Cardioprotective potential of oleuropein, hydroxytyrosol, oleocanthal and their combination: Unravelling complementary effects on acute myocardial infarction and metabolic syndrome.

Clinical studies have previously established the role of olive products in cardiovascular disease (CVD) prevention, whilst the identification of the responsible constituents for the beneficial effects is still pending. We sought to assess and compare the cardioprotective potential of oleuropein (OL), hydroxytyrosol (HT), oleocanthal (OC) and oleanolic Acid (OA), regarding Ischemia/Reperfusion Injury (IRI) and CVD risk factors alleviation. The scope of the study was to design a potent and safe combinatorial therapy for high-cardiovascular-risk patients on a bench-to-bedside approach. We evaluated the IRI-limiting potential of 6-weeks treatment with OL, HT, OC or OA at nutritional doses, in healthy and metabolic syndrome (MS)-burdened mice. Three combinatorial regimens were designed and the mixture with preponderant benefits (OL-HT-OC, Combo 2), including infarct sparing and antiglycemic potency, compared to the isolated compounds, was further investigated for its anti-atherosclerotic effects. In vivo experiments revealed that the combination regimen of Combo 2 presented the most favorable effects in limiting infarct size and hyperglycemia, which was selected to be further investigated in the clinical setting in Chronic Coronary Artery Syndrome (CCAS) patients. Cardiac function, inflammation markers and oxidative stress were assessed at baseline and after 4 weeks of treatment with the OL-HT-OC supplement in the clinical study. We found that OL, OC and OA significantly reduced infarct size in vivo compared to Controls. OL exhibited antihyperglycemic properties and OA attenuated hypercholesterolemia. OL-HT-OA, OL-HT-OC and OL-HT-OC-OA combination regimens were cardioprotective, whereas only OL-HT-OC mitigated hyperglycemia. Combo 2 cardioprotection was attributed to apoptosis suppression, enhanced antioxidant effects and upregulation of antioxidant enzymes. Additionally, it reduced atherosclerotic plaque extent in vivo. OL-HT-OC supplement ameliorated cardiac, vascular and endothelial function in the small-scale clinical study. Conclusively, OL-HT-OC combination therapy exerts potent cardioprotective, antihyperglycemic and anti-atherosclerotic properties in vivo, with remarkable and clinically translatable cardiovascular benefits in high-risk patients.

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.

Pharmacokinetics and Metabolism Investigation of Oleocanthal.

Oleocanthal is a secoiridoid found in olive oil, which lately gained great scientific interest due to its important pharmacological spectrum and biological properties. However, limited data exist on the metabolic fate of oleocanthal in vivo, a commonly underestimated aspect in natural products research. Especially, its pharmacokinetic (PK) characteristics have never been described so far. Thus, in the current study, a mouse-based protocol was designed, and oleocanthal was administered intraperitoneally in a standard dose of 5 mg/kg. In order to determine the PK parameters of oleocanthal or its metabolites, plasma samples were collected at 10 time points. Extraction and analysis protocols were developed and applied for the recovery and detection of oleocanthal in plasma, as well as the identification of its metabolites, using LC-HRMS/MS. Oleocanthal was not detected, proving the short lifetime of the compound in vivo, and 13 metabolites were identified. Among them, oleocanthalic acid and tyrosol sulfate were proposed as oleocanthal's biomarkers, in vivo. This is the first report associating oleocanthalic acid with oleocanthal administration in vivo, while its PK parameters, Tmax (T0) and Cmax (926 µg/mL), were also determined. The current study enlightens bioavailability and metabolism aspects of oleocanthal and suggests the association of specific metabolites with the biological effects attributed to oleocanthal administration. More studies are needed to give better insights into the metabolism and the mechanism of action of secoiridoids as well as to respond to identification challenges related to secoiridoid in vivo setups.

Synthesis, cytotoxic activity evaluation and mechanistic investigation of novel 3,7-diarylsubstituted 6-azaindoles.

