Tyrosol prevents apoptosis in irradiated keratinocytes

Enhancing Bioactivity through the Transfer of the 2-(Hydroxymethoxy)Vinyl Moiety: Application in the Modification of Tyrosol and Hinokitiol

Utilizing Density Functional Theory (DFT) calculations at the B3LYP/QZVP level and incorporating the Conductor-like Polarizable Continuum Model (C-PCM) for solvation, the thermodynamic and chemical activity properties of 21-(hydroxymethoxy)henicosadecaenal, identified in cultured freshwater pearls from the mollusk Hyriopsis cumingii, have been elucidated. The study demonstrates that this compound releases formaldehyde, a potent antimicrobial agent, through dehydrogenation and deprotonation processes in both hydrophilic and lipophilic environments. Moreover, this polyenal exhibits strong anti-reductant properties, effectively scavenging free radicals. These critical properties classify the pearl-derived ingredient as a natural multi-functional compound, serving as a coloring, antiradical, and antimicrobial agent. The 2-(hydroxymethoxy)vinyl (HMV) moiety responsible for the formaldehyde release can be transferred to other compounds, thereby enhancing their biological activity. For instance, tyrosol (4-(2-hydroxyethyl)phenol) can be modified by substituting the less active 2-hydroxyethyl group with the active HMV one, and hinokitiol (4-isopropylotropolone) can be functionalized by attaching this moiety to the tropolone ring. A new type of meso-carrier, structurally modeled on pearls, with active substances loaded both in the layers and the mineral part, has been proposed.

New insights into the anti-inflammatory and anti-melanoma mechanisms of action of azelaic acid and other Fusarium solani metabolites via in vitro and in silico studies

Metabolites exploration of the ethyl acetate extract of Fusarium solani culture broth that was isolated from Euphorbia tirucalli root afforded five compounds; 4-hydroxybenzaldehyde (1), 4-hydroxybenzoic acid (2), tyrosol (3), azelaic acid (4), malic acid (5), and fusaric acid (6). Fungal extract as well as its metabolites were evaluated for their anti-inflammatory and anti-hyperpigmentation potential via in vitro cyclooxygenases and tyrosinase inhibition assays, respectively. Azelaic acid (4) exhibited powerful and selective COX-2 inhibition followed by fusaric acid (6) with IC50 values (2.21 ± 0.06 and 4.81 ± 0.14 μM, respectively). As well, azelaic acid (4) had the most impressive tyrosinase inhibitory effect with IC50 value of 8.75 ± 0.18 μM compared to kojic acid (IC50 = 9.27 ± 0.19 μM). Exclusive computational studies of azelaic acid and fusaric acid with COX-2 were in good accord with the in vitro results. Interestingly, this is the first time to investigate and report the potential of compounds 3-6 to inhibit cyclooxygenase enzymes. One of the most invasive forms of skin cancer is melanoma, a molecular docking study using a set of enzymes related to melanoma suggested pirin to be therapeutic target for azelaic acid and fusaric acid as a plausible mechanism for their anti-melanoma activity.

Comparison among Different Green Extraction Methods of Polyphenolic Compounds from Exhausted Olive Oil Pomace and the Bioactivity of the Extracts

The use of by-products as a source of bioactive compounds with economic added value is one of the objectives of a circular economy. The olive oil industry is a source of olive pomace as a by-product. The olive pomace used in the present study was the exhausted olive pomace, which is the by-product generated from the air drying and subsequent hexane extraction of residual oil from the olive pomace. The objective was to extract bioactive compounds remaining in this by-product. Various types of green extraction were used in the present study: solvent extraction (water and hydroalcoholic); ultrasound-assisted extraction; Ultra-Turrax-assisted extraction; and enzyme-assisted extraction (cellulase; viscoenzyme). The phenolic profile of each extract was determined using HPLC-DAD and the total phenolic content (TPC) and antioxidant activity (ABTS, DPPH, and ORAC) were determined as well. The results showed significant differences in the yield of extraction among the different methods used, with the enzyme-assisted, with or without ultrasound, extraction presenting the highest values. The ultrasound-assisted hydroethanolic extraction (USAHE) was the method that resulted in the highest content of the identified phenolic compounds: 2.021 ± 0.29 mg hydroxytyrosol/100 mg extract, 0.987 ± 0.09 mg tyrosol/100 mg extract, and 0.121 ± 0.005 mg catechol/100 mg extract. The conventional extraction with water at 50 °C produced the best results for TPC and antioxidant activity of the extracts. The extracts from the USAHE were able to inhibit Gram-positive bacteria, especially Bacillus cereus, showing 67.2% inhibition at 3% extract concentration.

