Nemorosone is a bicyclic polyprenylated acylphloroglucinol derivative originally isolated from Clusia spp. and it can be obtained through chemical synthesis employing different synthetic strategies. Since its discovery, it has attracted great attention both from a biological and chemical viewpoint. In the present article, we attempted to review various chemical and biological topics around nemorosone, with an emphasis on its antiproliferative activities. For this purpose, relevant data was collected from different scientific databases including Google Scholar, PubMed, Scopus and ISI Web of Knowledge. This natural compound has shown activity against several types of malignancies such as leukemia, human colorectal, pancreatic, and breast cancer because it modulates multiple molecular pathways. Nemorosone has both cytostatic and cytotoxic activity and it also seems to induce apoptosis and ferroptosis. Additionally, it has antimicrobial capabilities against Gram-positive bacteria and parasites belonging to genus Leishmania. Its promising antiproliferative pre-clinical effects deserve further attention for anticancer and anti-parasitic drug development and translation to the clinic.

Ferroptosis is an iron-dependent cell death-driven by excessive peroxidation of polyunsaturated fatty acids (PUFAs) of membranes. A growing body of evidence suggests the induction of ferroptosis as a cutting-edge strategy in cancer treatment research. Despite the essential role of mitochondria in cellular metabolism, bioenergetics, and cell death, their function in ferroptosis is still poorly understood. Recently, mitochondria were elucidated as an important component in cysteine-deprivation-induced (CDI) ferroptosis, which provides novel targets in the search for new ferroptosis-inducing compounds (FINs). Here, we identified the natural mitochondrial uncoupler nemorosone as a ferroptosis inducer in cancer cells. Interestingly, nemorosone triggers ferroptosis by a double-edged mechanism. In addition to decreasing the glutathione (GSH) levels by blocking the System xc cystine/glutamate antiporter (SLC7A11), nemorosone increases the intracellular labile Fe2+ pool via heme oxygenase-1 (HMOX1) induction. Interestingly, a structural variant of nemorosone (O-methylated nemorosone), having lost the capacity to uncouple mitochondrial respiration, does not trigger cell death anymore, suggesting that the mitochondrial bioenergetic disruption via mitochondrial uncoupling is necessary for nemorosone-induced ferroptosis. Our results open novel opportunities for cancer cell killing by mitochondrial uncoupling-induced ferroptosis.

Background:Ischemic stroke produces a large health impact worldwide, with scarce therapeutic options.Objective:This study aimed to reveal the role of NADPH oxidase and neuroinflammatory genes in the cerebral anti-ischemic effects of C-Phycocyanin (C-PC), the chief biliprotein of Spirulina platensis.Methods:Rats with either focal cerebral ischemia/reperfusion (I/R) or acute brain hypoperfusion, received C-PC at different doses, or a vehicle, for up to 6 h post-stroke. Neurological, behavioral and histochemical parameters were assessed in I/R rats at 24 h. Cerebral gene expression and hippocampal neuron viability were evaluated in hypoperfused rats at acute (24 h) or chronic phases (30 days), respectively. A molecular docking analysis of NOX2 and C-PC-derived Phycocyanobilin (PCB) was also performed.Results:C-PC, obtained with a purity of 4.342, significantly reduced the infarct volume and neurological deficit in a dose-dependent manner, and improved the exploratory activity of I/R rats. This biliprotein inhibited NOX2 expression, a crucial NADPH oxidase isoform in the brain, and the superoxide increase produced by the ischemic event. Moreover, C-PC-derived PCB showed a high binding affinity in silico with NOX2. C-PC downregulated the expression of pro-inflammatory genes (IFN-γ, IL-6, IL-17A, CD74, CCL12) and upregulated immune suppressive genes (Foxp3, IL-4, TGF-β) in hypoperfused brain areas. This compound also decreased chronic neuronal death in the hippocampus of hypoperfused rats.Conclusion:These results suggest that the inhibition of cerebral NADPH oxidase and the improvement of neuroinflammation are key mechanisms mediating the neuroprotective actions of C-PC against brain ischemia.

