Anthrotainin, an inhibitor of substance P binding produced by Gliocladium catenulatum.

Substance P (SP) is an undecapeptide belonging to a family of chemically related neurotransmitters and neuromodulators known as neurokinins. In our search for SP antagonists, we screened microbial broth extracts for the ability to inhibit radiolabeled SP binding to membranes prepared from rat forebrain. Anthrotainin was isolated from a fungal culture and determined to be a novel tetracyclic compound, with an IC50 of 3 microM against [125I]SP. The structure, spectroscopic, chemical, and pharmacological properties of anthrotainin are presented.