A number of new disubstituted 6-azaindoles have been designed and synthesized bearing a crucial structural modification in respect to an analogous antiproliferative hit compound. The synthesis was performed using 2-amino-3-nitro-4-picoline, that was suitably modified and converted to 7-chloro-3-iodo-6-azaindole and this central scaffold was used for successive Suzuki-type couplings, to result in the target compounds. The evaluation of the cytotoxic activity was performed against four human cancer cell lines, as well as a normal human fibroblast strain. Certain compounds possessed strong anticancer activity without affecting normal cells. At subcytotoxic concentrations for cancer cells, these compounds displayed an anti-proliferative effect by arresting the cells at the G2/M phase of the cell cycle, which could be associated with the observed decrease in the phosphorylation levels of the MEK1- ERK1/2 pathway and/or the activation of the p53-p21WAF1 axis.

Next-generation sequencing reveals altered gene expression and enriched pathways in triple-negative breast cancer cells treated with oleuropein and oleocanthal.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by poor prognosis and limited treatment options. Oleuropein and oleocanthal are bioactive chemicals found in extra-virgin olive oil; they have been shown to have anti-cancer potential. In this study, we examined the inhibitory effects of these two natural compounds, on MDA-MB-231 and MDA-MB-468 TNBC cell lines. The human TNBC MDA-MB-231 and MDA-MB-468 cell lines were treated with oleuropein or oleocanthal at ranging concentrations for 48 h. After determining the optimum concentration to reach IC50, using the sulforhodamine B assay, total RNA was extracted after 12, 24, and 48 h from treated and untreated cells. Poly(A)-RNA selection was conducted, followed by library construction and RNA sequencing. Differential gene expression (DEG) analysis was performed to identify DEGs between treated and untreated cells. Pathway analysis was carried out using the KEGG and GO databases. Oleuropein and oleocanthal considerably reduced the proliferation of TNBC cells, with oleocanthal having a slightly stronger effect than oleuropein. Furthermore, multi-time series RNA sequencing showed that the expression profile of TNBC cells was significantly altered after treatment with these compounds, with temporal dynamics and groups of genes consistently affected at all time points. Pathway analysis revealed several significant pathways associated with TNBC, including cell death, apoptotic process, programmed cell death, response to stress, mitotic cell cycle process, cell division, and cancer progression. Our findings suggest that oleuropein and oleocanthal have potential therapeutic benefits for TNBC and can be further investigated as alternative treatment options.

Development of Stilbenoid and Chalconoid Analogues as Potent Tyrosinase Modulators and Antioxidant Agents.

A number of stilbenoid and chalconoid derivatives were prepared by straightforward methods, and their ability to modulate tyrosinase activity and to scavenge free radicals were evaluated in vitro. The cell-free in vitro evaluation revealed two diarylpropanes, 24 and 25, as potent tyrosinase inhibitors, whereas diarylpropenoic acids seemed to enhance the enzymatic activity. An in silico evaluation of the binding affinity of the selected compounds with the crystal structure of tyrosinase was also conducted in order to obtain better insight into the mechanism. Representative synthetic compounds with inhibitory and activating properties were further evaluated in melanoma cell lines B16F1 and B16F10 for their ability to moderate tyrosinase activity and affect melanin production. Dihydrostilbene analogues I and II, exhibited a stronger anti-melanogenic effect than kojic acid through the inhibition of cellular tyrosinase activity and melanin formation, while diarylpropanoic acid 44 proved to be a potent melanogenic factor, inducing cellular tyrosinase activity and melanin formation. Moreover, the antioxidant evaluation disclosed two analogues (29 and 11) with significant free-radical-scavenging activity (12.4 and 20.3 µM), which were 10- and 6-fold more potent than ascorbic acid (122.1 µΜ), respectively.

Antioxidant and Neuroprotective Effect of a Grape Pomace Extract on Oxaliplatin-Induced Peripheral Neuropathy in Rats: Biochemical, Behavioral and Histopathological Evaluation.