The use of nanomaterials rationally engineered to treat cancer is a burgeoning field that has reported great medical achievements. Iron-based polymeric nano-formulations with precisely tuned physicochemical properties are an expanding and versatile therapeutic strategy for tumor treatment. Recently, a peculiar type of regulated necrosis named ferroptosis has gained increased attention as a target for cancer therapy. Here, we show for the first time that novel iron oxide nanoparticles coated with gallic acid and polyacrylic acid (IONP–GA/PAA) possess intrinsic cytotoxic activity on various cancer cell lines. Indeed, IONP–GA/PAA treatment efficiently induces ferroptosis in glioblastoma, neuroblastoma, and fibrosarcoma cells. IONP–GA/PAA-induced ferroptosis was blocked by the canonical ferroptosis inhibitors, including deferoxamine and ciclopirox olamine (iron chelators), and ferrostatin-1, the lipophilic radical trap. These ferroptosis inhibitors also prevented the lipid hydroperoxide generation promoted by the nanoparticles. Altogether, we report on novel ferroptosis-inducing iron encapsulated nanoparticles with potent anti-cancer properties, which has promising potential for further in vivo validation.

Cerebral ischemia constitutes the most frequent type of cerebrovascular disease. The reduction of blood supply to the brain initiates the ischemic cascade starting from ionic imbalance to subsequent glutamate excitotoxicity, neuroinflammation and oxidative stress, eventually causing neuronal death. Previously, the authors have demonstrated the in vitro cytoprotective and antioxidant effects of a new arylidene malonate derivative, KM-34, against oxidizing agents like hydrogen peroxide, glutamate or Fe3+/ascorbate. Here, we examined for the first time the neuroprotective effect of KM-34 on ischemia/reperfusion models. In vitro, treatment with 10 and 50 μM KM-34 reduced the cellular death (propidium iodide incorporation) induced by oxygen glucose deprivation (OGD) in rat organotypic hippocampal slices cultures. In vivo, stroke was induced in male Wistar rats through middle cerebral artery occlusion (MCAO), followed by 23 h of reperfusion. KM-34 was orally administered 105 min after MCAO onset. We noticed that 1 mg/kg KM-34 reduced infarct volume and neurological score, and increased the latency to fall in the Hanging Wire test compared to vehicle-treated ischemic animals. While ischemic and sham-operated groups showed similar horizontal locomotor activity, vertical counts decreased after MCAO, suggesting that vertical movements are more sensitive to the ischemic injury. Treatment with KM-34 also alleviated the mitochondrial impairment (ROS generation, swelling and membrane potential dissipation) induced by transient MCAO but not significant alterations were found in oxidative stress parameters. Overall, the study provides preclinical evidences confirming the neuroprotective effects of a novel synthetic molecule and paved the way for future investigations regarding its therapeutic potential against brain ischemia/reperfusion injury.

The disruption of iron homeostasis is an important factor in the loss of mitochondrial function in neural cells, leading to neurodegeneration. Here, we assessed the protective action of gossypitrin (Gos), a naturally occurring flavonoid, on iron-induced neuronal cell damage using mouse hippocampal HT-22 cells and mitochondria isolated from rat brains. Gos was able to rescue HT22 cells from the damage induced by 100 µM Fe(II)-citrate (EC50 8.6 µM). This protection was linked to the prevention of both iron-induced mitochondrial membrane potential dissipation and ATP depletion. In isolated mitochondria, Gos (50 µM) elicited an almost complete protection against iron-induced mitochondrial swelling, the loss of mitochondrial transmembrane potential and ATP depletion. Gos also prevented Fe(II)-citrate-induced mitochondrial lipid peroxidation with an IC50 value (12.45 µM) that was about nine time lower than that for the tert-butylhydroperoxide-induced oxidation. Furthermore, the flavonoid was effective in inhibiting the degradation of both 15 and 1.5 mM 2-deoxyribose. It also decreased Fe(II) concentration with time, while increasing O2 consumption rate, and impairing the reduction of Fe(III) by ascorbate. Gos–Fe(II) complexes were detected by UV-VIS and IR spectroscopies, with an apparent Gos-iron stoichiometry of 2:1. Results suggest that Gos does not generally act as a classical antioxidant, but it directly affects iron, by maintaining it in its ferric form after stimulating Fe(II) oxidation. Metal ions would therefore be unable to participate in a Fenton-type reaction and the lipid peroxidation propagation phase. Hence, Gos could be used to treat neuronal diseases associated with iron-induced oxidative stress and mitochondrial damage.

