4-Desmethyl 7-Prenyl Mollicellin Analogue Isolated from Chaetomium brasiliense

A new depsidone, termed mollicellin Z2 (1), and three known mollicellins D, H, and I (2-4), were isolated from cultured Chaetomium brasiliense NBRC 6548 mycelia. The structure of 1 was determined from one dimensional (1D) and 2D-NMR and high resolution electron ionization (HREI)MS spectra. It is the first 4-desmethyl mollicellin analogue found to contain a C-7 prenyl group and is likely generated via a biosynthetic pathway that is distinct from those that produce the 27 known analogues. This is the first report of mollicellin derivatives with antibacterial activity against nontuberculous mycobacteria.