Biological Activity of Phenolic Compounds in Extra Virgin Olive Oils through Their Phenolic Profile and Their Combination with Anticancer Drugs Observed in Human Cervical Carcinoma and Colon Adenocarcinoma Cells

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.

Quercus floribunda Lindl. Ex A. Camus; a tremendous remedy against inflammation and associated symptoms

Crude extracts prepared from aerial parts and nut galls of Quercus floribunda Lindl. Ex. A. Camus were evaluated for phytochemical screening, in vitro antioxidant, and in vivo analgesic, anti-inflammatory and antipyretic activities. Various solvents including methanol (M), acetone (A), distilled water (DW), distilled water + methanol (DWM) were used for extraction. Highest total phenolic (66.9 ± 0.05 μg GAE/mgE) and flavonoid content (38.4 ± 0.72 μg QE/mgE) were measured in QFAA extract by colorimetric methods. Cumulative maximum concentrations of polyphenols were quantified in QFMG, QFAA, and QFMA extracts i.e. 19.036, 15. 574 and 11.647 μg/mg of extract by RP-HPLC analysis. From aerial parts extracts, apentacyclic tritepenoid, glutinol was isolated using column chromatography techniques and structure was elucidated using spectroscopic techniques. QFDWMA (205.5 ± 0.56 μg AAE/mg of extract) showed highest total reducing power while highest total antioxidant capacity (207.1 ± 0.49 AAE/mg of extract) and free radical scavenging potential (96.1 ± 0.42%) were observed in QFAA extract. QFAA extract showed significant (p ≤ 0.001) analgesic potential in different pain models i.e. hot plate method, cold plate method, Haffner's tail clip method and acetic acid induced writhing assay having 50.20%, 62.07%, 57.26% and 70.49% analgesia respectively at 300 mg/kg. QFAA extract showed maximum anti-inflammatory activity in croton oil induced edema (68.83%) and in carrageenan induced paw edema models (72.32%) at 300 mg/kg concentration. QFAA extract markedly reduced the rectal temperature at 300 mg/kg concentration, in brewer's yeast induced pyrexia model. Detailed investigations can be executed in future to determine the molecular mechanisms of these pharmacological attributes.

Phenolic metabolites as therapeutic in inflammation and neoplasms: molecular pathways explaining their efficacy

Polyphenols, also known as phenolic compounds, are chemical substances containing aromatic rings as well as at least two hydroxyl groups. Natural phenolic compounds exist widely in plants, which protect plants from ultraviolet radiation and other insults. Phenolic compounds have superior pharmacological and nutritional properties (antimicrobial, antibacterial, antiviral, anti-sclerosis, antioxidant, and anti-inflammatory activities), which have been paid more and more attention by the scientific community. Phenols can protect key cellular components from reactive free radical damage, which is mainly due to their property to activate antioxidant enzymes and alleviate oxidative stress and inflammation. It can also inhibit or isolate reactive oxygen species and transfer electrons to free radicals, thereby avoiding cell damage. It has a regulatory role in glucose metabolism, which has a promising prospect in the prevention and intervention of diabetes. It also prevents cardiovascular disease by regulating blood pressure and blood lipids. Polyphenols can inhibit cell proliferation by affecting Erk1/2, CDK, and PI3K/Akt signaling pathways. Polyphenols can function as enhancers of intrinsic defense systems, including superoxide dismutase (SOD) and glutathione peroxidase (GPX). Simultaneously, they can modulate multiple proteins and transcription factors, making them promising candidates in the investigation of anti-cancer medications. This review focuses on multiple aspects of phenolic substances, including their natural origins, production process, disinfection activity, oxidative and anti-inflammatory functions, and the effects of different phenolic substances on tumors.

