Research strategies in the study of the pro-oxidant nature of polyphenol nutraceuticals

Preliminary Insights into the Cyto/Genoprotective Properties of Propolis and Its Constituent Galangin In Vitro

Propolis has been well known for centuries as a natural preventive and therapeutic agent. Its numerous health benefits are mainly attributed to its high content of phenolic compounds that have a remarkable antioxidant activity. Since phenolics may exert a dual nature (pro-oxidant and antioxidant) the aim of this study was to investigate the safety profile of the ethanolic extract of propolis and the related flavonoid galangin and their ability to protect lymphocytes from irinotecan-induced cyto/genotoxicity in vitro. Isolated human peripheral blood lymphocytes were exposed for 3 h to three concentrations of propolis extract and galangin corresponding to the average daily dose of 0.25 mL of extract [propolis in 70% ethanol (3:7, w/w)], as well as a five- and ten-fold higher concentration. Cyto- and genoprotective effects were tested using a cytokinesis-block micronucleus cytome assay. Treatment with propolis and galangin in the selected concentrations exerted high biocompatibility with lymphocytes and diminished the level of cytogenetic damage caused by irinotecan. Propolis at the same concentration offered a stronger protective effect than single galangin. Also, apoptosis was the prevailing mechanism of cell death in our experimental conditions. These preliminary results speak in favour of future investigations of propolis using other available cytogenetic methods and cell models.

Effect of Ixeris dentata extract on anti-inflammatory by inhibition of Nf-kb and cytokine levels

Chronic inflammation is persistent disease caused by unregulated activation of Nf-kb pathway and production of pro-inflammatory cytokines, induced by accumulation of reactive oxygen species above thresholds. The purpose of this study was to evaluate the anti-oxidant, anti-lipidemia, inhibition Nf-kb pathway, and reduction of pro-inflammatory cytokine activities of Ixeris dentata extract (IDE) to demonstrate its inhibitory ability against chronic inflammatory in RAW264.7. Polyphenol content, radical scavenging activity, and lipase activity inhibition of IDE were 9.2 ± 0.2 GAE mg/g dry matter, 84.7%, and 72.4%, respectively, showing high effects against anti-oxidant and lipolysis inhibitory. Furthermore, anti-inflammatory effects of IDE on LPS-induced RAW 264.7 were investigated, and expression of inflammatory genes such as Cox-2, Inos, Tnf-α, Il-6, Nf-kb, and Il-1β were decreased by 36.5%-83.4%. Studies have confirmed that IDE has excellent antioxidant, lipolysis inhibitory, and anti-inflammatory effects, and Ixeris dentata can be used as natural ingredients for food and medicine to prevent.

Phytochemical Characterization, Prooxidant, Antiproliferative and Anti-Inflammatory Potential of Meyna spinosa Roxb. Ex Link Ripe Fruit

This study highlights the prooxidant, antiproliferative and anti-inflammatory potential of ripe Meyna spinosa Roxb. Ex Link fruit extracts. Chemical analysis by high-resolution mass spectrometry and AAS identified compounds like ursolic acid, oleanolic acid, lupeol, betulin, scopoletin, phloroglucinol and secoxyloganin and micro-elements like iron, copper, zinc and manganese. Antioxidant assays (DPPH, FRAP, metal chelation, reaction oxygen species) revealed that the M. spinosa ethyl acetate extract (MSEA) had higher phenolic (37.83 mg GAE/g DW) and flavonoid (60.22 mg QE/g DW) content, showing strong antioxidant activity (IC50 of 7.5 µg/mL), while the M. spinosa methanolic extract (MSM) exhibited higher FRAP activity (39.666 µg AAE/g DW). Prooxidant activity was demonstrated through Trolox and NADH oxidation. Both extracts exhibited antiproliferative effects in A549 and MCF7 cancer cells with an increase in concentration and time. Anti-inflammatory effects were observed by reductions in nitric oxide, COX-2, IL-6 and TNF-α levels in lipopolysaccharides-stimulated RAW 264.7 and THP-1 cells. Nitrite levels reduced from 23.778 to 5.222 µM, COX-2 levels from 51.136 to 9.581 µg/mL, IL-6 levels from 62.728 ng/mL to 13.463 pg/mL and TNF-α level from 474.890 to 143.115 pg/mL. In vivo, MSEA reduced carrageenan-induced paw oedema by 23.45%.

In vitro cytotoxicity and genotoxicity assessment of methanolic extracts of vanillas from Brazilian biodiversity with commercial potential

The Vanilla genus is crucial for global production in food, perfume, and pharmaceutical industries. However, exploitation threatens some species, leading to extinction. Traditional communities use vanilla for medicinal purposes, and there are species like Vanilla chamissonis Klotzsch and Vanilla bahiana Hoehne with potential to occupy the market. For this, methanolic extraction of these two mentioned species was conducted alongside Vanilla planifolia. Analyzes of the cell viability, mutagenic and genotoxic potential were performed. In the Ames test, the assays were performed with concentrations from 0.5 and 5000 μg/ml and on five strains. Only Vanilla planifolia exhibited mutagenicity at the highest concentration in the TA98 strain. Viability tests were performed within a dose range of 0.05-5000 µg/ml and 24, 48, and 72-hour exposures. It was possible to observe a reduction in cell viability observed only at the highest concentration, for all three species and both cell types tested. Genotoxicity induction by the extracts was assessed at concentrations from 0.5 to 500 µg/ml through the cytokinesis-block micronucleus assay. No genotoxic damage or reduction in the Nucleus Division Index (NDI). The study found no mutagenicity, cytotoxicity, or genotoxicity in the species tested, indicating potential human use for food or pharmaceutical purposes.

Cell Type-Specific Anti- and Pro-Oxidative Effects of Punica granatum L. Ellagitannins

Pomegranate and its by-products contain a broad spectrum of phytochemicals, such as flavonoids, phenolic acids and tannins, having pleiotropic preventive and prophylactic properties in health disorders related to oxidative stress and microbial contamination. Here, we examined the biological effects of a pomegranate peel ellagitannins-enriched (>90%) extract, PETE. In vitro studies revealed that PETE has a strong antiradical action towards synthetic radicals and biologically relevant ROS surpassing or comparable to that of Trolox. In cellular models, it showed concentration-dependent (25-100 µg/mL) yet opposing effects depending on the cell membrane type and exposure conditions. In erythrocytes, PETE protected membrane integrity in the presence of the strong oxidant HClO and restored reduced glutathione levels to up to 85% of the control value while having much weaker acute and long-term intrinsic effects. Such protection persisted even after the removal of the extract from cells, indicating strong membrane interaction. In HeLa cancer cells, and at concentrations lower than those used for red blood cells, PETE induced robust potentiation of ROS production and mitochondrial potential dissipation, leading to autophagy-like membrane morphology changes and cell death. In S. aureus, the growth arrest and bacterial death in the presence of PETE (with MIC = 31.25 µg/mL and MBC = 125 µg/mL, respectively) can be linked to the tripled ROS induction by the extract in the same concentration range. This study indicates a specificity of ROS production by the pomegranate extract depending on the type of cell, the concentration of the extract and the time of incubation. This specificity witnesses a strong potential of the extract components as candidates in antioxidant and pro-oxidant therapy.

Antibacterial efficacy of copper-based metal-organic frameworks against Escherichia coli and Lactobacillus

The widespread and excessive use of antimicrobial drugs has resulted in a concerning rise in bacterial resistance, leading to a risk of untreatable infections. The aim of this study was to formulate a robust and efficient antibacterial treatment to address this challenge. Previous work focused on the effectiveness of the Cu-BTC metal-organic framework (MOF; BTC stands for 1,3,5-benzenetricarboxylate) in combatting various bacterial strains. Herein, we compare the antibacterial properties of Cu-BTC with our newly designed Cu-GA MOF, consisting of copper ions bridged by deprotonated gallate ligands (H2gal2-), against Escherichia coli (E. coli) and Lactobacillus bacteria. Cu-GA was synthesized hydrothermally from copper salt and naturally derived gallic acid (H4gal) and characterized for antibacterial evaluation. The gradual breakdown of Cu(H2gal) resulted in a significant antibacterial effect that is due to the release of copper ions and gallate ligands from the framework. Both copper MOFs were nontoxic to bacteria at low concentrations and growth was completely inhibited at high concentrations when treated with Cu-BTC (1500 μg for E. coli and 1700 μg for Lactobacillus) and Cu-GA (2000 μg for both bacterial strains). Furthermore, our agarose gel electrophoresis results indicate that both MOFs could disrupt bacterial cell membranes, hindering the synthesis of DNA. These findings confirm the antibacterial properties of Cu-BTC and the successful internalization of Cu2+ ions and gallic acid by bacteria from the Cu-GA MOF framework, suggesting the potential for a sustained and effective therapeutic approach against pathogenic microorganisms.

