Sandro R. Giacomelli

Fluconazole and amphotericin-B resistance are associated with increased catalase and superoxide dismutase activity in Candida albicans and Candida dubliniensis

INTRODUCTION Candida dubliniensis, a new species of Candida that has been recovered from several sites in healthy people, has been associated with recurrent episodes of oral candidiasis in AIDS and HIV-positive patients. This species is closely related to C. albicans. The enzymatic activity of C. dubliniensis in response to oxidative stress is of interest for the development of drugs to combat C. dubliniensis. METHODS Fluconazole- and amphotericin B-resistant strains were generated as described by Fekete-Forgács et al. (2000). Superoxide dismutase (SOD) and catalase assays were performed as described by McCord and Fridovich (1969) and Aebi (1984), respectively. RESULTS We demonstrated that superoxide dismutase (SOD) and catalase activities were significantly higher (p<0.05) in the fluconazole- and amphotericin B-resistant strains of C. dubliniensis and C. albicans than in the sensitive strains. The catalase and SOD activities were also significantly (p<0.01) higher in the sensitive and resistant C. albicans strains than in the respective C. dubliniensis strains. CONCLUSIONS These data suggest that C. albicans is better protected from oxidative stress than C. dubliniensis and that fluconazole, like amphotericin B, can induce oxidative stress in Candida; oxidative stress induces an adaptive response that results in a coordinated increase in catalase and SOD activities.

CHIRAL ANALYSIS OF MONOTERPENES IN VOLATILE OILS FROM PROPOLIS

The essential oils obtained by hydrodistillation from samples of propolis manufactured in three regions of Rio Grande do Sul State at Brazil, were analyzed through CG, CG-MS and chiral phase gas chromatography (CPGC). These analyses display the presence of samples with elevated essential oil purport, when compared with plants. The yields obtained were until 3.8%. The samples exhibited similar composition, with predominance of the monoterpenes a-pinene (5763%), b-pinene (12.5-30.8%) and limonene (1.5-11.2%). In chiral analysis of these constituents were observed modifications in the enantiomeric excess of isomers of a-pinene and limonene in relation with source location of the sample, already in the chiral analysis of b-pinene were detected only elevated excess of the enantiomer with the (-) configuration. The antimicrobial activity of the crude essential oil was assayed against five bacteria. The best result was obtained against Staphylococcus aureus.

Influence of Harvest Season and Cultivar on the Variation of Phenolic Compounds Composition and Antioxidant Properties in Vaccinium ashei Leaves

The effect of variation of harvest season and cultivar on the total phenolic content (TPC), total flavonoid content (TFC), HPLC-UV/DAD profile and antioxidant properties in Vaccinium ashei (Rabbiteye blueberry) leaves grown in Brazil was evaluated. The cultivars collected in December and March were Aliceblue, Powderblue, Climax, Bluegem and FloridaM. It was observed that leaves from March had the highest TPC values (222 ± 1 mg gallic acid equivalents/g to Aliceblue cultivar) and highest TFC values (49.8 ± 0.8 and 48.7 ± 0.7 µg rutin/g to Clímax and Powderblue cultivars, respectively). The chromatographic profile was quantitatively similar, however, the proportions of each compound were influenced by cultivar and harvest season. Chlorogenic acid and rutin were the main identified phenolic compounds, but chlorogenic acid was the most abundant in both harvest seasons. Antioxidant capacities values ranged from 5.80 ± 0.04 to 105 ± 2 µg/mL (DPPH) and 178 ± 5 to 431 ± 8 mmol Trolox/100 g (ORAC). The cultivar Bluegem by March had the highest values in both assays. The results indicate that the blueberry leaves from different cultivars and harvest seasons have different phenolic compounds content and different antioxidant capacities. In addition, the antioxidant properties demonstrated a high correlation with rutin content.