A new mycalamide, mycalamide D (3), has been isolated from the New Zealand
marine sponge Mycale sp. This new metabolite, in which the C13-O-methyl gro
up of mycalamide A (1) is replaced by a hydrogen atom, was found to be cyto
toxic to a range of mammalian cell lines, with a potency approximately 20-f
old less than that of 1.