Marketable 1,3-dimethylamylamine and caffeine-based thermogenic supplements: Regulatory genotoxicity assessment through in vitro and in silico approaches

The consumption of dietary supplements to enhance physical performance has increased significantly in the last century, especially thermogenic pre-workout supplements. Nevertheless, this industry has faced criticism for inadequate safety measures surveillance in regulatory issues regarding their products. The aims of our study were to investigate two pre-workout supplements with respect to (1) mutagenicity utilizing Salmonella/microsome assay; (2) genotoxicity employing cytokinesis-block micronucleus (CBMN) assay protocols; and (3) hepatocytoxicity using WST cell proliferation, activities of lactate dehydrogenase (LDH) and alkaline phosphatase using human liver carcinoma (HepG2) and mouse fibroblast (F C3H) cells. Oxidative stress was determined through glutathione (GSH) measurement and in silico for predictions of pharmacokinetics and toxicity for the most abundant isolated substances present in these supplements. Both supplements induced mutagenicity in all examined bacterial strains, especially in the presence of exogenous metabolism. Further, tested supplements significantly elevated the formation of micronuclei (MN) as well as other cellular phenomena. Concentration- and time-dependent curves were observed for hepatotoxicity in both studied cell lines. In addition, both supplements decreased levels of intracellular and extracellular GSH. In silico predictions showed that the isolated individual compounds failed to induce the observed outcomes. Our findings provide contributions to the molecular mechanisms underlying two pre-workout supplement-induced toxicity and the need for surveillance.

The Bioactivity of a Hydroxytyrosol-Enriched Extract Originated after Direct Hydrolysis of Olive Leaves from Greek Cultivars

Nowadays, olive leaf polyphenols have been at the center of scientific interest due to their beneficial effects on human health. The most abundant polyphenol in olive leaves is oleuropein. The biological properties of oleuropein are mainly due to the hydroxytyrosol moiety, a drastic catechol group, whose biological activity has been mentioned many times in the literature. Hence, in recent years, many nutritional supplements, food products, and cosmetics enriched in hydroxytyrosol have been developed and marketed, with unexpectedly positive results. However, the concentration levels of hydroxytyrosol in olive leaves are low, as it depends on several agricultural factors. In this study, a rapid and easy methodology for the production of hydroxytyrosol-enriched extracts from olive leaves was described. The proposed method is based on the direct acidic hydrolysis of olive leaves, where the extraction procedure and the hydrolysis of oleuropein are carried out in one step. Furthermore, we tested the in vitro bioactivity of this extract using cell-free and cell-based methods, evaluating its antioxidant and DNA-protective properties. Our results showed that the hydroxytyrosol-enriched extract produced after direct hydrolysis of olive leaves exerted significant in vitro antioxidant and geno-protective activity, and potentially these extracts could have various applications in the pharmaceutical, food, and cosmetic industries.

Studying the Functional Potential of Ground Ivy (Glechoma hederacea L.) Extract Using an In Vitro Methodology

Glechoma hederacea L., known as ground ivy, has a long history of use in folk medicine. The main bioactive compounds in ground ivy are polyphenolic compounds known for their potent antioxidant and antimicrobial activities and thus have high potential as functional ingredients against bacterial infections and the occurrence of chronic diseases associated with oxidative stress in the human body. The aim of the present study was to determine the biological activity of ground ivy extract on selected human cell lines, including hepatic (HepG2), tongue (CAL 27), gastric (AGS) and colon (Caco-2) cancer cell lines by evaluating cytotoxicity, formation of reactive oxygen species and genotoxicity. The antioxidant capacity of the extract was additionally evaluated using cellular model macromolecules of protein and DNA, bovine serum album and plasmid phiX174 RF1 DNA. The effect of ground ivy extract on representatives of human microflora, including L. plantarum, E. coli and S. aureus, was also studied. The cytotoxicity of the extract depended on the type of cells treated, and the pro-oxidant effect generally decreased with increasing exposure time. The most pronounced genoprotective effect against hydroxyl radical damage was monitored in model plasmid DNA and occurred at the highest tested concentration (0.25 mg mL-1), with 95.89% preservation of the supercoiled form of the plasmid. This concentration also had the most significant antioxidant activity on the model protein-14.01% more than the positive control prepared using Trolox. The ground ivy extract showed high antimicrobial potential against the pathogenic bacteria E. coli and S. aureus.

Could alder buckthorn (Frangula alnus Mill) be a source of chemotherapeutics effective against hepato- and colorectal carcinoma? An in vitro study

Among numerous types of cancer, hepatocellular and colorectal carcinoma are important causes of mortality. Given the nature of these cancer types and their resistance, it is of great importance to find new chemotherapeutics and therapy targets, so plant products seem to be an excellent choice in such search. The main goal of this study was to investigate anticancer activity of Frangula alnus ethyl-acetate extract (FA) and its dominant constituent emodin (E) on hepatocellular and colorectal carcinoma cell lines, HepG2 and HCT116, as well as on normal MRC-5 fibroblasts. Cytotoxicity was investigated in MTT test and both FA and E showed strong reduction of cell viability in cancer cells. Flow cytometer analysis demonstrated that FA and E led to G1 phase arrest and slight accumulation of cells in the G2/M phase; additionally, annexinV-FITC/7AAD dying showed that FA and E decreased cell viability and triggered apoptosis in all cell lines. FA and E evidenced strong genotoxic potential in comet assay performed on all cell lines, while tests measuring antioxidative potential (DPPH and TBA) demonstrated strong effect of FA. It could be concluded that both FA and E have significant anticancer activity against hepatocellular and colorectal carcinoma cell lines HepG2 and HCT116, but notable selectivity was not observed.

Cellular Red-Ox system in health and disease: The latest update

Cells are continually exposed to reactive oxygen species (ROS) generated during cellular metabolism. Apoptosis, necrosis, and autophagy are biological processes involving a feedback cycle that causes ROS molecules to induce oxidative stress. To adapt to ROS exposure, living cells develop various defense mechanisms to neutralize and use ROS as a signaling molecule. The cellular redox networks combine signaling pathways that regulate cell metabolism, energy, cell survival, and cell death. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) are essential antioxidant enzymes that are required for scavenging ROS in various cell compartments and response to stressful situations. Among the non-enzymatic defenses, vitamin C, glutathione (GSH), polyphenols, carotenoids, vitamin E, etc., are also essential. This review article describes how ROS are produced as byproducts of oxidation/reduction (redox) processes and how the antioxidants defense system is directly or indirectly engaged in scavenging ROS. In addition, we used computational methods to determine the comparative profile of binding energies of several antioxidants with antioxidant enzymes. The computational analysis demonstrates that antioxidants with a high affinity for antioxidant enzymes regulate their structures.

Evaluation of different blackcurrant seed ingredients in meatballs by using conventional quality assessment and untargeted metabolomics

Blackcurrants are sources of phenolic compounds, such as anthocyanins, possessing strong antioxidant, antimicrobial and antifungal activity. Therefore, the addition of different blackcurrant pomace ingredients may affect the overall meat quality. The actual chemical profile and bioactivities of blackcurrant pomace ingredients may strongly depend on its preparation; for instance, in our study the highest values of the in vitro antioxidant capacity were determined for blackcurrant seeds after supercritical CO₂ extraction. Starting from these background conditions, in this work, we evaluated the ability of three different concentrations (namely 1, 3, and 5% w/w) of blackcurrant (BC) seeds following EtOH/water extraction (BC-AE), before supercritical fluid CO₂ extraction (BC-RS), and after supercritical fluid CO₂ extraction (BC-ASC) to affect different quality parameters of pork meatballs. These latter were stored considering three different time-points, namely 1, 3 and 6 days at 4 °C packed under modified atmosphere (i.e., 70% N₂ and 30% CO₂). Untargeted metabolomics allowed to identify several lipid and protein-related oxidation products involved in redox reactions, such as 13-L-hydroperoxylinoleic acid, (12S,13S)-epoxylinolenic acid, 9,10-epoxyoctadecenoic acid, glutathione, glutathione disulfide, L-carnosine, l-ascorbic acid, and tocotrienols. Besides, multivariate statistics applied on the metabolomics dataset confirmed that the chemical profile of meatballs was an exclusive combination of both BC inclusion levels and type of BC-ingredients considered. Our findings showed that the higher the concentration of BC seed ingredients in meatballs, the lower the cooking loss and the higher the fibre content. Also, all the ingredients significantly affected the colour parameters.

