ABSTRACT
The extract of the strain Aspergillus flavipes DL-11 exerted antibacterial activities against six Gram-positive bacteria. During the following bioassay-guided separation, ten diphenyl ethers (1-10), two benzophenones (11-12), together with two xanthones (13-14) were isolated. Among them, 4'-chloroasterric acid (1) was a new chlorinated diphenyl ether. Their structures were elucidated by extensive spectroscopic data analysis, including IR, HR-ESI-MS, NMR experiments, and by comparison with the literature data. All compounds showed moderate to strong antibacterial effects on different Gram-positive bacteria with MIC values that ranged from 3.13 to 50â µg/mL, but none of the compounds exhibited activity against Gram-negative bacteria Vibrio parahaemolyticus ATCC17802 (MIC>100â µg/mL). In particular, the MICs of some compounds are at the level of positive control.
Subject(s)
Anti-Bacterial Agents/chemistry , Aspergillus/chemistry , Benzophenones/chemistry , Phenyl Ethers/chemistry , Xanthones/chemistry , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Aspergillus/metabolism , Benzophenones/isolation & purification , Benzophenones/pharmacology , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Magnetic Resonance Spectroscopy , Microbial Sensitivity Tests , Molecular Conformation , Phenyl Ethers/isolation & purification , Phenyl Ethers/pharmacology , Xanthones/isolation & purification , Xanthones/pharmacologyABSTRACT
Celastrus orbiculatus is a medicinal plant belonging to the Celastraceae family. In this survey on the secondary metabolites of plants for obtaining antitumor substances, the chemical constituents of the stems of C. orbiculatus were investigated. Nortriptonoterpene (1), a new C19-norabietane diterpenoid, together with six other known abietane-type diterpenoids (2-7) and five known kaurane-type diterpenoids (8-12) were isolated and identified from the EtOAc extract of C. orbiculatus. Their structures were elucidated on the basis of extensive spectroscopic methods, including UV, IR, HR-ESI-MS, ECD, and NMR experiments, and by comparison with literature data. Compound 1 is a new C19-norabietane diterpenoid with 19 carbons. All compounds except for 10 and 11 were isolated from C. orbiculatus for the first time. The NMR data of 9 were reported for the first time. Compounds 1, 7 and 11 showed cytotoxicities against SGC-7901 with IC50 values of 63.2, 80.9 and 56.7 µM, respectively.
Subject(s)
Abietanes/isolation & purification , Celastrus/chemistry , Diterpenes, Kaurane/isolation & purification , Abietanes/chemistry , Diterpenes, Kaurane/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , Plants, Medicinal/chemistryABSTRACT
Four new steroids, named 7-dehydroerectasteroid F (1), 11α-acetoxyarmatinol A (2), 22,23-didehydroarmatinol A (3), and 3-O-acetylhyrtiosterol (4), together with 11 previously described analogues, were isolated from a South China Sea collection of the soft coral Dendronephthya gigantea. The structures of the new steroids were elucidated by comprehensive spectroscopic analysis and by comparison with previously reported data. Compound 1 showed potent protection against H2O2-induced oxidative damage in neuron-like PC12 cells by promoting nuclear translocation of Nrf2 and enhancing the expression of HO-1. 1 represents the first steroid-type antioxidant from marine organisms.
