Multi-targeting effects of a new synthetic molecule (JM-20) in experimental models of cerebral ischemia.

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.

Mangifera indica L. extract (Vimang®) reduces plasma and liver cholesterol and leucocyte oxidative stress in hypercholesterolemic LDL receptor deficient mice.

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.

The cytotoxic effects of VE-3N, a novel 1,4-dihydropyridine derivative, involve the mitochondrial bioenergetic disruption via uncoupling mechanisms.

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.

The cytotoxic effects of brown Cuban propolis depend on the nemorosone content and may be mediated by mitochondrial uncoupling.

Three main types of Cuban propolis directly related to their secondary metabolite composition have been identified: brown, red and yellow propolis; the former is majoritarian and is characterized by the presence of nemorosone. In this study, brown Cuban propolis extracts were found cytotoxic against HepG2 cells and primary rat hepatocytes, in close association with the nemorosone contents. In mitochondria isolated from rat liver the extracts displayed uncoupling activity, which was demonstrated by the increase in succinate-supported state 4 respiration rates, dissipation of mitochondrial membrane potential, Ca(2+) release from Ca(2+)-loaded mitochondria, and a marked ATP depletion. As in cells, the degree of such mitotoxic events was closely correlated to the nemorosone content. The propolis extracts that do not contain nemorosone were neither cytotoxic nor mitotoxic, except R-29, whose detrimental effect upon cells and mitochondria could be mediated by its isoflavonoids and chalcones components, well known mitochondrial uncouplers. Our results at least partly unravel the cytotoxic mechanism of Cuban propolis, particularly regarding brown propolis, and raise concerns about the toxicological implication of Cuban propolis consumption.

Characterization of the anxiolytic and sedative profile of JM-20: a novel benzodiazepine-dihydropyridine hybrid molecule.

OBJECTIVES: The aim of this study was to investigate the effects of oral administration of a novel benzodiazepine derivative, JM-20, on the neurological behavior of different rodent models, focusing on the GABAergic effect. We have also investigated the acute toxicity of oral administration of JM-20 in mice. METHODS: Mice or rats received oral administration of JM-20 at 2, 4, 8, and 10 mg/kg to evaluate the sedative/hypnotic, anxiolytic, and anticonvulsant effects, as well as the influence on the stereotyped behavior induced by amphetamine. Diazepam (DZP) was used as a positive control. In addition, the mice received a single oral JM-20 dose of 2000 mg/kg to evaluate the acute toxicity. RESULTS: In a dose-dependent manner, JM-20 (i) increased the number of crossings and decreased the number of rearings in the open-field test; (ii) decreased the aggressive behavior of socially-isolated mice; and (iii) increased the latency period for tonic seizure's onset and the percentage of survival of animals with seizures. Moreover, JM-20 increased the sleeping time induced by barbiturates and the time spent and the number of entries in the open arms of the elevated plus-maze test. In the JM-20 toxicity test, no mortality was observed and only minor signs of toxicity associated with sedation were detected. CONCLUSIONS: These results indicate that JM-20 has an anxiolytic profile similar to DZP and its dihydropyridine moiety did not appear to interfere with the GABAergic activity associated with benzodiazepine. Furthermore, JM-20 did not show significant acute toxic effects in mice.

Mangifera indica extract (Vimang) impairs aversive memory without affecting open field behaviour or habituation in rats.

Vimang is an aqueous extract of Mangifera indica L, used in Cuba for the treatment of immunopathological disorders. Increasing evidence from preclinical studies indicates that Vimang displays antioxidant, antiallergic, analgesic and antiinflammatory actions. The present study investigated the effects of systemic administration of Vimang on behavioural outcomes of neurological function in rats. A single oral administration of Vimang produced an impairment of short- and long-term retention of memory for aversive training when given either 1 h pretraining or immediately posttraining, but not 8 h posttraining. Vimang did not affect open field behaviour or habituation. The results indicate that Vimang might induce deficits of emotionally motivated memory without affecting nonassociative memory, locomotion, exploratory behaviour or anxiety.

Mangifera indica L. extract (Vimang) and its main polyphenol mangiferin prevent mitochondrial oxidative stress in atherosclerosis-prone hypercholesterolemic mouse.

Atherosclerosis is linked to a number of oxidative events ranging from low-density lipoprotein (LDL) oxidation to the increased production of intracellular reactive oxygen species (ROS). We have recently demonstrated that liver mitochondria isolated from the atherosclerosis-prone hypercholesterolemic LDL receptor knockout (LDLr(-/-)) mice have lower content of NADP(H)-linked substrates than the controls and, as consequence, higher sensitivity to oxidative stress and mitochondrial membrane permeability transition (MPT). In the present work, we show that oral supplementation with the antioxidants Mangifera indica L. extract (Vimang) or its main polyphenol mangiferin shifted the sensitivity of LDLr(-/-) liver mitochondria to MPT to control levels. These in vivo treatments with Vimang and mangiferin also significantly reduced ROS generation by both isolated LDLr(-/-) liver mitochondria and spleen lymphocytes. In addition, these antioxidant treatments prevented mitochondrial NAD(P)H-linked substrates depletion and NADPH spontaneous oxidation. In summary, Vimang and mangiferin spared the endogenous reducing equivalents (NADPH) in LDLr(-/-) mice mitochondria correcting their lower antioxidant capacity and restoring the organelle redox homeostasis. The effective bioavailability of these compounds makes them suitable antioxidants with potential use in atherosclerosis susceptible conditions.

