Ergochaeglobosins A—E, Unprecedented Heterodimers of Cytochalasan and Ergosterol fromChaeglobosin globosumP2‐2‐2

Abstract

Comprehensive Summary Five novel heterodimers of cytochalasan and ergosterol, ergochaeglobosins A—E, were isolated from an endophytic fungus Chaetomium globosum P2‐2‐2. Ergochaeglobosin A (1) possesses an unprecedented 5/6/13/6/5/6/6/6 fused octacyclic ring system, and ergochaeglobosins B (2) and C (3) form a unique 5/6/13/6/6/6/6/5 fused octacyclic ring system, whereas ergochaeglobosins D (4) and F (5) are the first cytochalasan heterodimers formed via a N‐1′/C‐3′′ single bond. Their structures with absolute configurations were established by extensive spectroscopic analyses, single‐crystal X‐ray diffraction, and ECD calculations. The plausible biogenetic pathway of 1—5 was postulated. Compound 1 exhibited inhibitory effects against ConA‐induced T cells and LPS‐induced B cells proliferation with IC50 values of 19.2 and 14.1 μmol/L, respectively. Co‐treatment of 3 (20 μmol/L) with TRAIL (150 ng/mL) could significantly decrease the cell viability of A549 by 24.9% comparing with monotherapy of 3 (20 μmol/L).

Polyaspers A and B, the First Ergosterol‐Polyether Adducts with Unprecedented 6/6/6/5/5/6/6/6/6 Nonacyclic Architecture from Aspergillus sp. TJ507

“…Finally, the Diels‐Alder addition between ii and vi constructed the C‐5–O–C‐3' and C‐6–O–C‐4' bonds to decorate the compound 1 , whereas formed the C‐5–O–C‐4' and C‐6–O–C‐3' linkages to build compound 2 . [ 35,43 ]…”

Recent advances in the total synthesis of cytochalasan natural products using bioinspired strategies

“…2). 5 Structurally, these “merocytochalasans” are generated by the fusion of one or more cytochalasans with one or more other natural product units, such as epicoccine and sterols. Currently, there are three types of merocytochalasans, including dimers (aspochalamins, 5 a , b spicarins, 5 c bisapochalasin A 5 i 18 , and ergochaeglobosin A 5 m 19 ), trimers (asperchalasine A 5 d 17 , aspergilasine A 5 f 23 , epicochalasine A, 5 e and 24 amichalasine A 5 h 25 ), and tetramers (asperflavipine A 5 g 20 ).…”

Lignans and [11]-chaetoglobosins from Pseudeurotium bakeri and their immunosuppressive activity

“…Since the discovery of the representative immunosuppressant, cyclosporine A, from Tvichoderrna polysporum in 1976, [9][10][11] an increasing number of immunosuppressive drugs have been developed from microbial secondary metabolites, such as rapamycin, tacrolimus, and rituximab. 12 In our previous search for new potential immunosuppressive agents from fungal sources, a series of natural compounds with novel structures and significant immunosuppressive effects were successfully identified, including ilyoresorcy C, 13 ilyomycins C, G, J, and K, 14 podospin A, 15 podomycin F, 16 ergochaeglobosin A, 17 and pseudeurglobosins A and E. 18 Inspired by the aforementioned findings, an in-depth investigation was conducted on the fungus Pseudeurotium bakeri P1-1-1, resulting in the identification of two previously unreported lignans (1-2), and four undescribed [11]-chaetoglobosins (3-6) (Fig. 1).…”