Maigheotides A–C, Peptides from the Deep-Sea Black Coral Phanopathes sp.

Black corals have been poorly studied with respect to their secondary metabolite chemistry. With the aim of discovering new bioactive metabolites, we collected deep-sea black corals from the Irish continental margin. Our analysis of the black coral Phanopathes sp. yielded three new peptides (maigheotides A-C). Through a combination of 2D NMR, mass spectrometry, and Marfey's analysis, the absolute configuration of all three structures was elucidated. The maigheotides are characterized by a noncanonical amino acid ΔZ-Trp, the cyclized N-terminal Glu (pyroGlu), and C-terminal amide (maigheotide B). Similar characteristics are critical features found in neuropeptides. Screening in a number of assays has identified only weak activity, although the breadth of assays screened was limited by the small mass of peptides obtained.