Context: Momordica charantia (Cucurbitaceae) is extensively distributed in tropical areas, and it is traditionally used as antidiabetic. Nevertheless, few studies supporting the metabolic effects of its foliage extracts have been reported elsewhere. Aims: To evaluate the effects of M. charantia foliage extract (MCh) on blood glucose and lipids levels in animal models of hyperglycemia. The anti-inflammatory and antioxidant properties together with the acute toxicity and genotoxic effects were also assessed. Methods: An MCh powder was obtained by spray-drying techniques. The anti-hyperglycemic and hypolipidemic effects of MCh were evaluated in the glucose tolerance test and the alloxan-induced diabetes, respectively. The in vitro and ex vivo MCh antioxidant effects were assessed against the 2,2´-azinobis3-ethylbenzothiazoline-6-sulfonic acid (ABTS), peroxyl, and superoxide anion radicals. The MCh anti-inflammatory effects were also assessed together with its toxicological profile by means of the Acute Toxic Class Method, and the chromosome aberration assay. Results: MCh administered orally diminished the glucose and lipids levels in normoglycemic healthy rats and alloxan-induced hyperglycemic mice. Strong in vitro free radical scavenging effects was demonstrated by MCh against ABTS, peroxyl, and superoxide anion radicals. The extract also improved the free radical scavenging ability of diabetic mice serum. Moreover, MCh reduced the weight of cotton-induced granulomas in mice, the exudate volume, and its leukocyte counts in carrageenan-induced pleurisy in rats. Very low MCh toxicity was also verified. Conclusions: The hypoglycemic, hypolipidemic, anti-inflammatory, and antioxidant activities here observed make the spray-drayed powder from M. charantia foliage extract an interesting alternative for the correction of diabetes and its complications.

Context: Almost one year after the onset of COVID-19 pandemic in Wuhan, China and still no specific therapy has emerged, counting millions of dead worldwide. The association of an uncontrolled SARS-CoV-2 replication and host-dependent mechanisms in COVID-19 pathogenesis suggest that any therapeutic strategy must combine antiviral drugs and adjuvant therapy to modulate the host’s responses. Owing to the multiplicity of mechanisms involved in COVID-19 pathogenic expressions, such as severe hypoxia, excessive inflammatory reaction and impaired immune response, an emerging therapeutic paradigm is the searching for agents acting as multifunctional drugs. Methylene blue (MB), the antique medication, seems to meet the above criterion. Aims: To summarize the probable beneficial effects of MB against COVID-19 supported by a discussion of the drug mechanisms of action counteracting the pathogenic mechanisms of the disease. Methods: PubMed, Google Scholar, and Scopus databases were used to collect the biomedical research on MB, and the discussed dataset finally included 150 published articles. Those COVID-19 pathogenic pathways possibly targeted by MB were critically appraised. Results: It was found that MB may act as multimodal agent by targeting simultaneously several pathogenic mechanisms of COVID-19 as hypoxic damage, hyper-inflammatory reaction and death signaling activation. It also may act as a virucidal agent by preventing virus-induced metabolic re-orientation. Its high safety profile, low cost, along with the mechanisms discussed herein might be essential criteria to test MB as an adjuvant therapy against COVID-19. Conclusions: Overall, this critical review provides theoretical grounds for MB clinical evaluation in the therapeutic management of SARS-CoV-2 infection.

