Jéssica Pereira Costa

Antinociceptive and Antioxidant Activities of Phytol In Vivo and In Vitro Models.

The objective of the present study was to evaluate the antinociceptive effects of phytol using chemical and thermal models of nociception in mice and to assess its antioxidant effects in vitro. Phytol was administered intraperitoneally (i.p.) to mice at doses of 25, 50, 100, and 200 mg/kg. In the acetic acid-induced writhing test, phytol significantly reduced the number of contortions compared to the control group (P < 0.001). In the formalin test, phytol reduced significantly the amount of time spent in paw licking in both phases (the neurogenic and inflammatory phases), this effect being more pronounced in the second phase (P < 0.001). Phytol also provoked a significant increase in latency in the hot plate test. These antinociceptive effects did not impaire the motor performance, as shown in the rotarod test. Phytol demonstrated a strong antioxidant effect in vitro in its capacity to remove hydroxyl radicals and nitric oxide as well as to prevent the formation of thiobarbituric acid reactive substances (TBARS). Taken as a whole, these results show the pronounced antinociceptive effects of phytol in the nociception models used, both through its central and peripheral actions, but also its antioxidant properties demonstrated in the in vitro methods used.

Evaluation of acute toxicity of a natural compound (+)-limonene epoxide and its anxiolytic-like action

The aim of the study is to determine the acute toxicity and anxiolytic-like effects of a mixture of cis and trans of (+)-limonene epoxide in animal models of anxiety. After acute treatment with (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg (i.p.) no mortality was noted during 14 days of observation. In general, behavior, food and water consumption showed no significant changes. In open field test, (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg, after intraperitoneal administration, significantly decreased the number of crossings, grooming and rearing (p<0.001). All these effects were reversed by the pre-treatment with flumazenil (25 mg/kg, i.p.), similar to those observed with diazepam used as a positive standard. In the elevated-plus-maze test, (+)-limonene epoxide increased the time of permanence and the number of entrances in the open arms. All these effects were reversed by flumazenil, an antagonist of benzodiazepine receptors. In addition, (+)-limonene epoxide (75 mg/kg) also produced a significant inhibition of the motor coordination (p<0.01), that was reversed by flumazenil. In conclusion, the present work evidenced sedative and anxiolytic-like effects of (+)-limonene epoxide, which might involve an action on benzodiazepine-type receptors. These results indicate that the properties of (+)-limonene epoxide should be more thoroughly examined in order to achieve newer tools for management and/or treatment of central nervous system diseases and anxiolytic-like effects. The LD50 obtained for the acute toxicity studies using intraperitoneal route of administration was 4.0 g/kg. These findings suggest that acute administration of the (+)-limonene epoxide exerts an anxiolytic-like effect on mice, and it could serve as a new approach for the treatment anxiety, since it practically does not produce toxic effects.

Phytol, a Diterpene Alcohol from Chlorophyll, as a Drug against Neglected Tropical Disease Schistosomiasis Mansoni

Background Schistosomiasis is a major endemic disease that affects hundreds of millions worldwide. Since the treatment and control of this parasitic disease rely on a single drug, praziquantel, it is imperative that new effective drugs are developed. Here, we report that phytol, a diterpene alcohol from chlorophyll widely used as a food additive and in medicinal fields, possesses promising antischistosomal properties in vitro and in a mouse model of schistosomiasis mansoni. Methods and findings In vitro, phytol reduced the motor activity of worms, caused their death and confocal laser scanning microscopy analysis showed extensive tegumental alterations in a concentration-dependent manner (50 to 100 µg/mL). Additionally, phytol at sublethal doses (25 µg/mL) reduced the number of Schistosoma mansoni eggs. In vivo, a single dose of phytol (40 mg/kg) administered orally to mice infected with adult S. mansoni resulted in total and female worm burden reductions of 51.2% and 70.3%, respectively. Moreover, phytol reduced the number of eggs in faeces (76.6%) and the frequency of immature eggs (oogram pattern) was significantly reduced. The oogram also showed increases in the proportion of dead eggs. Confocal microcopy studies revealed tegumental damage in adult S. mansoni recovered from mice, especially in female worms. Conclusions The significant reduction in parasite burden by this chlorophyll molecule validates phytol as a promising drug and offers the potential of a new direction for chemotherapy of human schistosomiasis. Phytol is a common food additive and nonmutagenic, with satisfactory safety. Thus, phytol has potential as a safe and cost-effective addition to antischistosomal therapy.

