Validation of a method of broth microdilution for the determination of antibacterial activity of essential oils.

OBJECTIVE: The aim of the present study was to adapt and optimize a broth microdilution method and compare it to the agar dilution method for the evaluation of activity of essential oils from medicinal plants against Gram-negative bacteria. Based on bibliographic research, active and not active oils were selected. The sensitivity and specificity were established as parameters for validation. The comparison between both methods was made using contingency analysis tables, based on the observed frequencies. For both methods, the minimum inhibitory concentration was determined against Escherichia coli strains, in an essential oil concentration range between 0.03 and 0.48% (v/v). RESULTS: A stable emulsion formation was achieved with the addition of Tween 80 and constant agitation, guaranteeing the continuous contact of oil with bacteria (critical step in the microdilution method). The statistical analysis of results obtained with both methods presented a good sensitivity and specificity (100% in both cases), which let us correctly discriminate between active and non-active oils. The values obtained for the minimal inhibitory concentration were independent of the technique used. Finally, the obtained results show that the validated microtechnique allows important diminishment of time and resources for investigations dealing with essential oils or lipophilic extracts evaluation.

Anti-inflammatory and sedative activities of Peperomia galioides: in vivo studies in mice.

Aerial parts (leaves, flowers, stem) of Peperomia galioides extract administered to mice, was used to confirm its anti-inflammatory and sedative folk uses. The anti-inflammatory activity was assessed by croton oil-induced ear oedema and myeloperoxidase (acute inflammation); cotton pellet-induced granuloma (sub-acute inflammation) and Escherichia coli Lipopolysaccharide (LPS) induced inflammation (cellular mediators). The sedative activity was studied by the pentobarbital-induced sleeping time test. Single doses (300 and 600 mg/kg; i.p.) of the extract reduced croton oil-induced ear oedema and myeloperoxidase activity. Six days administration of the extract (300 mg/kg, i.p.) to mice implanted with cotton pellets diminished granuloma formation. LPS (20 mg/kg, i.p.) enhanced plasma nitrites and TNF-α levels that were inhibited by the extract. The duration but not the onset of sleeping time was enhanced by 300 and 600 mg/kg of the extract. Our results show that P. galioides has anti-inflammatory and sedative activities in mice, which validates its traditional use.

Evaluation of anti-inflammatory activity of the methanolic extract from Jungia rugosa leaves in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Jungia rugosa Less (Asteraceae), popularly known in Ecuador as "Carne humana" or "Fompo", is a vine present into the Andean region. It is traditionally used as medicine for the treatment of bruises, cuts and other external inflammatory processes. This study was designed to investigate the anti-inflammatory activity of J. rugosa leaves extract (JRLE) in rodents. MATERIAL AND METHODS: The acute anti-inflammatory activity was evaluated by animal models, including croton oil-induced ear oedema in mice, carrageenan-induced paw oedema in rats and myeloperoxidase (MPO); the chronic anti-inflammatory activity was evaluated by cotton pellet-induced granuloma. RESULTS: Intraperitoneal administration of JRLE (125, 250, 500mg/kg) significantly (p<0.01-0.001) inhibited the croton oil-induced ear oedema and MPO activity in mice; the carrageenan-induced paw oedema in rats was significantly (p<0.05) reduced by 500mg/kg. Repeated (6 days) administration of the extract to mice previously implanted with cotton pellets reduced the formed granuloma (125mg/kg: 11.7%; 250mg/kg: 17.9%; 500mg/kg: 32.4%) but only the inhibition by 500mg/kg reached statistical significance (p<0.01). CONCLUSIONS: The results show that JRLE is effective as an anti-inflammatory agent in acute and chronic inflammation in mice, supporting its traditional use.