M. Pilar Gómez-Serranillos

Mitochondria-Targeted Protective Compounds in Parkinson's and Alzheimer's Diseases

Mitochondria are cytoplasmic organelles that regulate both metabolic and apoptotic signaling pathways; their most highlighted functions include cellular energy generation in the form of adenosine triphosphate (ATP), regulation of cellular calcium homeostasis, balance between ROS production and detoxification, mediation of apoptosis cell death, and synthesis and metabolism of various key molecules. Consistent evidence suggests that mitochondrial failure is associated with early events in the pathogenesis of ageing-related neurodegenerative disorders including Parkinsons disease and Alzheimers disease. Mitochondria-targeted protective compounds that prevent or minimize mitochondrial dysfunction constitute potential therapeutic strategies in the prevention and treatment of these central nervous system diseases. This paper provides an overview of the involvement of mitochondrial dysfunction in Parkinsons and Alzheimers diseases, with particular attention to in vitro and in vivo studies on promising endogenous and exogenous mitochondria-targeted protective compounds.

Neuroprotective properties of Spanish red wine and its isolated polyphenols on astrocytes

The neuroprotective effect of Merlot red wine and its isolated polyphenols was evaluated in an oxidative stress model induced by Fenton reaction and hydrogen peroxide in the human astrocytoma U373 MG cell line. Compared with cells treated only with oxidative stress inductors, the pre-incubation with Merlot red wine for 24h caused a significant increase in cell viability for all concentrations assayed. The most abundant polyphenols found in Merlot red wine were the flavonoids catechin (37.8mg/l), epicatechin (52.3mg/l), quercetin (5.89mg/l) and procyanidins (15.2mg/l), the hydroxybenzoic acid gallic acid (16.7mg/l), and the phenolic alcohol tyrosol (31.4mg/l). The potential protective role of these polyphenols when isolated was then assessed in treated Fenton reaction U373 MG cells. Polyphenols decreased reactive oxygen species generation and increased the activity and the protein expression of the antioxidant enzymes catalase, superoxide dismutase, glutathione reductase and glutathione peroxidase. Of the polyphenols, quercetin and procyanidins showed the highest neuroprotective effect.

Study of Red Wine Neuroprotection on Astrocytes

Phenolic composition of wine depends not only on the grape variety from which it is made, but on some external factors such as winemaking technology. Red wine possesses the most antioxidant effect because of its high polyphenolic content. The aim of this work is to study for the first time, the neuroprotective activity of four monovarietal Spanish red wines (Merlot (ME), Tempranillo (T), Garnacha (G) and Cabernet-Sauvignon (CS)) through its antioxidant ability, and to relate this neuroprotection to its polyphenolic composition, if possible. The wine effect on neuroprotection was studied through its effect as free radical scavenger against FeSO4, H2O2 and FeSO4 + H2O2. Effect on cell survival was determined by 3(4,5-dimethyltiazol-2-il)-2,5-diphenyltetrazolium reduction assay (MTT) and lactate dehydrogenase (LDH) release assay on astrocytes cultures. Results showed that most of the studied wine varieties induced neuroprotection through their antioxidant ability in astrocytes, Merlot being the most active; this variety is especially rich in phenolic compounds, mainly catechins and oligomeric proanthocyanidins. Our results show that red wine exerts a protection against oxidative stress generated by different toxic agents and that the observed neuroprotective activity is related to their polyphenolic content.

Parmeliaceae family: phytochemistry, pharmacological potential and phylogenetic features

Parmeliaceae is the largest family of lichenized fungi comprising about 2700 species distributed in about 80 genera. A wide array of secondary metabolites including depsides, depsidones, aliphatic acids, triterpenes, anthraquinones, secalonic acids, pulvinic acid derivatives and xanthones have been identified within this family. Many of these bioactive compounds such as usnic acid and atranorin are exclusively found in this family, being of great relevance for the systematics and phylogeny. Moreover, these compounds exert different biological roles including antimicrobial, antioxidant, cytotoxic, anti-inflammatory, analgesic and enzyme inhibitory actions. The current review focuses on the phytochemistry and main phylogenetic aspects of Parmeliaceae, and it discusses the pharmacological findings and mechanisms of action of their extracts and isolated compounds. The present work actually collects information related to more than 65 lichen species (from 21 different genuses and heterogeneous distribution) and 75 isolated metabolites. As reported, the best studied genus from a pharmacological point of view is Parmelia, followed by Usnea. At the species level, Cetraria islandica and Evernia prunastri attract remarkable interest in their bioactive activities and metabolite content. The major pharmacological activities investigated on extracts and compounds from Parmeliaceae spp. have been antimicrobial, anticancer and antioxidant potentials; and regarding isolated compounds, the aforementioned usnic acid and atranorin are among the most studied metabolites. Reviewed data suggest that some of these lichens and natural compounds are worthy of further investigation.

