Oral administration of curcumin relieves behavioral alterations and oxidative stress in the frontal cortex, hippocampus, and striatum of ovariectomized Wistar rats.

Menopause occurs gradually and is characterized by increased susceptibility to developing mood disorders. Several studies have suggested treatments based on the antioxidant properties of vitamins and herbal compounds as an alternative to hormone replacement therapies, with few or none reporting toxicity. The present study was performed to explore the effects of curcumin oral supplementation on anxiety-like behavior and oxidative stress parameters in different central nervous system (CNS) areas of ovariectomized (OVX) rats. Female Wistar rats were randomly divided into either sham-operated or OVX groups. Sham-operated group (n=8) and an OVX group (n=11) were treated with vehicle, and the other two OVX groups received curcumin at 50 or 100mg/kg/day doses (n=8/group). Elevated plus maze (EPM) test was performed on the 28th day of treatment. On the 30th day, animals were killed and the dissected brain regions were removed and stored at-80°C until analysis. Ovariectomy induced deficit in the locomotor activity and increased anxiety-like behavior. Moreover, OVX rats showed increased lipid oxidized in the frontal cortex and striatum, increased hippocampal and striatal carbonylated protein level, and decreased striatal thiol content of non-protein fraction indicative of a glutathione (GSH) pool. Curcumin oral treatment for 30days reduced oxidative stress in the CNS areas as well as the behavior alterations resulting from ovariectomy. Curcumin supplementation attenuated most of these parameters to sham comparable values, suggesting that curcumin could have positive effects against anxiety-like disturbances and brain oxidative damage due to hormone deprivation.

Curcumin Supplementation Decreases Intestinal Adiposity Accumulation, Serum Cholesterol Alterations, and Oxidative Stress in Ovariectomized Rats.

The aim of this study was to investigate the potential of curcumin oral supplementation (50 and 100 mg/Kg/day, for 30 days) in circumventing menopause-associated oxidative stress and lipid profile dysfunctions in a rat ovariectomy (OVX) model. Female Wistar rats were operated and randomly divided into either sham-operated or OVX groups. Sham-operated group (n = 8) and one OVX group (n = 11) were treated with vehicle (refined olive oil), and the other two OVX groups received curcumin at 50 or 100 mg/Kg/day doses (n = 8/group). OVX vehicle-treated animals presented a higher deposition of intestinal adipose tissue as well as increased serum levels of IL-6, LDL, and total cholesterol when compared to sham-operated rats. In addition, several oxidative stress markers in serum, blood, and liver (such as TBARS, carbonyl, reduced-sulphydryl, and nonenzymatic antioxidant defenses) were altered toward a prooxidant status by OVX. Interestingly, curcumin supplementation attenuated most of these parameters to sham comparable values. Thus, the herein presented results show that curcumin may be useful to ameliorate lipid metabolism alterations and oxidative damage associated with hormone deprivation in menopause.

Major components of energy drinks (caffeine, taurine, and guarana) exert cytotoxic effects on human neuronal SH-SY5Y cells by decreasing reactive oxygen species production.

SCOPE: To elucidate the morphological and biochemical in vitro effects exerted by caffeine, taurine, and guarana, alone or in combination, since they are major components in energy drinks (EDs). METHODS AND RESULTS: On human neuronal SH-SY5Y cells, caffeine (0.125-2 mg/mL), taurine (1-16 mg/mL), and guarana (3.125-50 mg/mL) showed concentration-dependent nonenzymatic antioxidant potential, decreased the basal levels of free radical generation, and reduced both superoxide dismutase (SOD) and catalase (CAT) activities, especially when combined together. However, guarana-treated cells developed signs of neurite degeneration in the form of swellings at various segments in a beaded or pearl chain-like appearance and fragmentation of such neurites at concentrations ranging from 12.5 to 50 mg/mL. Swellings, but not neuritic fragmentation, were detected when cells were treated with 0.5 mg/mL (or higher doses) of caffeine, concentrations that are present in EDs. Cells treated with guarana also showed qualitative signs of apoptosis, including membrane blebbing, cell shrinkage, and cleaved caspase-3 positivity. Flow cytometric analysis confirmed that cells treated with 12.5-50 mg/mL of guarana and its combinations with caffeine and/or taurine underwent apoptosis. CONCLUSION: Excessive removal of intracellular reactive oxygen species, to nonphysiological levels (or "antioxidative stress"), could be a cause of in vitro toxicity induced by these drugs.

