Fábio de Oliveira Silva

Variation of Ursolic Acid Content in Eight Ocimum Species from Northeastern Brazil

Ursolic acid is a very important compound due to its biological potential as an anti-inflammatory, trypanocidal, antirheumatic, antiviral, antioxidant and antitumoral agent. This study presents the HPLC analysis of ursolic acid (UA) content in eight different Ocimum species: O. americanum L., O. basilicum L, O. basilicum var purpurascens Benth, O. basilicum var. minimum L, O. gratissimum L, O. micranthum Willd, O. selloi Benth. and O. tenuiflorum L. grown in Northeastern Brazil. In these Ocimum species, UA was detected in different yields, with O. tenuiflorum showing the highest content (2.02%). This yield is very significant when compared with other sources of UA.

Evaluation of central nervous system effects of iso-6-cassine isolated from Senna spectabilis var. excelsa (Schrad) in mice

The depressant and anticonvulsant activities of iso-6-cassine (ISO) from Senna spectabilis (0.5, 1.0 and 1.5mg/kg) injected by oral route in mice caused a significant decrease in the motor activity of animals when compared with the control group, up to 30 days after the administration and at dose of 1.5mg/kg, it reduced the remaining time of animals on Rota-rod apparatus. Additionally, ISO at doses tested was also capable to promote an increase of latency for development of convulsions induced by pentylenetetrazole and picrotoxin. These results suggest possible depressant and anticonvulsant activities in mice that need further investigation.

Essential Oil Composition of the Leaves of Ocimum micranthum Willd.

Abstract Variation on chemical composition of essential oils produced from Ocimum micranthum Willd. obtained from plants growing in northeast Brazil, at different stages of development and throughout the day. The oils, which were obtained by microwave oven distillation, were analyzed by GC/MS. A discreet variation in the eugenol contents from 97% at 6:00 a.m. to 84% at 6:00 p.m. was observed. The highest value was found in oil obtained from a specimen with a fully developed inflorescence. The eugenol production in O. micranthum does not appear to be influenced by solar light throughout the day.

Synthesis and In Vitro Anti Leishmania amazonensis Biological Screening of Morita-Baylis-Hillman Adducts Prepared from Eugenol, Thymol and Carvacrol

Leishmaniasis represents a series of severe neglected tropical diseases caused by protozoa of the genus Leishmania and is widely distributed around the world. Here, we present the syntheses of Morita-Baylis-Hillman adducts (MBHAs) prepared from eugenol, thymol and carvacrol, and their bioevaluation against promastigotes of Leishmania amazonensis. The new MBHAs are prepared in two steps from essential oils in moderate to good yields and present IC50 values in the range of 22.30–4.71 μM. Moreover, the selectivity index to the most potent compound is very high (SIrb > 84.92), far better than that of Glucantime® (SIrb 1.39) and amphotericin B (SIrb = 22.34). Conformational analysis were carried out at the M062X//6-31+G(d,p) level of theory to corroborate a hypothesis about the nitroaromatic bioreduction mechanism.

Lipoic acid alters amino acid neurotransmitters content in rat hippocampus after pilocarpine‐induced seizures

This study was aimed at investigating the anticonvulsant activity of lipoic acid (LA) against pilocarpine‐induced seizures as well as the effects of this metabolic antioxidant on the hippocampal extracellular concentrations of amino acid neurotransmitters glutamate, aspartate, glycine and glutamate and γ‐aminobutyric acid (GABA). In vivo microdialysis demonstrated that an intraperitoneal administration of pilocarpine induced a pronounced increment of hippocampal glutamate and aspartate concentrations, whereas no significant change was observed in the levels of glycine or GABA. LA (10, 20 or 30 mg/kg) pretreatment completely blocked pilocarpine‐evoked increases in extracellular glutamate and aspartate concentrations. Significant reductions in hippocampal GABA and glycine concentrations were also observed although not as pronounced as those shown by glutamate and aspartate. Based on the finding that LA protected rats against pilocarpine‐induced seizures, it could be suggested that the reduction in inhibitory amino acid neurotransmitters levels was comparatively minor and offset by a more pronounced reduction in glutamate and aspartate extracellular concentrations. Therefore, the fact that LA could drastically reduce pilocarpine‐induced increases in glutamate and aspartate should account, at least partly, for its anticonvulsant activity observed in pilocarpine‐induced seizure in rats.

Constituintes químicos das folhas de Senna spectabilis (DC) Irwin & Barneby var. excelsa (Schrad.) Irwin & Barneby

From leaves of Senna spectabilis var. excelsa were isolated caffeine, the triterpenes lupeol, α-amyrin, β-amyrin, cycloeucalenol, friedelin and ursolic, oleanolic and betulinic acids, besides the steroids sitosterol and stigmasterol and their respective glucosides. The structures of these compounds were established by spectroscopic analysis including two-dimensional NMR methods and comparison with published spectral data. This paper deals with the first report of these compounds in S. spectabilis var. excelsa.

Antioxidant mechanisms of iso-6-cassine in suppressing seizures induced by pilocarpine

The aim of this study was to evaluate the in vitro antioxidant effects of 12-[(2R,5R,6R)-5-hydroxy-6-methylpiperidin-2-yl]dodecan-2-one (iso-6-cassine; ISO) and the anticonvulsant effects of ISO on pilocarpine-induced seizures in rats. Wistar rats were treated with 0.9% saline (i.p., control group), pilocarpine (400 mg/kg, i.p., pilocarpine group), and the association of ISO (1.0 mg/kg, i.p.) plus pilocarpine (400 mg/kg, i.p.), 30 min after administration of ISO (ISO plus pilocarpine group). After the treatments all groups were observed for 1h. The antioxidant effect of ISO on the pilocarpine model was assessed by determining the activity of glutathione peroxidase (GPx), glutathione-S-transferase (GST) and catalase (CAT) as well as the levels of reactive species (RS) and lipid peroxidation (LP). In vitro, ISO (5 μM) reduced RS and LP. ISO (1.0 mg/kg) and abolished seizures and death induced by pilocarpine in rats. ISO protected against the increase in the RS and LP levels, GST activity as well as the inhibition of GPx activity caused by pilocarpine. In addition, ISO increased the catalase activity in hippocampus of seized rats. In conclusion, the dta suggest that ISO can present anticonvulsant and antioxidant properties in the pilocarpine model of seizures in rats.

Synthesis and Anticancer Activities of Novel Guanylhydrazone and Aminoguanidine Tetrahydropyran Derivatives

In this paper we present the convenient syntheses of six new guanylhydrazone and aminoguanidine tetrahydropyran derivatives 2–7. The guanylhydrazone 2, 3 and 4 were prepared in 100% yield, starting from corresponding aromatic ketones 8a–c and aminoguanidine hydrochloride accessed by microwave irradiation. The aminoguanidine 5, 6 and 7 were prepared by reduction of guanylhydrazone 2–4 with sodium cyanoborohydride (94% yield of 5, and 100% yield of 6 and 7). The aromatic ketones 8a–c were prepared from the Barbier reaction followed by the Prins cyclization reaction (two steps, 63%–65% and 95%–98%). Cytotoxicity studies have demonstrated the effects of compounds 2–7 in various cancer and normal cell lines. That way, we showed that these compounds decreased cell viabilities in a micromolar range, and from all the compounds tested we can state that, at least, compound 3 can be considered a promising molecule for target-directed drug design.