Diverse indole-diterpenoids with protein tyrosine phosphatase 1B inhibitory activities from the marine coral-derived fungus Aspergillus sp. ZF-104

Abstract

Eight previously undescribed indole-diterpenoids named penerpenes O–V (1–8), together with seven known analogues (9–14), were isolated from the marine soft coral-derived fungus Aspergillus sp. ZF-104. Their structures including the absolute configurations of these compounds were assigned on the basis of spectroscopic data and ECD analysis along with quantum ECD and NMR calculations. Compounds 4 and 5 bear rare indolin-2-one units in their structures and 6 bears a reconstructed novel skeleton in which the indole ring and the terpenoid substructure are cleaved before they are reconnected through the nitrogen atom. Compounds 1, 2, 7, and 10 showed protein tyrosine phosphatase 1B (PTP1B) inhibitory activities comparable to that of the positive control NaVO3.