Increased cerebral oxidative damage and decreased antioxidant defenses in ovariectomized and sham-operated rats supplemented with vitamin A.

Previous studies have linked oxidative stress with aging and aging-related processes, including menopause. Abnormalities in the redox state similar to those observed in menopausal women can be modeled experimentally with rat ovariectomy. The aim of the present study was to investigate the effects of vitamin A (retinol palmitate) supplementation (500 or 1,500 IU kg(-1) day(-1) for 30 days) on behavioral parameters and brain redox profile in ovariectomized (OVX) and sham-operated rats. Ovariectomy caused pronounced uterine atrophy and decreased locomotor/exploratory activity. Moreover, we found increased hypothalamic and frontal cortex superoxide dismutase/catalase (SOD/CAT) ratio and decreased hippocampal thiol content, accompanied by increased frontal cortex lipid oxidative damage (TBARS) in OVX rats. Vitamin A at 1,500 IUkg(-1) day(-1) decreased exploratory behavior and decreased total hippocampal thiol content in sham-operated rats, increased hippocampal SOD/CAT ratio and decreased total antioxidant potential in the hippocampus of both sham and OVX groups, and increased cortical TBARS levels in OVX rats. Thus, vitamin A may induce a pro-oxidant state in discrete brain regions of sham-operated and OVX rats. These results suggest some caution regarding the use of high doses of vitamin A supplementation during menopause.

Evaluation of the neurotoxic/neuroprotective role of organoselenides using differentiated human neuroblastoma SH-SY5Y cell line challenged with 6-hydroxydopamine.

It is well established that oxidative stress plays a major role in several neurodegenerative conditions, like Parkinson disease (PD). Hence, there is an enormous effort for the development of new antioxidants compounds with therapeutic potential for the management of PD, such as synthetic organoselenides molecules. In this study, we selected between nine different synthetic organoselenides the most eligible ones for further neuroprotection assays, using the differentiated human neuroblastoma SH-SY5Y cell line as in vitro model. Neuronal differentiation of exponentially growing human neuroblastoma SH-SY5Y cells was triggered by cultivating cells with DMEM/F12 medium with 1% of fetal bovine serum (FBS) with the combination of 10 µM retinoic acid for 7 days. Differentiated cells were further incubated with different concentrations of nine organoselenides (0.1, 0.3, 3, 10, and 30 µM) for 24 h and cell viability, neurites densities and the immunocontent of neuronal markers were evaluated. Peroxyl radical scavenging potential of each compound was determined with TRAP assay. Three organoselenides tested presented low cytotoxicity and high antioxidant properties. Pre-treatment of cells with those compounds for 24 h lead to a significantly neuroprotection against 6-hydroxydopamine (6-OHDA) toxicity, which were directly related to their antioxidant properties. Neuroprotective activity of all three organoselenides was compared to diphenyl diselenide (PhSe)2, the simplest of the diaryl diselenides tested. Our results demonstrate that differentiated human SH-SY5Y cells are suitable cellular model to evaluate neuroprotective/neurotoxic role of compounds, and support further evaluation of selected organoselenium molecules as potential pharmacological and therapeutic drugs in the treatment of PD.

Increased blood oxidative stress in experimental menopause rat model: the effects of vitamin A low-dose supplementation upon antioxidant status in bilateral ovariectomized rats.