Metabolomics Analysis Reveals Novel Targets of Chemosensitizing Polyphenols and Omega-3 Polyunsaturated Fatty Acids in Triple Negative Breast Cancer Cells

Triple negative breast cancer (TNBC) is a subtype of breast cancer with typically poorer outcomes due to its aggressive clinical behavior and lack of targeted treatment options. Currently, treatment is limited to the administration of high-dose chemotherapeutics, which results in significant toxicities and drug resistance. As such, there is a need to de-escalate chemotherapeutic doses in TNBC while also retaining/improving treatment efficacy. Dietary polyphenols and omega-3 polyunsaturated fatty acids (PUFAs) have been demonstrated to have unique properties in experimental models of TNBC, improving the efficacy of doxorubicin and reversing multi-drug resistance. However, the pleiotropic nature of these compounds has caused their mechanisms to remain elusive, preventing the development of more potent mimetics to take advantage of their properties. Using untargeted metabolomics, we identify a diverse set of metabolites/metabolic pathways that are targeted by these compounds following treatment in MDA-MB-231 cells. Furthermore, we demonstrate that these chemosensitizers do not all target the same metabolic processes, but rather organize into distinct clusters based on similarities among metabolic targets. Common themes in metabolic targets included amino acid metabolism (particularly one-carbon and glutamine metabolism) and alterations in fatty acid oxidation. Moreover, doxorubicin treatment alone generally targeted different metabolites/pathways than chemosensitizers. This information provides novel insights into chemosensitization mechanisms in TNBC.

Cobalt-mediated oxidative DNA damage and its prevention by polyphenol antioxidants

Although cobalt is a required nutrient, it is toxic due to its ability to generate reactive oxygen species (ROS) and damage DNA. ROS generation by Co²⁺ often has been compared to that of Fe²⁺ or Cu⁺, disregarding the reduction potential differences among these metal ions. In plasmid DNA damage studies, a maximum of 15% DNA damage is observed with Co²⁺/H₂O₂ treatment (up to 50 μM and 400 μM, respectively) significantly lower than the 90% damage observed for Fe²⁺/H₂O₂ or Cu⁺/H₂O₂ treatment. However, when ascorbate is added to the Co²⁺/H₂O₂ system, a synergistic effect results in 90% DNA damage. DNA damage by Fe²⁺/H₂O₂ can be prevented by polyphenol antioxidants, but polyphenols both prevent and promote DNA damage by Cu⁺/H₂O₂. When tested for cobalt-mediated DNA damage affects, eight of ten polyphenols (epicatechin gallate, epigallocatechin gallate, propyl gallate, gallic acid, methyl-3,4,5-trihydroxybenzoate, methyl-4,5-dihydroxybenzoate, protocatechuic acid, and epicatechin) prevent cobalt-mediated DNA damage with IC₅₀ values of 1.3 to 27 μM and two (epigallocatechin and vanillic acid) prevent little to no DNA damage. EPR studies demonstrate cobalt-mediated formation of ^•OH, O₂^•-, and ^•OOH, but not ¹O₂ in the presence of H₂O₂ and ascorbate. Epigallocatechin gallate and methyl-4,5-dihydroxybenzoate significantly reduce ROS generated by Co²⁺/H₂O₂/ascorbate, consistent with their prevention of cobalt-mediated DNA damage. Thus, while cobalt, iron, and copper are all d-block metal ions, cobalt ROS generation and its prevention is significantly different from that of iron and copper.

Bioactive nutraceutical ligands and their efficiency to chelate elemental iron of varying dynamic oxidation states to mitigate associated clinical conditions

The natural bioactive or nutraceuticals exhibit several health benefits, including anti-inflammatory, anti-cancer, metal chelation, antiviral, and antimicrobial activity. The inherent limitation of nutraceuticals or bioactive ligand(s) in terms of poor pharmacokinetic and other physicochemical properties affects their overall therapeutic efficiency. The excess of iron in the physiological compartments and its varying dynamic oxidation state [Fe(II) and Fe(III)] precipitates various clinical conditions such as non-transferrin bound iron (NTBI), labile iron pool (LIP), ferroptosis, cancer, etc. Though several natural bioactive ligands are proposed to chelate iron, the efficiency of bioactive ligands is limited due to poor bioavailability, denticity, and other related physicochemical properties. The present review provides insight into the relevance of studying the dynamic oxidation state of iron(II) and iron(III) in the physiological compartments and its clinical significance for selecting diagnostics and therapeutic regimes. We suggested a three-pronged approach, i.e., diagnosis, selection of therapeutic regime (natural bioactive), and integration of novel drug delivery systems (NDDS) or nanotechnology-based principles. This systematic approach improves the overall therapeutic efficiency of natural iron chelators to manage iron overload-related clinical conditions.

Role of Phytochemicals in Skin Photoprotection via Regulation of Nrf2

Ethnopharmacological studies have become increasingly valuable in the development of botanical products and their bioactive phytochemicals as novel and effective preventive and therapeutic strategies for various diseases including skin photoaging and photodamage-related skin problems including abnormal pigmentation and inflammation. Exploring the roles of phytochemicals in mitigating ultraviolet radiation (UVR)-induced skin damage is thus of importance to offer insights into medicinal and ethnopharmacological potential for development of novel and effective photoprotective agents. UVR plays a role in the skin premature aging (or photoaging) or impaired skin integrity and function through triggering various biological responses of skin cells including apoptosis, oxidative stress, DNA damage and inflammation. In addition, melanin produced by epidermal melanocytes play a protective role against UVR-induced skin damage and therefore hyperpigmentation mediated by UV irradiation could reflect a sign of defensive response of the skin to stress. However, alteration in melanin synthesis may be implicated in skin damage, particularly in individuals with fair skin. Oxidative stress induced by UVR contributes to the process of skin aging and inflammation through the activation of related signaling pathways such as the mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1), the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), the nuclear factor kappa B (NF-κB) and the signal transducer and activator of transcription (STAT) in epidermal keratinocytes and dermal fibroblasts. ROS formation induced by UVR also plays a role in regulation of melanogenesis in melanocytes via modulating MAPK, PI3K/Akt and the melanocortin 1 receptor (MC1R)-microphthalmia-associated transcription factor (MITF) signaling cascades. Additionally, nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated antioxidant defenses can affect the major signaling pathways involved in regulation of photoaging, inflammation associated with skin barrier dysfunction and melanogenesis. This review thus highlights the roles of phytochemicals potentially acting as Nrf2 inducers in improving photoaging, inflammation and hyperpigmentation via regulation of cellular homeostasis involved in skin integrity and function. Taken together, understanding the role of phytochemicals targeting Nrf2 in photoprotection could provide an insight into potential development of natural products as a promising strategy to delay skin photoaging and improve skin conditions.

Phenolic Compounds Regulating the Susceptibility of Adult Pine Species to Bursaphelenchus xylophilus

Pine wilt disease (PWD), caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus, is one of the most destructive diseases in trees of the genus Pinus and is responsible for significant environmental and economic losses in North America, Eastern Asia, and Western Europe. However, pine species are not equally affected, with some being tolerant/resistant while others are susceptible to nematode infection for reasons still unclear. The present study aims to investigate differential chemical responses of susceptible and tolerant/resistant pine species shortly after nematode infection by characterizing the phenolic profiles of adult Pinus sylvestris, Pinus pinaster, Pinus pinea, and Pinus halepensis. HPLC and LC-MS were used to identify and quantify the pine´s phenolic compounds: gallic acid, ferulic acid, taxifolin, rutin, resveratrol, (+)-secoisolariciresinol, (−)-epicatechin, protocatechuic acid hexoside, gallic acid hexoside, ferulic acid glucoside, quercetin hexoside, and two unidentified compounds (#A and #B). Prior to infection, we could not differentiate between nematode-tolerant/resistant and susceptible adult pine species based on their constitutive phenolic compounds. In the presence of the PWN, the phenolic profile allowed for a noticeable separation of the PWN-tolerant/resistant P. halepensis from the susceptible P. sylvestris, contrasting with a more homogenous response from P. pinea and P. pinaster. Observations on P. halepensis suggest that taxifolin, resveratrol, and rutin may have an active role in protecting against B. xylophilus, possibly in conjugation with other biochemical and anatomical characters. We emphasize the importance of studying pine tolerant/resistance on adult trees, and not on excised branches, saplings, or seedlings to accurately simulate the nematode–pine host interactions occurring under natural conditions.

