New Indole Diketopiperazine Alkaloids from Soft Coral-associated Epiphytic Fungus Aspergillus sp. EGF 15-0-3.

New Indole Diketopiperazine Alkaloids from Soft Coral-associated Epiphytic Fungus Aspergillus sp. EGF 15-0-3.

Chem Biodivers. 2020 Mar 24;:

Authors: Zhang CX, Wei X, Feng C, Wang SY, Zhang DM, Li XH

Abstract
Three new indole diketopiperazine alkaloids, 11-methylneoechinulin E ( 1 ) and variecolorin M ( 2 ), and (+)-Variecolorin G ( 3a ), along with 12 known analogues ( 3b – 14 ), were isolated from a soft coral-associated epiphytic fungus Aspergillus sp. EGF 15-0-3. The structures of the new compounds were unambiguously established by extensive spectroscopic analyses including HRESIMS, 1D and 2D NMR spectroscopy and optical rotation measurements. The absolute configurations of 3a and 3b were determined by experimental and quantum-chemical ECD investigations and single- crystal X-ray diffraction analysis. 3 is a pair of enantiomeric mixtures with a ratio of 1:2. Moreover, 9 is firstly reported as a natural product. The cytotoxic activities of all the isolated compounds against NCI-H1975 gefitinib resistance (NCI-H1975/GR) cell lines were preliminarily evaluated by MTT method.

PMID: 32212241 [PubMed – as supplied by publisher]

Source: Industry