A Systematic Ex-Vivo Study of the Anti-Proliferative/Cytotoxic Bioactivity of Major Olive Secoiridoids' Double Combinations and of Total Olive Oil Phenolic Extracts on Multiple Cell-Culture Based Cancer Models Highlights Synergistic Effects

Several individual olive oil phenols (OOPs) and their secoiridoid derivatives have been shown to exert anti-proliferative and pro-apoptotic activity in treatments of human cancer cell lines originating from several tissues. This study evaluated the synergistic anti-proliferative/cytotoxic effects of five olive secoiridoid derivatives (oleocanthal, oleacein, oleuropein aglycone, ligstroside aglycone and oleomissional) in all possible double combinations and of total phenolic extracts (TPEs) on eleven human cancer cell lines representing eight cell-culture-based cancer models. Individual OOPs were used to treat cells for 72 h in half of their EC₅₀ values for each cell line and their synergistic, additive or antagonistic interactions were evaluated by calculating the coefficient for drug interactions (CDI) for each double combination of OOPs. Olive oil TPEs of determined OOPs' content, originating from three different harvests of autochthonous olive cultivars in Greece, were evaluated as an attempt to investigate the efficacy of OOPs to reduce cancer cell numbers as part of olive oil consumption. Most combinations of OOPs showed strong synergistic effect (CDIs < 0.9) in their efficacy, whereas TPEs strongly impaired cancer cell viability, better than most individual OOPs tested herein, including the most resistant cancer cell lines evaluated.

Minor Variety of Campania Olive Germplasm ("Racioppella"): Effects of Kaolin on Production and Bioactive Components of Drupes and Oil

The effects of climate change have a great impact on the Mediterranean regions which are experiencing an increase in drought periods with extreme temperatures. Among the various solutions reported to reduce the damage caused by extreme environmental conditions on olive plants, the application of anti-transpirant products is widespread. In an increasingly current scenario of climate change, this study was designed to evaluate the effect of kaolin on the quantitative and qualitative parameters of drupes and oil in a little-known olive cultivar known as "Racioppella", belonging to the autochthonous germplasm of Campania (Southern Italy). To this purpose, the determination of maturation index, olive yield/plant, and bioactive components analysis (anthocyanins, carotenoids, total polyphenols, antioxidant activity, and fatty acids) were carried out. Kaolin applications showed no statistically significant differences in terms of production/plant while a significant increase in the drupe oil content was observed. Kaolin treatments resulted in increased anthocyanins (+24%) and total polyphenols (+60%) content and at the same time a significant increase in the antioxidant activity (+41%) of drupes was recorded. As far as oil is concerned, the results showed an increase in monounsaturated fatty acids, oleic and linoleic acids, and total polyphenols (+11%). On the basis of the results obtained, we can conclude that kaolin treatment can be considered as a sustainable solution to improve qualitative parameters in olive drupes and oil.

Comparative Assessment of the Antioxidant and Anticancer Activities of Plicosepalus acacia and Plicosepalus curviflorus: Metabolomic Profiling and In Silico Studies

This study presents a comparison between two mistletoe plants—P. acacia and P. curviflorus—regarding their total phenolic contents and antioxidant and anticancer activities. P. curviflorus exhibited a higher total phenolics content (340.62 ± 19.46 mg GAE/g extract), and demonstrated higher DPPH free radical scavenging activity (IC₅₀ = 48.28 ± 3.41µg/mL), stronger reducing power (1.43 ± 0.54 mMol Fe⁺²/g) for ferric ions, and a greater total antioxidant capacity (41.89 ± 3.15 mg GAE/g) compared to P. acacia. The cytotoxic effects of P. acacia and P. curviflorus methanol extracts were examined on lung (A549), prostate (PC-3), ovarian (A2780) and breast (MDA-MB-231) cancer cells. The highest anticancer potential for the two extracts was observed on PC-3 prostate cancer cells, where P. curviflorus exhibited more pronounced antiproliferative activity (IC₅₀ = 25.83 μg/mL) than P. acacia (IC₅₀ = 34.12 μg/mL). In addition, both of the tested extracts arrested the cell cycle at the Pre-G1 and G1 phases, and induced apoptosis. However, P. curviflorus extract possessed the highest apoptotic effect, mediated by the upregulation of p53, Bax, and caspase-3, 8 and 9, and the downregulation of Bcl-2 expression. In the pursuit to link the chemical diversity of P. curviflorus with the exhibited bioactivities, its metabolomic profiling was achieved by the LC-ESI-TOF-MS/MS technique. This permitted the tentative identification of several phenolics—chiefly flavonoid derivatives, beside some triterpenes and sterols—in the P. curviflorus extract. Furthermore, all of the metabolites in P. curviflorus and P. acacia were inspected for their binding modes towards both CDK-2 and EGFR proteins using molecular docking studies in an attempt to understand the superiority of P. curviflorus over P. acacia regarding their antiproliferative effect on PC-3 cancer cells. Docking studies supported our experimental results; with all of this taken together, P. curviflorus could be regarded as a potential prospect for the development of chemotherapeutics for prostate cancer.

