Methylthio-Aspochalasins from a Marine-Derived Fungus Aspergillus sp.

Abstract

Two novel aspochalasins, 20-β-methylthio-aspochalsin Q (named as aspochalasin V), (1) and aspochalasin W (2), were isolated from culture broth of Aspergillus sp., which was found in the gut of a marine isopod Ligia oceanica. The structures were determined on the basis of NMR and mass spectral data analysis. This is the first report about methylthio-substituted aspochalasin derivatives. Cytotoxicity against the prostate cancer PC3 cell line and HCT116 cell line was assayed using the MTT method. Apochalasin V showed moderate activity at IC50 values of 30.4 and 39.2 μM, respectively.

Potential Pharmacological Resources: Natural Bioactive Compounds from Marine-Derived Fungi

“…This is the first report about methylthio-substituted aspochalasin derivative. Apochalasin V showed moderate cytotoxic activity against the prostate cancer PC3 cell line and HCT116 cell line with IC 50 values of 30.4 and 39.2 μM, respectively ( Figure 11 ) [ 30 ].…”

Recent Discovery of Heterocyclic Alkaloids from Marine-Derived Aspergillus Species

“…Compounds 84-91 were identified and characterized as having a spiro-heterocyclic γ-lactam skeleton and they were isolated from a culture broth of the marine fish-associated endophytic fungi A. fumigatus [50]. Compounds 92-96 were characterized as four aspochalasin analogs and they were obtained from the intestines of the marine isopod Ligia oceanica, collected along the coast of Dinghai in Zhoushan, Zhejiang Province, China [51][52][53]. Aspochalasins are a small group of cytochalasans structurally featuring a macrocyclic ring system and perhydroisoindol-1-one unit with an isobutyl side chain.…”

“…Among them, the structure of compound 92 includes a unique 5/6/6 tricyclic ring fused with the skeleton of aspochalasin [51]. Compounds 94 and 95 represent the first thiomethyl-substituted aspochalasin analogs [52]. Compound 96 is rare, in that it contains two nitrogen atoms in its molecular structure and an unusual skeleton that includes an azabicyclo moiety [53].…”

“…Six heterocyclic alkaloids (30 and 92-96) were also isolated from the endophytic fungi (A. sp. Z-4) residing in the marine isopod Ligia oceanica [37,[51][52][53], while only one heterocyclic alkaloid (130) was identified from the endophytic fungi obtained from the marine crab Xenograpsus testudinatus [71]. Moreover, the producing strains of 21, 22, and 54-56 originated from marine shrimp or prawns [34,45], while those of compounds 12-15 were derived from an unidentified colonial ascidian that was collected at Shikotan Island in the Pacific Ocean [29].…”

Two Novel Aspochalasins from the Gut Fungus Aspergillus sp. Z4

“…With diverse oxygenated regions in the macrocyclic ring, there are several unusual analogues among these known compounds including chaetochalasin A [ 10 ], aspergillin PZ [ 11 ], spicochalasin A [ 12 ], epicochalasines A and B [ 13 ]. In our ongoing search for new bioactive metabolites of marine fungi, some new compounds have been purified from the marine-derived fungus Z4 [ 14 , 15 , 16 , 17 ], and one strain isolated from the gut of the marine isopod Ligia oceanica . In order to find more novel natural products from this fungus, we employed the OSMAC (one strain, many compounds) approach by varying the culture conditions of Z4.…”