clove and Candidiasis

In addition to the bio-guided investigation of the antifungal activity of Plinia cauliflora leaves against different Candida species, the major aim of the present study was the search for targets on the fungal cell. The most active antifungal fraction was purified by chromatography and characterized by NMR and mass spectrometry. The antifungal activity was evaluated against five Candida strains according to referenced guidelines. Cytotoxicity against fibroblast cells was determined. The likely targets of Candida albicans cells were assessed through interactions with ergosterol and cell wall composition, porosity and architecture. The chemical major component within the most active antifungal fraction of P. cauliflora leaves identified was the hydrolysable tannin casuarinin. The cytotoxic concentration was higher than the antifungal one. The first indication of plant target on cellular integrity was suggested by the antifungal activity ameliorated when using an osmotic support. The most important target for the tannin fraction studied was suggested by ultrastructural analysis of yeast cell walls revealing a denser mannan outer layer and wall porosity reduced. It is possible to imply that P. cauliflora targeted the C. albicans cell wall inducing some changes in the architecture, notably the outer glycoprotein layer, affecting the cell wall porosity without alteration of the polysaccharide or protein level.

Topics: Antifungal Agents; Candida; Candidiasis; Cell Wall; Glycoproteins; Hydrolyzable Tannins; Microbial Sensitivity Tests; Myrtaceae; Plant Leaves; Porosity

Atypical Candida strains were isolated from patients in Madagascar, Angola and Germany. These isolates were slow growing and were unable to produce chlamydospores. They had atypical carbohydrate assimilation profiles. All strains were unable to assimilate the amino sugars N-acteylglucosamine and glucosamine as well as the disaccharide trehalose and the organic acid DL-lactate. They were germ-tube-positive in serum, but only some of these organisms produced pseudohyphae after a long incubation. As shown by Fourier transform infrared spectroscopy the atypical Candida isolates clustered as a monophyletic group different from C. albicans and C. dubliniensis. All strains belonged to C. albicans serotype B. Considering all data presented here, this group of Candida strains differs from any other known member of the genus Candida. Therefore, it is suggested to represent a new species within the genus Candida for which the name Candida africana is proposed.

Topics: Angola; Candida; Candidiasis; Carbohydrate Metabolism; Female; Germany; Humans; Madagascar; Male; Species Specificity