Oxaliplatin is a widely used chemotherapeutic agent. Despite its many beneficial aspects in fighting many malignancies, it shares an aversive effect of neuropathy. Many substances have been used to limit this oxaliplatin-driven neuropathy in patients. This study evaluates the neuroprotective role of a grape pomace extract (GPE) into an oxaliplatin induced neuropathy in rats. For this reason, following the delivery of the substance into the animals prior to or simultaneously with oxaliplatin, their performance was evaluated by behavioral tests. Blood tests were also performed for the antioxidant activity of the extract, along with a histological and pathological evaluation of dorsal root ganglion (DRG) cells as the major components of the neuropathy. All behavioral tests were corrected following the use of the grape pomace. Oxidative stressors were also limited with the use of the extract. Additionally, the morphometrical analysis of the DRG cells and their immunohistochemical phenotype revealed the fidelity of the animal model and the changes into the parvalbumin and GFAP concentration indicative of the neuroprotective role of the pomace. In conclusion, the grape pomace extract with its antioxidant properties alleviates the harmful effects of the oxaliplatin induced chronic neuropathy in rats.

Higher Yield and Polyphenol Content in Olive Pomace Extracts Using 2-Methyloxolane as Bio-Based Solvent.

Despite its severe toxicity and negative environmental impact, hexane remain the solvent of choice for the extraction of vegetable oils. This is in contrast with the constantly growing demand for sustainable and green extraction processes. In recent years a variety of alternatives to hexane have been reported, among them 2-methyloxolane (2-MeOx), which has emerged as a promising bio-based alternative. This study evaluates the possibility of replacing hexane, in the extraction of olive pomace (OP), with 2-MeOx, both dry and saturated with water (4.5%), the latter of which is called 2-MeOx 95.5%. The three solvents have been compared in terms of extraction yield and quality, as well as the lipid and polyphenol profiles of the extracts. The work concluded that both dry 2-MeOx and 2-MeOx 95.5% can replace hexane in OP extraction, resulting in higher yields and extracts richer in phenolic compounds. This study should open the road to further semi-industrial scale investigations toward more sustainable production processes.

Drug delivery of 6-bromoindirubin-3'-glycerol-oxime ether employing poly(D,L-lactide-co-glycolide)-based nanoencapsulation techniques with sustainable solvents.

BACKGROUND: Insufficient solubility and stability of bioactive small molecules as well as poor biocompatibility may cause low bioavailability and are common obstacles in drug development. One example of such problematic molecules is 6-bromoindirubin-3'-glycerol-oxime ether (6BIGOE), a hydrophobic indirubin derivative. 6BIGOE potently modulates the release of inflammatory cytokines and lipid mediators from isolated human monocytes through inhibition of glycogen synthase kinase-3 in a favorable fashion. However, 6BIGOE suffers from poor solubility and short half-lives in biological aqueous environment and exerts cytotoxic effects in various mammalian cells. In order to overcome the poor water solubility, instability and cytotoxicity of 6BIGOE, we applied encapsulation into poly(D,L-lactide-co-glycolide) (PLGA)-based nanoparticles by employing formulation methods using the sustainable solvents Cyrene™ or 400 g/mol poly(ethylene glycol) as suitable technology for efficient drug delivery of 6BIGOE. RESULTS: For all preparation techniques the physicochemical characterization of 6BIGOE-loaded nanoparticles revealed comparable crystallinity, sizes of about 230 nm with low polydispersity, negative zeta potentials around - 15 to - 25 mV, and biphasic release profiles over up to 24 h. Nanoparticles with improved cellular uptake and the ability to mask cytotoxic effects of 6BIGOE were obtained as shown in human monocytes over 48 h as well as in a shell-less hen's egg model. Intriguingly, encapsulation into these nanoparticles fully retains the anti-inflammatory properties of 6BIGOE, that is, favorable modulation of the release of inflammation-relevant cytokines and lipid mediators from human monocytes. CONCLUSIONS: Our formulation method of PLGA-based nanoparticles by applying sustainable, non-toxic solvents is a feasible nanotechnology that circumvents the poor bioavailability and biocompatibility of the cargo 6BIGOE. This technology yields favorable drug delivery systems for efficient interference with inflammatory processes, with improved pharmacotherapeutic potential.

Palmatine, a Bioactive Protoberberine Alkaloid Isolated from Berberis cretica, Inhibits the Growth of Human Estrogen Receptor-Positive Breast Cancer Cells and Acts Synergistically and Additively with Doxorubicin.

