Candida albicans is the most common cause of opportunistic fungal disease in humans. 1) In fact, this fungus is also known as the fourth leading cause of nosocomial infections. 2,3) Over the past few decades, increasing incidence of candidiasis due to this fungus parallels the growing numbers of immmunocompromised people. [2][3][4][5] In immunocompromised people, disseminated candidiasis is sometimes a serious disease which often results in death. 6) In addition to the disseminated disease, C. albicans also causes local infections such as vaginitis and thrush. In case of vulvovaginal candidiasis, C. albicans is the most common etiological agent. 7,8) The treatment for the candidiasis includes antifungal drugs, mainly amphotericin B (Amp B) and the azoles. Furthermore, Amp B has been considered as the drug of choice for the treatment of fungal infections.9,10) However, due to its poor permeability across the membrane, 11) an increased amount of Amp B must be administered to patients in clinical situations, thus often resulting in severe side effects such as renal damage. 12,13) To lessen the severity of the side effects, Amp B is often combined with other antifungal drugs such as the azole, [14][15][16] but data reporting resistance of C. albicans to the azole have been recently increasing. [17][18][19] Thus investigation of reducing the Amp B dose by combining it with a new antifungal product appears to be important.As a part of the investigation, we tested a possibility of combination therapy with an alkaloid berberine that has quaternary nitrogen, polycyclic and planar structure.20) The plants that produce berberine is well protected against microorganisms due to the allelochemical activities of berberine, and thus, it appears likely that the berberine functions as a chemical defence compound. 20) Berberine can be assumed to be quite safe considering that the lethal dose of berberine is known to be approximately 23 mg/kg of body weight in mice.21) According to the previous reports of others berberine is shown to have both antifungal [22][23][24] and antibacterial effects 25,26) under the in vitro condition. We also reported that berberine had antifungal effect on the growth of C. albicans as determined by agar diffusion method.27) Continuing the study of antifungal activity of berberine, we investigated if berberine had a synergic effect with Amp B against disseminated candidiasis caused by C. albicans in animal models.
MATERIALS AND METHODSOrganisms and Culture Conditions C. albicans strains CA-1 and A-9, characterized previously, [28][29][30][31] were each grown in glucose-yeast extract-peptone (GYEP) broth at 37°C. Yeast cells collected from the broth cultures were washed with sterile cold Dulbecco's phosphate-buffered saline (DPBS; Sigma, St. Louis, U.S.A.) solution and enumerated by hemocytometer to obtain desired numbers of yeast cells.Mice BALB/c female mice (Charles River Labs, U.S.A.) were used at 6 to 7 weeks of age. The mice were maintained in the animal facility at Dongduk Women's University.Berber...