Rapanone is a natural occurring benzoquinone with several biological effects including unclear cytotoxic mechanisms. Here we addressed if mitochondria are involved in the cytotoxicity of rapanone towards cancer cells by employing hepatic carcinoma (HepG2) cells and isolated rat liver mitochondria. In the HepG2, rapanone (20-40 mu M) induced a concentration-dependent mitochondria] membrane potential dissipation, ATP depletion, hydrogen peroxide generation and, phosphatidyl serine externalization; the latter being indicative of apoptosis induction. Rapanone toxicity towards primary rats hepatocytes (IC50 = 35.58 +/- 1.50 mu M) was lower than that found for HepG2 cells (IC50 = 27.89 +/- 0.75 mu M). Loading of isolated mitochondria with rapanone (5-20 mu M) caused a concentration-dependent inhibition of phosphorylating and uncoupled respirations supported by complex I (glutamate and malate) or the complex II (succinate) substrates, being the latter eliminated by complex IV substrate (TMPD/ascorbate). Rapanone also dissipated mitochondrial membrane potential, depleted ATP content, released Ca2+ from Ca2+ -loaded mitochondria, increased ROS generation, cytochrome c release and membrane fluidity. Further analysis demonstrated that rapanone prevented the cytochrome c reduction in the presence of decylbenzilquinol, identifying complex III as the site of its inhibitory action. Computational docking results of rapanone to cytochrome bc1 (Cyt bc1) complex from the human sources found spontaneous thermodynamic processes for the quinone-Q(o) and Q(i) binding interactions, supporting the experimental in vitro assays. Collectively, these observations suggest that rapanone impairs mitochondrial respiration by inhibiting electron transport chain at Complex III and promotes mitochondrial dysfunction. This property is potentially involved in rapanone toxicity on cancer cells.

Context: Mitochondria represent a key intracellular signalling hub that is emerging as important determinants of numerous aspects of cancer development and progression. In this sense, the organelle constitutes a promising target for the development of novel anticancer agents. Despite the negative history, mitochondrial uncoupling has recently proposed as a pharmacological target against cancer, but little is known about the mechanisms involved. Aims: To demonstrate the role of mitochondria in tumor formation and to describe how targeting of mitochondria uncoupling can be beneficial in the therapy of these diseases, which affect a large human population. Methods: The data for this systematic review were collected from three popular databases including PubMed, Google Scholar, and Scopus and included in the search terms the words “mitochondrial uncoupling” and “cancer”. The influence of mitochondrial uncoupling on cells physiology that could lead to cancer cells death, invasion and metastasis was critically appraised from relevant researches. The anticancer effects of small molecules mitochondrial uncouplers and their anticancer mechanisms were also discussed. The present dataset finally included 201 published articles. Results: It was found that the mitochondrial uncoupling-mediated responses possibly involved in the anti-cancer/anti-metastatic effects include Ca2+ homeostasis and bioenergetics disruption, mitochondrial membrane potential dissipation, reactive oxygen species generation, mitochondrial dynamics alteration, and gene expression modulation. Conclusions: Overall, this critical review suggests that mitochondrial uncoupling could be an interesting pharmacological target to be considered in the design and synthesis of novel anti-cancer compounds with optimal physic-chemical and biopharmaceutical properties and improved safety profiles.

Stroke is frequently associated with severe neurological decline and mortality, and its incidence is expected to increase due to aging population. The only available pharmacological treatment for cerebral ischemia is thrombolysis, with narrow therapeutic windows. Efforts aimed to identify new therapeutics are crucial. In this study, we look into plausible molecular and cellular targets for JM-20, a new hybrid molecule, against ischemic stroke in vivo. Male Wistar rats were subjected to 90 min middle cerebral artery occlusion (MCAO) following 23 h of reperfusion. Animals treated with 8 mg/kg JM-20 (p.o., 1 h after reperfusion) showed minimal neurological impairment and lower GABA and IL-1β levels in CSF when compared to damaged rats that received vehicle. Immunocontent of pro-survival, phosphorylated Akt protein decreased in the cortex after 24 h as result of the ischemic insult, accompanied by decreased number of NeuN+ cells in the peri-infarct cortex, cornu ammonis 1 (CA1) and dentate gyrus (DG) areas. Widespread reactive astrogliosis in both cortex and hippocampus (CA1, CA3, and DG areas) was observed 24 h post-ischemia. JM-20 prevented the activated Akt reduction, neuronal death, and astrocytes reactivity throughout the brain. Overall, the results reinforce the pharmacological potential of JM-20 as neuroprotective agent and provide important evidences about its molecular and cellular targets in this model of cerebral ischemia.