Dietary Polyphenols and Their Role in Oxidative Stress-Induced Human Diseases: Insights Into Protective Effects, Antioxidant Potentials and Mechanism(s) of Action

Dietary polyphenols including phenolic acids, flavonoids, catechins, tannins, lignans, stilbenes, and anthocyanidins are widely found in grains, cereals, pulses, vegetables, spices, fruits, chocolates, and beverages like fruit juices, tea, coffee and wine. In recent years, dietary polyphenols have gained significant interest among researchers due to their potential chemopreventive/protective functions in the maintenance of human health and diseases. It is believed that dietary polyphenols/flavonoids exert powerful antioxidant action for protection against reactive oxygen species (ROS)/cellular oxidative stress (OS) towards the prevention of OS-related pathological conditions or diseases. Pre-clinical and clinical evidence strongly suggest that long term consumption of diets rich in polyphenols offer protection against the development of various chronic diseases such as neurodegenerative diseases, cardiovascular diseases (CVDs), cancer, diabetes, inflammatory disorders and infectious illness. Increased intake of foods containing polyphenols (for example, quercetin, epigallocatechin-3-gallate, resveratrol, cyanidin etc.) has been claimed to reduce the extent of a majority of chronic oxidative cellular damage, DNA damage, tissue inflammations, viral/bacterial infections, and neurodegenerative diseases. It has been suggested that the antioxidant activity of dietary polyphenols plays a pivotal role in the prevention of OS-induced human diseases. In this narrative review, the biological/pharmacological significance of dietary polyphenols in the prevention of and/or protection against OS-induced major human diseases such as cancers, neurodegenerative diseases, CVDs, diabetes mellitus, cancer, inflammatory disorders and infectious diseases have been delineated. This review specifically focuses a current understanding on the dietary sources of polyphenols and their protective effects including mechanisms of action against various major human diseases.

Polyphenol effects on CuO-nanoparticle-mediated DNA damage, reactive oxygen species generation, and fibroblast cell death

The ability of ten polyphenolic antioxidants to prevent CuO nanoparticle (NPCuO) and H2O2-mediated DNA damage and cytotoxicity was investigated. Five of the polyphenols (MEPCA, PREGA, MEGA, ECG, and EGCG) prevent NPCuO/H2O2-mediated DNA damage (IC50 values of 7.5-800 μM), three have no effect (PCA, VA, and EC), and two (GA and EGC) result in increased DNA damage. Most polyphenols had similar antioxidant/prooxidant activity in the presence of NPCuO or free copper ions. Electron paramagnetic resonance (EPR) spectroscopy of reactive oxygen species (ROS) generated by NPCuO/H2O2 in the presence of representative polyphenols correlate with results of DNA damage studies: in the presence of NPCuO/H2O2, MEPCA prevents ROS formation, VA has no effect on ROS levels, and EGC increases ROS levels. EPR results with CuO nanoparticles washed to remove dissolved copper in solution (wCuO) in the presence of H2O2/ascorbate suggest that MEPCA prevents ROS formation on the nanoparticle surface in addition to preventing ROS formation from dissolved copper. In mouse fibroblast (L929) cells, combining NPCuO with H2O2 results in significantly greater cytotoxicity than observed for either component alone. After 3 h incubation with MEPCA or MEGA, the viability loss in L929 cells induced by NPCuO/H2O2 challenge was significantly rescued at physiologically relevant polyphenol levels (1 μM). These studies show that polyphenols can protect DNA and inhibit cytotoxicity generated by NPCuO under oxidative stress conditions.

Molecular Mechanisms of Malignant Transformation of Oral Submucous Fibrosis by Different Betel Quid Constituents-Does Fibroblast Senescence Play a Role?

Betel quid (BQ) is a package of mixed constituents that is chewed by more than 600 million people worldwide, particularly in Asia. The formulation of BQ depends on a variety of factors but typically includes areca nut, betel leaf, and slaked lime and may or may not contain tobacco. BQ chewing is strongly associated with the development of potentially malignant and malignant diseases of the mouth such as oral submucous fibrosis (OSMF) and oral squamous cell carcinoma (OSCC), respectively. We have shown recently that the constituents of BQ vary geographically and that the capacity to induce disease reflects the distinct chemical composition of the BQ. In this review, we examined the diverse chemical constituents of BQ and their putative role in oral carcinogenesis. Four major areca alkaloids—arecoline, arecaidine, guvacoline and guvacine—together with the polyphenols, were identified as being potentially involved in oral carcinogenesis. Further, we propose that fibroblast senescence, which is induced by certain BQ components, may be a key driver of tumour progression in OSMF and OSCC. Our study emphasizes that the characterization of the detrimental or protective effects of specific BQ ingredients may facilitate the development of targeted BQ formulations to prevent and/or treat potentially malignant oral disorders and oral cancer in BQ users.

Targeting the redox imbalance in mitochondria: A novel mode for cancer therapy

Changes in reactive oxygen species (ROS) levels affect many aspects of cell behavior. During carcinogenesis, moderate ROS production modifies gene expression to alter cell function, elevating metabolic activity and ROS. To avoid extreme ROS-activated death, cancer cells increase antioxidative capacity, regulating sustained ROS levels that promote growth. Anticancer therapies are exploring inducing supranormal, cytotoxic oxidative stress levels either inhibiting antioxidative capacity or promoting excess ROS to selectively destroy cancer cells, triggering mechanisms such as apoptosis, autophagy, necrosis, or ferroptosis. This review exemplifies pro-oxidants (natural/synthetic/repurposed drugs) and their clinical significance as cancer therapies providing revolutionary approaches.

Comparative Study of Bioactivity and Safety Evaluation of Ethanolic Extracts of Zanthoxylum schinifolium Fruit and Pericarp

The fruit and pericarp of Zanthoxylum schinifolium (ZS) have been used in traditional medicine; however, few studies have characterized ZS fruit and pericarp. Therefore, in the present study, we evaluated the safety of ZS fruit (ZSF) and pericarp (ZSP) extracts and compared their bioactivity. To evaluate the safety of ZSF and ZSP, mutagenicity, cytotoxicity, and oxidative stress assays were performed and nontoxic concentration ranges were obtained. ZSP was found to be superior to ZSF in terms of its antimutagenic, antioxidant, and anti-inflammatory activities. In the S9 mix, the mutation inhibition rate of ZSP was close to 100% at concentrations exceeding 625 µg·plate⁻¹ for both the TA98 and TA100 strains. ZSP exhibited efficient DPPH (IC₅₀ = 75.6 ± 6.1 µg·mL⁻¹) and ABTS (IC₅₀ = 57.4 ± 6 µg·mL⁻¹) scavenging activities. ZSP inhibited the release of cytokines, involved in IL-1β (IC₅₀ = 134.4 ± 7.8), IL-6 (IC₅₀ = 262.8 ± 11.2), and TNF-α (IC₅₀ = 223.8 ± 5.8). These results indicate that ZSP contains a higher amount of biochemicals than ZSF, or that ZSP contains unique biochemicals. In conclusion, for certain physiological activities, the use of ZSP alone may be more beneficial than the combined use of ZSF and ZSP.

Cellular Defensive Mechanisms of Tea Polyphenols: Structure-Activity Relationship

Tea is particularly rich in polyphenols, including catechins and theaflavins, thearubigins, flavonols, and phenolic acids, which are believed to contribute to the health benefits of tea. The health-promoting effects of tea polyphenols are believed to be related to their cellular defensive properties. This review is intended to briefly summarize the relationship between the chemical structures of tea polyphenols and their biological activities. Tea polyphenols appear as direct antioxidants by scavenging reactive oxygen/nitrogen species; chelating transition metals; and inhibiting lipid, protein, and DNA oxidations. They also act directly by suppressing “pro-oxidant” enzymes, inducing endogenous antioxidants, and cooperating with vitamins. Moreover, tea polyphenols regulate cellular signaling transduction pathways, importantly contributing to the prevention of chronic diseases and the promotion of physiological functions. Apparently, the features in the chemical structures of tea polyphenols are closely associated with their antioxidant potentials.

