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. .

Toxicological and pharmacological evaluation of Discaria americana Gillies & Hook (Rhamnaceae) in mice

Medicinal plants (e.g. Discaria americana) have been used by populations for centuries. However, popular use is not enough to validate these plants as safe and effective medicinal products. The present study sought to evaluate the acute and subacute toxicity as well as the anxiolytic and antinociceptive effects of D. americana root bark and aerial parts extracts in mice. In acute toxicity studies, mice were treated with single intraperitoneal doses of the aforementioned extracts. Subacute toxicity studies were performed by oral administration of the extracts over 14 days. Anxiolytic studies consisted of the elevated plus maze method, and antinociceptive studies were based on the hot plate test. The LD50 value for D. americana aerial parts extract was established at >500 mg/kg, and for the root bark extract, 400 mg/kg. D. americana aerial parts extract produced anxiolytic (250 mg/kg) and antinociceptive effects (125, 200 and 250 mg/kg). Conversely, D. americana root bark extract showed neither anxiolytic nor antinociceptive effects in mice.

As plantas medicinais (i. e. Discaria americana) têm sido utilizadas pela população por séculos, entretanto, o conhecimento popular não é suficiente para validá-las como medicamentos seguros e/ou efetivos. Assim, o presente estudo teve por objetivo avaliar a toxicidade aguda e subaguda, bem como o efeito ansiolítico e antinociceptivo dos extratos da casca da raiz e das partes aéreas da D. americana em camundongos. A toxicidade aguda foi avaliada pela administração dos extratos, via intraperitoneal. Para o estudo da toxicidade subaguda os animais foram tratados oralmente com os extratos por 14 dias. O efeito ansiolítico dos extratos foi determinado através do modelo do labirinto em cruz elevado e o efeito antinociceptivo, mediante o teste da placa quente. O valor da DL50 para o extrato das partes aéreas da D. americana foi definido como > 500 mg/kg, enquanto que para o extrato da casca da raiz foi estabelecido em 400 mg/kg. O extrato das partes aéreas da D. americana apresentou atividade ansiolítica (250 mg/kg) e antinociceptiva (125, 200 e 250 mg/kg). O extrato da casca da raiz da D. americana não apresentou efeito ansiolítico nem antinociceptivo.

Extração de ecdisterona em raízes de ginseng brasileiro / Extraction of ecdysterone from roots of Brazilian ginseng

Este estudo teve como objetivo otimizar a extração de ecdisterona em raízes de ginseng brasileiro. Primeiramente, para se avaliar a eficiência do solvente extrator, amostras de raízes dois acessos (BRA e JB-UFSM) de P. glomerata foram extraídas em Soxhlet com metanol e clorofórmio, separadamente, durante 4 horas. No segundo ensaio, com o intuito de se escolher o método extrator, a extração foi conduzida em Soxhlet e em ultrassom, utilizando metanol como solvente. Em P. tuberosa, as amostras foram extraídas com metanol, e a extração foi conduzida em Soxhlet e em banho ultrasônico. O conteúdo de ecdisterona foi determinado em Cromatógrafo Líquido de Alta Eficiência (CLAE). Em ambas as espécies, um maior conteúdo de ecdisterona foi detectado nas amostras extraídas com metanol e em Soxhlet. A metodologia proposta mostrou-se eficaz para a quantificação da ecdisterona a partir das raízes de P. glomerata e P. tuberosa, podendo ser aplicada no controle de qualidade de drogas vegetais e/ou fitoterápicos.

This study aimed at optimizing the extraction method from ecdysterone of Brazilian ginseng. Root samples of two accessions (BRA and JB-UFSM) of P. glomerata were extracted in a Soxhlet with methanol or chloroform for 4h. In the second trial, the extration was conduced in a Soxhlet or ultrasonic using metanol as a solvent. In P. tuberosa, the roots samples were extracted with methanol in a Soxhlet or in ultrasonic. The ecdysterone content was determinated using high efficiency liquid chromatography methods. In both studied species, the highest ecdisterone content was detected from samples extracted in a Soxhlet and using methanol as a solvent. This extration method has been successfully applied for determination of ecdysterone content from roots of Brazilian ginseng, and could be useful for the quality control of drugs and pharmaceutical formulations.