Phomapyrrolidones A–C, Antitubercular Alkaloids from the Endophytic Fungus <i>Phoma</i> sp. NRRL 46751

Abstract

Three new alkaloids, phomapyrrolidones A-C (1-3), bearing a cyclopenta[b]fluorene ring system were isolated from the mycelium extract of the endophytic fungal strain Phoma sp. NRRL 46751, inhabiting Saurauia scaberrinae. Methylation of 1 afforded its N-methyl derivative 4. The planar structures and relative configurations of 1-4 were elucidated by extensive spectroscopic analysis. Phomapyrrolidones B (2) and C (3) exhibited weak antitubercular activity at subcytotoxic concentrations.