Recently, our research group identified and reported 1,8-cineole (CIN), a monoterpene that naturally occur in many aromatic plants, as one of the major constituent of the essential oil from leaves of Hyptis martiusii (EOHM), as well as characterized the gastroprotective action of this oil. The aim of this study was to investigate the mechanisms of action involved in the antiulcer and healing activity of CIN, in order to confirm its correlation with the gastroprotective effect of EOHM. Wistar rats were exposed to different protocols (acute ulceration, gastrointestinal motility and antisecretory activity). In addition, were determinated the involvement of nitric oxide and sulphydryl groups; the levels of gastric mucus, lipid peroxidation, sulphydryl groups and myeloperoxidase activity. The healing ability was evaluated by acetic acid-induced chronic ulcer and histological and immunohistochemical analysis (PCNA, Ki-67 and BrdU). The treatment with CIN inhibited ethanol-, ethanol/HCl- and indomethacin-induced gastric lesions. The highest doses of CIN inhibited gastric emptying, but did not affect intestinal transit. CIN (100 mg/kg) reduced the volume of basal but not stimulated acid secretion. CIN increased levels of mucus (89.3%), prevented depletion of –SH groups (62.6%) and reduced the level of lipid peroxidation (55.3%) and myeloperoxidase activity (59.4%) in the gastric mucosa. In chronic ulcer model, CIN reduced in 43.1% the gastric area lesion, promoted significant regeneration and restoration of the levels of mucus in glandular cells as confirmed by histological analysis; and promoted increase in cell proliferation as evidenced by reactivity for PCNA, Ki-67 and BrdU. This findings demonstrate the role of 1,8-cineole as an important ulcer healing agent and indicate the involvement of antioxidant and cytoprotective mechanisms in the gastroprotective effect of compound. This study also provides evidence that 1,8-cineole is related to the gastroprotective effect of the essential oil of Hyptis martiusii.

The results indicate that the essential oil of leaves of Hyptis martiusii has an antiulcerogenic activity, as evidenced by its significant inhibition of the formation of ulcers in various models. This effect could be related to an increase of gastric mucosal defensive factors. Further pharmacological studies are being undertaken in order to provide more precise elucidation of the action mechanism involved in this activity.

Spondias mombin L. is used in folk medicine for the treatment of inflammation and gastrointestinal diseases. Our study investigated the antiulcer activity of S. mombin ethanolic extract (SmEE) and its majority compounds gallic acid (GA) and ellagic acid (EA). Phytochemical characterization was performed by HPLC. The SmEE was screened for in vitro antioxidant activities using phosphomolybdenum, ABTS, DPPH, and FRAP assays. The antiulcer activity of SmEE, GA, EA, or GA + EA was evaluated by gastric lesion models induced by absolute ethanol and indomethacin. Following this, it is capable of stimulating mucus production, antisecretory capacity, and the influence of −SH groups and NO in the effect of SmEE. Its healing activity was demonstrated by acetic acid-induced chronic ulcer model. Anti-Helicobacter pylori activity was assessed by determining the MIC of the SmEE (64–1024 μg/mL). The HPLC results identified the presence of gallic acid and ellagic acid in SmEE. The extract showed antioxidant activity in vitro. SmEE (50, 100, and 200 mg/kg) reduced the area of ulcerative lesions induced by ethanol in 23.8, 90.3, and 90.2%, respectively. In NSAID model, the SmEE induced protection of 36.8, 49.4, and 49.9%, respectively. GA (10 mg/kg) or EA (7 mg/kg) or the association of GA + EA (10 + 7 mg/kg) inhibited the ethanol-induced lesions in 71.8, 70.9, and 94.9%, respectively, indicating synergistic action. SmEE (100 mg/kg) decreased acid secretion and H+ concentration in the gastric contents, increased levels of mucus, and showed to be dependent of −SH groups and NO on the protection of the gastric mucosa. In chronic ulcer model, SmEE reduced the gastric area lesion. SmEE showed anti-H. pylori activity. In conclusion, our study showed that SmEE has antiulcerogenic activity. GA and EA are isolated gastric protectors and, when associated, acted synergistically to protect the gastric mucosa.

RESUMO:Tendo em vista que bactérias resistentes a antimicrobianos representam um desafi o no tratamento de infecções, é notória a necessidade de encontrar novas substâncias com propriedades antimicrobianas para serem utilizadas no combate a esses microrganismos. Este trabalho relata a avaliação da atividade antibacteriana, toxicidade e identifi cação dos componentes químicos do óleo essencial de Croton zehntneri (variedade estragol), planta utilizada na medicina popular como calmante e estimulante do apetite. A atividade antimicrobiana e a concentração inibitória mínima (CIM) foram determinadas pelo método de difusão em discos. A avaliação da toxicidade foi realizada frente à Artemia salina com resultado considerado ativo (CL 50 < 100 μg/mL). O óleo essencial das folhas apresentou atividade antibacteriana frente a todas as bactérias testadas exceto contra Salmonella typhimurium, sendo o melhor resultado frente a Shigella fl exneri com CIM de 50 μg/mL. A análise da composição química foi obtida por cromatografi a gasosa acoplada a espectrometria de massa (CG/EM) e permitiu identifi car um total de 97,4% dos componentes, com presença majoritária de estragol (76,8%). A presença de tal constituinte nos impulsiona a realização de estudos com outras bactérias, já que o estragol foi anteriormente relatado como sendo responsável por atividades antibacterianas. Unitermos:Croton zehntneri, Euphorbiaceae, estragol, óleo essencial, atividade antibacteriana, toxicidade, CIM.ABSTRACT: "Chemical composition and evaluation of the antibacterial activity and toxicity of the essential oil of Croton zehntneri (variety estragol)". Observing that bacteria resistant to antimicrobials represent a challenge in the treatment of infections, it is notorious the need of fi nding new substances with antimicrobial features to be used in the fi ght against these microorganisms. This work relates the evaluation of the antibacterial activity, toxicity and identifi cation of the chemical components of the essential oil of Croton zehntneri (variety estragol), plant used in the popular medicine as tranquilizer and appetite stimulant. The antimicrobial activity and minimum inhibitory concentration (MIC) were determined by the method of diffusion in discs. The evaluation of the toxicity was held through brine shrimp test with results considered active (LC 50 < 100 μg/mL). The essential oil of leaves presented antibacterial activity with all the bacteria tested except with Salmonlla typhimurium, being the best result with the Shigella fl exneri with MIC of 50 μg/mL. The analysis of the chemical composition was obtained by gas chromatography coupled to mass spectrometry (GC/MS) and permitted to identify a total of 97.4 % of the components, with major presence of estragol (76.8%). The presence of the latter drives us to studies with other bacteria, as the estragol was previously reported as being responsible for antibacterial activities.

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