Palmatine (PLT) is a natural isoquinoline alkaloid that belongs to the class of protoberberines and exhibits a wide spectrum of pharmacological and biological properties, including anti-cancer activity. The aim of our study was to isolate PLT from the roots of Berberis cretica and investigate its cytotoxic and anti-proliferative effects in vitro alone and in combination with doxorubicine (DOX) using human ER+/HER2- breast cancer cell lines. The alkaloid was purified by column chromatography filled with silica gel NP and Sephadex LH-20 resin developed in the mixture of methanol: water (50:50 v/v) that provided high-purity alkaloid for bioactivity studies. The purity of the alkaloid was confirmed by high resolution mass measurement and MS/MS fragmentation analysis in the HPLC-ESI-QTOF-MS/MS-based analysis. It was found that PLT treatment inhibited the viability and proliferation of breast cancer cells in a dose-dependent manner as demonstrated by MTT and BrdU assays. PLT showed a quite similar growth inhibition on breast cancer cells with IC50 values ranging from 5.126 to 5.805 µg/mL. In contrast, growth of normal human breast epithelial cells was not affected by PLT. The growth inhibitory activity of PLT was related to the induction of apoptosis, as determined by Annexin V/PI staining. Moreover, PLT sensitized breast cancer cells to DOX. Isobolographic analysis revealed synergistic and additive interactions between studied agents. Our studies suggest that PLT can be a potential candidate agent for preventing and treating breast cancer.

An enriched polyphenolic extract obtained from the by-product of Rosa damascena hydrodistillation activates antioxidant and proteostatic modules.

BACKGROUND: Prolonged maintenance of proteome stability and functionality (proteostasis) is of emerging significance in aging retardation and healthspan. PURPOSE: An enriched polyphenolic extract obtained from the hydrodistillation of rose petals was tested for its capacity to activate the proteostasis network modules, and thus modulate health- and/or lifespan at the cellular and whole organism level. METHODS: The aqueous extract that remained after the hydrodistillation of Rosa damascena petals, was processed with a polystyrene-FPX66 adsorption resin and sequentially fractionated by FCPC. NMR and UHPLC-HRMS analyses revealed the presence of 28 metabolites, mainly glycosides of kaempferol and quercetin. RESULTS: The extract showed high in vitro antioxidant activity and was not toxic in normal human skin fibroblasts, while it promoted the upregulation of NRF2-induced antioxidant genes and main proteostatic modules. Consistently, supplementation of this extract in Drosophila flies' culture medium induced a cncC/NRF2-mediated upregulation of antioxidant and proteostatic modules. Prolonged administration of the extract in flies' culture medium was not toxic and did not affect food intake rate or fecundity; also, it delayed the age-related decline of stress tolerance and locomotion performance (neuromuscular functionality) and dose-dependently extended flies' lifespan. CONCLUSION: Our findings indicate that the enriched polyphenolic extract obtained from the residue of R. damascena hydrodistillation activates cytoprotective cellular modules that, likely, contribute to its potential anti-aging properties.

Acute administration of the olive constituent, oleuropein, combined with ischemic postconditioning increases myocardial protection by modulating oxidative defense.

Oleuropein, one of the main polyphenolic constituents of olive, is cardioprotective against ischemia reperfusion injury (IRI). We aimed to assess the cardioprotection afforded by acute administration of oleuropein and to evaluate the underlying mechanism. Importantly, since antioxidant therapies have yielded inconclusive results in attenuating IRI-induced damage on top of conditioning strategies, we investigated whether oleuropein could enhance or imbed the cardioprotective manifestation of ischemic postconditioning (PostC). Oleuropein, given during ischemia as a single intravenous bolus dose reduced the infarct size compared to the control group both in rabbits and mice subjected to myocardial IRI. None of the inhibitors of the cardioprotective pathways, l-NAME, wortmannin and AG490, influence its infarct size limiting effects. Combined oleuropein and PostC cause further limitation of infarct size in comparison with PostC alone in both animal models. Oleuropein did not inhibit the calcium induced mitochondrial permeability transition pore opening in isolated mitochondria and did not increase cGMP production. To provide further insights to the different cardioprotective mechanism of oleuropein, we sought to characterize its anti-inflammatory potential in vivo. Oleuropein, PostC and their combination reduce inflammatory monocytes infiltration into the heart and the circulating monocyte cell population. Oleuropein's mechanism of action involves a direct protective effect on cardiomyocytes since it significantly increased their viability following simulated IRI as compared to non-treated cells. Οleuropein confers additive cardioprotection on top of PostC, via increasing the expression of the transcription factor Nrf-2 and its downstream targets in vivo. In conclusion, acute oleuropein administration during ischemia in combination with PostC provides robust and synergistic cardioprotection in experimental models of IRI by inducing antioxidant defense genes through Nrf-2 axis and independently of the classic cardioprotective signaling pathways (RISK, cGMP/PKG, SAFE).