Anticonvulsant effect of phytol in a pilocarpine model in mice

The present study investigated the effects of phytol in pilocarpine-induced seizures. The latency for development of convulsions and mortality rate was recorded in this model using mice. The results revealed that phytol (25, 50 and 75 mg/kg, i.p.) increased latency to first seizure and decreased percentage of these seizures. Moreover, phytol also protected the animals against status epilepticus induced by pilocarpine, and decreased the mortality rate. Mice treated with pilocarpine (n=24) presented 100% of mortality during the first hour of observation. In turn, phytol-pretreated animals within 30 min before the administration of pilocarpine (400 mg/kg) remained alive during the first hour of observation. On the other hand, 6-8h after administration of pilocarpine it was observed that 10 (41.66%), 8 (33.33%) and 4 (16.66%) animals died (respectively). Thus, the pretreatment with phytol was able to block mortality rate during the first hour in acute phase of seizures, and significantly reduced this rate in a dose-dependent manner (p<0.05), suggesting an anticonvulsant effect. In addition, none of the phytol effects was blocked by pre-treatment with flumazenil, an antagonist of benzodiazepine receptors. In conclusion, phytol exhibits anticonvulsant activity by modulating of neurotransmitter systems, but further investigations are in progress to confirm this pharmacological property.

Anxiolytic-like effects of phytol: possible involvement of GABAergic transmission.

Phytol, a branched chain unsaturated alcohol, is particularly interesting because it is an isolated compound from essential oils of different medicinal plants. The aim of this study was to evaluate the anxiolytic-like effects of phytol in animal models to clarify their possible action mechanism. After acute intraperitoneal treatment with phytol at doses of 25, 50 and 75 mg/kg behavioral models of open-field, elevated-plus-maze, rota-rod, light-dark, marble-burying and pentobarbital sleeping time tests were utilized. In open field test, phytol (25, 50 and 75 mg/kg) [p<0.01] increased the number of crossings and rearings. However, the number of groomings [p<0.01] was reduced. Likewise, the number of entries and the time spent in light space were increased [p<0.01] while the number of marble-burying was decreased [p<0.001], in elevated-plus-maze, light-dark and marble-burying tests, respectively. In motor activity test, phytol (75 mg/kg) impaired the rota-rod performance of mice [p<0.01]. In pentobarbital sleeping time test, phytol 75 mg/kg decreased for latency of sleeping and phytol (25, 50 and 75 mg/kg) increased the sleep time when compared to negative control [p<0.05]. All these effects were reversed by pre-treatment with flumazenil (2.5mg/kg, i.p.), similarly to those observed with diazepam (2mg/kg, i.p.; positive control) suggesting that the phytol presents mechanism of action by interaction with the GABAergic system. These findings suggest that acute administration of phytol exerts an anxiolytic-like effect on mice. Furthermore, suppose that phytol interacts with GABAA receptor, probably at the receptor subtypes that mediate benzodiazepines effects, to produce sedative and anxiolytic activities.

Oxidative stress in rat striatum after pilocarpine-induced seizures is diminished by alpha-tocopherol

Alpha-tocopherol has numerous nonenzymatic actions and is a powerful liposoluble antioxidant. The objective of the present study was to evaluate the neuroprotective effects of alpha-tocopherol in rats against oxidative stress caused by pilocarpine-induced seizures. Wistar rats were intraperitoneally treated with 0.9% saline (control group), alpha-tocopherol (200 mg/kg, alpha-tocopherol group), pilocarpine (400 mg/kg, pilocarpine group), or the combination of alpha-tocopherol (200 mg/kg) and pilocarpine (400 mg/kg, i.p.; alpha-tocopherol plus pilocarpine group). After the treatments, all groups were observed for 24 h. The superoxide dismutase (Mn-SOD) and catalase activities, lipid peroxidation and nitrite concentrations were measured using spectrophotometrically methods. To clarify the mechanism of alpha-tocopherol on oxidative stress in pilocarpine model, Western blot analysis of Mn-SOD and catalase in rat striatum were performed. In the pilocarpine group, rats showed a significant increase in lipid peroxidation and nitrite levels. However, there were no alterations on Mn-SOD activity. On the other hand, the catalase activity augmented in pilocarpine group. In the alpha-tocopherol and pilocarpine co-administered rats, antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content and increased the Mn-SOD and catalase activities in rat striatum after seizures. Pilocarpine, alpha-tocopherol plus pilocarpine and alpha-tocopherol groups did not affect of the Mn-SOD and catalase mRNA or protein levels. Our findings strongly support the hypothesis that oxidative stress occurs in striatum during pilocarpine-induced seizures, indicating that brain damage induced by the oxidative process plays a crucial role in seizures pathogenic consequences, which implies that strong protective effect could be achieved using alpha-tocopherol.