Neuroprotective activity and cytotoxic potential of two Parmeliaceae lichens: Identification of active compounds.

BACKGROUND Lichens are symbiotic organisms capable of producing unique secondary metabolites, whose pharmacological activities are attracting much interest. PURPOSE The present study aimed to investigate the in vitro neuroprotective effects and anticancer potential of methanol extracts of two Parmeliaceae lichens: Cetraria islandica and Vulpicida canadensis. The chemical composition of the two lichens was also determined. METHODS Neuroprotective activity was studied with respect to the antioxidant properties of the extracts; radical scavenging tests (ORAC and DPPH assays) were performed and oxidative stress markers (intracellular ROS production, caspase-3 activity, MDA and glutathione levels) were assessed in a hydrogen peroxide-induced oxidative stress model in astrocytes. Cytotoxic activity was tested against human HepG2 (hepatocellular carcinoma) and MCF-7 (breast adenocarcinoma) cell lines. RESULTS Cell viability studies identified a single concentration for each extract that was subsequently used to measure oxidative stress markers. Lichen extracts were able to reverse the oxidative damage caused by hydrogen peroxide, thus promoting astrocyte survival. Both lichen extracts also had anticancer activity in the cell lines, with IC50 values of 19.51-181.05 µg/ml. The extracts had a high total phenolic content, and the main constituents identified by HPLC were fumarprotocetraric acid in Cetraria islandica, and usnic, pinastric and vulpinic acids in Vulpicida canadensis. The biological activities of the lichen extracts can be attributed to these secondary metabolites. CONCLUSION The lichen species studied are promising sources of natural compounds with neuroprotective activity and cytotoxic potential, and warrant further research.

Protective effects of Merlot red wine extract and its major polyphenols in PC12 cells under oxidative stress conditions.

UNLABELLED The potential effect of the extracts from free-run and pressed Merlot red wine has been evaluated in PC12 cells under oxidative stress situation. Comparing both vinification process, pressed Merlot red wine extract possessed higher neuroprotective activity than the free run wine, possibly attributed to the major content in all global polyphenolic families. High performance liquid chromatography determination of individual polyphenols showed that the major compounds found in Merlot red wine extract were quercetin, catechin, epicatechin, tyrosol, gallic acid, and procyanidins. Pretreatments with these polyphenolic compounds (0.25 mM and 0.1 mM, 24 h) significantly increased cell viability of H(2)O(2) and Fenton reaction treated cells. Moreover, these polyphenols attenuated ROS production and decreased the Redox Index of glutathione (RI = GSSG/GSH + GSSG) in cells treated only with Fenton reaction. Furthermore, some polyphenols induced antioxidant enzymes activity and protein expression. Quercetin was the most active. These results support the beneficial effects of red wine extracts and some of its polyphenols under oxidative stress conditions. PRACTICAL APPLICATION This research provides evidences of the preventive properties of wine extracts and its major polyphenols under oxidative stress conditions.

Nrf2-dependent neuroprotective activity of diterpenoids isolated from Sideritis spp