Assessment of the Nutraceutical Effects of Oleuropein and the Cytotoxic Effects of Adriamycin, When Administered Alone and in Combination, in MG-63 Human Osteosarcoma Cells.

Oleuropein (OLEU) is the most distinguished phenolic compound found in olive fruit and the leaves of Olea europaea L., with several pharmacological properties, including anti-cancer actions. Adriamycin (ADR) is an anthracycline widely used as a chemotherapeutic agent, although it presents significant side effects. The aim of the present study was to investigate the effect of oleuropein alone (20 µg/mL) and in co-treatment with ADR (50 nM), in MG-63 human osteosarcoma cells. Therefore, cellular and molecular techniques, such as MTT assay, flow cytometry, real-time Polymerase Chain Reaction (PCR), western blot and Elisa method, as well as Nuclear Magnetic Resonance (NMR) spectroscopy, were applied to unveil changes in the signal transduction pathways involved in osteosarcoma cells survival. The observed alterations in gene, protein and metabolite levels denote that OLEU not only inhibits MG-63 cells proliferation and potentiates ADR's cytotoxicity, but also exerts its action, at least in part, through the induction of autophagy.

Behavioral and Neurochemical Effects of Extra Virgin Olive Oil Total Phenolic Content and Sideritis Extract in Female Mice.

The aim of this study was to determine the cognitive and behavioral effects of extra virgin olive oil total phenolic content (TPC) and Sideritis (SID) extracts in female mice, and identify the associated neurochemical changes in the hippocampus and the prefrontal cortex. All animals received intraperitoneal low or high doses of TPC, SID or vehicle treatment for 7 days and were subjected to the Open Field (OF), Novel Object Recognition (NOR) and Tail Suspension Test (TST). The prefrontal cortex and hippocampus were dissected for analysis of neurotransmitters and aminoacids with high performance liquid chromatography with electrochemical detection (HPLC-ED). Both TPC doses enhanced vertical activity and center entries in the OF, which could indicate an anxiolytic-like effect. In addition, TPC enhanced non-spatial working memory and, in high doses, exerted antidepressant effects. On the other hand, high SID doses remarkably decreased the animals' overall activity. Locomotor and exploratory activities were closely associated with cortical increases in serotonin turnover induced by both treatments. Cognitive performance was linked to glutamate level changes. Furthermore, TPC reduced cortical taurine levels, while SID reduced cortical aspartate levels. TPC seems to have promising cognitive, anxiolytic and antidepressant effects, whereas SID has sedative effects in high doses. Both extracts act in the brain, but their specific actions and properties merit further exploration.

The indirubin derivative 6-bromoindirubin-3'-glycerol-oxime ether (6BIGOE) potently modulates inflammatory cytokine and prostaglandin release from human monocytes through GSK-3 interference.