Design and synthesis of salidroside analogs and their bioactivity against septic myocardial injury

Cardiac tissue suffers much from sepsis, and the incidence of myocardial injury is high in septic patients. The treatment of sepsis myocardial injury (SMI) has been the focus of clinical medicine. Salidroside shows myocardial cell protection, anti-oxidation and anti- inflammation effects, and it is thought as one of the potential compounds to treat sepsis myocardial injury. However, its anti-inflammatory activity is lower and its pharmacokinetic properties are not ideal, which is far from clinical application. Here, a series of salidroside analogs were synthesized, and their bioactivities were evaluated from several aspects, including their anti-oxidant and anti-inflammatory activities in vitro and anti-sepsis myocardial injury activities in vivo. Of all the compounds which synthesized, compounds 2 and 3 exhibited stronger anti-inflammatory activities than the others; after treating LPS-stimulated RAW264.7 or H9c2 cells with each of them, the levels of IL-1β, IL-6 and TNF-α were down-regulated in a dose-dependent manner. In the anti-oxidative stress injury test, compounds 2 and 3 not only markedly increased the survival rate of cells, and but also improved the cellular oxidative stress-related indicators MDA, SOD and cell damage marker LDH in a dose-dependent manner. In the LPS-induced septic rat myocardial injury models (in vivo), the two compounds also showed good bioactivities. They also reduced the expression of IL-1β, IL-6 and TNF-α, and blocked cell damage by suppressing overhauled oxidation in septic rats. In addition, the myocardial injury was significantly improved and the inflammatory infiltration was reduced after treatment with the two compounds. In conclusion, the salidroside analogs (2 and 3) showed promising therapeutical effect on septic myocardial injury in LPS-model rats, and they could be good candidates for clinical trials against inflammation and septic myocardial injury.

Automated–Mechanical Procedure Compared to Gentle Enzymatic Tissue Dissociation in Cell Function Studies

The first step to obtain a cellular suspension from tissues is the disaggregation procedure. The cell suspension method has to provide a representative sample of the different cellular subpopulations and to maximize the number of viable functional cells. Here, we analyzed specific cell functions in cell suspensions from several rat tissues obtained by two different methods, automated–mechanical and enzymatic disaggregation. Flow cytometric, confocal, and ultrastructural (TEM) analyses were applied to the spleen, testis, liver and other tissues. Samples were treated by an enzymatic trypsin solution or processed by the Medimachine II (MMII). The automated–mechanical and enzymatic disaggregation procedures have shown to work similarly in some tissues, which displayed comparable amounts of apoptotic/necrotic cells. However, cells obtained by the enzyme-free Medimachine II protocols show a better preservation lysosome and mitochondria labeling, whereas the enzymatic gentle dissociation appears to constantly induce a lower amount of intracellular ROS; nevertheless, lightly increased ROS can be recognized as a complimentary signal to promote cell survival. Therefore, MMII represents a simple, fast, and standardized method for tissue processing, which allows to minimize bias arising from the operator’s ability. Our study points out technical issues to be adopted for specific organs and tissues to obtain functional cells.

Characterization of a fluorescent 1,8-naphthalimide-functionalized PAMAM dendrimer and its Cu(ii) complexes as cytotoxic drugs: EPR and biological studies in myeloid tumor cells

The activity and interacting ability of a polyamidoamine (PAMAM) dendrimer modified with 4-N-methylpiperazine-1,8-naphthalimide units (termed D) and complexed by Cu(ii) ions, towards healthy and cancer cells were studied. Comparative electron paramagnetic resonance (EPR) studies of the Cu(ii)-D complex are presented: coordination mode, chemical structure, flexibility and stability of these complexes, in the absence and presence of myeloid cancer cells and peripheral blood mononuclear cells (PBMC). The interactions of Cu(ii) ions in the biological media at different equilibrium times were studied, highlighting different stability and interacting conditions with the cells. Furthermore, flow cytometry and confocal analysis, trace the peculiar properties of the dendrimers in PBMC and U937 cells. Indeed, a new probe (Fly) was used as a potential fluorescent tool for biological imaging of Cu(ii). The study highlights that dendrimer and, mainly, the Cu(ii) metallodendrimer are cytotoxic agents for the cells, specifically for U937 tumor cells, inducing mitochondrial dysfunction, ROS increase and lysosome involvement. The metallodendrimer shows antitumor selectivity, fewer affecting healthy PBMC, inducing a massive apoptotic cell death on U937 cells, in line with the high stability of this complex, as verified by EPR studies. The results underline the potentiality of this metallodendrimer to be used as anticancer drug.

