The magainins are a class of antimicrobial peptides found in the African clawed frog (Xenopus laevis).
[1] The peptides are cationic, generally lack a stable conformation in water but form amphipathic α-helix in membranes; their mechanism against micro-organisms is unclear but they disrupt the cell membranes of a broad spectrum of bacteria, protozoa, and fungi.
[2] They were independently discovered at around the same time by the labs of Michael Zasloff at the NIH and Dudley H. Williams at the University of Cambridge.
[2] They were named by Zasloff, after the Hebrew word for "shield," מגן māgēn (Ashkenazi pronunciation: magain).
[2][5][6] Another company, Dipexium Pharmaceuticals, ran further phase III clinical trials for the same use, which failed in 2016.