ETHNOPHARMACOLOGICAL RELEVANCE The species of the genus Sideritis are extensively used in the Mediterranean area in folk medicine for their digestive, antimicrobial, anti-inflammatory and antioxidant properties, among others. Moreover, Sideritis species as tea infusions are popularly known for improving memory function and cognitive ability. Diterpenoids are one of the most abundant and important pharmacological interest of the classes of natural products presented in these medicinal plants. AIM OF THE STUDY To determine for the first time the neuroprotective effects, based on their antioxidant properties, of the three isolated major diterpenoids andalusol, conchitriol and lagascatriol in an oxidative stress model. MATERIALS AND METHODS H2O2 was used as oxidant inductor and rat adrenal pheochromocytoma PC12 cells as cellular model. Cell viability was measured using MTT and LDH assays, lipid peroxidation was determined by HPLC, GSH and GSSG levels assessed by fluorometric techniques, enzymatic activity and protein expression were determined by spectrofometric techniques and Western blot, respectively. RESULTS Pretreatments with the three diterpenoids significantly attenuated H2O2-induced changes in mitochondrial integrity and activity (MTT assay), in cell membrane integrity (LDH assay) and in cell morphology. Moreover, these diterpenoids inhibited intracellular ROS production H2O2-induced, reduced lipid peroxidation and counteracted GSH/GSSG changes. Furthermore, both activities and protein expression of the endogenous antioxidant enzymes (CAT, SOD, GR, GPx and HO-1) were increased. The Nrf2 pathway was involved, at least in part, in the protective effects of these diterpenoids. CONCLUSION These findings suggest that these natural compounds provide significant antioxidant effects in PC12 under for counteracting the oxidative damage H2O2-induced and their potential role as useful agents for the prevention of those oxidative stress-mediated dementia disorders. Andalusol was the most active compound among the studied diterpenoids.

In vitro neuroprotective potential of the monoterpenes α-pinene and 1,8-cineole against H2O2-induced oxidative stress in PC12 cells

Abstract Oxidative stress is involved in the pathogenesis of several neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases. Natural products are considered as therapeutically useful antioxidant agents against reactive oxygen species (ROS). We have evaluated the antioxidant and protective potential of the monoterpenes 1,8-cineole and α-pinene against H2O2-induced oxidative stress in PC12 (rat pheochromocytoma) cells. Pretreatment with these monoterpenes was found to attenuate the loss of cell viability and the changes in cell morphology. Moreover, they inhibited the intracellular ROS production and markedly enhanced the expression of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and heme-oxygenase 1 (HO-1). In addition, they were able to decrease apoptosis as is evident from reduced capase-3 activity. The mechanisms of their antioxidant action appear to involve ROS scavenging and induction of the nuclear Nrf2 factor. This study demonstrates the potential beneficial therapeutic effect of these common monoterpenes on the oxidant/antioxidant balance in diseases of the nervous system.

Diterpenoids Isolated from Sideritis Species Protect Astrocytes against Oxidative Stress via Nrf2

Andalusol (1), conchitriol (2), and lagascatriol (3) are diterpenoids produced by Sideritis species. Hydrogen peroxide-induced oxidative stress in U373-MG cells was used as an in vitro model to evaluate the cytoprotective potential, based on antioxidant properties, of these isolated compounds and to investigate the underlying mechanisms. Experimental results revealed that pretreatment with compounds 1 and 3 restored H₂O₂-induced oxidative changes by increasing cell viability, attenuating morphological changes, inhibiting intracellular ROS production and lipid peroxidation, and enhancing the antioxidant defense system. Furthermore, nuclear factor E2-related factor 2 (Nrf2) signaling was involved in the protective mechanisms of 1-3. The present findings suggest that two of the compounds studied (1 and 3) might play a preventive role in neurodegenerative diseases associated with oxidative stress.

In vitro permeability study of CNS-active diterpenes from Sideritis spp. using cellular models of blood-brain barrier.

The major diterpenes andalusol, conchitriol, foliol, lagascatriol, linearol, and sidol, isolated from Sideritis spp., have been recently identified as neuroprotective agents. In this study, the blood brain-barrier permeability characteristics of these natural compounds were investigated for the first time using in silico and in vitro (RBE4 monocultures and ECV304/C6 co-cultures) methods. Computational tools revealed that these diterpenes have a favorable permeability profile to pass across the blood brain-barrier. In the RBE4 cell model, used for uptake studies, all compounds were taken up in a concentration and time-dependent manner. A bidirectional transport of diterpenes was observed across the ECV304/C6 co-culture model, with Papp values in the range of 3.7 × 10(-6) cm/sec and 9.5 × 10(-6) cm/sec for foliol and andalusol, respectively. Andalusol and lagascatriol were the most efficiently in being taken up and transported across the established blood brain-barrier in vitro model. These findings suggest that the investigated compounds from Sideritis spp. may predominantly move across the blood brain-barrier by passive diffusion. The observations have implications for understanding how CNS-active diterpenes enter the brain endothelium and traverse the blood brain-barrier, and thus exert their neuroprotective actions.