New Aromadendrane Sesquiterpenoid Pseuboydone F from the Marine-derived Fungus Pseudallescheria boydii F44-1

Abstract

A new aromadendrane sesquiterpenoid pseuboydone F (1), along with a known pseuboydone A (2), were isolated from the marine-derived fungus Pseudallescheria boydii F44-1 associated with the soft coral Sarcophyton sp.. The structures were elucidated by HRMS, 1D and 2D NMR spectroscopic data.

Species Diversity and Secondary Metabolites of Sarcophyton-Associated Marine Fungi

“…A total of 13 additional indole alkaloids were also isolated from the Saracophyton sp. associated marine fungus Pseudallescheria boydii from the South China Sea [ 59 ]. These compounds comprised the two bisindoles, pseudboindoles A ( 31 ) and B ( 32 ).…”

“…These compounds were isolated from the EtOAc extract of the laboratory-cultured strain after fractionation over Petr Eth and EtOAc. The compounds were purified using HPLC and a Capcell-Pak C18 UG80 (250 × 20 mm) column with methanol and purified water as the mobile phase [ 59 ].…”

“…Pseudoindole A ( 31 ) was isolated as an amorphous brown powder, consisting of one methylene group, six methine groups, three quaternary carbon atoms and is built of two identical structural moieties comprising an ortho-disubstituted aromatic ring and 3-substituted indole connected at the electronegative carbon C-9 [ 59 ]. Chemically, pseudoindole A ( 31 ) was deduced as 1,3-di(1H-indol-3-yl)propan-2-ol.…”

“…Compounds 33 to 37 share a common basic structure comprising two identical groups of ortho-disubstituted aromatic ring and 3-substituted indole joined at carbon C-8, making them a member of the bisindole alkaloid class. Similar to compound 31 and 32 , 3,3 ′ -cyclohexylidenebis(1H-indole) ( 33 ) was also isolated as a brown amorphous powder [ 59 ]. It can be synthesised by reacting an indole with cyclohexanone.…”

“…This compound exhibited a 140% enhancing potential towards the Am80-induced HL-60 (myeloid leukemic cell lines) cell. When treated with eight human cancer cell lines (A549, GLC82, CNE1, CNE2, HONE1, SUNE1, BEL7402 and the human hepatocarcinoma cell line (SMMC7721)), compound 33 showed cytotoxicity with IC 50 values of 22.84, 22.04, 18.69, 20.84, 26.62, 20.54, 27.52 and 22.50 μM, respectively [ 59 ]. 3,3-bis(3-indolyl)butane-2-one ( 34 ) was previously reported as a synthesised product but was later isolated as a natural metabolite from the bacterium Vibrio parahaemolyticus of the North Sea, as a pale yellowish solid [ 83 ].…”