ABSTRACT
Two new compounds with the character of diphenyl ether structure, oxisterigmatocystin D (1) and 9-acetyldiorcinol B (6), were isolated from the endolichenic fungal strain Aspergillus sp. (No. 16-20-8-1), along with six known compounds, oxisterigmatocystin A (2), oxisterigmatocystin C (3), sterigmatocystin (4), diorcinol B (5), violaceol-I (7), and violaceol-II (8). The structures of the new compounds were determined by extensive NMR spectroscopic data, and the absolute configuration of 1 was established by single-crystal X-ray diffraction analysis. Moreover, the Aß42 aggregation inhibitory activities of 5-8 were evaluated by the standard thioflavin T (ThT) fluorescence assay using epigallocatechin gallate (EGCG) as the positive control. Compounds 7 and 8 displayed significant anti-Aß42 aggregation activity with IC50 values of 5.1 and 2.3µM, respectively. Preliminary structure-activity relationship of these diphenyl ethers as anti-Aß42 aggregation inhibitors was proposed.
Subject(s)
Amyloid beta-Peptides/chemistry , Aspergillus/chemistry , Peptide Fragments/chemistry , Phenyl Ethers/chemistry , Inhibitory Concentration 50 , Molecular Structure , Phenyl Ethers/isolation & purification , Protein Aggregates/drug effects , Protein Aggregation, Pathological/prevention & control , Structure-Activity RelationshipABSTRACT
Chaetoglobosin Y (1), was isolated from the endolichenic fungal strain Chaetomium globosum (No. 64-5-8-2), along with related six known cytochalasans, chaetoglobosin Fex (2), chaetoglobosin E (3), isochaetoglobosin D (4), chaetoglobosin G (5), cytoglobosin B (6), and cytoglobosin C (7). Their structures were determined by detailed spectroscopic analyses and comparison with those of the closely related compounds previously reported. The cytotoxicity to HCT-116 cell line of 2-7 was evaluated in vitro with doxorubicin as positive control.
Subject(s)
Chaetomium/chemistry , Indole Alkaloids/isolation & purification , Antineoplastic Agents/analysis , Drug Screening Assays, Antitumor , HCT116 Cells , Humans , Indole Alkaloids/chemistry , Molecular StructureABSTRACT
Two new 4-methyl-progesteroids, nodulisporisteriod A (1) and nodulisporisteriod B (2), were isolated from the extract of an endolichenic fungal strain Nodulisporium sp. (No. 65-17-2-1), along with two related metabolites, demethoxyviridin (3) and inoterpene B (4). Their structures were determined by detailed spectroscopic analyses, X-ray crystallographic analysis and comparison of the NMR data with those of the closely related compounds previously reported. Nodulisporisteriod A (1) and nodulisporisteriod B (2) possess new carbon skeletons, which are the first cases of fission at C-3,4 in 4-methyl-progesteroids. A hypothetical biosynthetic pathway for 1 and 2 was proposed. Moreover, the Aß42 aggregation inhibitory activities of 1-4 were evaluated using standard thioflavin T (ThT) fluorescence assay with epigallocatechin gallate (EGCG) as positive control. Demethoxyviridin (3) displayed anti-Aß42 aggregation activity with IC50 value of 13.4µM.
