Ten new (1–10) and nine known (11–19) austocystins, along with four known anthraquinones (20–23), were isolated from the culture of Aspergillus ustus NRRL 5856 by bioactivity-guided fractionation. The structures of the new compounds were elucidated by spectroscopic data analysis, X-ray crystallographic study, the modified Mosher's method, [Rh2(OCOCF3)4]-induced ECD spectral analysis, and comparison of the experimental ECD spectra with those of the similar analogues. Compounds 1–8 represent the first examples of austocystins with a C-4′ oxygenated substitution. The absolute configuration of 1″-hydroxy austocystin D (11) was determined by single-crystal X-ray diffraction and consideration of its biosynthetic origin. Compounds 5, 9, and 11 exhibited significant inhibitory effects against the proliferation of ConA-induced T cells with IC50 values of 1.1, 1.0, and 0.93 μM, respectively. Furthermore, these compounds suppressed the expression of IL-6 in a dose-dependent manner. Compounds 10–12 and 14 showed pronounced cytotoxicities against MCF-7 with IC50 values of 3.9, 1.3, 0.46, and 2.3 μM, respectively.
Ergocytochalasin A (1), an unprecedented merocytochalasan with a 5/6/14/6/5/6/6/6 fused octacyclic ring system, was isolated from an endophytic fungus Phoma multirostrata XJ-2-1.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Eight unreported andrastin-type meroterpenoids, namely eniandrastins A−H (1−8), along with six known analogues (9−14), were isolated from the fermentation of a soil-derived fungus Penicillium sp.sb62. Their structures with absolute configurations were elucidated by detailed analysis of the spectroscopic data and single-crystal X-ray diffraction. Compounds 1−4 belong to a rare class of 21-nor-andrastin meroterpenoids, of which 1 bears a 10-hydroperoxyl group, and 2 and 3 feature a 6/6/6/5/5 and a 6/6/6/5/6 pentacyclic systems, respectively. Compounds 5−8 are C25 andrastin-type meroterpenoids, wherein 5 features an unprecedented cyclopentan-1-keton-3-hemiacetal moiety. Additionally, the absolute configuration of compound 9 was corroborated by single-crystal X-ray crystallography for the first time. All isolates were evaluated for their immunosuppressive activities. As a result, compounds 1, 3, 4, 7−9 and 12−14 inhibited concanavalin A-induced T cell proliferation with IC50 values ranging from 7.49 to 36.52 μM, and 1−4, 6−9 and 12−14 inhibited lipopolysaccharide-induced B cell proliferation with IC50 values ranging from 6.73 to 26.27 μM. The preliminary structure–activity relationships (SARs) of those isolates were also discussed.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.