Effects of Pimenta pseudocaryophyllus (Gomes) L. R. Landrum, on melanized and non-melanized Cryptococcus neoformans

Abstract

In the present study, the in vitro susceptibility and capsular width from both melanized and non-melanized Cryptococcus neoformans cells in the presence of Pimenta pseudocaryophyllus crude extract were determined. The results were compared with those obtained for voriconazole and amphotericin B. Melanization was obtained in minimal medium broth with the addition of L-dopa, and the antifungal susceptibility tests were performed using the broth microdilution method. Capsular width of 30 cells of each one of the isolates in medium with crude extracts of P. pseudocaryophyllus or voriconazole or amphotericin B at a concentration corresponding to 0.5 times the minimal inhibitory concentration (MIC) was measured, and the mean was calculated. The MICs and minimal fungicidal concentrations (MFCs) for plant extract and voriconazole were identical for both melanized and non-melanized C. neoformans isolates, but for amphotericin, the MFCs for melanized cells were up to 8 times higher than for non-melanized cells. The capsular width of C. neoformans cells was smaller (p < 0.001) in the presence crude extract of P. pseudocaryophyllus and of voriconazole regardless melanization. The findings of capsule alterations of C. neoformans verified in this study provide fertile ways for future research into the effects of antifungal agents on the pathogenesis of cryptococcosis.