Abstract
The mangrove endophytic fungus Aspergillus terreus (No. GX7-3B) was cultivated in potato dextrose liquid medium, and one rare thiophene compound (1), together with anhydrojavanicin (2), 8-O-methylbostrycoidin (3), 8-O-methyljavanicin (4), botryosphaerone D (5), 6-ethyl-5-hydroxy-3,7-dimethoxynaphthoquinone (6), 3β,5α-dihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (7), 3β,5α,14α-trihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (8), NGA0187 (9) and beauvericin (10), were isolated. Their structures were elucidated by analysis of spectroscopic data. This is the first report of a natural origin for compound 6. Moreover, compounds 3, 4, 5, 7, 8 and 10 were obtained from marine microorganism for the first time. In the bioactive assays in vitro, compounds 2, 3, 9 and 10 displayed remarkable inhibiting actions against α-acetylcholinesterase (AChE) with IC50 values 2.01, 6.71, 1.89, and 3.09 μM, respectively. Furthermore, in the cytotoxicity assays, compounds 7 and 10 exhibited strong or moderate cytotoxic activities against MCF-7, A549, Hela and KB cell lines with IC50 values 4.98 and 2.02 (MCF-7), 1.95 and 0.82 (A549), 0.68 and 1.14 (Hela), and 1.50 and 1.10 μM (KB), respectively; compound 8 had weak inhibitory activities against these tumor cell lines; compounds 1, 2, 3, 4, 5, 6 and 9 exhibited no inhibitory activities against them.
Highlights
Marine fungi have been proven to be an important source of structurally novel and bioactive secondary metabolites [1,2,3,4,5], and it is well-known that under various culture conditions, many marine fungi can produce various secondary metabolites, which possess unique structures and bioactivities [6,7].Aspergillus terreus (No GX7-3B) is a mangrove endophytic fungal strain from the South China Sea.We have previously reported that four sesquiterpenes together with cyclo [IIe–IIe] dipeptide, ergosterol and ergosterol peroxide were isolated from this strain using glucose yeast-extract peptone (GYP) as the cultivation medium
On further investigation, when the fungal strain was fermented on potato dextrose broth (PDB) medium, many different metabolites from those cultivated on GYP medium were obtained, including compound (1), as well as anhydrojavanicin (2), 8-O-methylbostrycoidin (3), 8-O-methyljavanicin (4), botryosphaerone D (5), 6-ethyl-5-hydroxy-3,7-dimethoxynaphthoquinone
This work showed that Aspergillus terreus (No GX7-3B) could produce a rich variety of secondary metabolites, and small changes in the cultivation conditions could completely shift the metabolic profile of this strain
Summary
Marine fungi have been proven to be an important source of structurally novel and bioactive secondary metabolites [1,2,3,4,5], and it is well-known that under various culture conditions, many marine fungi can produce various secondary metabolites, which possess unique structures and bioactivities [6,7]. Compound 1 possessed the naphtho[2,3-b]thiophene-4,9-dione system, such a structure hasn’t been encountered in the described yet from nature. This is the first time compound 6 has been isolated from natural sources. Compounds 3, 4, 5, 7, 8 and 10 were isolated from marine microorganism for the first time. Their inhibitory activities against AChE and their cytotoxic activities against MCF-7, A549, Hela and KB cell lines were examined in vitro. We report the isolation, structure elucidation and biological activities of these compounds
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
