Álefe Brito Monteiro

Antiulcerogenic Activity of the Hydroalcoholic Extract of Leaves of Croton campestris A. St.-Hill in Rodents

Croton campestris A. St.-Hill., popularly known as “velame do campo,” is a species native to the savannah area of Northeast Brazil, which is used by traditional communities in folk medicine for variety of health problems, especially detoxification, inflammation, and gastritis. The hydroalcoholic extract of C. campestris leaves (HELCC) was assessed for its antiulcerogenic effect in gastric lesion models and effect on intestinal motility in mice, and possible mechanisms of action were examined. HELCC showed significant gastroprotective action in all models of gastric ulcer evaluated; the results suggest that this action probably involves the nitric oxide pathway. HELCC did not show alteration of intestinal motility in mice. It was also found that C. campestris represents a promising natural source with important biological potential, justifying some of its uses in folk medicine.

Antiulcerogenic activity of the hydroalcoholic extract of leaves of Annona muricata Linnaeus in mice

Annona muricata Linnaeus, popularly known as “graviola” and also called soursop, is a species typical of countries with a tropical climate, and it is used in folk medicine as an anticancer, analgesic and antispasmodic agent. The aim of the present study was to validate the gastroprotective activity of the hydroalcoholic extract of the leaves of A. muricata (HEAM) and to investigate the underlying mechanisms of action for this effect. Gastric lesions were induced in mice by absolute ethanol, acidified ethanol or indomethacin. Before, the animals were pretreated with saline, omeprazole or HEAM orally at doses of 50–400 mg/kg. To determine the mechanism of action of the extract, we investigated, using specific inhibitors, the involvement of nitric oxide (NO), prostaglandins (PGEs), ATP-dependent K+ channels and α2-noradrenergic receptors. HEAM showed significant antiulcer activity against lesions induced by absolute ethanol, acidified ethanol or indomethacin, which was mediated by endogenous gastric prostaglandins.

Comparative study of alpha- and beta-pinene effect on PTZ-induced convulsions in mice

Convulsions occur in response to a loss of balance between excitatory and inhibitory neurotransmitters, and the treatment for this condition consists in restore such lost balance. Many anticonvulsant drugs present side effects which may limit their use. This fact has stimulated the search for new sources of treatment from aromatic plants. Many monoterpenes commonly present in essential oils are known because of their anticonvulsant properties. The anticonvulsant effect of α‐ and β‐pinene, two structural isomers, is still little studied. Thus, the present work evaluated the anticonvulsant effect of α‐ and β‐pinene in pentylenetetrazole‐induced convulsions model. Initially, the oral LD50 for α‐ and β‐pinene was estimated. Following the oral administration, a mild sedation was observed and no deaths were recorded; the LD50 estimated for both monoterpenes was greater than 2 000 mg/kg, p.o. Further, animals were orally treated with α‐pinene (100, 200 and 400 mg/kg), β‐pinene (100, 200 and 400 mg/kg) and the equimolar mixture of α‐ and β‐pinene (400 mg/kg) and subjected to the pentylenetetrazole‐induced convulsions model. In this model, only the dose of 400 mg/kg of the compounds was able to significantly decrease the seizure intensity. The latency of first convulsion was significantly increased by the mixture of α‐ and β‐pinene (400 mg/kg). In addition, β‐pinene and the mixture of the two monoterpenes, both at a dose of 400 mg/kg, significantly increased the time of death of animals. The treatment with β‐pinene and the equimolar mixture of the two monoterpenes significantly reduced hippocampal nitrite level and striatal content of dopamine (DA) and norepinephrine (NE). Taken together, the results suggest that α‐pinene appears to be devoid of anticonvulsant action. This fact, however, seems to be dependent on the chemical structure of the compound, since pretreatment with the β‐pinene increased the time of death pf PTZ‐treated mice, which seems to depend on the ability of the compound to reduce nitrite concentration and NE and DA content, during the pentylenetetrazole‐induced seizure.