Molecular Action of Polyphenols in Leukaemia and Their Therapeutic Potential

Leukaemia is a malignant disease of the blood. Current treatments for leukaemia are associated with serious side-effects. Plant-derived polyphenols have been identified as potent anti-cancer agents and have been shown to work synergistically with standard chemotherapy agents in leukaemia cell lines. Polyphenols have multiple mechanisms of action and have been reported to decrease cell proliferation, arrest cell cycle and induce apoptosis via the activation of caspase (3, 8 and 9); the loss of mitochondrial membrane potential and the release of cytochrome c. Polyphenols have been shown to suppress activation of transcription factors, including NF-kB and STAT3. Furthermore, polyphenols have pro-oxidant properties, with increasing evidence that polyphenols inhibit the antioxidant activity of glutathione, causing oxidative DNA damage. Polyphenols also induce autophagy-driven cancer cell death and regulate multidrug resistance proteins, and thus may be able to reverse resistance to chemotherapy agents. This review examines the molecular mechanism of action of polyphenols and discusses their potential therapeutic targets. Here, we discuss the pharmacological properties of polyphenols, including their anti-inflammatory, antioxidant, anti-proliferative, and anti-tumour activities, and suggest that polyphenols are potent natural agents that can be useful therapeutically; and discuss why data on bioavailability, toxicity and metabolism are essential to evaluate their clinical use.

The homeostatic role of hydrogen peroxide, superoxide anion and nitric oxide in the vasculature

Reactive oxygen and nitrogen species are produced in a wide range of physiological reactions that, at low concentrations, play essential roles in living organisms. There is a delicate equilibrium between formation and degradation of these mediators in a healthy vascular system, which contributes to maintaining these species under non-pathological levels to preserve normal vascular functions. Antioxidants scavenge reactive oxygen and nitrogen species to prevent or reduce damage caused by excessive oxidation. However, an excessive reductive environment induced by exogenous antioxidants may disrupt redox balance and lead to vascular pathology. This review summarizes the main aspects of free radical biochemistry (formation, sources and elimination) and the crucial actions of some of the most biologically relevant and well-characterized reactive oxygen and nitrogen species (hydrogen peroxide, superoxide anion and nitric oxide) in the physiological regulation of vascular function, structure and angiogenesis. Furthermore, current preclinical and clinical evidence is discussed on how excessive removal of these crucial responses by exogenous antioxidants (vitamins and related compounds, polyphenols) may perturb vascular homeostasis. The aim of this review is to provide information of the crucial physiological roles of oxidation in the endothelium, vascular smooth muscle cells and perivascular adipose tissue for developing safer and more effective vascular interventions with antioxidants.

Seasonality Modulates the Cellular Antioxidant Activity and Antiproliferative Effect of Sonoran Desert Propolis

The main chemical composition and pharmacological potential of propolis from arid and semi-arid regions of the Sonoran Desert have been previously reported. Caborca propolis (CP), from an arid zone of the Sonoran Desert, has shown a polyphenolic profile that suggests a mixed plant origin, presenting poplar-type markers, as well as a 6-methoxylated flavonoid, xanthomicrol, characteristic of Asteraceae plants. In addition, CP has shown significant antioxidant properties and antiproliferative activity on cancer cells. In this study, we analyzed the influence of collection time on the chemical constitution, antiproliferative activity and protective capacity of CP against reactive oxygen species (ROS), by using HPLC–UV–diode array detection (DAD) analysis, 3-(4,5-dimethylthiazol-2-yl)-2,5-Dimethyltetrazoliumbromide (MTT) and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assays, as well as cellular antioxidant activity (CAA) assay on murine B-cell lymphoma M12.C3.F6 cells. HPLC–UV–DAD analyses of seasonally collected CP (one-year period) revealed quantitative differences among the most abundant CP constituents: pinocembrin, galangin, chrysin and pinobanksin-3-O-acetate. Though all seasonal samples of CP induced an antiproliferative effect in M12.C3.F6 cells, CP from autumn showed the highest inhibitory activity (IC₅₀: 5.9 ± 0.6 µg/mL). The DPPH assay pointed out that CP collected in autumn presented the highest antioxidant potential (IC₅₀: 58.8 ± 6.7 µg/mL), followed by winter (65.7 ± 12.2 µg/mL) and spring (67.0 ± 7.5 µg/mL); meanwhile, the summer sample showed a lesser antioxidant capacity (IC₅₀: 98.7 ± 2.5 µg/mL). The CAA assay demonstrated that CP induced a significant protective effect against ROS production elicited by H₂O₂ in M12.C3.F6 cells. Pretreatment of M12.C3.F6 cells with CP from spring and autumn (25 and 50 µg/mL for 1 h) showed the highest reduction in intracellular ROS induced by H₂O₂ (1 and 5 mM). These results indicate that the antiproliferative effect and cellular antioxidant activity of CP are modulated by quantitative fluctuations in its polyphenolic profile due to its collection time.

Physalis alkekengi L. Extract Reduces the Oxidative Stress, Inflammation and Apoptosis in Endothelial Vascular Cells Exposed to Hyperglycemia

To find new natural remedies in diabetes, this study investigated the biological activity of two extracts obtained from the fruits (PhyF) and herba (PhyH) of Physalis alkekengi var. franchetii L. on human umbilical vein endothelial cells (HUVECs) exposed to normo- and hyperglycemic conditions. The biological effect was quantified by malondialdehyde, IL-31 and IL-33 levels in correlation with physico-chemical characterization and antioxidant activity. Additionally, from PhyP extract, the caspase-3, IL-6, IL-10, tumor necrosis factor (TNF)-α and nuclear transcription factor NFkB expressions were evaluated. HPLC analysis revealed a significant number of phenolic compounds, especially in PhyF extract, with a good antioxidant activity as highlighted by TEAC, CUPRAC or DPPH methods. On HUVECS cells, the extracts were not toxic even at high concentrations. Particularly PhyF extract, diminished lipid peroxidation and inhibited the IL-31 and IL-33 secretions induced by hyperglycemia. The inhibitory effect on proinflammatory cytokines was noticed after both doses of PhyF extract in parallel with the upregulation of anti-inflammatory cytokine IL-10. Moreover, PhyF, especially in a low dose, reduced caspase-3 active form. These experimental findings suggest that Physalis fruits extract exerted beneficial effects in hyperglycemia by inhibition of oxidative stress, inflammation and apoptosis being a good adjuvant option in diabetes.

DNA damage and DNA protection from digested raw and griddled green pepper (poly)phenols in human colorectal adenocarcinoma cells (HT-29)

PURPOSE

To determine whether (poly)phenols from gastrointestinal-digested green pepper possess genoprotective properties in human colon cells and whether the application of a culinary treatment (griddling) on the vegetable influences the potential genoprotective activity.

METHODS

(Poly)phenols of raw and griddled green pepper (Capsicum annuum L.) submitted to in vitro-simulated gastrointestinal digestion were characterized by LC-MS/MS. Cytotoxicity (MTT, trypan blue and cell proliferation assays), DNA damage and DNA protection (standard alkaline and formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay) of different concentrations of (poly)phenolic extracts were assessed in colon HT-29 cells.

RESULTS

A total of 32 (poly)phenolic compounds were identified and quantified in digested raw and griddled green pepper. Twenty of them were flavonoids and 12 were phenolic acids. Griddled pepper doubled the (poly)phenol concentration compared to raw; luteolin 7-O-(2-apiosyl)-glucoside and quercitrin constituted the major (poly)phenols in both extracts. Raw and griddled pepper (poly)phenolic extracts impaired cell proliferation and induced low levels of Fpg-sensitive sites, in a dose-dependent manner, even at a non-cytotoxic concentration. None of the concentrations tested induced DNA strand breaks or alkaline labile sites. Nor did they show significant genoprotection against the DNA damage induced by H₂O₂ or KBrO₃.

CONCLUSIONS

Green pepper (poly)phenols did not show genoprotection against oxidatively generated damage in HT-29 cells at simulated physiological concentrations, regardless of the application, or not, of a culinary treatment (griddling). Furthermore, high concentrations of (poly)phenolic extracts induced a slight pro-oxidant effect, even at a non-cytotoxic concentration.

