Anti-Acanthamoeba castellanii activity of alkaloid-enriched extracts and lycorine from the Amaryllidaceae species

Abstract Free-living amoebae of the genus Acanthamoeba are the causative agents of granulomatous encephalitis and keratitis, severe human infections. Bioactive compounds from plants are recognized as an alternative source for the development of new drugs. The Amaryllidaceae is a botanical family able to synthesize a very specific and consistent group of biologically active isoquinoline-like alkaloids. The alkaloidal fractions from the Brazilian species Hippeastrum canastrense, H. diniz-cruziae, H. puniceum, and Crinum x amabile, along with the alkaloid lycorine, were investigated against Acanthamoeba castellanii. The in vitro assays were performed with distinct concentrations of lycorine and alkaloidal fractions, while the cell viability was evaluated by the MTT method upon MDCK cells. Chlorhexidine 0.02% was used as the positive control. The effect of alkaloid fractions was concentration dependent, and 2000 µg mL-1 of H. canastrense and H. diniz-cruziae provided a 100% inhibition. At concentrations of 250, 500, and 1000 µg mL-1, the H. diniz-cruziae alkaloidal fraction showed the lowest cytotoxic effect (5%-7%) and remarkable anti-amoebic activity, demonstrating values of IC50 285.61 µg mL-1, low cytotoxicity (5%-7%), and selectivity index (7.0). Taken together, the results are indicative of the great potential that the alkaloids from H. diniz-cruziae have as new candidates for anti-amoebicidal compounds

Parasitological stool sample exam by spontaneous sedimentation method using conical tubes: effectiveness, practice, and biosafety / Exame parasitológico de fezes pelo método de sedimentação espontânea utilizando tubos cônicos: eficácia, praticidade e biossegurança

INTRODUCTION: Spontaneous sedimentation is an important procedure for stool examination. A modification of this technique using conical tubes was performed and evaluated. METHODS: Fifty fecal samples were processed in sedimentation glass and in polypropylene conical tubes. Another 50 samples were used for quantitative evaluation of protozoan cysts. RESULTS: Although no significant differences occurred in the frequency of protozoa and helminths detected, significant differences in protozoan cyst counts did occur. CONCLUSIONS: The use of tube predicts a shorter path in the sedimentation of the sample, increases concentration of parasites for microscopy analysis, minimizes the risks of contamination, reduces the odor, and optimizes the workspace.

INTRODUÇÃO: A sedimentação espontânea é um procedimento importante para o exame parasitológico de fezes. Uma modificação desta técnica utilizando tubos cônicos foi realizada e avaliada. MÉTODOS: Cinquenta amostras de fezes foram processadas em cálices de sedimentação de vidro e em tubos cônicos de polipropileno. Outras 50 amostras foram usadas para avaliação quantitativa de cistos de protozoários. RESULTADOS: Embora não tenham sido encontradas diferenças significativas na frequência de helmintos e protozoários identificados, houve diferença significativa na contagem de cistos de protozoários. CONCLUSÕES: O uso do tubo prevê um caminho mais curto na sedimentação da amostra, aumenta a concentração de parasitas para a análise microscópica, minimiza os riscos de contaminação, reduz o odor e otimiza o espaço de trabalho.