Menopause has been reported to be associated with increased oxidative stress and metabolic disorders among women worldwide. Disarrangements in the redox state similar to those observed in women during the decline of ovarian hormonal activity can be obtained experimentally through rat bilateral ovariectomy. The search for alternative treatments to improve life quality in postmenopausal woman is really important. The aim of this study was to evaluate biochemical and oxidative stress parameters that distinguish sham-operated female rats from Wistar rats bilaterally ovariectomized (OVX). Additionally, we have also investigated the effects of retinol palmitate (a vitamin A supplement) low-dose supplementation (500 or 1500 IU/kg/day, during 30 days) upon blood and plasma antioxidant status in OVX rats. Ovariectomy caused an increase in body weight gain, pronounced uterine atrophy, decreased plasma triglycerides and increased total cholesterol levels, and reduced acid uric content. Moreover, we found increased blood peroxidase activities (catalase and glutathione peroxidase), decreased plasma non-enzymatic antioxidant defenses total reactive antioxidant potential and total antioxidant reactivity, decreased protein and non-protein SH levels, accompanied by increased protein oxidative damage (carbonyl). In addition, vitamin A low-dose supplementation was capable to ameliorate antioxidant status in OVX rats, restoring both enzymatic and non-enzymatic defenses, promoting reduction in plasma SH content, and decreasing protein oxidative damage levels. This is the first work in the literature showing that vitamin A at low dose may be beneficial in the treatment of menopause symptoms. Further studies will be made to better understand the effects of vitamin A supplementation in menopause rat model.

In vitro optimization of retinoic acid-induced neuritogenesis and TH endogenous expression in human SH-SY5Y neuroblastoma cells by the antioxidant Trolox.

Though, it is quite well-known how retinoic acid (RA) is able to induce neuritogenesis in different in vitro models, the putative role exerted by reactive oxygen species (ROS) during this process still need to be further studied. For such purpose, we used a neuronal-like cell line (SH-SY5Y cells) in order to investigate whether the antioxidant Trolox (a hydrophilic analog of alpha-tocopherol) could have any effect on the number of RA-induced neurites, and how significant changes in cellular redox homeostasis may affect the cellular endogenous expression of tyrosine hydroxylase (TH). Our results show a significant enhancement of RA (10 µM)-induced neuritogenesis and TH endogenous expression, when cells were co-treated with Trolox (100 µM) for 7 days. Moreover, this effect was associated with an improvement in cellular viability. The mechanism seems to mainly involve PI3 K/Akt rather than MEK signaling pathway. Therefore, our data demonstrate that concomitant decreases in basal reactive oxygen species (ROS) production could exert a positive effect on the neuritogenic process of RA-treated SH-SY5Y cells.

The effects of vitamin A supplementation to rats during gestation and lactation upon redox parameters: increased oxidative stress and redox modulation in mothers and their offspring.

Vitamin A is an essential nutrient required in adequate amounts for reproduction and development. Subtle variations in the status of maternal nutrition may affect physiological and metabolic parameters in the fetus. Evidence suggests a key role for oxidative stress in these events. Literature is controversial about the effects of vitamin A supplementation. Here, we studied the effects of vitamin A supplementation on female Wistar rats during gestation and lactation on oxidative stress parameters of maternal and offspring tissues. Rats received daily doses of vitamin A at 2500, 12,500 and 25,000IU/kg. We observed an increase of oxidative damage markers in the reproductive tissues and plasma of dams. The activity of glutathione-S-transferase was modulated by vitamin A supplementation. It was found to be increased in the liver of dams and decreased in the kidneys of mothers and offspring. In pups, supplementation decreased the total antioxidant potential of the liver along with decreased superoxide dismutase/catalase activity ratio in the kidney. The levels of lipoperoxidation were increased in male offspring, but decreased in female pups. Collectively, the results suggest that excessive vitamin A intake during gestation and lactation might be toxic for mothers with adverse effects for the developing offspring.

Animal model of autism induced by prenatal exposure to valproate: behavioral changes and liver parameters.