Protective effects of Mangifera indica L extract (Vimang), and its major component mangiferin, on iron-induced oxidative damage to rat serum and liver.

In vivo preventive effects of a Mangifera indica L extract (Vimang) or its major component mangiferin on iron overload injury have been studied in rats given respectively, 50, 100, 250 mg kg(-1) body weight of Vimang, or 40 mg kg(-1) body weight of mangiferin, for 7 days prior to, and for 7 days following the administration of toxic amounts of iron-dextran. Both Vimang or mangiferin treatment prevented iron overload in serum as well as liver oxidative stress, decreased serum and liver lipid peroxidation, serum GPx activity, and increased serum and liver GSH, serum SOD and the animals overall antioxidant condition. Serum iron concentration was decreased although at higher doses, Vimang tended to increase it; percent tranferrin saturation, liver weight/body mass ratios, liver iron content was decreased. Treatment increased serum iron-binding capacity and decreased serum levels of aspartate-amine transferase (ASAT) and alanine-amine transferase (ALAT), as well as the number of abnormal Kupffer cells in iron-loaded livers. It is suggested that besides acting as antioxidants, Vimang extract or its mangiferin component decrease liver iron by increasing its excretion. Complementing earlier in vitro results from our group, it appears possible to support the hypothesis that Vimang and mangiferin present therapeutically useful effects in iron overload related diseases.

Experiencias de la terapia antioxidante con Vimang en la atención primaria de salud en Cuba / Experience of antioxidant therapy with Vimang in primary health care in Cuba

La terapia antioxidante con Vimang en la atención primaria de salud constituye una posible alternativa para el tratamiento eficaz, adyuvante o no, de enfermedades relacionadas con el estrés oxidativo o componentes de dolor e inflamación. Se muestra los resultados de estudios clínicos con Vimang en la atención al adulto mayor, el tratamiento de la displasia de mamas, leve o moderada, y el tratamiento de dermatopatías, a partir de experiencias etnomédicas publicadas con anterioridad. En la atención al adulto mayor (n = 31, tabletas Vimang, 300 mg) mejoró, en ocho de nueve indicadores evaluados de la calidad de vida (Cuestionario de Salud SF-36), la autopercepción del estado de salud de los ancianos; el indicador más significativo fue el dolor corporal. En la terapia de la displasia de mamas (n = 100, tabletas Vimang, 300 mg) se demostró una eficacia mayor al 85 por ciento, con resultados similares o superiores a la vitamina E. En el tratamiento de enfermedades de la piel (n = 590, crema Vimang, 1,2 por ciento), se observó mejoría en 86,8 y 96,7 por ciento de los pacientes tratados por inflamación y dolor, respectivamente, y más del 90 por ciento fueron curados de forma total o parcial. Los resultados más relevantes se obtuvieron en la recuperación del color de la piel en melasma del embarazo y pitiriasis versicolor, (52 pacientes), procesos infecciosos (53 pacientes), micosis (169 pacientes). No se observaron reacciones adversas ni signos de toxicidad durante el tratamiento.

Antioxidant therapy with Vimang in primary health care is a possible alternative for the effective treatment, either adjuvant or not, of diseases related to oxidative stress, pain and inflammation. The results of clinical studies with Vimang on the elderly, breast dysplasia (mild or moderate) and skin diseases were shown taking into account previously reported ethnomedical experience. On elderly subjects (n=31 , 300mg Vimang tablets), the self perception of their health status improved in 8 of 9 evaluated parameters of life quality, being body pain the most significant (health questionnaire SF-36). In the treatment of breast dysplasia (n=100, 300mg Vimang tablets), the efficacy was over 85 percent, with similar or higher results than vitamin E. In treating skin diseases (n=590, 1.2 percent Vimang cream), 86.8 percent and 96.7 percent of patients treated because of inflammation and pain improved their condition whereas over 90 percent of patients completely or partially recovered. The most relevant results were seen in the recovery of skin pigmentation in pregnancy melasme and pitiriasis versicolor (52 patients), infectious processes (53 patients), and mycosis (169 patients). Neither adverse reactions nor toxic signs were observed in the treatment.

The paradox of natural products as pharmaceuticals. Experimental evidences of a mango stem bark extract.