Farnesol: antinociceptive effect and histopathological analysis of the striatum and hippocampus of mice

Farnesol, a sesquiterpene alcohol, has been shown to have antioxidant and anti‐inflammatory properties. Recent studies have found that antioxidant compounds may exert a certain protective effect against neurotoxicity. The objective of this study was to evaluate the antinociceptive activity of farnesol (FAR) and its neurotoxic effects on the brains of adult mice. In this study, two mouse models of analgesia were used to evaluate FAR at doses of 50, 100, and 200 mg/kg, injected intraperitoneally (i.p.). In the acetic acid–induced writhing test, a significant decrease was found in the number of contortions in the FAR‐treated mice at doses of 50, 100, and 200 mg/kg. FAR was also found to inhibit the licking response in the injected paw at doses of 100 and 200 mg/kg (i.p.) in the first (0–5 min) and second phases (15–30 min) of the formalin test. To evaluate neurotoxic effects, Swiss mice were treated with 0.9% saline (i.p., control group), 0.05 Tween 80 dissolved in 0.9% saline (i.p., vehicle group), and FAR 50, 100, or 200 mg/kg, i.p. Following treatment, all groups were observed for 72 h. In the FAR 200‐mg group, 16% of the animals suffered brain injury that affected 12% of the area of the hippocampus. No lesions were found in the hippocampal and striatal regions of the brain in any of the animals treated with the 50 and 100 mg/kg doses of FAR. In conclusion, FAR exerts an antinociceptive effect with no significant neurotoxicity in the brains of adult mice.

Superoxide dismutase and catalase activities in rat hippocampus pretreated with garcinielliptone FC from Platonia insignis

Context: Platonia insignis Mart. (Clusiaceae), commonly known as “bacuri,” is a timber and fruit native species of the Brazilian Amazon. Some plants of the Clusiaceae family have their pharmacological properties associated with the presence of xanthone and polycyclic polyprenylated acylphloroglucinols derivatives, which have antioxidant and anticarcinogenic activities. Objective: The aim of this study was to assess the in vivo potential of extracts, fractions, and garcinielliptone FC isolated from of Platonia insignis seeds as a natural antioxidant. Materials and methods: Male Wistar rats (250–280 g; 2 months old) were treated with Tween 80 0.05% dissolved in 0.9% saline (i.p, vehicle – control group), ethanol extract (EE), hexane extract (HE), dichloromethane fraction (DMF), ethyl acetate fraction (EAF), and garcinielliptone FC (GFC) isolated from P. insignis at doses 2 mg/kg (i.p.). All groups were observed for 24 h after the treatment. The antioxidant enzymatic activities [superoxide dismutase (SOD) and catalase (CAT)] were measured using spectrophotometric methods. Results: There were no marked alterations in SOD and CAT activities in rat hippocampus after pretreatment with EE, HE, DMF, EAF, and GFC. However, the pretreatment with GFC induced a significantly increase of 13, 17, 19, and 13% in SOD activities when compared to EE, HE, DMF, or EAF groups, respectively. Discussion and conclusion: Our findings strongly support the hypothesis that GFC isolated from P. insignis has a significant potential to be used as a natural antioxidant agent probably due to the modulation of enzymatic activity of hippocampal SOD.

AVALIAÇÃO DA TOXICIDADE AGUDA E DO EFEITO ANSIOLÍTICO DE UM DERIVADO SINTÉTICO DA CARVONA

Objective: To evaluate the safety of cyano-carvone by means of acute toxicity studies and to investigate its anxiolytic potential. Material and Methods: Swiss male mice were treated with cyano-carvone (v.o) in escalating doses from 25 to 2000 mg/kg and observed for 14 days as regards behavioral changes and mortality rate. After this time period, hematological, biochemical and morphological analyses of the main macroscopic organs were carried out. In addition, other groups of animals were treated with doses of 25, 50 and 75 mg/kg in order to assess locomotor activity, anxiolytic effect and motor coordination. Results: In the Hippocratic test, the compound did not cause any deaths among the mice, thus the LD50 was not determined and clinical signs that emerged were discrete, reversible and observed only in higher doses. Accordingly, hematological and biochemical analyses did not show significant alterations. In the behavioral analysis, it was found a reduction of locomotor activity and a greater number of entries in open arms, as well as a longer time spent with open arms, suggesting an anxiolytic effect. In the Rota-rod test it was observed no change in the permanence time on the spinning rod, as well as no changes were detected for the number of falls. Conclusion: This study demonstrated that cyano-carvone has no acute toxicity, and suggests a possible anxiolytic effect that needs to be further investigated in order to elucidate its mechanism of action. DESCRIPTORS: Anxiety. Monoterpenes. Acute Toxicity. Central Nervous System.