ABSTRACT Objective: JM-20, a novel hybrid synthetic molecule, has been reported to have antioxidant, mitoprotective, anti-excitotoxic, anti-apoptotic and anti-inflammatory properties. However, the neuroprotective effect of JM-20 against memory impairment in preclinical AD-like models has not been analyzed. The aim of this study was to evaluate the potential neuroprotection of JM-20 that preserves essential memory process from cholinergic dysfunction and other molecular damages. Methods: The effects of JM-20 on scopolamine (1 mg/kg)-induced cognitive disorders were studied. Male Wistar rats (220-230 g) were treated with JM-20 and/or scopolamine, and behavioral tasks were performed. The AChE activity, superoxide dismutase activity, catalase activity, MDA and T-SH level on brain tissue were determined by spectrophotometric methods. Mitochondrial functionality parameters were measured after behavioral tests. Histological analyses on hippocampus and prefrontal cortex were processed with hematoxylin and eosin, and neuronal and axonal damage were determined. Results: The behavioral, biochemical and histopathological studies revealed that oral pre-treatment with JM-20 (8 mg/kg) significantly attenuated the scopolamine-induced memory deficits, mitochondrial malfunction, oxidative stress, and prevented AChE hyperactivity probably due to specific inhibition of AChE enzyme. It was also observed marked histological protection on hippocampal and prefrontal-cortex regions. Conclusions: The multimodal action of this molecule could mediate the memory protection here observed and suggest that it may modulate different pathological aspects of memory deficits associated with AD in humans.

Cardiovascular diseases are major causes of death worldwide. Beyond the classical cholesterol risk factor, other conditions such as oxidative stress are well documented to promote atherosclerosis. The Mangifera indica L. extract (Vimang®) was reported to present antioxidant and hypocholesterolemic properties. Thus, here we evaluate the effects of Vimang treatment on risk factors of the atherosclerosis prone model of familial hypercholesterolemia, the LDL receptor knockout mice. Mice were treated with Vimang during 2 weeks and were fed a cholesterol-enriched diet during the second week. The Vimang treated mice presented significantly reduced levels of plasma (15%) and liver (20%) cholesterol, increased plasma total antioxidant capacity (10%) and decreased reactive oxygen species (ROS) production by spleen mononuclear cells (50%), P < 0.05 for all. In spite of these benefits, the average size of aortic atherosclerotic lesions stablished in this short experimental period did not change significantly in Vimang treated mice. Therefore, in this study we demonstrated that Vimang has protective effects on systemic and tissue-specific risk factors, but it is not sufficient to promote a reduction in the initial steps of atherosclerosis development. In addition, we disclosed a new antioxidant target of Vimang, the spleen mononuclear cells that might be relevant for more advanced stages of atherosclerosis.

Oxidative stress and mitochondrial dysfunction are two pathophysiological factors often associated with the neurodegenerative process involved in Parkinson's disease (PD). The aim of this study was to investigate the effects of a novel hybrid molecule, named JM-20, in different in vitro and in vivo models of PD induced by rotenone. To perform in vitro studies, SHSY-5Y cells were exposed to rotenone and/or treated with JM-20. To perform in vivo studies male Wistar rats were intoxicated with rotenone (2.5 mg/kg) via intraperitoneal injection and/or treated with JM-20 (40 mg/kg) administered via oral (for 25 days, both treatment). Rats were evaluated for global motor activity by measurement of locomotor activity. In addition, the effects on mortality, general behavior and redox parameters were also investigated. JM-20 protected SHSY-5Y cells against rotenone-induced cytotoxicity, evidenced by a significant diminution of cell death. In in vivo studies, JM-20 prevented rotenone induced vertical exploration and locomotion frequency reductions, moreover prevented body weight loss and mortality induced by rotenone. It also improved the redox state of rotenone-exposured animals by increasing superoxide dismutase and catalase activities, total tissue-SH levels and decreasing malondialdehyde concentrations. Finally, JM-20 inhibited spontaneous mitochondrial swelling and membrane potential dissipation in isolated rats brain mitochondria. These results demonstrate that JM-20 is a potential neuroprotective agent against rotenone-induced damage in both in vitro and in vivo models, resulting in reduced neuronal oxidative injury and protection of mitochondria from impairment.

