stilbenes and Candidiasis

Rhapontigenin, an aglycone of rhapontin, was produced by biotransformation and we investigated its antifungal activity against Candida albicans, one of the most important opportunistic fungal pathogens. Rhapontigenin is found to have, in vitro, inhibitory activity with a minimal inhibitory concentration (MIC) value against all test isolates of 128-256 μg/ml. We detected increased reactive oxygen species (ROS) levels in yeast cultures treated with rhapontigenin at the MIC. Rhapontigenin inhibited DNA, RNA, and protein synthesis, especially RNA synthesis, and induced morphological changes and apoptosis of C. albicans. The apoptotic effect of rhapontigenin on C. albicans at subinhibitory concentrations was higher in the stationary growth phase than in the exponential phase, while the opposite results were noted with amphotericin B. The mechanism of antifungal activity of rhapontigenin may be associated with the generation of ROS that might induce apoptosis and it may also involve the inhibition of ergosterol biosynthesis.

Topics: Antifungal Agents; Apoptosis; Candida albicans; Candidiasis; Drug Resistance, Fungal; Ergosterol; Flow Cytometry; Microbial Sensitivity Tests; Protoplasts; Reactive Oxygen Species; Stilbenes

Riccardin D, a macrocyclic bisbibenzyl isolated from Chinese liverwort Dumortiera hirsute, has been proved to have inhibitory effect on biofilms formation of Candida albicans in in vitro study. Our present study aims to investigate the in vivo effect and mechanisms of riccardin D against C. albicans biofilms when used alone or in combination with clinical using antifungal agent fluconazole. XTT reduction assay revealed riccardin D had both prophylactic and therapeutic effect against C. albicans biofilms formation in a dose-dependent manner when using a central venous catheter related infective animal model. Scanning electron microscope and laser confocal scanning microscope showed that the morphology of biofilms was altered remarkably after riccardin D treatment, especially hypha growth inhibition. To uncover the underlying molecular mechanisms, quantitative real-time RT-PCR was performed to observe the variation of related genes. The downregulation of hypha-specific genes such as ALS1, ALS3, ECE1, EFG1, HWP1 and CDC35 following riccardin D treatment suggested riccardin D inhibited the Ras-cAMP-Efg pathway to retard the hypha formation, then leading to the defect of biofilms maturation. Moreover, riccardin D displayed an increased antifungal activity when administered in combination with fluconazole. Our study provides a potential clinical application to eliminate the biofilms of relevant pathogens.

Topics: Animals; Antifungal Agents; Biofilms; Candida albicans; Candidiasis; Catheters; Hepatophyta; Phenyl Ethers; Rabbits; Stilbenes

Resveratrol is a natural stilbene synthesised by plants. This compound has been shown to inhibit the growth of Candida albicans TIMM 1768 efficiently. Till date, no information is available for other Candida species. The evaluation of the antimicrobial activity of resveratrol was analysed by the inhibition of the growth and metabolism assays. Our data indicate that resveratrol is not effective against Candida albicans and non-C. albicans species (C. dubliniensis, C. glabrata, C. tropicalis, C. parapsilosis and C. krusei) in vitro. The potential candidacidal activity could not be confirmed.

Topics: Antifungal Agents; Candida; Candidiasis; Humans; Microbial Sensitivity Tests; Resveratrol; Stilbenes

The ability of the human fungal pathogen Candida albicans to undergo the morphological transition from a single yeast form to pseudohyphal and hyphal forms in response to various conditions is known to be an important for its virulence. Many studies have shown the pharmacological effects of resveratrol, a phytoalexin polyphenolic compound. In this study, we investigated the antifungal activity of resveratrol against C. albicans. Both yeast-form and mycelial growth of C. albicans were inhibited by resveratrol. In addition, normal filamentation of C. albicans was affected and yeast-to-hypha transition under serum-, pH-, and nutrient-induced hyphal growth conditions was impaired by resveratrol.

Topics: Candida albicans; Candidiasis; Humans; Hyphae; Resveratrol; Stilbenes

Fluorescent staining using optical brighteners (diaminostilbenes) affords the semispecific and rapid detection of fungal elements in clinical specimens. After yielding a first hint of mycosis, the identification of the involved fungal genus is often desirable in cases when culture proves unsuccessful. In such cases, immunohistochemistry or in situ hybridisation may further the diagnosis with respect to establish an appropriate therapy.

Topics: Aspergillosis; Aspergillus fumigatus; Candida albicans; Candidiasis; Coloring Agents; Fluorescence; Fluorescent Dyes; Humans; Mucormycosis; Mycoses; Rhizopus; Staining and Labeling; Stilbenes

Topics: Amidines; Aniline Compounds; Antimony; Antimony Sodium Gluconate; Candida albicans; Candidiasis; Humans; Pentamidine; Stilbamidines; Stilbenes

Topics: Amidines; Animals; Blastomycosis; Candida; Candidiasis; Mice; Pentamidine; Stilbenes