Cytotoxic Naphtho‐<i>γ</i>‐pyrones from the Mangrove Endophytic Fungus <i>Aspergillus tubingensis</i> (GX1‐5E)

Abstract

Abstract Four new dimeric naphtho‐ γ ‐pyrones, named rubasperone D ( 1 ), rubasperone E ( 2 ), rubasperone F ( 3 ), and its atropisomer rubasperone G ( 4 ), together with four known monomeric naphtho‐ γ ‐pyrones, TMC 256 A1 ( 5 ), rubrofusarin B ( 6 ), fonsecin ( 7 ), and flavasperone ( 8 ), were isolated from the mangrove endophytic fungus Aspergillus tubingensis (GX1‐5E) cultivated in solid rice medium. Their structures were elucidated by spectroscopic methods, including IR, 1D‐ and 2D‐NMR, and MS. In the in vitro cytotoxicity assays, 5 displayed inhibitory activities against tumor cell lines of MCF‐7, MDA‐MB‐435, Hep3B, Huh7, SNB19, and U87 MG with IC 50 values between 19.92 and 47.98 μ M . Compounds 1, 6 , and 8 also showed mild cytotoxic activity.