Potential of Olive Oil Mill Wastewater as a Source of Polyphenols for the Treatment of Skin Disorders: A Review

Current trends toward naturally occurring compounds of therapeutic interest have contributed to an increasing number of studies on olive oil phenolics in the treatment of diseases with oxidative and inflammatory origins. Recent focus has been on olive oil wastewater, which is richer in phenolic compounds than olive oil itself. In this review, we present findings demonstrating the potential use of olive mill wastewater in dermatology. Particular attention is given to compounds with proven benefits in topical pharmacology: caffeic and ferulic acids, tyrosol and hydroxytyrosol, verbascoside, and oleuropein. The review is divided into different sections: inflammatory skin diseases, microbial effects, wound healing in addition to the antimelanoma properties of olive mill waste phenolics, and their potential in sun protection agents. There is strong evidence to support further studies into the valorization of this abundant and sustainable source of phenolic compounds for use in dermatology and dermo-cosmetic preparations.

Tyrosol as a Neuroprotector: Strong Effects of a "Weak" Antioxidant

The use of neuroprotective agents for stroke is pathogenetically justified, but the translation of the results of preclinical studies of neuroprotectors into clinical practice has been a noticeable failure. One of the leading reasons for these failures is the one-target mechanism of their activity. p-Tyrosol (Tyr), a biophenol, is present in a variety of natural sources, mainly in foods, such as olive oil and wine. Tyr has a wide spectrum of biological activity: antioxidant, stress-protective, anti-inflammatory, anticancer, cardioprotective, neuroprotective and many others. This review analyzes data on the neuroprotective, antioxidant, anti-inflammatory, anti-apoptotic and other kinds of Tyr activity as well as data on the pharmacokinetics of the substance. The data presented in the review substantiate the acceptability of tyr as the basis for the development of a new neuroprotective drug with multitarget activity for the treatment of ischemic stroke. Tyr is a promising molecule for the development of an effective neuroprotective agent for use in ischemic stroke.

Investigations of Olive Oil Industry By-Products Extracts with Potential Skin Benefits in Topical Formulations

The by-products of olive oil industry are a major ecological issue due to their phenolic content, highly toxic organic load, and low pH. However, they can be recovered and reused, since their components have antioxidant, anti-inflammatory, and photoprotector properties. In this work, oil-in-water creams containing three different olive oil industry by-products extracts were produced without the use of organic solvents. First, the extracts were thoroughly characterized in vitro for cytotoxicity, inhibition of skin enzymes, and antioxidant and photoprotection capacities. Safety studies were then performed, including ocular and skin irritation tests, ecotoxicity evaluation, and in vivo Human Repeat Insult Patch Test. The results obtained in this initial characterization supported the incorporation of the extracts in the cream formulations. After preparation, the creams were characterized for their organoleptic, physicochemical, droplet size and rheological properties, and microbial contamination. The results showed that all formulations were semi-solid creams, with stable pH, compatible with the skin, without microbial contamination, and with the expected droplet size range. The rheological analysis showed shear-thinning behavior with yield stress, with the viscosity decreasing with increasing shear rate. The oscillatory results suggest that the creams have a strong network structure, being easily rubbed into the skin. Finally, compatibility, acceptability and antioxidant efficacy were evaluated in vivo, in human volunteers. No adverse reactions were observed after application of the formulations on skin and the cream with the highest concentrations of phenolic compounds showed the highest antioxidant efficiency. In conclusion, the results suggest that olive oil industry by-products extracts have valuable properties that favor their re-use in the cosmetic industry. The example presented here showed their successful incorporation into creams and their impact in these formulations' appearance, pH, and rheological performance, as well as their in vivo compatibility with skin and antioxidant efficiency.

Keratinocytes Migration Promotion, Proliferation Induction, and Free Radical Injury Prevention by 3-Hydroxytirosol

3-hydroxytyrosol (HT) is the main phenolic compound found in olive oil with known antioxidant, anti-inflammatory, and antimicrobial properties in several dermatological conditions, both when taken in the form of olive oil or pure in cosmeceutical formulations. To date, its direct effect on the wound healing process and the molecular mechanisms involved have not yet been elucidated. Thus, in the present study, we aimed to explore its effects in vitro in epidermal keratinocyte cultures focusing on the molecular mechanism implied. HT was able to induce keratinocyte proliferation in the low micromolar range, increasing the expression of cyclin dependent kinases fundamental for cell cycle progression such as CDK2 and CDK6. Furthermore, it increased cell migration through the activation of tissue remodeling factors such as matrix metalloproteinase-9 (MMP-9) protein. Then, we evaluated whether HT also showed antioxidant activity at this concentration range, protecting from H₂O₂-induced cytotoxicity. The HT prevented the activation of ATM serine/threonine kinase (ATM), Checkpoint kinase 1 (Chk1), Checkpoint kinase 2 (Chk2), and p53, reducing the number of apoptotic cells. Our study highlighted novel pharmacological properties of HT, providing the first evidence of its capability to induce keratinocyte migration and proliferation required for healing processes and re-epithelialization.

