Chemical composition and microbicidal activity of extracts from Brazilian and Bulgarian propolis.

AIMS: The chemical composition of ethanol extracts from a Brazilian (Et-Bra) and a Bulgarian (Et-Blg) propolis, and their activity against the protozoan Trypanosoma cruzi, several fungi and bacteria species were determined. METHODS AND RESULTS: The chemical composition was determined by high temperature high resolution gas chromatography coupled to mass spectrometry. Microbiological activity was assayed in vitro against T. cruzi, Candida albicans, Sporothrix schenckii, Paracoccidioides brasiliensis, Neisseria meningitidis, Streptococcus pneumoniae and Staphylococcus aureus. CONCLUSIONS: Et-Bra and Et-Blg, although with totally distinct compositions, were active against T. cruzi and the three species of fungi. Et-Blg was more effective than Et-Bra against bacteria, particularly N. meningitidis and Strep. pneumoniae. SIGNIFICANCE AND IMPACT OF THE STUDY: Although with different classes of components, both propolis extracts showed microbicidal activity. For the bactericidal activity it was possible to establish a positive correlation with the high content of flavonoids of the Bulgarian extract.

Inoculation experimental animals with Paracoccidioides brasiliensis strains: an attempt to reestablish the dimorphic process and variation in pathogenicity as a function of time of preservation under mineral oil.

In an attempt to reestablish the dimorphic process in strains of Paracoccidioides brasiliensis in the transition phase (Y reversible M) and to reisolate them, five strains in the transitional phase due to the long time of preservation under mineral oil and two strains in the yeast-like phase were inoculated into male albino rats. The animals were then studied for the presence of paracoccidioidomycotic granulomata. Of the seven strains inoculated, five caused granulomatous nodules in several organs of the animals and only two of these five strains, which had been preserved for the shortest period of time (9 years) were reisolated in culture. Two strains were unable to provoke infection, with no lesions detected in any organ. It is assumed that the long period of time during which the strains were left under oil favored the alteration of celt wall contents, leading to differences in pathogenicity.

Viability and morphological alterations of Paracoccidioides brasiliensis strains preserved under mineral oil for long periods of time.

We evaluated the survival and the morphological alteration of 70 strains of Paracoccidioides brasiliensis maintained in the Fungal Culture Collection of Institute Oswaldo Cruz and initially preserved by successive subculturing and later under mineral oil at room temperature from 1923 to 1992. Of the 70 strains preserved under mineral oil, 18 (26%) continued to be viable. The mycelia of the 18 viable strains and the mycelia of four representatives of the non-viable strains presented transitional micromorphology under mineral oil. Macroscopy and microscopy of the first subcultures of five of the seven strains, taken as random samples from the 18 viable strains and plated onto peptone-yeast extract-glucose agar, glucose-glycine-yeast extract agar and brain-heart infusion agar media at room temperature, revealed that all samples appeared to be in a transition phase (Y<-->M). These five strains were unable to grow and complete thermal dimorphism at a temperature of 37 degrees C. Only two strains were able to complete the entire dimorphic process. The period of preservation of these strains under oil was relatively short, i.e. 9 and 10 years. The results demonstrate that less widely spaced subculturing and more appropriate culture and environmental conditions are needed to preserve P. brasiliensis strains under oil.