Metabolomic analysis of Cyrtopodium glutiniferum extract by UHPLC-MS/MS and in vitro antiproliferative and genotoxicity assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of orchids have been traditionally used as human phytotherapeutics. Cyrtopodium flavum, for example, due to the analgesic and anti-inflammatory properties, beside the capacity of heal skin lesions has been focus of research. Also Cyrtopodium glutiniferum, an orchid found in the Brazilian southeastern rainforest, is known to synthesize anti-inflammatory glucomannans in the pseudobulbs, as other potentially therapeutic compounds.

AIM OF THE STUDY

We have reported the first metabolomic analysis focused on the phenols expression of the neotropical orchid Cyrtopodium glutiniferum Raddi, besides free radical scavenging, anti-inflammatory and antiproliferative activities, and the genotoxicity properties of the aqueous extract.

MATERIAL AND METHODS

The metabolomics of C. glutiniferum aqueous extract was performed through UHPLC-MSⁿ acquisition. We have detected the scavenging potential of the extract using DPPH assay. The genotoxic potential was performed by Ames Test (0-5000 μg mL^-1) and micronucleous assay (0-5000 μg mL^-1) in RAW264.7 cells. The cytotoxic potential of the extract against RAW264.7 was tested by WST-1 assay (0-500 μg mL^-1). And after all, the RAW264.7 cells were treated with non-cytotoxic concentrations of C. glutiniferum (0-50 μg mL^-1) to evaluate the antiproliferative and anti-inflammatory potential, besides the mitochondrial activity.

RESULTS

From the 55 molecules identified, 45.5% belonged to the phenolic compounds database from Phenol Explorer, 29% to an in-house Orchidaceae molecules database, and 25.5% to both. Among the identified phenolic compounds, 18 subclasses were discriminated, being phenanthrenes the most abundant. Doses-dependent of C. glutiniferum extracts were able to induce DPPH free radicals scavenging and also to increase TA100 His⁺ revertants, in metabolic environment, showing mutagenicity just in the highest concentration, of 5 mg/plate. On Eukaryotic cell models, the extract also has induced dose-response and time-response cytotoxicity against RAW264.7 macrophages, mainly after 48 h and 72 h, even though the extract has not been able to induce the increase of micronucleated cells and mitotic index alteration on Micronucleus assay. The activation and proliferation of macrophages cultures were downregulated after 24 h and 48 h by the non-cytotoxic concentrations of the extract in a dose-dependent manner.

CONCLUSIONS

The Cyrtopodium glutiniferum metabolomics, anti-inflammatory and anti-proliferative properties observed in this study suggest a therapeutic efficacy of the orchid extract applied in folk medicine.

Epicatechin-3-Gallate Signaling and Protection against Cardiac Ischemia/Reperfusion Injury

At concentrations found in humans after ingestion of one to two cups of green tea, epicatechin-3-gallate (ECG) modulates Na/K-ATPase conformation and activity. Akin to ouabain, an archetypal Na/K-ATPase ligand of the cardiotonic steroid (CTS) family, ECG also activates protein kinase C epsilon type (PKCε) translocation and increases the force of contraction of the rat heart. This study evaluated whether, like ouabain, ECG also modulates Na/K-ATPase/Src receptor function and triggers pre- and postconditioning against ischemia/reperfusion (I/R) injury. In vitro, ECG activated the purified Na/K-ATPase/Src complex. In Langendorff-perfused rat hearts, submicromolar concentrations of ECG administered either before or after ischemia reduced infarct size by more than 40%, decreased lactate dehydrogenase release, and improved the recovery of cardiac function. ECG protection was blocked by PKCε inhibition and attenuated by mitochondrial KATP channel inhibition. In a unique mammalian cell system with depleted Na/K-ATPase α1 expression, ECG-induced PKCε activation persisted but protection against I/R was blunted. Taken together, these results reveal a Na/K-ATPase- and PKCε-dependent mechanism of protection by ECG that is also distinct from the mechanism of action of ouabain. These ECG properties likely contribute to the positive impact of green tea consumption on cardiovaascular health and warrant further investigation into the role of cardiac Na/K-ATPase signaling in the cardioprotective effect of green tea consumption. SIGNIFICANCE STATEMENT: Consumption of green tea, the richest dietary source of ECG, is associated with a reduced risk of cardiac mortality. Antioxidant effects of ECG and other tea polyphenols are well known, but reported for concentrations well above dietary levels. Therefore, the mechanism underlying the cardioprotective effect of green tea remains incompletely understood. This study provides experimental evidence that ECG concentrations commonly detected in humans after consumption of a cup of tea trigger the Na/K-ATPase/Src receptor in a cell-free system, activate a CTS-like signaling pathway, and provide PKCε-dependent protection against ischemia/reperfusion injury in rat hearts. Mechanistic studies in mammalian cells with targeted Na/K-ATPase depletion revealed that although Na/K-ATPase does not mediate ECG-induced PKCε activation, it is required for ECG-induced protection against ischemia/reperfusion injury.

Ginkgo biloba L. Leaf Extract Protects HepG2 Cells Against Paraquat-Induced Oxidative DNA Damage

Ginkgo biloba L. leaf extracts and herbal infusions are used worldwide due to the health benefits that are attributed to its use, including anti-neoplastic, anti-aging, neuro-protection, antioxidant and others. The aim of this study was to evaluate the effect of an aqueous Ginkgo biloba extract on HepG2 cell viability, genotoxicity and DNA protection against paraquat-induced oxidative damage. Exposure to paraquat (PQ), over 24 h incubation at 1.0 and 1.5 µM, did not significantly reduce cell viability but induced concentration and time-dependent oxidative DNA damage. Ginkgo biloba leaf extract produced dose-dependent cytotoxicity (IC₅₀ = 540.8 ± 40.5 µg/mL at 24 h exposure), and short incubations (1 h) produced basal and oxidative DNA damage (>750 and 1500 µg/mL, respectively). However, lower concentrations (e.g., 75 µg/mL) of Ginkgo biloba leaf extract were not cytotoxic and reduced basal DNA damage, indicating a protective effect at incubations up to 4 h. On the other hand, longer incubations (24 h) induced oxidative DNA damage. Co-incubation of HepG2 cells for 4 h, with G. biloba leaf extract (75 µg/mL) and PQ (1.0 or 1.5 µM) significantly reduced PQ-induced oxidative DNA damage. In conclusion, the consumption of Ginkgo biloba leaf extract for long periods at high doses/concentrations is potentially toxic; however, low doses protect the cells against basal oxidative damage and against environmentally derived toxicants that induce oxidative DNA damage.

An in silico investigation on the inhibitory potential of the constituents of Pomegranate juice on antioxidant defense mechanism: Relevance to neurodegenerative diseases

Elevation in the levels of reactive oxygen and nitrogen species (RONS), and downregulation of cellular antixoidants, have ubiquitously been reported from studies in animal models of neurodegenerative diseases, including Parkinson’s disease (PD) and Alzheimer’s disease (AD). Thus, plant-derived compounds are widely being investigated for their beneficial effects in these models. However, while studies have reported antioxidant potentials of several phytochemicals, a large number of studies have demonstrated different phytochemicals to be rather pro-oxidant and exaggerate oxidative stress (OS). One such study aimed to investigate possible ameliorative effect of Pomegranate juice (PJ) in rat model of toxin-induced parkinsonism revealed that PJ exacerbates OS, inflammation and promotes neurodegeneration. Thus, it remains to be investigated whether different constituents and metabolites of PJ are pro-oxidant or anti-oxidant. Using computational modeling, we investigated possible inhibitory potential of different constituents of PJ and their metabolites viz. delphinidin-3-glucoside, dimethylellagic acid-glucuronide, ellagic acid, ellagitannin, gallic acid, gallotannin 23, pelargonidin, punicalagin, urolithin A, urolithin A-glucuronide and urolithin B, on anti-oxidant defense system of the brain. The results indicate that the constituents of PJ have the potential to inhibit five key enzymes of the neuronal antioxidant defense system, viz. catalase, superoxide dismutase, glutathione peroxidase 4, glutathione reductase and glutathione-S-transferase. Thus, it is surmised that the constituents of PJ may contribute to OS and neurodegeneration by way of affecting antioxidant defense mechanism. This may particularly be more pronounced in neurodegenerative diseases, since neurons are known to be more vulnerable to OS. Thus, the present findings caution the use of PJ in patients prone to OS, especially those suffering from neurodegenerative diseases, and warrant further experimental studies to unveil the effects of individual components and metabolites of PJ on antioxidant defense system of brain.