Protective effect of olive oil polyphenol phase II sulfate conjugates on erythrocyte oxidative-induced hemolysis

The consumption of extra virgin olive oil (EVOO) has been associated with a lower incidence of cardiovascular diseases partly due to its polyphenol content. The metabolites hydroxytyrosol sulfate and hydroxytyrosol acetate sulfate were shown to be the most concentrated polyphenol metabolites found in plasma after EVOO consumption. Therefore, the capacity of hydroxytyrosol, hydroxytyrosol acetate, homovanillyl alcohol, homovanillyl alcohol acetate and tyrosol sulfate metabolites, to protect red blood cells (RBCs) from oxidative injury induced by the radical initiator 2,2'-azo-bis(2-amidinopropane) dihydrochloride (AAPH) was evaluated. In the presence of AAPH, all non-sulfated compounds and the hydroxytyrosol and hydroxytyrosol acetate monosulfate metabolites showed a significant protective activity against RBCs induced oxidative hemolysis. Moreover, even at 5 μM, the protection was highly significant for hydroxytyrosol acetate, hydroxytyrosol and hydroxytyrosol acetate 3' and 4' monosulfates. The morphological changes of RBC and the nature of their hemoglobin were in accordance with the hemolysis assay. Results showed that a free phenolic hydroxyl group is needed for the antioxidant protection given by compounds. Hydroxytyrosol metabolites present as phase II sulfate conjugates are actually able to protect RBC from oxidative injury by a non-transcriptional mechanism and are likely to contribute for the anti-atherosclerosis properties of regular EVOO consumption.

Skin photo-protection with phytochemicals against photo-oxidative stress, photo-carcinogenesis, signal transduction pathways and extracellular matrix remodeling-An overview

Excessive exposure of skin to UV radiation triggers the generation of oxidative stress, inflammation, immunosuppression, apoptosis, matrix-metalloproteases production, and DNA mutations leading to the onset of photo ageing and photo-carcinogenesis. At the molecular level, these changes occur via activation of several protein kinases as well as transcription pathways, formation of reactive oxygen species, and release of cytokines, interleukins and prostaglandins together. Current therapies available on the market only provide limited solutions and exhibit several side effects. The present paper provides insight into scientific studies that have elucidated the positive role of phytochemicals in counteracting the UV-induced depletion of antioxidant enzymes, increased lipid peroxidation, inflammation, DNA mutations, increased senescence, dysfunctional apoptosis and immune suppression. The contribution of phytochemicals to the downregulation of expression of oxidative-stress sensitive transcription factors (Nrf2, NF-Kb, AP-1 and p53) and protein kinases (MSK, ERK, JNK, p38 MAPK, p90RSK2 and CaMKs) involved in inflammation, apoptosis, immune suppression, extracellular matrix remodelling, senescence, photo ageing and photo-carcinogenesis, is also discussed. Conclusively, several phytochemicals hold potential for the development of a viable solution against UV irradiation-mediated photo ageing, photo-carcinogenesis and related manifestations.

Extrapolation of hydroxytyrosol and its analogues as potential anti-inflammatory agents

Discovery of potential lead molecule is a challenging, and complex process which require lots of money, patience, and manpower. Human beings are using natural products, predominantly secondary metabolites, for this purpose since ancient time and they are still working on them as a potent source for drug discovery due to their wide structural diversity. Phenolic phytochemicals such as hydroxytyrosol and tyrosol are natural antioxidant and involved in many biological disease cure. Herein, we have carried out the quantum chemical calculations for conformational analysis, geometry optimization and computation of electronic as well as optical properties of hydroxytyrosol and its analogues (1a-1k) in terms of density functional theory by using Gaussian 09 program suite. The eventual charge transfer within the molecules has been confirmed by the analysis of frontier molecular orbitals. The molecular docking studies of 1a-1k with cyclooxygenase-2 showed the noticeable binding affinity as compared to other nonsteroidal anti-inflammatory drugs viz. aspirin, naproxen and celecoxib. Computation of pharmacokinetics and pharmacological properties confirmed the lead/drug like potential of these screened molecules. Furthermore, the molecular dynamics simulation of best three docked ligands (1f, 1h and 1k)-receptor complex and their binding free energy calculations reveals that these molecules bind in the catalytic cavity of cyclooxygenase-2 and found stable during the 100 ns of simulation. Communicated by Ramaswamy H. Sarma.