Several 1,4-dihydropyridine derivatives overcome the multidrug resistance in tumors, but their intrinsic cytotoxic mechanisms remain unclear. Here we addressed if mitochondria are involved in the cytotoxicity of the novel 1,4-dihydropyridine derivative VE-3N [ethyl 6-chloro-5-formyl-2-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylate] towards cancer cells by employing hepatic carcinoma (HepG2) cells and isolated rat liver mitochondria. In HepG2 cells, VE-3N induced mitochondrial membrane potential dissipation, ATP depletion, annexin V/propidium iodide double labeling, and Hoechst staining; events indicating apoptosis induction. In isolated rat liver mitochondria, VE-3N promoted mitochondrial uncoupling by exerting protonophoric actions and by increasing membrane fluidity. Mitochondrial uncoupling was evidenced by an increase in resting respiration, dissipation of mitochondrial membrane potential, inhibition of Ca2+ uptake, stimulation of Ca2+ release, decrease in ATP synthesis, and swelling of valinomycin-treated organelles in hyposmotic potassium acetate media. Furthermore, uncoupling concentrations of VE-3N in the presence of Ca2+ plus ruthenium red induced the mitochondrial permeability transition process. These results indicate that mitochondrial uncoupling is potentially involved in the VE-3N cytotoxic actions towards HepG2 cells. Considering that hepatocellular carcinoma is the most common form of liver cancer, our findings may open a new avenue for the development of VE-3N-based cancer therapies, and help to unravel the cytotoxic mechanisms of 1,4-dihydropyridines towards cancer cells.

Ischemic stroke is a major cause of death and disability worldwide. Thrombolysis by tissue plasminogen activator is the only pharmacological treatment approved for clinical practice, but has a narrow therapeutic window and poor efficacy when the cell death cascade is activated. Numerous drugs that are thought to protect neurons against injury have previously failed in human trials despite showing efficacy in experimental models of stroke. Herein, we reviewed the main pre-clinical results of the neuroprotective effects of JM-20, a new hybrid molecule, against brain ischemia. JM-20 appears to protect the brain from ischemic damage by interfering with several elements of the ischemic cascade: antiexcitotoxic, anticalcic, antioxidant, antiapoptotic, and anti-inflammatory. Its ability to protect not only neurons but also glial cells together with its ability to target and preserve mitochondrial function makes JM-20 a promising molecule that may be able to shield the whole neurovascular unit. The multimodal and multi-cell action of JM-20 may explain the high degree of protection observed in a rat model of brain ischemia, as assayed through histological (hematoxylin-eosin, and luxol fast blue staining), neurochemical (glutamate and aspartate levels in cerebrospinal fluid), mitochondrial functionality and behavioural (neurological scale) analysis at doses of 4 and 8mg/kg. Furthermore, the wide therapeutic window of JM-20 of 8h also suggests that this molecule could be of potential interest in situations where brain perfusion is compromised.