Autism is characterized by behavioral impairments in three main domains: social interaction; language, communication and imaginative play; and range of interests and activities. This syndrome has attracted social attention by its high prevalence. The animal model induced by prenatal exposure to valproic acid (VPA) has been proposed to study autism. Several characteristics of behavioral abnormalities found in the VPA rats, such as repetitive/stereotypic-like activity and deficit in social interaction have been correlated with autism. Features like flexibility to change strategy, social memory and metabolic status of the induced rats have not been examined. Thus, the main aim of this work was to investigate additional behavioral rodent similarities with autism, as well as, liver redox parameters after prenatal exposure to VPA. Young rats from the VPA group presented aberrant approach to a stranger rat, decreased conditioned place preference to conspecifics, normal spatial learning and a lack of flexibility to change their strategy. As adults, they presented inappropriate social approach to a stranger rat, decreased preference for social novelty, apparently normal social recognition and no spatial learning deficits. Examination of the liver from the VPA group presented significantly increased (12%) levels of catalase (CAT) activity, no alteration in superoxide dismutase (SOD) activity and a decrease in the SOD/CAT ratio. TBARS, sulfhydril and carbonyl contents, and serum levels of aminotransferases remained unchanged. In summary, rats prenatally exposed to VPA presented decreased flexibility to change strategy and social impairments similar to the autism symptoms, contributing to the understanding of neurodevelopmental symptoms and oxidative imbalance associated to the autism spectrum disorder.

Treatment with N-methyl-D-aspartate receptor antagonist (MK-801) protects against oxidative stress in lipopolysaccharide-induced acute lung injury in the rat.

Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) are common syndromes that affect both clinical and surgical patients. This study describes the effects of a potent and specific N-methyl-d-aspartate receptor antagonist (MK-801) against oxidative stress in acute lung injury induced by intratracheal lipopolysaccharide (LPS) injection. This study was performed using male Wistar rats weighing 200-250g. Rats were randomly divided into four groups: control with isotonic saline instillation (n=6); LPS (100µg/100g of body weight) treated with saline (n=6); LPS treated with MK-801 (0.3mg/kg, intraperitoneally; n=6); LPS treated with MK-801 (0.3mg/kg, intratracheally; n=6). Twelve hours after the LPS instillation, rats were anesthetized and a bronchoalveolar lavage (BAL) was performed in order to determine the alveolar-capillary membrane alterations and the inflammatory infiltrate level. Blood and lung samples were isolated and assayed for oxidative stress variables and histopathologic analysis. The use of MK-801 decreased bronchoalveolar lavage fluid protein, LDH activity and inflammatory cells. Indeed, the treatment with MK-801 significantly attenuated lung oxidative damage and histopathologic alterations after LPS instillation. Our data provide the first experimental demonstration that MK-801 decreases oxidative stress and limits inflammatory response and alveolar disarray in lipopolysaccharide-induced acute lung injury.

Vitamin A supplementation in rats under pregnancy and nursing induces behavioral changes and oxidative stress upon striatum and hippocampus of dams and their offspring.

Vitamin A is important for both development and maintenance of adult brain homeostasis. However, excessive vitamin A exposure has been linked to cognitive impairments and may induce congenital defects, including neuronal malformations. Recently, we demonstrated that vitamin A supplementation is able to alter behavioral parameters and induce a pro-oxidant state in hippocampus and striatum of adult male rat. Thus, the aim of the present work was to investigate the effects of vitamin A supplementation in pregnant and nursing rats on maternal and offspring striatum and hippocampus. Wistar female rats (7 per group) were orally supplemented with retinyl palmitate (2500, 12,500 and 25,000 IU/kg/day) or saline (control) throughout pregnancy and nursing. Homing test was performed at postnatal days (PND) 5 and 10 for offspring, while open field test (OFT) was carried out at PND19 and 20 for dams and offspring, respectively. Redox parameters were evaluated at PND21 for both. Vitamin A supplementation during pregnancy and nursing increased superoxide dismutase/catalase (SOD/CAT) ratio and oxidative damage in maternal and offspring striatum and hippocampus. Additionally, supplementation induced behavioral alterations. In conclusion, we suggest some caution regarding vitamin A intake during pregnancy and breastfeeding, since oxidative stress can disturb several biological phenomena, including neuronal signaling and neurotransmission, which may induce several behavioral deficits.

Vascular redox imbalance in rats submitted to chronic exercise.