Synthesis, α-Glucosidase inhibition and molecular docking studies of tyrosol derivatives

To find a potent α-glucosidase inhibitor, 24 tyrosol derivatives with different substituents located at the meta, ortho, or para position of the phenyl group have been synthesised via the Mitsunobu reaction, characterised by ¹H NMR, ¹³C NMR, ESI-MS and IR and evaluated for inhibition. The derivatives possessed varying degrees of in vitro inhibitory activity against α-glucosidase and a relationship between the structure and activity was subsequently established for all compounds. Two of these compounds with substituents at the para position showed significant inhibitory effects surpassing that of the control standard acarbose. Molecular docking studies performed to better understand the binding interactions between the enzyme and the two most active compounds showed substantial binding within the active site of α-glucosidase. Taken together, these results indicate that the position of the substituent plays a crucial role in this inhibition and may facilitate the development of new α-glucosidase inhibitors.

Synthesis of Lipophilic Esters of Tyrosol, Homovanillyl Alcohol and Hydroxytyrosol

Low-molecular weight phenols such as tyrosol, homovanillyl alcohol and hydroxytyrosol are valuable compounds that exhibit a high number of health-promoting effects such as antioxidant, anti-inflammatory and anticancer activity. Despite these remarkable properties, their applications such as dietary supplements and stabilizers of foods and cosmetics in non-aqueous media are limited for the hydrophilic character. With the aim to overcome this limitation, the paper describes a simple and low-cost procedure for the synthesis of lipophilic esters of tyrosol, homovanillyl alcohol and hydroxytyrosol. The reactions were carried out under mild and green chemistry conditions, at room temperature, solubilizing the phenolic compounds in dimethyl carbonate, an eco-friendly solvent, and adding a little excess of the appropriate C2-C18 acyl chloride. The final products were isolated in good yields. Finally, according to the "circular economy" strategy, the procedure was applied to hydroxytyrosol-enriched extracts obtained by Olea europaea by-products to prepare a panel of lipophilic extracts that are useful for applications where solubility in lipid media is required.

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

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

Exploration of interaction mechanism of tyrosol as a potent anti-inflammatory agent

Drug discovery for a vigorous and feasible lead candidate is a challenging scientific mission as it requires expertise, experience, and huge investment. Natural products and their derivatives having structural diversity are renowned source of therapeutic agents since many years. Tyrosol (a natural phenylethanoid) has been extracted from olive oil, and its structure was confirmed by elemental analysis, FT-IR, FT-NMR, and single crystal X-ray crystallography. The conformational analysis for tyrosol geometry was performed by Gaussian 09 in terms of density functional theory. Validation of bond lengths and bond angles obtained experimentally as well as theoretically were performed with the help of curve fitting analysis, and values of correlation coefficient (R) obtained as 0.988 and 0.984, respectively. The charge transfer within the tyrosol molecule was confirmed by analysis of HOMO→LUMO molecular orbitals. In molecular docking with COX-2 (PDB ID: 5F1A), tyrosol was found to possess satisfactory binding affinity as compared to other NSAIDs (Aspirin, Ibuprofen, and Naproxen) and a COX-2 selective drug (Celecoxib). ADMET prediction, drug-likeness and bioactivity score altogether confirm the lead/drug like potential of tyrosol. Further investigation of simulation quality plot, RMSD and RMSF plots, ligands behavior plot as well as post simulation analysis manifest the consistency of 5F1A-tyrosol complex throughout the 20 ns molecular simulation process that signifies its compactness and stability within the receptor pocket. AbbreviationsADMETAbsorption, Distribution, Metabolism, Excretion and ToxicityÅAngstromCOX-2Cyclooxygenase-2DFTDensity Functional TheoryDMFDimethylformamideFMOFrontier Molecular OrbitalFT-IRFourier-transform Infrared SpectroscopyFT-NMRNuclear Magnetic Resonance SpectroscopyHOMOHighest Occupied Molecular OrbitalLUMOLowest Unoccupied Molecular OrbitalMDMolecular DynamicsNSNanosecondNSAIDsNon-steroidal anti-inflammatory drugsOPEOsiris Property ExplorerRMSDRoot-Mean-Square DeviationRMSFRoot Sean Square FluctuationCommunicated by Ramaswamy H. Sarma.

