Cinzia Lotti,1 Gabriellen M. Migliani de Castro,2,3 Leandro F. Reis de Sá,2 Beatriz dos Anjos Fonseca Sampaio da Silva,2,3 Ana Claudia Tessis,3 Anna L. Piccinelli,1 Luca Rastrelli,1 Antonio Ferreira-Pereira*,2
1Dipartimento di Scienze Farmaceutiche, Università degli Studi di Salerno, Italy, 2Laboratório de Bioquímica Microbiana, Departamento de Microbiologia Geral/ IMPPG/CCS, Universidade Federal do Rio de Janeiro, Brazil,
3Instituto Federal do Rio de Janeiro, Brazil.
Multidrug resistance of cancer cells and pathogenic microorganisms leading to the treatment failure of some forms of cancer or life-threatening bacterial or fungal infections is often caused by the overexpression of multidrug efflux pumps belonging to the ATP-binding cassette transporters superfamily. The multidrug resistance of fungal cells often involves the overexpression of efflux pumps belonging to the pleiotropic drug resistance (PDR) family of ABC transporters. Possibly the best-studied fungal PDR transporter is the multidrug resistance transporter Pdr5p of Saccharomyces cerevisiae. Some research groups have been searching for new inhibitors of these efflux pumps in order to alleviate resistance. Natural products are a great source for the discovery of new compounds with biological activity. Propolis is a complex resinous material collected by honeybees from exudates and buds of certain plant sources and this material is thought to serve as a defense substance for bee hives. Propolis is widely used in traditional medicine and is reported to have a broad spectrum of pharmacological properties. Literature reported some biological functionalities of propolis, such as antibacterial, antiviral, fungicidal, anti- inflammatory and anti-carcinogenic activities. The chemical composition of propolis is qualitatively and quantitatively variable. Components isolated from methanolic extract of red Brazilian propolis (Alagoas, Northeast of Brazil) are isoflavonoids (including pterocarpans, isoflavans, isoflavones), flavanones and polyprenylated benzophenones. In this work we demonstrated the effects of five different isolated compounds on the ATPase activity of Pdr5p. Out of all five substances tested, only BRP-1 was able to completely abolish the enzymatic activity while others worked as positive modulators of the enzyme activity. BRP-1also inhibited the efflux of Rhodamine 6G from yeast cells overexpressing Pdr5p. Taken together, these results demonstrate that Brazilian propolis could be a source of promising compounds that can alleviate the MDR phenomenon, particularly in some fungi, where it could be used as an adjuvant for the treatment with azoles.
* THESE STATEMENTS HAVE NOT BEEN EVALUATED BY THE FOOD AND DRUG ADMINISTRATION. THIS IS NOT INTENDED TO DIAGNOSE, TREAT CURE OR PREVENT ANY DISEASE.