Modulacija stanične stijenke gljivične vrste Candida albicans berberinom
Modulation of the cell wall of yeast Candida albicans with berberine
I. Bobnjarić1, J. Vlainić2, N. Zorić3, I. Kosalec4
1
University of Zagreb, Faculty of Pharmacy and Biochemistry, A. Kovačića 1, Zagreb,
Croatia (student)
2
Ruđer Bošković Institute, Division of Molecular Medicine, Laboratory of Molecular
Neuropharmacology, Bijenička 54, Zagreb, Croatia
3
Agency for Medicinal Product and Medical Devices, Ksaverska cesta 4, Zagreb, Croatia
4
University of Zagreb, Faculty of Pharmacy and Biochemistry, Department of Microbiology,
Schrottova 39/I, Zagreb, Croatia
Candida albicans is endogenous opportunistic yeast that does not cause infections in healthy
individuals but rather cause superficial to systemic infections in immuno-compromised
individuals. The use of fungistatic drugs and the lack of -cidal drugs often results in strains
that are not susceptible to commonly used antifungals, and/or display multidrug resistance
(MDR). Therefore, there is a need to find new antifungals with novel targets.
The aim of the present study was to determine the antifungal effects of the isoquinoline
alkaloid berberine and to elucidate the mechanism of this effect in C. albicans.
Using serial dilution assays we determined the minimal inhibitory concentration (MIC) of
berberine against C. albicans. The ergosterol levels were assessed measuring the
spectrophotometric absorbance profile between 240 and 300 nm (sterol quantitation method,
SQM). To analyse the possible effects of berberine on the cell wall we tested the releasing of
the crucial cell content using spectrophotometric measurement at 260/280 nm and 750 nm
(corresponding to nucleic acids and proteins). Since secretion of aspartic proteinases is one of
the important determinants associated with the pathogenicity of Candida species, we
deterimened the effect of berberine on SAP2 activity using secreted aspartyl proteinase (SAP)
test.
In the present study, we observed that berberine affected cell growth of tested Candida
albicans strain at the 17.75 μg/ml indicating its good antifungal properties. In our study, the
significant differences in mean ergosterol content were observed in berberine treated and nontreated group, which were dose and time dependent. Moreover, the results indicate that
berberine and positive control (voriconazol) produce the same levels of ergosterol indicating
their entanglement in the ergosterol biosynthesis. Moreover, berberine treatment caused the
elevated levels of proteins and nucleic acids indicating the releasing of the cell content in the
extracellular matrix. Namely, on the basis of these results we assumed that berberine
treatment affects the cell membrane permeability and or integrity. In addition, as determined it
is indicative that berberine does not inhibit proteinase activity (e.g. SAP2).
In summary, the data obtained indicate that berberine inhibit ergosterol biosynthesis.
Moreover, according to our results one might assume that berberine binds to the membrane
sterols consequently causing aqueous pores formation and the leakage of cellular components
what can lead to cell death. Thus, further investigation on the mechanisms of actions on the
cell wall is required.