Biological Relevance of Extra Virgin Olive Oil Polyphenols Metabolites

Extra virgin olive oil (EVOO) polyphenols beneficial effects have widely been debated throughout the last three decades, with greater attention to hydroxytyrosol and tyrosol, which are by far the most studied. The main concern about the evaluation of EVOO phenols activities in vitro and in vivo is that the absorption and metabolism of these compounds once ingested lead to the production of different metabolites in the human body. EVOO phenols in the ingested forms are less concentrated in human tissues than their glucuronide, sulfate and methyl metabolites; on the other hand, metabolites may undergo deconjugation before entering the cells and thus act as free forms or may be reformed inside the cells so acting as conjugated forms. In most in vitro studies the presence of methyl/sulfate/glucuronide functional groups does not seem to inhibit biological activity. Parent compounds and metabolites have been shown to reach tissue concentrations useful to exert beneficial effects others than antioxidant and scavenging properties, by modulating intracellular signaling and improving cellular response to oxidative stress and pro-inflammatory stimuli. This review aims to give an overview on the reported evidence of the positive effects exerted by the main EVOO polyphenols metabolites in comparison with the parent compounds.

Biological Relevance of Extra Virgin Olive Oil Polyphenols Metabolites

Extra virgin olive oil (EVOO) polyphenols beneficial effects have widely been debated throughout the last three decades, with greater attention to hydroxytyrosol and tyrosol, which are by far the most studied. The main concern about the evaluation of EVOO phenols activities in vitro and in vivo is that the absorption and metabolism of these compounds once ingested lead to the production of different metabolites in the human body. EVOO phenols in the ingested forms are less concentrated in human tissues than their glucuronide, sulfate and methyl metabolites; on the other hand, metabolites may undergo deconjugation before entering the cells and thus act as free forms or may be reformed inside the cells so acting as conjugated forms. In most in vitro studies the presence of methyl/sulfate/glucuronide functional groups does not seem to inhibit biological activity. Parent compounds and metabolites have been shown to reach tissue concentrations useful to exert beneficial effects others than antioxidant and scavenging properties, by modulating intracellular signaling and improving cellular response to oxidative stress and pro-inflammatory stimuli. This review aims to give an overview on the reported evidence of the positive effects exerted by the main EVOO polyphenols metabolites in comparison with the parent compounds.

Hydroxytyrosol from olive fruits prevents blue-light-induced damage in human keratinocytes and fibroblasts

Skin aging is a complex biological process influenced by a combination of endogenous or intrinsic and exogenous or extrinsic factors due to environmental damage. The primary environmental factor that causes human skin aging is the ultraviolet irradiation from the sun. Recently, it was established that the long-term exposure to light-emitting-diode-generated blue light (LED-BL) from electronic devices seems to have a relevant implication in the molecular mechanisms of premature photoaging. BL irradiation induces changes in the synthesis of various skin structures through DNA damage and overproduction of reactive oxygen species (ROS), matrix metalloproteinase-1 and -12, which are responsible for the loss of the main components of the extracellular matrix of skin like collagen type I and elastin. In the current study, using human keratinocytes and fibroblasts exposed to specific LED-BL radiation doses (45 and 15 J/cm ² ), we produced an in vitro model of skin photoaging. We verified that, compared with untreated controls, the treatment with LED-BL irradiation results in the alteration of metalloprotease-1 (collagenase), metalloprotease-12 (elastase), 8-dihydroxy-2'-deoxyguanosine, proliferating cell nuclear antigen, and collagen type I. Moreover, we showed that the photoaging prevention is possible via the use of hydroxytyrosol extracted from olive fruits, well known for antioxidant properties. Our results demonstrated that hydroxytyrosol protects keratinocytes and fibroblasts from LED-BL-induced damage. Thus, hydroxytyrosol might be proposed as an encouraging candidate for the prevention of BL-induced premature photoaging.