Indirubin is a natural bis-indole alkaloid contained as active ingredient in the traditional Chinese remedy Danggui Longhui Wan. Indirubin and its 3'-oxime derivatives exhibit anti-cancer and anti-inflammatory properties and they inhibit glycogen synthase kinase (GSK)-3 in cell-free assays where 6-bromoindirubin-3'-oxime (6BIO) is among the most potent analogs. Here, we reveal 6-bromoindirubin-3'-glycerol-oxime ether (6BIGOE) as highly potent derivative able to inhibit pro-inflammatory cytokine, chemokine and prostaglandin (PG) release in human primary monocytes while increasing anti-inflammatory interleukin (IL)-10 levels. 6BIGOE suppressed lipopolysaccharide (LPS)-induced IL-1ß and PGE2 release with IC50 of 0.008 and 0.02 µM, respectively, being ≥ 12-fold more potent than 6BIO. The effects of 6BIGOE are mediated via intracellular inhibition of GSK-3, where 6BIGOE again surpassed the effectiveness of 6BIO despite the higher potency of the latter in cell-free GSK-3 activity assays. Side-by-side comparison of 6BIGOE (0.1 µM) with the selective GSK-3 inhibitor SB216763 (5 µM) revealed congruent properties such as enrichment of ß-catenin and suppression of cyclooxygenase (COX)-2 protein levels due to GSK-3 inhibition. Metabololipidomics using ultra-performance liquid chromatography-tandem mass spectrometry showed that 6BIGOE selectively decreases pro-inflammatory COX-derived product formation without marked modulation of other lipid mediators. In summary, 6BIGOE is a highly potent indirubin derivative in the cellular context that favorably modulates pro- and anti-inflammatory cytokines as well as COX-2-derived PG via interference with GSK-3.

Biomimetic Synthesis of Oleocanthal, Oleacein, and Their Analogues Starting from Oleuropein, A Major Compound of Olive Leaves.

Oleocanthal and oleacein are known for a wide range of beneficial activities in human health and the prevention of diseases. The inability to isolate significant and pure amounts of these natural compounds and their demanding synthesis lead to the development of an efficient, five-step, three-pot procedure. The synthesis is performed by a convenient biomimetic approach, starting from oleuropein, an abundant raw material in olive leaves, through the mixed anhydride of oleoside. The method is stereocontrolled and provides an efficient approach to the synthesis of various oleocanthal analogues; thus, a small library of four compounds was prepared with 35-45% overall yield.

Design and Synthesis of New Substituted Pyrazolopyridines with Potent Antiproliferative Activity.

BACKGROUND: Purine isosteres are often endowed with interesting pharmacological properties, due to their involvement in cellular processes replacing the natural purines. Among these compounds, pyrazolopyridines are under active investigation for potential anticancer properties. OBJECTIVES: Based on previously discovered substituted pyrazolopyridines with promising antiproliferative activity, we designed and synthesized new, suitably substituted analogues aiming to investigate their potential activity and contribute to SAR studies of this class of bioactive compounds. METHODS: The new compounds were synthesized using suitably substituted 2-amino-4-picolines, which upon ring-closure provided substituted pyrazolo[3,4-c] pyridine-5-carbonitriles that served as key intermediates for the preparation of the target 3,5,7 trisubstituted derivatives. The antiproliferative activity of 31 new target derivatives was evaluated against three cancer cell lines (MIA PaCa-2, PC-3 and SCOV3), whereas cell-cycle perturbations of exponentially growing PC-3 cells, using three selected derivatives were also performed. RESULTS: Eight compounds displayed IC50 values in the low µM range, allowing the extraction of interesting SAR's. Two of the most potent compounds against all cell lines share a common pattern, by accumulating cells at the G0/G1 phase. From this project, a new carboxamidine-substituted hit has emerged. CONCLUSION: Among the new compounds, those possessing the 3-phenylpyrazolo[3,4-c]pyridine scaffold, proved to be worth investigating and the majority of them showed strong cytotoxic activity against all cell lines, with IC50 values ranging from 0.87-4.3 µM. A carboxamidine analogue that resulted from the synthetic procedure, proved to be highly active against the cancer cells and could be considered as a useful lead for further optimization.

Glycyrrhiza glabra-Enhanced Extract and Adriamycin Antiproliferative Effect on PC-3 Prostate Cancer Cells.

