Peptidolipins B–F, Antibacterial Lipopeptides from an Ascidian-Derived Nocardia sp

A marine Nocardia sp. isolated from the ascidian Trididemnum orbiculatum was found to produce five new lipopeptides, peptidolipins B–F (1–5), which show distinct similarities to the previously reported l-Val­(6) analog of peptidolipin NA. Synthetic modification of peptidolipin E (4) was used to determine the location of an olefin within the lipid chain. The advanced Marfey’s method was used to determine the absolute configurations of the amino acids. Peptidolipins B (1) and E (4) demonstrated moderate antibacterial activity against methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus.