Petromylidenes A⁻C: 2-Alkylidene Bile Salt Derivatives Isolated from Sea Lamprey ( Petromyzon marinus ).

Three novel bile acid derivatives, petromylidenes A⁻C ( 1 ⁻ 3 ), featuring uncommon alkylidene adductive scaffolds, were isolated from water conditioned with sexually mature male sea lampreys ( Petromyzon marinus ). Their structures were elucidated by mass spectrometry and NMR spectroscopy, and by comparison to spectral data of related structures. The identification of compounds 1 ⁻ 3 , further illustrates the structural diversity of the 5α bile salt family. Compounds 1 ⁻ 3 exhibited notable biological properties as well, including high olfactory potencies in adult sea lampreys and strong behavioral attraction of ovulated female sea lampreys. Electro-olfactogram recordings indicated that the limit of detection for 1 was 10 ^-9 M, 2 was 10 ^-11 M, and 3 was less than 10 ^-13 M. These results suggested 1 ⁻ 3 were likely male pheromones, which guide reproductive behaviors in the sea lamprey.