Extra Virgin Olive Oil Secoiridoids Modulate the Metabolic Activity of Dacarbazine Pre-Treated and Treatment-Naive Melanoma Cells

Nowadays, many individuals, whether healthy or diagnosed with disease, tend to expose themselves to various easily accessible natural products in hopes of benefiting their health and well-being. Mediterranean populations have traditionally used olive oil not only in nutrition but also in cosmetics, including skincare. In this study, the phenolic profile—composed of twelve compounds altogether, including the secoiridoids oleocanthal (OCAL) and oleacein (OCEIN)—of extra virgin olive oil (EVOO) from autochthonous cultivars from Croatia was determined using ¹H qNMR spectroscopy and HPLC-DAD analysis, and its biological activity was investigated in melanoma cell lines. The EVOO with the highest OCEIN content had the strongest anti-cancer activity in A375 melanoma cells and the least toxic effect on the non-cancerous keratocyte cell line (HaCaT). On the other hand, pure OCAL was shown to be more effective and safer than pure OCEIN. Post-treatment with any of the EVOO phenolic extracts (EVOO-PEs) enhanced the anti-cancer effect of the anti-cancerous drug dacarbazine (DTIC) applied in pre-treatment, while they did not compromise the viability of non-cancerous cells. The metastatic melanoma A375M cell line was almost unresponsive to the EVOO-PEs themselves, as well as to pure OCEIN and OCAL. Our results demonstrate that olive oils and/or their compounds may have a potentially beneficial effect on melanoma treatment. However, their usage can be detrimental or futile, especially in healthy cells, due to inadequately applied concentrations/combinations or the presence of resistant cells.

Protective Effects and Benefits of Olive Oil and Its Extracts on Women's Health

Women and men share similar diseases; however, women have unique issues, including gynecologic diseases and diseases related to menstruation, menopause, and post menopause. In recent decades, scientists paid more attention to natural products and their derivatives because of their good tolerability and effectiveness in disease prevention and treatment. Olive oil is an essential component in the Mediterranean diet, a diet well known for its protective impact on human well-being. Investigation of the active components in olive oil, such as oleuropein and hydroxytyrosol, showed positive effects in various diseases. Their effects have been clarified in many suggested mechanisms and have shown promising results in animal and human studies, especially in breast cancer, ovarian cancer, postmenopausal osteoporosis, and other disorders. This review summarizes the current evidence of the role of olives and olive polyphenols in women's health issues and their potential implications in the treatment and prevention of health problems in women.

Potential of olive oil and its phenolic compounds as therapeutic intervention against colorectal cancer: a comprehensive review

Colorectal cancer (CRC) is one of the major causes of death across the world and incidence rate of CRC increasing alarmingly each passing year. Diet, genomic anomalies, inflammation and deregulated signalling pathways are among the major causes of CRC. Because of numerous side effects of CRC therapies available now, researchers all over the world looking for alternative treatment/preventive strategy with lesser/no side effects. Olive oil which is part of Mediterranean diet contains numerous phenolic compounds that fight against free radicals and inflammation and also well-known for protective role against CRC. The current review focused on the recent evidences where olive oil and its phenolic compounds such as hydroxytyrosol, oleuropein and oleocanthal showed activities against CRC as well to analyse the cellular and molecular signalling mechanism through which these compounds act on. These compounds shown to combat CRC by reducing proliferation, migration, invasion and angiogenesis through regulation of numerous signalling pathways including MAPK pathway, PI3K-Akt pathway and Wnt/β-catenin pathway and at the same time, induce apoptosis in different CRC model. However, further research is an absolute necessity to establish these compounds as nutritional supplements and develop therapeutic strategy in CRC.

Polyphenols, Olive oil and Colonrectal cancer: the effect of Mediterranean Diet in the prevention

In recent years, scientific research has shown that the incidence of various diseases, including some cancers, is relatively low in the Mediterranean Countries compared to that of other European countries or North America. This support the hypothesis that the Mediterranean diet, rich in bioactive food components, including methyl group donors, polyphenols, and fatty acids has efficacy in terms of prevention. Few studies evaluated the efficacy of Med Diet on colon cancer however they all support the beneficial effects of this Diet in preventing cancer.