Prostate cancer is the second most commonly diagnosed cancer in men worldwide, which is almost incurable, once it progresses into the metastatic stage. Adriamycin (ADR) is a known chemotherapeutic agent that causes severe side effects. In recent years, studies in natural plant products have revealed their anticancer activities. In particular, Glycyrrhiza glabra enhanced extract (GGE), commonly known as licorice, has been reported to exert antiproliferative properties against cancer cells. In this study, the cytotoxic potential of GGE was assessed in PC-3 cells, when it is administrated alone or in combination with Adriamycin. PC-3 cells were treated with GGE and/or ADR, and the inhibition of cell proliferation was evaluated by the MTT assay. Cell cycle alterations and apoptosis rate were measured through flow cytometry. Expression levels of autophagy-related genes were evaluated with specific ELISA kits, Western blotting, and real-time PCR, while NMR spectrometry was used to identify the implication of specific metabolites. Our results demonstrated that GGE alone or in co-treatment with ADR shows antiproliferative properties against PC-3 cells, which are mediated by both apoptosis and autophagy mechanisms.

A Biomimetic, One-Step Transformation of Simple Indolic Compounds to Malassezia-Related Alkaloids with High AhR Potency and Efficacy.

Malassezia furfur isolates from diseased skin preferentially biosynthesize compounds which are among the most active known aryl-hydrocarbon receptor (AhR) inducers, such as indirubin, tryptanthrin, indolo[3,2-b]carbazole, and 6-formylindolo[3,2-b]carbazole. In our effort to study their production from Malassezia spp., we investigated the role of indole-3-carbaldehyde (I3A), the most abundant metabolite of Malassezia when grown on tryptophan agar, as a possible starting material for the biosynthesis of the alkaloids. Treatment of I3A with H2O2 and use of catalysts like diphenyldiselenide resulted in the simultaneous one-step transformation of I3A to indirubin and tryptanthrin in good yields. The same reaction was first applied on simple indole and then on substituted indoles and indole-3-carbaldehydes, leading to a series of mono- and bisubstituted indirubins and tryptanthrins bearing halogens, alkyl, or carbomethoxy groups. Afterward, they were evaluated for their AhR agonist activity in recombinant human and mouse hepatoma cell lines containing a stably transfected AhR-response luciferase reporter gene. Among them, 3,9-dibromotryptanthrin was found to be equipotent to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as an AhR agonist, and 3-bromotryptanthrin was 10-times more potent than TCDD in the human HG2L7.5c1 cell line. In contrast, 3,9-dibromotryptanthrin and 3-bromotryptanthrin were ∼4000 and >10,000 times less potent than TCDD in the mouse H1L7.5c3 cell line, respectively, demonstrating that they are species-specific AhR agonists. Involvement of the AhR in the action of 3-bromotryptanthrin was confirmed by the ability of the AhR antagonists CH223191 and SR1 to inhibit 3-bromotryptanthrin-dependent reporter gene induction in human HG2L7.5c1 cells. In conclusion, I3A can be the starting material used by Malassezia for the production of both indirubin and tryptanthrin through an oxidation mechanism, and modification of these compounds can produce some highly potent, efficacious and species-selective AhR agonists.

Οlive tree blossom polyphenolic extracts exert antioxidant and antimutagenic activities in vitro and in various cell lines.

Olive oil has held a prominent place in the Mediterranean diet since ancient times due to its beneficial effects on human health thus, becoming the subject of great scientific interest. Although numerous studies have examined the biological action of olive and olive oil extracts, the literature lacks studies investigating the putative antioxidant capacity of olive tree flower extracts. Given that olive tree flowers are actually by-products of the olive oil production process with high waste burden for the environment, it becomes evident that their exploitation could increase their added value. Therefore, in this study the potential antioxidant action of four olive flower extracts was investigated. All the extracts exerted potent antioxidant activity as indicated using the DPPH• and ABTS•+ assays, as well as antigenotoxic and antimutagenic properties, identified by the results of the plasmid relaxation assay and the Ames test, respectively. Furthermore, the extracts also improved redox status of four cell lines (i.e., EA.hy926, C2C12, HeLa, and HepG2) enhancing reduced glutathione and reducing reactive oxygen species levels using flow cytometry. Taking into account that during olive tree cultivation a considerable amount of olive flowers is generated, the waste burden is high and the management is difficult. Given the optimistic findings of the present study, we believe that the flower-derived extracts may have high added value since they could be used as antioxidants or as foodstuff, food additives and functional food constituents.