Three new epipolythiodioxopiperazines, chaetocochins A (1), B (2), and C (3), along with dethio-tetra (methylthio) chetomin (4) and chetomin (5), were isolated from the ethyl acetate extract of the solid-state fermented rice culture of the fungus Chaetomium cochliodes. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 1, 3, and 4 exhibited significant cytotoxicity in vitro against cancer cell lines Bre-04, Lu-04, and N-04.
Brevianamide J (1), a new indole alkaloid dimer, was isolated together with four new diketopiperazine alkaloids (brevianamide K-N, 2-5) from the solid-state fermented culture of Aspergillus versicolor. Their structures were elucidated on the basis of spectral data. X-ray crystallographic analysis confirmed the structures of 1 and 4.Diketopiperazine alkaloids, a class of important secondary metabolites, are widely found in fungi such as Aspergillus, 1 Penicillium, 2 Pestalotiopsis, 3 and Chromocleista. 4 This class of alkaloids are derived from different amino acids and one or more isoprene units. Most of them are characteristic of diverse ring systems and possess diverse biological activities, 5 which attracted much attention of synthetic chemists. 6 Species of Aspergillus are important medically and commercially. Members of the genus are sources of natural products that can be potentially used to treat human diseases. 7 In the course to investigate the alkaloids from the fungus Aspergillus Versicolor, a new alkaloid dimer (1), together
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