This study aims to examine the effects of a new 1,4-dihydropyridine derivative, VdiE-2N, on cell signaling pathways and mitochondrial events in head and neck squamous cell carcinoma (HNSCC) cells, and on a mice model of xenograft tumor growth/cell proliferation. Four HNSCC cell lines (HN13, HN12, HN6, and CAL27), HEK293 cells (human embryonic kidney 293 cells), and human oral healthy mucosa fibroblasts (OHMF) were used for in vitro assessment of cell viability (resazurin assay) and invasion capacity (modified Boyden chamber assay), and mitochondrial membrane potential (JC-1 fluorescence assay), morphology (transmission electron microscopy), and number of mitochondria (MitoTracker® imaging). SET and pDRP1 proteins were analyzed by immunofluorescence, and proteins involved in cell death/survival pathways were analyzed by Western blotting. HN12 xenograft tumors were established in the flank of Balb/c nude mice, and their characteristics and sensitivity to VdiE-2N were determined by immunohistochemistry and histology. VdiE-2N decreased cell viability in HNSCC cells (IC50 = 9.56 and 22.45µM for HN13 and HN12 cells, respectively) more strongly than it decreased cell viability in OHMF and HEK293 cells (IC50 = 32.90 and > 50µM, respectively). In HN13 cells, VdiE-2N dissipated mitochondrial membrane potential and altered the mitochondria size, shape, and number in a concentration-dependent manner, as well as it induced apoptosis and reduced their invasion capacity. Treatment of mice bearing xenograft tumors with VdiE-2N significantly diminished proliferation of cancer cells. Therefore, VdiE-2N induces HNSCC cell death in vitro through mitochondria-mediated apoptotic pathways and dampens tumor growth in vivo, thus supporting a potential anti-cancer effect.

Context: Some flavonoids have been described as neuroprotectors. Gossypitrin (Gos) is a natural occurring flavonoid and the main bioactive substance from the flowers of Talipariti elatum Sw. (Majagua azul), traditionally used in Cuba as expectorant and antiasthmatic. Only few reports have documented its antioxidant properties. Aims: To evaluate the antioxidant and cytoprotective effects of Gos against cyanide-induced oxidative stress and cell death in PC12 cells. Methods: Gos effects on DPPH/ ABTS radical scavenging, ferric reducing power and lipid peroxidation were examined. The ischemia/reperfusion neuronal damage was produced by exposing PC12 cells to KCN in glucose-free medium. Gos was added to the incubation medium 30 min before chemical hypoxia induction. The neuroprotective potential of Gos was assessed by measuring cell viability by the MTT assay, the antioxidant enzymes SOD and CAT, and GSH and lipid peroxidation levels. Rutin (Rut), the well-known antioxidant, was used as a reference compound. Results: Gos showed a potent intrinsic antioxidant capacity evidenced by low IC50 and EC50 values for DPPH/ABTS/malondialdehyde and ferric reducing power, respectively. Pre-treatment of PC12 cells with Gos, significantly increased their survival against KCN, restored the levels of GSH and the SOD and CAT enzymes activities, as well as reduced the level of lipid peroxidation. Its antioxidant effects were higher than those elicited by Rut. Conclusions: The results show for the first time the neuroprotective potential of Gos against hypoxic cell damage, probably associated to its antioxidant effects.

Abstract Free radicals are important mediators in a number of neurodegenerative diseases and molecules capable of scavenging reactive oxygen species (ROS) may be a feasible strategy for protecting neuronal cells. In this sense, polyphenols have been studied for their antioxidant effects, KM-34 (5-(3, 4-dydroxyl-benzylidene)-2, 2-dimethyl-1, 3-dioxane-4, 6-Dione) is a novel synthetic catechol with potential neuroprotective and antioxidant properties. We have assessed the antioxidant (as scavenging and iron-chelating compound) and neuroprotectant in vitro (in PC12 cell injury induced by H2O2, glutamate or FeSO4/AA) of KM-34. KM-34 was found to be a potent antioxidant, as shown by (i) inhibition of iron induced-brain lipid peroxidation, (ii) inhibition of 2-deoxyribose degradation, (iii) inhibition of superoxide radicals generation (IC50=11.04 μM) and (iv) inhibition of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical reduction (IC50=16.26 μM). The overall anti-oxidant action of KM-34 appears to be a combination of a direct reaction with free radicals and chelating the metal ions responsible for the production of ROS. Our work suggests that the antioxidant properties of KM-34 may provide future therapeutic approaches for neurodegenerative disorders.