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OBJECTIVES: Copaiba oil oleoresin exuded from Copaifera reticulata Ducke (CRD) is commonly used in anti-inflammatory, healing and anti-tumoral folk medicines. The purpose of this study was to investigate the putative anxiolytic effect of acute administration of CRD. METHODS: CRD was administered (100, 400 and 800 mg/kg, p.o.) to male Wistar rats submitted to the elevated plus-maze model of anxiety using an ethopharmacological analysis. KEY FINDINGS: In comparison with control rats, CRD increased the percentage of entries in the open arms over the entire dose range tested (vehicle, 33.6 +/- 4.5; CRD 100 mg/kg, 44.67 +/- 3.68; CRD 400 mg/kg, 47.2 +/- 2.3; CRD 800 mg/kg, 50.7 +/- 2.2) and the percentage of time spent in the open arms of the elevated plus-maze at the highest dose (800 mg/kg) (vehicle, 26.4 +/- 5.7; CRD 800 mg/kg, 52.0 +/- 2.7). A standard anxiolytic, diazepam (3 mg/kg, p.o.), was used as a positive control. In a similar way, diazepam increased the percentage of entries and time spent in the open arms when compared with vehicle (% open entries: vehicle, 45.4 +/- 1.3; diazepam, 50.7 +/- 1.9; % time spent in open arms: vehicle, 28.2 +/- 0.9; diazepam, 38.9 +/- 1.2). Regarding ethological measures, CRD at the highest dose (800 mg/kg) reduced peeping out (anxiety-related behaviour) (vehicle, 3.1 +/- 0.6; CRD, 0.9 +/- 0.2) and increased end-arm activity (vehicle, 0.2 +/- 0.2; CRD, 2.0 +/- 0.4), indicating an enhanced tendency of the rats to explore actively the potentially dangerous areas of the maze. Diazepam decreased peeping out (vehicle, 3.3 +/- 0.3; diazepam, 1.0 +/- 0.2) and flat-back approach (vehicle, 0.8 +/- 0.2; diazepam, 0.2 +/- 0.1) and increased end-arm activity (vehicle, 0.3 +/- 0.1; diazepam, 2.5 +/- 0.3) and head-dipping (vehicle, 8.2 +/- 0.4; diazepam, 12.0 +/- 0.5). CONCLUSIONS: These data showed, for the first time, that acute treatment with CRD copaiba oil produced a dose-dependent anxiolytic-like effect over the dose range tested, on conventional and ethological parameters, without adversely affecting general activity levels.

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The antimicrobial activity of copaiba oils was tested against Gram-positive and Gram-negative bacteria, yeast, and dermatophytes. Oils obtained from Copaifera martii, Copaifera officinalis, and Copaifera reticulata (collected in the state of Acre) were active against Gram-positive species (Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Bacillus subtilis, and Enterococcus faecalis) with minimum inhibitory concentrations ranging from 31.3-62.5 microg/ml. The oils showed bactericidal activity, decreasing the viability of these Gram-positive bacteria within 3 h. Moderate activity was observed against dermatophyte fungi (Trichophyton rubrum and Microsporum canis). The oils showed no activity against Gram-negative bacteria and yeast. Scannning electron microscopy of S. aureus treated with resin oil from C. martii revealed lysis of the bacteria, causing cellular agglomerates. Transmission electron microscopy revealed disruption and damage to the cell wall, resulting in the release of cytoplasmic compounds, alterations in morphology, and a decrease in cell volume, indicating that copaiba oil may affect the cell wall.

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The antimicrobial activity of copaiba oils was tested against Gram-positive and Gram-negative bacteria, yeast, and dermatophytes. Oils obtained from Copaifera martii, Copaifera officinalis, and Copaifera reticulata (collected in the state of Acre) were active against Gram-positive species (Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Bacillus subtilis, and Enterococcus faecalis) with minimum inhibitory concentrations ranging from 31.3-62.5 µg/ml. The oils showed bactericidal activity, decreasing the viability of these Gram-positive bacteria within 3 h. Moderate activity was observed against dermatophyte fungi (Trichophyton rubrum and Microsporum canis). The oils showed no activity against Gram-negative bacteria and yeast. Scannning electron microscopy of S. aureus treated with resin oil from C. martii revealed lysis of the bacteria, causing cellular agglomerates. Transmission electron microscopy revealed disruption and damage to the cell wall, resulting in the release of cytoplasmic compounds, alterations in morphology, and a decrease in cell volume, indicating that copaiba oil may affect the cell wall.

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The oleo-resin from Copaifera langsdorffii (Leguminosae) was evaluated in rats on acetic acid-induced colitis. Rats were pretreated orally (15 and 2 h) or rectally (2 h) before the induction of colitis with copaiba oleo-resin (200 and 400 mg/kg) or vehicle (1 ml, 2% Tween 80). Colitis was induced by intracolonic instillation of a 2 ml of 4% (v/v) acetic acid solution and 24 h later, the colonic mucosal damage was analyzed for the severity of macroscopic colonic damage, myeloperoxidase (MPO) activity, and malondialdehyde levels. A significant reduction in gross damage score and in wet weight/length ratio of colonic tissue were evident in test substance-pretreated animals as compared to vehicle or oleo-resin alone-treated controls. This effect was confirmed biochemically by a reduction in colonic myeloperoxidase activity, the marker of neutrophilic infiltration, and by a marked decrease in malondialdehyde level, an indicator of lipoperoxidation. Furthermore, microscopical examination revealed the diminution of inflammatory cell infiltration, and submucosal edema in the colon segments of rats treated with copaiba oleo-resin. The data indicate the protective effect of copaiba oleo-resin in the animal model of acute colitis possibly through an antioxidant and or anti-lipoperoxidative mechanism.

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