Exercise training has been used for treatment/prevention of many cardiovascular diseases, but the mechanisms need to be clarified. Thus, our aim was to compare oxidative stress parameters between rats submitted to a swimming training and sedentary rats (control). Twelve male rats were divided into two groups: control and exercise training. The exercise training had daily 1 h swimming sessions for 8 weeks and a load (5% of its body mass) was placed in rat's tail. Thereafter the animals were killed, aorta and heart were surgically removed and blood was collected. Body mass gain, thiobarbituric acid reactive species (TBARS), carbonyl content, total reactive antioxidant potential (TRAP), total antioxidant reactivity (TAR), superoxide dismutase (SOD) activity and catalase (CAT) activity were evaluated. The trained rats showed a lower body mass gain and no modifications on heart. An increased SOD activity was observed on aorta after the training, but no changes were seen for CAT activity, which led to an increased SOD/CAT ratio. The arterial TBARS was also increased for trained rats. The decrease in TRAP in exercise training was the single modification on plasma. Our findings suggest that the increased SOD activity could play a role in vascular adaptations to exercise training.

Increased receptor for advanced glycation endproducts immunocontent in the cerebral cortex of vitamin A-treated rats.

Vitamin A, beyond its biological role, is an alternative choice in treating some life threatening pathologies, for instance leukemia and immunodeficiency. On the other hand, vitamin A therapy at moderate to high doses has caused concern among public health researchers due to the toxicological aspect resulting from such habit. It has been described hepatotoxicity, cognitive disturbances and increased mortality rates among subjects ingesting increased levels of vitamin A daily. Then, based on the previously reported data, we investigated here receptor for advanced glycation endproducts (RAGE) immunocontent and oxidative damage levels in cerebral cortex of vitamin A-treated rats at clinical doses (1,000-9,000 IU/kg day(-1)). RAGE immunocontent, as well as oxidative damage levels, were observed increased in cerebral cortex of vitamin A-treated rats. Whether increased RAGE levels exert negative effects during vitamin A supplementation it remains to be investigated, but it is very likely that deleterious consequences may arise from such alteration.

Modulation in reproductive tissue redox profile in sexually receptive female rats after short-term exposure to male chemical cues.

It is well known that antioxidants play an important role in sperm fertility, but there is no data on the literature regarding the effect of male chemical cues in the antioxidant defenses of the female reproductive tract. Here, we evaluated oxidative parameters in ovaries and uterus of virgin female rats isolated from contact to males and exposed only to male-soiled bedding (MSB). Four-month-old Wistar (regular 4-day cyclic) virgin female rats were utilized from proestrus to estrus phase of the reproductive cycle for experimental exposure. In an isolated room, female rats were exposed for 90 min to MSB. For biochemical assays, female rats were killed by decapitation at 30, 90, 180, and 240 min after the end of exposure, and the ovaries and uterus were removed for further analysis. Antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase), the nonenzymatic antioxidant potential (total radical-trapping antioxidant parameter), and the oxidative damage parameters (thiobarbituric acid-reactive species and carbonyl content) were analyzed. We observed an increase in the nonenzymatic antioxidant potential and diminished free radical oxidative damage in uterine tissue, 30 and 90 min after exposure. Furthermore, in ovaries, enzymatic defenses were modulated distinctly along the 240 min after exposure. MSB exposure modulates the antioxidant profile in ovaries and uterus of receptive female rats. It is possible that the modifications in the oxidative profile of the female genital tract may have important implications in the process of fertilization.

Evaluation of the effects of vitamin A supplementation on adult rat substantia nigra and striatum redox and bioenergetic states: mitochondrial impairment, increased 3-nitrotyrosine and alpha-synuclein, but decreased D2 receptor contents.

