ABSTRACT
Total 23 eleven-residue peptaibols, including five reported ones (1-5) in our previous work, were isolated from the fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, which was obtained from the mushroom Clitocybe nebularis (Batsch) P. Kumm. The structures of the 13 new peptaibols (6-10 and 12-19) were determined by their NMR and MALDI-MS/MS data, their absolute structures were further determined by Marfey's analyses and their ECD data. Careful comparison of the structures of 1-23 showed that only seven residues varied including the 2nd (Gln2 /Asn2 ), 3rd (Ile3 /Val3 ), 4th (Ile4 /Val4 ), 6th (Pro6 /Hyp6 ), 8th (Leu8 /Val8 ), 10th (Pro10 /Hyp10 ) and 11th (Leuol11 /Ileol11 /Valol11 ) residues. Comparison of the IC50 s against the three tested cell lines of 1-23 indicated that 2nd, 3rd and 4th amino acid residues affected their cytotoxicities powerfully. Compounds 2, 5, 9, 11, 21 and 22 showed moderate antibacterial activities against Staphylococcus aureus MRSA T144, which also showed stronger cytotoxicities against BV2 and MCF-7 cells.
Subject(s)
Peptaibols , Trichoderma , Amino Acids/metabolism , Anti-Bacterial Agents/chemistry , Hypocreales , Peptaibols/chemistry , Peptaibols/pharmacology , Structure-Activity Relationship , Tandem Mass Spectrometry , Trichoderma/chemistryABSTRACT
Longibrachiamide A (1), a new 20-residue peptaibol, along with three known ones (2-4), were isolated from the fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, isolated from a mushroom Clitocybe nebularis (Batsch) P. Kumm, which was collected from coniferous forest of northeast China in our previous work. The structure of longibrachiamide A (1) was determined by its NMR and ESI-MS/MS data, the absolute configuration of 1 was further determined by Marfey's analyses. And the complete NMR data of 2-4 were also reported for the first time. The similar CD spectra of 1-4 showed that they all had mixed 310 -/α-helical conformations. Compounds 1-4 showed strong cytotoxicities against BV2, A549 and MCF-7 cells, and also showed moderate inhibitory effects against the tested Gram-positive bacteria, including MRSA T144 and VRE-10.
