Asperelines G and H, Two New Peptaibols from the Marine-Derived Fungus Trichoderma asperellum

Two new peptaibols, asperelines G (1) and H (2), together with five known compounds, asperelines A (3), C (4), D ( 5), E (6), and F (7) were isolated from the marine-derived fungus Trichoderma asperellum.The structures of these compounds were determined through spectroscopic methods, X-ray diffraction analysis, and chemical derivatization.This study is the first report on asperelines with an acetylated C-terminus and a crystal structure.Marine environment is an excellent source of novel compounds with higher pharmaceutical applications. 1 search for new anticancer compounds, more than 300 microbial strains isolated from sediment samples collected from the Min River estuary in China were screened for cytotoxicity against HL-60 cells.Among these strains, a fungal strain identified as Trichoderma asperellum showed significant cytotoxic activity.The active constituents of this strain were investigated through a bioassay-guided isolation procedure.The investigation resulted in the isolation of two new peptaibols (1 and 2), together with five known peptaibols (3-7).Peptaibols are fungal metabolites that have been mainly isolated from Trichoderma. 2 They have attracted increasing attention for their unusual structural features, such as the presence of α-aminoisobutyric acid residues (Aib) at a high ratio, an N-acyl terminus and a C-terminus with an amino alcohol residue, and a wide range of biological activities including antibacterial, 3 antifungal, 4 antiviral, 5 antiparasitic, 6 anticancer, 7 and neuroleptic effects. 8Aspereline is a subgroup of peptaibols with nine amino acid residues.