Vitamin A at moderate to high doses is applied in the treatment of some life threatening pathological conditions, for instance cancers. Additionally, vitamin A at low concentrations is a known antioxidant molecule. However, by increasing vitamin A (or its derivatives) concentrations, there is an increase in the levels of oxidative stress markers in several experimental models. Furthermore, it was reported that vitamin A therapy at high doses might induce cognitive decline among the patients, which may become anxious or depressive, for example, depending on vitamin A levels intake. We have previously reported increased levels of oxidative stress markers in rat substantia nigra and striatum. However, the mechanism by which this vitamin altered the redox environment in such rat brain regions remains to be elucidated. In the herein presented work, we have investigated the effects of vitamin A supplementation at clinical doses (1000-9000 IU/kg day(-1)) for 28 days on rat substantia nigra and striatum mitochondrial electron transfer chain (METC) activity, which may produce superoxide anion radical (O(2)(-*)) when impaired. Additionally, the levels of non-enzymatic antioxidant defenses were evaluated, as well as 3-nitrotyrosine, alpha- and beta-synucleins and TNF-alpha levels through ELISA assay. We observed impaired METC in both rat brain regions. Moreover, we found increased O(2)(-*) production and nitrotyrosine content in the nigrostriatal axis of vitamin A-treated rats, suggesting that the use of vitamin A at therapeutic doses may be rethought due to this toxic effects found here.

Vitamin A supplementation for different periods alters oxidative parameters in lungs of rats.

Lungs require an adequate supply of vitamin A (retinol) for normal embryonic development, postnatal maturation, and maintenance and repair during adult life. However, recent intervention studies revealed that supplementation with retinoids resulted in higher incidence of lung cancer, although the mechanisms underlying this effect are still unknown. Here, we studied the effect of vitamin A supplementation on oxidative stress parameters in lungs of Wistar rats. Vitamin A supplementation at either therapeutic (1,000 and 2,500 IU/kg) or excessive (4,500 and 9,000 IU/kg) doses for 3, 7, or 28 days induced lipid peroxidation, protein carbonylation, and oxidation of protein thiol groups, as well as change in catalase and superoxide dismutase activity. Together, these results suggest that vitamin A supplementation causes significant changes in redox balance, which are frequently associated with severe lung dysfunction.

Decreased anxiety-like behavior and locomotor/exploratory activity, and modulation in hypothalamus, hippocampus, and frontal cortex redox profile in sexually receptive female rats after short-term exposure to male chemical cues.

Chemical cues are widely used for intraspecific social communication in a vast majority of living organisms ranging from bacteria to mammals. As an example, mammals release olfactory cues with urine that promote neuroendocrine modulations with changes in behavior and physiology in the receiver. In this work, four-month-old Wistar (regular 4-day cyclic) virgin female rats were utilized in the proestrus-to-estrus phase of the reproductive cycle for experimental exposure. In an isolated room, female rats were exposed for 90 min to male-soiled bedding (MSB). Elevated plus-maze assay, open field test, and light/dark box task were performed to analyze behavioral alterations on females after exposure. For biochemical assays, female rats were killed and the hypothalamus, hippocampus, and frontal cortex were isolated for further analysis. Antioxidant enzyme activities (superoxide dismutase, catalase and glutathione peroxidase), non-enzymatic antioxidant defense measurements (TRAP and TAR), and the oxidative damage parameters (TBARS, Carbonyl and SH content) were analyzed. In behavioral analyses we observe that female rats show decreased anxiety and locomotory/exploratory activities after MSB exposure. In biochemical assays we observed an increase in both enzymatic and non-enzymatic antioxidant defenses in different central nervous system (CNS) structures analyzed 30 and 90 min after MSB exposure. Furthermore, hippocampus and frontal cortex showed diminished free radical oxidative damage at 180 and 240 min after exposure. These results provide the first evidence that oxidative profile of female CNS structures are altered by chemical cues present in the MSB, thus suggesting that pheromonal communication is able to modulate radical oxygen species production and/or clearance in the female brain.

Vitamin A supplementation at clinical doses induces a dysfunction in the redox and bioenergetics states, but did change neither caspases activities nor TNF-alpha levels in the frontal cortex of adult Wistar rats.

