Fungicidal potential of different Iranian honeys against some pathogenic Candida species.

Honey is well known to possess a broad spectrum of activity against medically important organisms. The purpose of this study was to investigate the anti-candidal activity of 28 locally produced honeys from two floral sources, 14 from southern and 14 from northern Iran, against some pathogenic Candida species such as Candida albicons, C. parapsilosis, C. tropicalis, C. kefyr, C. glabrata, and C. dubliniensis. A microdilution broth method was used to assess the activity of the selected honeys against six Candida species. The honeys were tested at 40 concentrations ranging from 20 to 60 % (v/v). Both northern and southern honeys possessed in vitro antifungal activity against the six Candida species tested. Little or no anti-candidal activity was seen at concentrations lower than 24 %. Increased honey concentrations resulted in reduced growth of Candida species. The highest inhibitory effect of different honeys was demonstrated in C. tropicalis, C. glabrata and C. dubliniensis. Candida kefyr and C. albicans showed more resistance to fungicidal activity of honeys, whereas C. glabrato was least affected. All honeys were able to produce complete inhibition of candidal growth with minimum fungicidal concentrations ranging from 29 to 56 %. Overall, varying sensitivities to the anti-candidal properties of different honeys were observed with six species of Candida emphasizing the variability in the antifungal effect of honey samples. Further research is needed to assess the efficacy of honey as an inhibitor of candidal growth in clinical trials, especially in treatment of patients with candidiasis.