Antifungal cyclopeptides from Halobacillus litoralis YS3106 of marine origin

Three new cyclopeptides, including halolitoralin A (a cyclic hexapeptide), halolitoralin B and C (two cyclic tetrapeptides), together with three known cyclic dipeptides, cyclo(Pro-Val), cyclo(Pro-Leu) and cyclo(Ile-Val) were isolated from the ferment broth of a marine sediment-derived Halobacillus litoralis YS3106. The cyclopeptides show surprisingly simple architectures with highly repeated residue units, which showed moderate antifungal and weak antitumor activities in vitro.