Marine bisindole alkaloid: A potential apoptotic inducer in human cancer cells

Marine organisms such as corals, sponges and tunicates produce active molecules which could represent a valid starting point for new drug development processes. Among the various structural classes, the attention has been focused on 2,2-bis(6-bromo-3-indolyl) ethylamine, a marine alkaloid which showed a good anticancer activity against several tumor cell lines. Here, for the first time, the mechanisms of action of 2,2-bis(6-bromo-3-indolyl) ethylamine have been evaluated in a U937 tumor cell model. Morpho-functional and molecular analyses, highlighting its preferred signaling pathway, demonstrated that apoptosis is the major death response induced by this marine compund. Chromatin condensation, micronuclei formation, blebbing and in situ DNA fragmentation, occurring through caspase activation (extrinsic and intrinsic pathways), were observed. In particular, the bisindole alkaloid induces a mitochondrial involvement in apoptosis machinery activation with Blc-2/Bcl-x down-regulation and Bax up-regulation. These findings demonstrated that 2,2-bis(6-bromo-3-indolyl) ethylamine alkaloid-induced apoptosis is regulated by the Bcl-2 protein family upstream of caspase activation.

Methods to detect apoptotic cell death

In concert with the increased understanding that there are many ways for cells to die, several methods have been developed to detect cell death. The classification of cell death posed some difficulties that were overcome by implementing strict selection criteria that should also apply to the detection methods. The selection of assays is based on morphological criteria and distinguishable marks of apoptotic patways. The detection of apoptosis includes methods related to membrane alterations, DNA fragmentation, cytotoxicity and cell proliferation, mitochondrial damage, immunological detection and mechanism based assays. Other less frequently used detections of apoptosis are: (a) light-scattering flow cytometry to avoid underestimating the extent and timing of apoptosis, (b) time-lapse microscopy perfusion platform to support the temporal aspects of detection, to measure cell surface area and cellular adhesion, and (c) genotoxicity specific chromatin changes. Attention is called to the advantages and limitations of various methods.

Protective effect of different antioxidant agents in UVB-irradiated keratinocytes

Skin cells can respond to UVB-induced damage either by tolerating it, or restoring it through antioxidant activation and DNA repair mechanisms or, ultimately, undergoing programmed cell death, when damage is massive. Nutritional factors, in particular, food antioxidants, have attracted much interest because of their potential use in new preventive, protective, and therapeutic strategies for chronic degenerative diseases, including skin inflammation and cancer. Some polyphenols, present in virgin olive oil, well tolerated by organism after oral administration, show a variety of pharmacological and clinical benefits such as antioxidant, anti-cancer, anti-inflammatory, and neuro-protective activities. Here, the protective effects of antioxidant compounds against UV-induced apoptosis have been described in HaCaT cell line. Human keratinocytes were pre-treated with antioxidants before UVB exposure and their effects have been evaluated by means of ultrastructural analyses. After UVB radiation, a known cell death trigger, typical apoptotic features, absent in control condition and in antioxidant alone-treated cells, appear. An evident numerical decrease of ultrastructural apoptotic patterns and TUNEL positive nuclei can be observed when natural antioxidants were supplied before cell death induction. These data have been confirmed by molecular investigation of caspase activity. In conclusion, this paper highlights antioxidant compound ability to prevent apoptotic cell death in human keratinocytes exposed to UVB, suggesting, for these molecules, a potential role in preventing skin damage.

Metabolomic analysis and lipid accumulation in a glucose tolerant Crypthecodinium cohnii strain obtained by adaptive laboratory evolution

Adaptive laboratory evolution (ALE) was commonly used for strain improvement. Crypthecodinium cohnii is known to accumulate lipids with a high fraction of docosahexaenoic acid (DHA). In order to improve DHA production under high substrate concentration, a glucose-tolerant C. cohnii strain was firstly obtained by ALE after 260 cycles for 650days with gradually increased glucose concentration. The results of lipids content showed that DHA-rich lipids accumulation in the evolved strain could increase by 15.49% at 45g/L glucose concentrations. To reveal mechanisms related to glucose tolerance of C. cohnii through ALE, metabolic profiles were then compared and the results showed that hub metabolites including glycerol, glutamic acid, malonic acid and succinic acid were positively regulated during ALE. The study demonstrated that metabolomic analysis complemented with ALE could be an effective and valuable strategy for basic mechanisms of molecular evolution and adaptive changes in C. cohnii.

N-(4-methoxyphenyl) caffeamide-induced melanogenesis inhibition mechanisms

Background

The derivative of caffeamide exhibits antioxidant and antityrosinase activity. The activity and mechanism of N-(4-methoxyphenyl) caffeamide (K36E) on melanogenesis was investigated.

Methods

B16F0 cells were treated with various concentrations of K36E; the melanin contents and related signal transduction were studied. Western blotting assay was applied to determine the protein expression, and spectrophotometry was performed to identify the tyrosinase activity and melanin content.

