Antimicrobial, modulatory and chemical analysis of the oil of Croton limae.

CONTEXT: Croton sp. are plants with a well-reported antimicrobial activity. Croton limae A.P. Gomes, M.F. Sales P.E. Berry (Euphorbiaceae), known as 'marmeleiro-prateado', is commonly used to manage abdominal pain in Brazil. OBJECTIVE: This work evaluates the phytochemical composition, antimicrobial and modulatory activities of the essential oil of C. limae leaves (EOCL). MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and the modulation of the antibiotic activity were determined using a microdilution method. The concentration of EOCL ranged between 512 and 8 µg/mL. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Candida tropicalis, C. krusei and C. albicans strains were used in the MIC and modulation assays. The antibiotics, amikacin, gentamicin and neomycin, and the antifungals, amphotericin B, benzoylmetronidazole and nystatin, were used in concentrations ranging between 2500 and 2.5 µg/mL. The phytochemical analysis of the EOCL was performed through gas chromatography coupled to a mass spectrometer (GC/MS). RESULTS: Only Staphylococcus aureus was inhibited by a clinically relevant concentration of EOCL (MIC 512 µg/mL). Synergism between the EOCL and amikacin against S. aureus (9.76 µg/mL) and E. coli (39.062 µg/mL); neomycin against E. coli (2.44 µg/mL); and benzoylmetronidazole against C. krusei (256 µg/mL) were observed. The GC/MS analysis identified cedrol, eucalyptol and α-pinene as the main compounds of EOCL. CONCLUSION: EOCL inhibited the growth of S. aureus and potentiated the antibiotic and antifungal effects of drugs against all bacterial and Candida strains, respectively.

Promising medicinal plants for bioprospection in a Cerrado area of Chapada do Araripe, Northeastern Brazil.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional medical systems represent an important source of knowledge about the use of biodiversity. Ethnobotanical and ethnopharmacological studies can encourage bioprospecting in the pursuit and selection of promising medicinal plants. This study investigated the diversity of medicinal plants in a disjunct area of cerrado in Chapada do Araripe, Ceará, Brazil, and assessed the species of interest for bioprospecting. MATERIALS AND METHODS: Structured and semi-structured interviews were conducted through free listing, and the informants were recruited using the "snowball" technique. The relative importance and informant consensus factor were analyzed for the selection of plant species with therapeutic potential. RESULTS: A total of 68 species were recorded and cited for 91 therapeutic purposes. Of these, 10 species showed great versatility of use, including Copaifera langsdorffii Desf., Caryocar coriaceum Wittn., Himatanthus drasticus (Mart.) Plumel, Stryphnodendron rotundifolium Mart., and Dimorphandra garderiana Tull. The therapeutic citations were grouped into 16 categories of body systems, of which Injuries, Poisonings and Other Consequences of External Causes, and Neoplasias showed the highest agreement of use. CONCLUSIONS: Regarding the diversity of the species, some including Tocoyena Formosa (Cham. & Schlecht.) Schum., Himatanthus drasticus, Caryocar coriaceum, Roupala montana Aubl. and Stryphnodendron rotundifolium showed both high relative importance and strong consensus among informants, and although many have already been investigated scientifically, others are almost unknown with respect to their medicinal properties and can be targets for bioprospecting.