CONICET | Buscador de Institutos y Recursos Humanos

Extracts rich in anthraquinones (AQs) of Heterophyllaea pustulata Hook. f. (Rubiaceae), have shown in vitro antifungal effect against planktonic microorganisms. We have established that their purified AQs exhibit photosensitizing activity type I and/or II[1]. Since the most important group of opportunistic fungal pathogens are Candida species[2], in this study we evaluate the antifungal activity of Rubiadina (RUB), one of the majority AQs from these extracts, against different Candida strains, analyzing whether this effect could be increased by irradiation. RUB was isolated from the benzenic extract of roots, and identified by using standard compounds in Thin Layer Chromatography and by means their UV-V spectrum. Minimum Inhibitory Concentration of RUB was determined by following the protocols of the Clinical and Laboratory Standards Institute[3], testing twelve concentrations (0.24 to 500 µg/ml) on two C. no albicans strains and a C albicans strain. The assay was performed simultaneously under darkness and irradiation with an Actinic Phillips lamp. The RUB antifungal activity was compared with Amphotericin B, a synthetic antifungal agent standard. RUB decreased meaningfully the growth of all strains in darkness (60 ? 70 %). Under irradiation, this inhibition percentage was achieved at lower concentrations: being two times lower for C. tropicalis ATCC, 4 times lower for C. albicans NCPF 3153 and 8 times lower for a clinical C. tropicalis strain. RUB exhibits a very good antifungal activity in vitro, which can be enhanced by light action, against several Candida species, specially on C. tropicalis. Therefore, RUB could have application in photodynamic therapy for Candida infections.