title: Novel bioactive metabolites from a marine derived bacterium Nocardia sp. ALAA 2000.
abstract: Extracts of the Egyptian marine actinomycete, Nocardia sp. ALAA 2000, were found to be highly bioactive. It was isolated from the marine red alga Laurenica spectabilis collected off the Ras-Gharib coast of the Red Sea, Egypt. According to detailed identification studies, the strain was classified as a member of the genus Nocardia. The cultivation and chemical analysis of this species yielded four structurally related compounds namely, chrysophanol 8-methyl ether (1), asphodelin; 4,7'-bichrysophanol (2) and justicidin B (3), in addition to a novel bioactive compound ayamycin; 1,1-dichloro-4-ethyl-5-(4-nitro-phenyl)-hexan-2-one (4) which is unique in contain both chlorination and a rarely observed nitro group. The compounds were isolated by a series of chromatographic steps and their structures of 1approximately 3 secured by detailed spectroscopic analysis of the MS and NMR data whereas that of 4 was elucidated by single crystal X-ray diffraction studies. These compounds displayed different potent antimicrobial activity against both Gram-positive and Gram-negative bacteria as well as fungi with MIC ranging from 0.1 to 10 microg/ml.
authors.affiliation: Chemistry of Natural and Microbial Products Department, National Research Centre, Cairo, Egypt.
authors.forename: Mervat M A
authors.initials: MM
authors.lastname: El-Gendy
authors.forename: Usama W
authors.initials: UW
authors.lastname: Hawas
authors.forename: Marcel
authors.initials: M
authors.lastname: Jaspars
mesh_terms: D000880:Anthraquinones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002845:Chromatography; D003374:Coumarins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018360:Crystallography, X-Ray; D004148:Dioxolanes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D004534:Egypt; D005658:Fungi / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D044722:Laurencia / Q000382:microbiology; D017705:Lignans / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D009615:Nocardia / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D003374:Coumarins; D004148:Dioxolanes; D017705:Lignans; C049719:justicidins; C070033:chrysophanol dimethyl ether; C027113:chrysophanic acid