Pulicatins A−E, Neuroactive Thiazoline Metabolites from Cone Snail-Associated Bacteria

The cone snail Conus pulicarius from the Philippines provides a specific habitat for actinomycetes and other bacteria. A phenotypic screen using primary cultures of mouse dorsal root ganglion neurons revealed that one C. pulicarius associate, Streptomyces sp. CP32, produces a series of natural products that enhance or diminish whole-cell Ca²⁺ flux. These compounds include known thiazoline compounds and a series of new derivatives, pulicatins A−E (6−10). Individual compounds were shown to bind to a series of human receptors, with selective binding to the human serotonin 5-HT_2B receptor. Here, we report the structure elucidation of the new compounds and results of the neurological assays.