Antimicrobial properties of melanocortins: comment to the manuscript "Anti-Candida activity of α-melanocyte-stimulating hormone (α-MSH) peptides" by Isabella Rauch et al.

In their report, Rauch et al. did not find candidacidal activity of α-melanocyte-stimulating hormone (α-MSH) in Sabouraud dextrose broth. The lack of killing activity by the natural α-MSH in broth medium may occur because of accelerated Candida replication or peptide degradation by fungal enzymes. It should be considered that in physiological conditions, there is sustained peptide release by host cells in an autocrine/paracrine manner. However, when the procedure described in the paper published in the Journal Leukocyte Biology was used, the investigation by Rauch et al. found that concentrations of α-MSH in the high micromolar range have candidacidal activity.