Chemical Profiling, Antioxidant, Cytotoxic Activities and Molecular Docking Simulation of Carrichtera annua DC. (Cruciferae)

Our investigation intended to analyze the chemical composition and the antioxidant activity of Carrichtera annua and to evaluate the antiproliferative effect of C. annua crude and phenolics extracts by MTT assay on a panel of cancerous and non-cancerous breast and liver cell lines. The total flavonoid and phenolic contents of C. annua were 47.3 ± 17.9 mg RE/g and 83.8 ± 5.3 mg respectively. C. annua extract exhibited remarkable antioxidant capacity (50.92 ± 5.64 mg GAE/g) in comparison with BHT (74.86 ± 3.92 mg GAE/g). Moreover, the extract exhibited promising reduction ability (1.17 mMol Fe+2/g) in comparison to the positive control (ascorbic acid with 2.75 ± 0.91) and it displayed some definite radical scavenging effect on DPPH (IC50 values of 211.9 ± 3.7 µg/mL). Chemical profiling of C. annua extract was achieved by LC-ESI-TOF-MS/MS analysis. Forty-nine hits mainly polyphenols were detected. Flavonoid fraction of C. annua was more active than the crude extract. It demonstrated selective cytotoxicity against the MCF-7 and HepG2 cells (IC50 = 13.04 and 19.3 µg/mL respectively), induced cell cycle arrest at pre-G1 and G2/M-phases and displayed apoptotic effect. Molecular docking studies supported our findings and revealed that kaempferol-3,7-O-bis-α-L-rhamnoside and kaempferol-3-rutinoside were the most active inhibitors of Bcl-2. Therefore, C. annua herb seems to be a promising candidate to further advance anticancer research. In extrapolation, the intake of C. annua phenolics might be adventitious for alleviating breast and liver malignancies and tumoral proliferation in humans.

Olive Pâté by Multi-Phase Decanter as Potential Source of Bioactive Compounds of Both Nutraceutical and Anticancer Effects

In the oil sector, a novelty in the centrifugal extraction system is represented by the multi-phase decanters (DMF) that work without adding process water and with the advantage of recovering a dried pomace and a by-product, called “pâté”, consisting of the pulp and its vegetation water, without traces of stone. The pâté has a high content of phenolic compounds, mainly represented by secoiridoids and verbascoside. The present work investigated the efficacy of two different ways of debittering (by sequential filtrations and spontaneous fermentation) of DMF pâté from three olive cultivars (Olea europaea L. “Leccino”, “Carboncella” and “Tortiglione”) to make the pâté edible, and, contemporary, investigated also the effect of its phenolic bioactive extracts on pathogenic bacteria and colon cancer cell model. Daily filtrations of pâté of the three cultivars have been shown to be more efficient in phenolic degradation. The activity of the indigenous microflora on the other hand takes a longer time to degrade the phenolic component and therefore to de-bitter it. None of pâté showed antibacterial activity. Colorimetric assay MTS for cell viability and metabolic activity tested on colon cancer cells Caco-2 and HCT116 suggest a potential beneficial effect of the dried extracts probably related to the modulation of gene expression under these treatments.

Antique Traditional Practice: Phenolic Profile of Virgin Olive Oil Obtained from Fruits Stored in Seawater

Virgin olive oil (VOO) is a functional food specific to the Mediterranean diet and related to human health, especially as a protector of cardiovascular health, in the prevention of several types of cancers, and in modification of immune and inflammatory response. Phenolic compounds have central importance for these extraordinary health benefits. In the production of high-quality olive oils, it is very important to process freshly picked olives and avoid any storage of fruits. However, in Croatia there is a very traditional and environmentally friendly method of olive oil production, where olive fruits are stored in seawater for some time prior to processing. This practice is also notable nowadays since there are people who prefer the characteristic flavor of the “seawater olive oil”, although some people argue against its quality and biomedical relevance. In this study, the phenolic contents of VOO prepared from the immediately processed fresh olives and olives processed after storage in seawater were compared with the use of high-performance liquid chromatography-mass spectrometry (HPLC-MS) and spectrophotometric analysis. The results suggest that “seawater olive oil” should be considered as a safe food of biomedical relevance, as it still contains a significant proportion of important phenolics like hydroxytyrosol, tyrosol and oleacein (e.g., 63.2% of total phenols in comparison to VOO).