Vitamin A and its derivatives, the retinoids, exert modulatory roles on central nervous system (CNS) function. However, the clinical use of vitamin A at moderate to high doses induces serious side effects, including dysfunctional brain metabolism and mood disorders. Then, we have investigated in this work the effects of vitamin A supplementation at 1000, 2500, 4500, or 9000IU/kg/day for 28 days on redox and bioenergetics parameters in adult rat frontal cortex. Additionally, we have measured caspase-3 and caspase-8 activities to analyze whether vitamin A supplementation as retinol palmitate induces neuronal death in such brain area. The levels of the pro-inflammatory cytokine TNF-alpha were also quantified. We have found increased rates of O(2)(-) production and increased levels of markers of oxidative insult in frontal cortex and also in mitochondrial membranes. Superoxide dismutase (SOD) enzyme activity was increased, and catalase (CAT) enzyme activity did not change in this experimental model. Surprisingly, we observed increased mitochondrial electron transfer chain (METC) activity. Caspase-3 and caspase-8 activities and TNF-alpha levels did not change in this experimental model. Finally, vitamin A supplementation did not induce depression in adult rats after 28 days of treatment. However, exploration in the center of an open field was decreased and time spent in freezing behavior was increased in vitamin A treated rats.

Pancreas beta-cells morphology, liver antioxidant enzymes and liver oxidative parameters in alloxan-resistant and alloxan-susceptible Wistar rats: a viable model system for the study of concepts into reactive oxygen species.

The aim of this study was to investigate biochemical and antioxidant parameters in alloxan-resistant (ALR) and alloxan-susceptible (ALS) rats. Diabetes was induced in 60-day-old male Wistar rats by a single intraperitonial injection of alloxan (AL, 150 mg/kg). Ten days after induction, a group of rats showed a significant decrease in glycemia. This group was named alloxan-resistant group. Susceptible rats showed a remarkable increase in the plasma lipid content, blood glucose and HbA1. Glycogen content in the liver decreased significantly in the ALS group (2.08 +/- 0.41 mg%) compared with ALR group (4.22 +/- 0.18). Aspartate aminotransferase and alanine aminotransferase activities were quantified in the plasma. Interestingly, ALR rats showed a decrease in both activities (42.1 +/- 6.11 and 21.7 +/- 5.54 U/mL) when compared with ALS rats (59.1 +/- 6.55 and 58.1 +/- 7.28 U/mL). The TBARS index was significantly increased in the ALS liver (0.38 +/- 0.08 nm/mg protein) when compared with the ALR liver (0.18 +/- 0.04). Superoxide dismutase and catalase activities in the ALR (230 +/- 13 and 131 +/- 15 U/mg protein) liver showed a marked increase when compared with the ALS liver (148 +/- 13 and 68 +/- 5 U/mg protein). The immunohistochemical and hematoxilin-eosin analysis also revealed that pancreatic islets of ALR rats display a different morphology amongst the groups. These results suggest an increased regenerative or recovery process in the ALR rat pancreatic islets and an increased hepatic antioxidant defenses in these group of alloxan-resistant rats.

Antioxidant activities and free radical scavenging potential of Bauhinia microstachya (RADDI) MACBR. (Caesalpinaceae) extracts linked to their polyphenol content.

Aqueous and hydro-ethanolic extracts of Bauhinia microstachya leaves (AEBM and HEBM) were investigated for their phenolic content and phytochemical profile (by spectrophotometry and HPLC), and for their antioxidant activities and free radical scavenging potential in different in vitro systems (TRAP, TEAC, TBARS, nitric oxide, superoxide and hydroxyl radical). HEBM presented a 27.4% higher content of phenolics when compared to AEBM and a distinct phytochemical profile was observed. Our work suggests that both extracts have potent antioxidant activities and that their antioxidant capacity and efficiency vary according to the radical-generating system. In general, HEBM was more effective than AEBM in avoiding ROS-generating damage and in scavenging the various radicals formed. Nevertheless, when results were normalized to total phenolic content, a different profile of antioxidant activities and free radical scavenging potential was observed, particularly against oxidative lipid damage and superoxide radical. B. microstachya extracts may be considered an interesting source of natural antioxidants as well as other phenolic-rich plants.