and stem extracts (LE, BE, and SE) by HPLC-DAD method. Total phenols (TPC), o-diphenols (o-DPC), and total flavonoids (TFC) content in extracts were assessed by UV-Vis measurements. LE prepared from leaves stored at +4 °C had the highest OLE content, 30.7 mg g-1 of dry extract (DE). SE from stems stored at +4 °C was the richest in TPC and TFC (193 mg GAE/g DE and 82.9 mg CE/g DE, respectively), due to the higher purity of the extract. The biological activity of extracts was determined on cervical cancer (HeLa), melanoma (A375), metastatic melanoma (A375M) tumor cell lines, and on spontaneously immortalized cell line of keratinocytes (HaCaT), using the MTT assay. The data show that all extracts had a similar dose-dependent effect on cell viability in HeLa cells, while the effect of LE on melanoma A375 and A375M, and HaCaT cells was cell-line dependent.

From antiquity to contemporary times: how olive oil by-products and waste water can contribute to health

Since antiquity, numerous advantages of olive oil and its by-products have been recognized in various domains, including cooking, skincare, and healthcare. Extra virgin olive oil is a crucial component of the Mediterranean diet; several of its compounds exert antioxidant, anti-proliferative, anti-angiogenic and pro-apoptotic effects against a variety of cancers, and also affect cellular metabolism, targeting cancer cells through their metabolic derangements. Numerous olive tree parts, including leaves, can contribute metabolites useful to human health. Olive mill waste water (OMWW), a dark and pungent liquid residue produced in vast amounts during olive oil extraction, contains high organic matter concentrations that may seriously contaminate the soil and surrounding waters if not managed properly. However, OMWW is a rich source of phytochemicals with various health benefits. In ancient Rome, the farmers would employ what was known as amurca, a mulch-like by-product of olive oil production, for many purposes and applications. Several studies have investigated anti-angiogenic and chemopreventive activities of OMWW extracts. The most prevalent polyphenol in OMWW extracts is hydroxytyrosol (HT). Verbascoside and oleuperin are also abundant. We assessed the impact of one such extract, A009, on endothelial cells (HUVEC) and cancer cells. A009 was anti-angiogenic in several in vitro assays (growth, migration, adhesion) and inhibited angiogenesis in vivo, outperforming HT alone. A009 inhibited cells from several tumors in vitro and in vivo and showed potential cardioprotective effects mitigating cardiotoxicity induced by chemotherapy drugs, commonly used in cancer treatment, and reducing up-regulation of pro-inflammatory markers in cardiomyocytes. Extracts from OMWW and other olive by-products have been evaluated for biological activities by various international research teams. The results obtained make them promising candidates for further development as nutraceutical and cosmeceutical agents or dietary supplement, especially in cancer prevention or even in co-treatments with anti-cancer drugs. Furthermore, their potential to offer cardioprotective benefits opens up avenues for application in the field of cardio-oncology.

Antiproliferative and Proapoptotic Effects of Erucin, a Diet-Derived H2S Donor, on Human Melanoma Cells

Melanoma is the most dangerous form of skin cancer and is characterized by chemotherapy resistance and recurrence despite the new promising therapeutic approaches. In the last years, erucin (ERU), the major isothiocyanate present in Eruca sativa, commonly known as rocket salads, has demonstrated great efficacy as an anticancer agent in different in vitro and in vivo models. More recently, the chemopreventive effects of ERU have been associated with its property of being a H₂S donor in human pancreatic adenocarcinoma. Here, we investigated the effects of ERU in modulating proliferation and inducing human melanoma cell death by using multiple in vitro approaches. ERU significantly reduced the proliferation of different human melanoma cell lines. A flow cytometry analysis with annexin V/PI demonstrated that ERU was able to induce apoptosis and cell cycle arrest in A375 melanoma cells. The proapoptotic effect of ERU was associated with the modulation of the epithelial-to-mesenchymal transition (EMT)-related cadherins and transcription factors. Moreover, ERU thwarted the migration, invasiveness and clonogenic abilities of A375 melanoma cells. These effects were associated with melanogenesis impairment and mitochondrial fitness modulation. Therefore, we demonstrated that ERU plays an important role in inhibiting the progression of melanoma and could represent a novel add-on therapy for the treatment of human melanoma.