Chemical identification and evaluation of the antimicrobial activity of fixed oil extracted from Rhinella jimi.

CONTEXT: The toad Rhinella jimi (Stevaux, 2002) (Bufonidae) is used in traditional medicine to treat a number of illnesses (inflammation, infections, and wounds) in humans as well as animals. OBJECTIVES: The present work examined the antimicrobial actions of the extracted oils from the body fat of R. jimi (ORJ) against fungi and standard and multi-resistant lines of bacteria, as well as their effects when combined with aminoglycosides. MATERIALS AND METHODS: The toads were collected in the municipality of Exu in Pernambuco State, Brazil, and their body fat oils extracted in a Soxhlet apparatus using hexane. A gas chromatograph coupled to a mass spectrometer was used to identify the fatty acids, based on their methyl esters. The antimicrobial activities of the oil were analyzed against standard and multi-resistant lines of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, as well as against fungal lines of Candida albicans and Candida krusei using the broth micro-dilution method. RESULTS: The minimum inhibitory concentrations (MIC) of ORJ were 512 µg/mL for Candida krusei and ≥1024 µg/mL for the other microorganisms. When associated with amikacin, ORJ demonstrated an increase in its ability to inhibit E. coli growth (from 156.25 to 39.06 µg/mL), indicating synergistic interaction. In the same way, when allied with amikacin, gentamicin, and neomycin, the ORJ reduced the MICs meaningly, against P. aeruginosa. CONCLUSIONS: These data will enable searches to be made to obtain new products in combination with antibiotics, enhancing the efficacy of these drugs against drug-resistant microorganisms.

Evaluations of the Antimicrobial Activities and Chemical Compositions of Body Fat from the Amphibians Leptodactylus macrosternum Miranda-Ribeiro (1926) and Leptodactylus vastus Adolf Lutz (1930) in Northeastern Brazil.

Leptodactylus macrosternum and L. vastus (family: Leptodactylidae) are commonly encountered in the "Caatinga" biome in northern Brazil. The body fat of L. vastus is used as a zootherapeutic for treating a number of human maladies. The aim of this work was to determine the chemical composition of the body fats of L. macrosternum and L. vastus and to evaluate their antimicrobial activities as well as the ecological implications of their use in traditional folk medicine. Oils were extracted from body fat located in the ventral region of L. macrosternum (OLM) and L. vastus (OLV) using hexane as a solvent. The fatty acids were identified by GC-MS. The antimicrobial activities of the oils, either alone or in combination with antibiotics and antifungal drugs, were tested on standard strains of microorganisms as well as on multiresistant strains of Escherichia coli and Staphylococcus. OLM contained 40% saturated and 60% unsaturated fatty acids, while OLV contained 58.33% saturated and 41.67% unsaturated fatty acids. Our results indicated that both OLM and OLV demonstrated relevant antimicrobial activities (with MIC 256 µ g/mL for both) against Pseudomonas aeruginosa and Candida krusei. However, no antimicrobial effects were observed when these oils were combined with antibiotics or antifungal drugs.