Resveratrol attenuates iron-induced toxicity in a chronic post-treatment paradigm in Caenorhabditis elegans

There is an increase in the number of studies indicating that a disturbance in iron homeostasis is involved in the pathogenesis of neurodegenerative diseases, in which oxidative stress plays an important role. Oxidative stress can be counteracted by bioactive molecules like the flavonoid resveratrol, which acts as scavenging agent, or by modulating enzymes and metabolic signalling pathways, thus depicting the neuroprotective potential. On the other hand, flavonoids, resveratrol included, have been reported to induce an increase in the reactive species production. In this study we aimed to evaluate in vivo the protective potential of resveratrol against iron imbalance using the Caenorhabditis elegans model. We acutely exposed C. elegans to iron and administered resveratrol pre- or post-iron treatment. Iron-treated worms demonstrated a significant decrease in the survival, neuronal change, decreased dehydrogenases activity and ATP levels, and a significant increase in the oxidative stress. Acute pre-exposure to resveratrol potentiated the toxic effect of the metal by reducing ATP levels, while post-iron chronic resveratrol treatment following the iron exposure increased the worms' survival and reduced the generation of reactive species and neuronal damage. In conclusion, our results demonstrated that resveratrol has various protective effects depending on the duration and order of administration, whereby chronic post-iron treatment to resveratrol as an antidote appeared to be a more effective approach.

Effect of liver pâté enrichment with flaxseed oil and flaxseed extract on lipid composition and stability

BACKGROUND

There is an increase interest from food technologists in the improvement of the nutritional value of meat products, especially their lipid profile and shelf life. The aim of this study was to determine the effect of animal fat replacement with flaxseed oil (20%) and flaxseed extract addition (0.05%-0.25%) on changes in composition and stability of liver pâté lipid fractions.

RESULTS

Replacement of animal fat with flaxseed oil was observed to lower the saturated and monoenoic fatty acid in the product's fatty acid profile by around 12% and to raise the polyene fatty acid contribution by more than 70% when compared to the control. The replacement also resulted in enriching the pâté with phytosterols (β-sitosterol, campesterol, and cycloartenol). The addition of 0.05% and 0.10% ethanol flaxseed extract significantly slowed down lipid oxidation changes during storage of the pâté.

CONCLUSIONS

The study showed that a storage-stable meat product - liver pâté - characterized by a high nutritional value can be designed through the addition of flax oil rich in unsaturated fatty acids and flaxseed extract. The addition of 0.05% of the extract was found to be sufficient to improve the liver pâté's oxidative stability; it can thus be recommended for this type of product. © 2018 Society of Chemical Industry.

Chemical characterization, antioxidant, genotoxic and in vitro cytotoxic activity assessment of Juniperus communis var. saxatilis

Chemical composition and antioxidative, genotoxic and cytotoxic potential of essential oil (EO) and post-distillation waste (PDW) of Serbian Juniperus communis L. var. saxatilis Pall. was studied in human lung carcinoma (A549) and normal lung fibroblast (MRC-5) cells. GC-MS analysis identified 93.95% of total EO content and determined α-pinen as a dominant component (23.61%). LC-MS/MS analysis of PDW pointed at rutin (12.2 mg g^-1) and quinic acid (11.1 mg g^-1) as the most abundant. Antioxidativity of PDW was strong in DPPH (IC₅₀ was 5.27 μg mL^-1), and moderate in TBA and FRAP assays. Both substances were more cytotoxic to A549 than to MRC-5 cells. Obtained IC₅₀ values were 69.4 μg mL^-1 and 120 μg mL^-1 for EO, and 1.27 mg mL^-1 and 2.86 mg mL^-1 for PDW, respectively. PDW was genotoxic (0.3 mg mL^-1 and 1 mg mL^-1 in A549 and MRC-5 cells, respectively) and induced apoptosis and arrested cell cycle in G2/M phase in A549 cells (0.3 mg mL^-1). In mixtures with doxorubicin cytotoxicity of EO and PDW increased, and combination index values (0.12-0.18) revealed clear synergistic effect, stronger in cancer cells. This indicates that J. communis var. saxatilis could decrease the chemotherapeutic doses of doxorubicin, potentially reducing its side effects.

Gamma-tocotrienol profoundly alters sphingolipids in cancer cells by inhibition of dihydroceramide desaturase and possibly activation of sphingolipid hydrolysis during prolonged treatment

Vitamin E gamma-tocotrienol (γTE) is known to have anticancer effects, but mechanisms underlying these actions are not clear. Here using liquid chromatography tandem mass spectrometry, we show that γTE induced marked changes of sphingolipids including rapid elevation of dihydrosphingosine and dihydroceramides (dhCers) in various types of cancer cells. The elevation of dihydrosphingolipids coincided with increased cellular stress, as indicated by JNK phosphorylation, and was prior to any sign of induction of apoptosis. Chemically blocking de novo synthesis of sphingolipids partially counteracted γTE-induced apoptosis and autophagy. Experiments using ¹³C₃, ¹⁵N-labeled l-serine together with enzyme assays indicate that γTE inhibited cellular dihydroceramide desaturase (DEGS) activity without affecting its protein expression or de novo synthesis of sphingolipids. Unlike the effect on dhCers, γTE decreased ceramides (Cers) after 8-h treatment but increased C_18:0-Cer and C_16:0-Cer after 16 and 24 h, respectively. The increase of Cers coincides with γTE-induced apoptosis and autophagy. Since γTE inhibits DEGS and decreases de novo Cer synthesis, elevation of Cers during prolonged γTE treatment is likely caused by sphingomeylinase-mediated hydrolysis of sphingomyelin. This idea is supported by the observation that an acid sphingomeylinase inhibitor partially reversed γTE-induced cell death. Our study demonstrates that γTE altered sphingolipid metabolism by inhibiting DEGS activity and possibly by activating SM hydrolysis during prolonged treatment in cancer cells.

Green Tea Catechins for Prostate Cancer Prevention: Present Achievements and Future Challenges

Green tea catechins (GTCs) are a family of chemically related compounds usually classified as antioxidant molecules. Epidemiological evidences, supported by interventional studies, highlighted a more than promising role for GTCs in human prostate cancer (PCa) chemoprevention. In the last decades, many efforts have been made to gain new insights into the mechanism of action of GTCs. Now it is clear that GTCs' anticancer action can no longer be simplistically limited to their direct antioxidant/pro-oxidant properties. Recent contributions to the advancement of knowledge in this field have shown that GTCs specifically interact with cellular targets, including cell surface receptors, lipid rafts, and endoplasmic reticulum, modulate gene expression through direct effect on transcription factors or indirect epigenetic mechanisms, and interfere with intracellular proteostasis at various levels. Many of the effects observed in vitro are dose and cell context dependent and take place at concentrations that cannot be achieved in vivo. Poor intestinal absorption together with an extensive systemic and enteric metabolism influence GTCs' bioavailability through still poorly understood mechanisms. Recent efforts to develop delivery systems that increase GTCs' overall bioavailability, by means of biopolymeric nanoparticles, represent the main way to translate preclinical results in a real clinical scenario for PCa chemoprevention.

Effect of Cold Plasma Treatment on the Functional Properties of Fresh-Cut Apples

Atmospheric double-barrier discharge (DBD) plasma technology is a promising tool in the food industry as an alternative to traditional food preservation methods. However, the effect of the reactive species generated during the treatment on the content of bioactive compounds in food is still little studied, and there are no data concerning potential deleterious effects of DBD-treated foods on human cells. Some functional properties of DBD-treated minimally processed Pink Lady apples were evaluated in comparison with untreated samples through different in vitro and ex vivo tests. Plasma treatment caused only a slight reduction of antioxidant content and antioxidant capacity (up to 10%), mainly limited to the amphiphilic fraction. Noteworthy, treated apple polyphenol extracts did not reduce cell viability and did not suppress the beneficial physiological cell response to oxidative stress in terms of reactive oxygen species production and phase II enzyme activation in human cultured colonocytes.

Pro-apoptotic and cytotoxic effects of enriched fraction of Elytranthe parasitica (L.) Danser against HepG2 Hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC), the most common type of liver cancer accounts for more than one million deaths worldwide. Current treatment modality for HCC is marginally effective. Plants belonging to Mistletoe family (Loranthaceae) have been used in chemotherapy for many years. The present study was aimed at exploring the anti-proliferative, pro-oxidant and pro-apoptotic potential of stem of Elytranthe parasitica (L.) Danser (EP), a parasitic shrub belonging to Loranthaceae.