Recent findings regarding basic, pre-clinical and clinical studies on a mango stem bark extract (MSBE) developed in Cuba (Vimang) on an industrial scale are summarized. Ethnomedical studies, extract reproducibility, biological effects and clinical evaluations in terms of patient quality of life are described as experimental evidences to support the statement that natural products, even being a mixture of compounds, could be as effective as "monoceuticals" for medical uses. Discussion about the use of "monoceuticals" versus "natureceuticals" in health care and medicine is based on effectiveness and availability, taking Vimang as an example of a natural product with supported scientific evidence to be used as antioxidant, analgesic, anti-inflammatory and immunomodulator.

Interaction of Vimang (Mangifera indica L. extract) with Fe(III) improves its antioxidant and cytoprotecting activity.

A standard aqueous stem bark extract from selected species of Mangifera indica L. (Anacardiaceae)--Vimang, whose major polyphenolic component is mangiferin, displays potent in vitro and in vivo antioxidant activity. The present study provides evidence that the Vimang-Fe(III) mixture is more effective at scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals, as well as in protecting against t-butyl hydroperoxide-induced mitochondrial lipid peroxidation and hypoxia/reoxygenation-induced hepatocytes injury, compared to Vimang alone. Voltammetric assays demonstrated that Vimang, in line with the high mangiferin content of the extract, behaves electrochemically like mangiferin, as well as interacts with Fe(III) in close similarity with mangiferin's interaction with the cation. These results justify the high efficiency of Vimang as an agent protecting from iron-induced oxidative damage. We propose Vimang as a potential therapy against the deleterious action of reactive oxygen species generated during iron-overload, such as that occurring in diseases like beta-thalassemia, Friedreich's ataxia and haemochromatosis.

Mangifera indica L. (Vimang) protection against serum oxidative stress in elderly humans.

BACKGROUND: We searched for the protective effect of a natural extract from stem bark of Mangifera indica L. extract (Vimang) on age-related oxidative stress. METHODS: Healthy subjects were classified in two groups, elderly (>65 years) and young group (<26 years). The elderly group received a daily dose of 900 mg of extract (three coated Vimang tablets, 300 mg each, before meals) for 60 days. Serum concentration of lipid peroxides, serum peroxidation potential, extracellular superoxide dismutase activity (EC-SOD), glutathione status (GSH, GSSG, GSSG/GSH ratio)) and total antioxidant status (TAS) were determined before (both experimental groups) and 15, 30, and 60 days after treatment (only elderly group). We confirmed the existence of an age-associated oxidative stress in human serum as documented by an age-related increase in serum lipoperoxides and GSSG and a decrease in serum antioxidant capacity and EC-SOD activity. RESULTS: Vimang tablet supplementation increased EC-SOD activity (p <0.01) and serum TAS (p <0.01). It also decreased serum thiobarbituric reactive substances (p <0.01) and GSSG levels (p <0.05). We suggested that the antioxidant components of the extract could have been utilized by the cells (especially blood and endothelial cells), sparing the intra- and extracellular antioxidant system and increasing serum peroxil scavenging capacity, thus preventing age-associated increase in GSH oxidation and lipoperoxidation. CONCLUSIONS: Vimang tablets prevent age-associated oxidative stress in elderly humans, which could retard the onset of age-associated disease, improving the quality of life for elderly persons.

Vimang (Mangifera indica L. extract) induces permeability transition in isolated mitochondria, closely reproducing the effect of mangiferin, Vimang's main component.

Mitochondrial permeability transition (MPT) is a Ca(2+)-dependent, cyclosporin A (CsA)-sensitive, non-selective inner membrane permeabilization process. It is often associated with apoptotic cell death, and is induced by a wide range of agents or conditions, usually involving reactive oxygen species (ROS). In this study, we demonstrated that Mangifera indica L. extract (Vimang), in the presence of 20 microM Ca(2+), induces MPT in isolated rat liver mitochondria, assessed as CsA-sensitive mitochondrial swelling, closely reproducing the same effect of mangiferin, the main component of the extract, as well as MPT-linked processes like oxidation of membrane protein thiols, mitochondrial membrane potential dissipation and Ca(2+) release from organelles. The flavonoid catechin, the second main component of Vimang, also induces MPT, although to a lesser extent; the minor, but still representative Vimang extract components, gallic and benzoic acids, show respectively, low and high MPT inducing abilities. Nevertheless, following exposure to H(2)O(2)/horseradish peroxidase, the visible spectra of these compounds does not present the same changes previously reported for mangiferin. It is concluded that Vimang-induced MPT closely reproduces mangiferin effects, and proposed that this xanthone is the main agent responsible for the extract's MPT inducing ability, by the action on mitochondrial membrane protein thiols of products arising as a consequence of the mangiferin's antioxidant activity. While this effect would oppose the beneficial effect of Vimang's antioxidant activity, it could nevertheless benefit cells exposed to over-production of ROS as occurring in cancer cells, in which triggering of MPT-mediated apoptosis may represent an important defense mechanism to their host.