ABSTRACT
Bioactivity-guided chemical investigation of a co-culture of marine-derived micro-organisms has yielded one new steroid, 7ß-hydroxycholesterol-1ß-carboxylic acid (1) with an unprecedented carboxylic acid group at C-1, together with three known steroidal metabolites (2-4). The chemical structures and stereochemistry of the isolated compounds were unambiguously determined based on extensive 1D, 2D NMR and HR-ESI-MS measurements. The isolated compounds were assessed for their cytotoxic activity against four different human tumour cell lines K562 (leukaemia), HCT116 (colon), A2780 (ovary) and its cisplatin-resistant mutant (A2780 CisR), and they revealed moderate activities with IC50 values ranging from 10.0 to 100.0 µM.
Subject(s)
Antineoplastic Agents/isolation & purification , Antineoplastic Agents/pharmacology , Hydroxycholesterols/isolation & purification , Hydroxycholesterols/pharmacology , Antineoplastic Agents/chemistry , Cell Proliferation/drug effects , Drug Resistance, Neoplasm/drug effects , Drug Screening Assays, Antitumor , Female , Fermentation , HCT116 Cells , Humans , Hydroxycholesterols/chemistry , Inhibitory Concentration 50 , K562 Cells , Marine Biology , Molecular Structure , Nuclear Magnetic Resonance, BiomolecularABSTRACT
Chemical investigation of the mycelial extract of a mixed culture of two marine alga-derived fungal strains of the genus Aspergillus has yielded one new cyclotripeptide, psychrophilin E (1), the recently reported oxepin-containing alkaloids, protuboxepin A (2) and oxepinamide E (3), together with three other polyketide derivatives (4-6). The chemical structure and relative and absolute configurations of psychrophilin E (1) were unambiguously established based on HRMS, 1D, 2D NMR and chiral-phase HPLC analysis of its hydrolysate. All the isolated compounds were assessed for their anti-proliferative activity against four different human cancer cell lines and some of them revealed selective activities.