Results

Our results indicated that K36E reduced α-melanocyte-stimulating hormone (α-MSH)-induced melanin content and tyrosinase activity in B16F0 cells. In addition, K36E inhibited the expression of phospho-cyclic adenosine monophosphate (cAMP)-response element-binding protein, microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1 (TRP-1). K36E activated the phosphorylation of protein kinase B (AKT) and glycogen synthase kinase 3 beta (GSK3β), leading to the inhibition of MITF transcription activity. K36E attenuated α-MSH induced cAMP pathways, contributing to hypopigmentation.

Conclusions

K36E regulated melanin synthesis through reducing the expression of downstream proteins including p-CREB, p-AKT, p-GSK3β, tyrosinase, and TRP-1, and activated the transcription factor, MITF. K36E may have the potential to be developed as a skin whitening agent.

Defective Autophagy, Mitochondrial Clearance and Lipophagy in Niemann-Pick Type B Lymphocytes

Niemann-Pick disease type A (NP-A) and type B (NP-B) are lysosomal storage diseases (LSDs) caused by sphingomyelin accumulation in lysosomes relying on reduced or absent acid sphingomyelinase. A considerable body of evidence suggests that lysosomal storage in many LSD impairs autophagy, resulting in the accumulation of poly-ubiquitinated proteins and dysfunctional mitochondria, ultimately leading to cell death. Here we test this hypothesis in a cellular model of Niemann-Pick disease type B, in which autophagy has never been studied. The basal autophagic pathway was first examined in order to evaluate its functionality using several autophagy-modulating substances such as rapamycin and nocodazole. We found that human NP-B B lymphocytes display considerable alteration in their autophagic vacuole accumulation and mitochondrial fragmentation, as well as mitophagy induction (for damaged mitochondria clearance). Furthermore, lipid traceability of intra and extra-cellular environments shows lipid accumulation in NP-B B lymphocytes and also reveals their peculiar trafficking/management, culminating in lipid microparticle extrusion (by lysosomal exocytosis mechanisms) or lipophagy. All of these features point to the presence of a deep autophagy/mitophagy alteration revealing autophagic stress and defective mitochondrial clearance. Hence, rapamycin might be used to regulate autophagy/mitophagy (at least in part) and to contribute to the clearance of lysosomal aberrant lipid storage.

Antioxidant effect of hydroxytyrosol on human sperm quality during in vitro incubation

The aim of the study was to evaluate the antioxidant potential of hydroxytyrosol (HT) on human sperm quality during incubation in vitro. Semen samples collected from men attending the Laboratory of Histology-Embryology of Sfax Faculty of Medicine (Tunisia) for infertility investigations were evaluated for initial sperm parameters. Only normal selected ejaculates (n = 15) were centrifuged and incubated further with or without HT (200ug ml^-1 ) at room temperature for 45 min. After incubation, sperm motility and viability, DNA oxidation and reactive oxygen species (ROS) production were assessed. The results showed that centrifugation significantly influenced sperm motility and viability. The supplementation of HT in incubating media improved (P = 0.01) significantly sperm viability and decreased sperm DNA oxidation (P < 0.001) and ROS levels (P = 0.03) following centrifugation. It can be concluded that supplementation of HT might be helpful to maintain the human spermatozoon after centrifugation.

Carotenoids exclusively synthesized in red pepper (capsanthin and capsorubin) protect human dermal fibroblasts against UVB induced DNA damage

Capsanthin and capsorubin, carotenoids exclusively synthesized in red pepper, protect human dermal fibroblasts against UVB induced DNA damage.

Tyrosol, an olive oil polyphenol, inhibits ER stress-induced apoptosis in pancreatic β-cell through JNK signaling

Dysfunction of pancreatic β-cell is a major determinant for the development of type 2 diabetes. Because of the stimulated insulin secretion in metabolic syndrome, endoplasmic reticulum (ER) stress plays a central mediator for β-cell failure. In this study, we investigated whether an antioxidant phenolic compound, tyrosol protects against β-cell dysfunction associated with ER stress. To address this issue, we exposed pancreatic β cells, NIT-1 to tunicamycin with tyrosol. We found tyrosol diminished tunicamycin-induced cell death in a dose-dependent manner. We also detected tyrosol decreased the expressions of apoptosis-related markers. Exposure to tunicamycin evoked UPR response and co-treatment of tyrosol led to reduction of ER stress. These effects of tyrosol were mediated by the phosphorylation of JNK. Moreover, we confirmed supplement of tyrosol ameliorated β-cell loss induced by high fat feeding. Taken together, our study provides a molecular basis for signaling transduction of protective effect of tyrosol against ER stress-induced β-cell death. Therefore, we suggest tyrosol could be a potential therapeutic candidate for amelioration of type 2 diabetes.