Antifungal activity of green and red Brazilian propolis extracts

Abstract

Background: Diseases associated to Candida spp. are recurrent and can be difficult to treat, mainly due to the new strains resistant to the limited number of available antifungals. Objective: Evaluate the in vitro and in vivo activity of Brazilian green propolis (GrProp) and red propolis (RdProp) ethanolic extracts against standard strains of Candida albicans, C. tropicalis, C. krusei, C. glabrata, C. parapsilosis and 10 clinical isolates of C. albicans. Methods: Antifungal activity in vitro was tested using the M-27-A3/CLSI protocol. The in vivo antifungal activity was evaluated using Tenebrio molitor model. And, the effect of extracts on adhesion of C. albicans in human buccal epithelial cells (BECs) was also studied. Results: GrProp and RdProp exhibited antifungal activity against at least one of the Candida strains tested. The adhesion inhibition of C. albicans in BECs was of 45% (GrProp28), 60% (GrProp50) and of 82% (RdProp), in comparison to amphotericin B (82%). All propolis extracts showed synergistic activity with fluconazole and amphotericin B. GrProp50 (10 mg/kg) showed the better protection of T. molitor, blocking the progression of C. albicans infection, increasing survival and delayed the larvae death. Conclusion: Brazilian GrProp and RdProp extracts inhibit the in vitro C. albicans growth and protect T. molitor against infection by this yeast. The physiochemical parameters found for the analyzed samples were in accordance to the standards established by the Brazilian Legislation for propolis and derivatives. GrProp and RdProp have potential to be used against Candida spp. infections, mainly in association with fluconazole or amphotericin B.