Methods

Elytranthe parasitica (L.) Danser, a climbing parasitic shrub was investigated for its cytotoxic activity against HepG2, a hepatocellular carcinoma cell line by Sulforhodamine B (SRB) assay. Further, pro-oxidant activity of EP extract/fractions was studied using copper phenanthroline assay. To understand the mechanism of cell death, the pro-apoptotic effects of Hep-G2 cells treated with EP extract/fractions were visualized by dual staining using acridine orange and ethidium bromide, a morphological marker of apoptosis. Phytochemical profiling of EP was explored by estimating the phenol, flavonoid and tannin content in its various fractions and extract. The occurrence of gallic acid, a principal polyphenol in EP extract and fractions was detected and further quantified using HPTLC (High Performance Thin Layer Chromatography) fingerprinting.

Result

Active fraction of Elytranthe parasitica, EP.DEE exhibited potent cytotoxic activity in a dose dependent manner against HepG2 hepatocellular carcinoma cell line with an IC50 of 56.7 ± 7.8 μg/mL. Dual staining with acridine orange and ethidium bromide revealed that HepG2 cells treated with EP active fractions underwent cell death chiefly by apoptosis. Highest phenol, flavonoid and tannin content were observed in active fractions, EP.EA (Ethyl acetate fraction) and EP.DEE (Diethyl ether fraction). Gallic acid was identified and quantified in EP extract and active fractions, EP.DEE and EP.EA.

Conclusion

Our findings indicate EP active fraction could be a promising contender in the treatment of hepatocellular carcinoma.

Cells Deficient in the Fanconi Anemia Protein FANCD2 are Hypersensitive to the Cytotoxicity and DNA Damage Induced by Coffee and Caffeic Acid

Epidemiological studies have found a positive association between coffee consumption and a lower risk of cardiovascular disorders, some cancers, diabetes, Parkinson and Alzheimer disease. Coffee consumption, however, has also been linked to an increased risk of developing some types of cancer, including bladder cancer in adults and leukemia in children of mothers who drink coffee during pregnancy. Since cancer is driven by the accumulation of DNA alterations, the ability of the coffee constituent caffeic acid to induce DNA damage in cells may play a role in the carcinogenic potential of this beverage. This carcinogenic potential may be exacerbated in cells with DNA repair defects. People with the genetic disease Fanconi Anemia have DNA repair deficiencies and are predisposed to several cancers, particularly acute myeloid leukemia. Defects in the DNA repair protein Fanconi Anemia D2 (FANCD2) also play an important role in the development of a variety of cancers (e.g., bladder cancer) in people without this genetic disease. This communication shows that cells deficient in FANCD2 are hypersensitive to the cytotoxicity (clonogenic assay) and DNA damage (γ-H2AX and 53BP1 focus assay) induced by caffeic acid and by a commercial lyophilized coffee extract. These data suggest that people with Fanconi Anemia, or healthy people who develop sporadic mutations in FANCD2, may be hypersensitive to the carcinogenic activity of coffee.

Autophagic effects of Hibiscus sabdariffa leaf polyphenols and epicatechin gallate (ECG) against oxidized LDL-induced injury of human endothelial cells

PURPOSE

Oxidized low-density lipoprotein (ox-LDL) contributes to the pathogenesis of atherosclerosis by promoting vascular endothelial cell injury. Hibiscus sabdariffa leaf polyphenols (HLP), rich in flavonoids, have been shown to possess antioxidant and antiatherosclerotic activities. In this study, we examined the protective role of HLP and its main compound (-)-epicatechin gallate (ECG) in human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL in vitro.

METHODS

In a model of ox-LDL-impaired HUVECs, assessments of cell viability, cytotoxicity, cell proliferation, apoptosis, and autophagy were detected. To highlight the mechanisms of the antiapoptotic effects of HLP and ECG, the expressions of molecular proteins were measured by Western blotting, real-time PCR, and so on.

RESULTS

HLP or ECG improved the survival of HUVECs from ox-LDL-induced viability loss. In addition, HLP or ECG showed potential in reducing ox-LDL-dependent apoptosis. Next, the ox-LDL-induced formation of acidic vesicular organelles and upregulation of the autophagy-related genes were increased by HLP or ECG. The HLP-triggered autophagic flux was further confirmed by increasing the LC3-II level under the pretreatment of an autophagy inhibitor chloroquine. Molecular data indicated the autophagic effect of HLP or ECG might be mediated via class III PI3K/Beclin-1 and PTEN/class I PI3K/Akt cascade signaling, as demonstrated by the usage of a class III PI3K inhibitor 3-methyladenine (3-MA) and a PTEN inhibitor SF1670.

CONCLUSIONS

Our data imply that ECG-enriched HLP upregulates the autophagic pathway, which in turn led to reduce ox-LDL-induced HUVECs injury and apoptosis and provide a new mechanism for its antiatherosclerotic activity.

Antioxidant and Hepatoprotective Activity of a New Tablets Formulation from Tamarindus indica L

Hepatotoxic chemicals damage liver cells primarily by producing reactive oxygen species. The decoction of the leaves of Tamarindus indica L. is used for liver disorders. In this work we evaluated the hepatoprotective activity of a tablet formulation of this plant. Thirty-five Sprague Dawley rats were randomly divided into five groups (n = 7). First group (I) is control group, fed with standard diet. Groups II to V (hepatotoxic groups) were subjected to a subcutaneous injection of CCl4 (0.5 mL/kg). Group II was negative control, fed with standard diet; group III was subjected to administration of Silymarin 150 mg/kg and groups IV and V were treated with tablets in dose of 100 mg/kg and 200 mg/kg, respectively. Lipid peroxidation and the activity of superoxide dismutase, catalase, and reduced glutathione were evaluated. Serum levels of alanine aminotransferase, aspartate aminotransferase, gamma-glutamine transferase, alkaline phosphatase, and a lipid profile were evaluated too. The tablets inhibit lipid peroxidation. The redox balance (SOD-CAT-GSH) remains normal in the experimental groups treated with tablets. The liver function using dose of 200 mg/kg of tablets was better than the other experimental groups. These results justify, scientifically, the ethnobotanical use of the leaves of Tamarindus indica L.

Effect of Allium flavum L. and Allium melanantherum Panč. Extracts on Oxidative DNA Damage and Antioxidative Enzymes Superoxide Dismutase and Catalase

Allium flavum L. and Allium melanantherum Panč. are wild growing plants used in traditional diet in Balkan region. While chemical composition and some biological activities of A. flavum have been reported, A. melanantherum, as an endemic in the Balkan Peninsula, has never been comprehensively examined. After chemical characterization of A. melanantherum, we examined the protective effect of methanol extracts of both species against t-butyl hydro-peroxide (t-BOOH)-induced DNA damage and mutagenesis. The bacterial reverse mutation assay was performed on Escherichia coli WP2 oxyR strain. DNA damage was monitored in human fetal lung fibroblasts (MRC-5) with alkaline comet assay. Obtained results indicated that extracts reduced t-BOOH-induced DNA damage up to 70 and 72% for A. flavum and A. melanantherum extract, respectively, and showed no effect on t-BOOH-induced mutagenesis. Since the results indicated modulatory effect on cell-mediated antioxidative defense, the effect of extracts on total protein content, and superoxide dismutase (SOD) and catalase (CAT) amounts and activities were monitored. Both extracts increased total protein content, while the increase of enzyme amount and activity was obtained only with A. melanantherum extract and restricted to CAT. The activity of CuZnSOD family was not affected, while SOD1 and SOD2 amounts were significantly decreased, indicating potential involvement of extracellular CuZnSOD. Obtained results strongly support the traditional use of A. flavum and A. melanantherum in nutrition and recommend them for further study.

Antioxidants in Cardiovascular Therapy: Panacea or False Hope?

Oxidative stress is a key feature of the atherothrombotic process involved in the etiology of heart attacks, ischemic strokes, and peripheral arterial disease. It stands to reason that antioxidants represent a credible therapeutic option to prevent disease progression and thereby improve outcome, but despite positive findings from in vitro studies, clinical trials have failed to consistently show benefit. The aim of this review is to re-appraise the concept of antioxidants in the prevention and management of cardiovascular disease. In particular, the review will explore the reasons behind failed antioxidant strategies with vitamin supplements and will evaluate how flavonoids might improve cardiovascular function despite bioavailability that is not sufficiently high to directly influence antioxidant capacity. As well as reaching conclusions relating to those antioxidant strategies that might hold merit, the major myths, limitations, and pitfalls associated with this research field are explored.