title: Constituents of Azadirachta indica: isolation and structure elucidation of a new antibacterial tetranortriterpenoid, mahmoodin, and a new protolimonoid, naheedin.
abstract: Mahmoodin [1], a new limonoid, has been isolated from Azadirachta indica (neem) oil, along with seven known tetranortriterpenoids, azadirone, epoxyazadiradione, nimbin, gedunin, azadiradione, deacetylnimbin, and 17-hydroxyazadiradione. A new protolimonoid, naheedin [3], has been obtained from the neem fruits along with azadirachtol. Their structures have been elucidated through chemical and spectral analyses including 2D nmr studies. The absolute configuration of 1 was established by comparison of its cd spectrum with those of the known tetranortriterpenoids. Mahmoodin showed significant antibacterial activity against various Gram-positive and Gram-negative organisms. Four hydrocarbons, icosane, docosane, 2-methyltricosane, and docosene, have also been identified by gc-ms of the EtOH extract of the fruit coats. Only docosane has earlier been reported from neem, while the remaining three are unreported from this plant.
authors.affiliation: H.E.J. Research Institute of Chemistry, University of Karachi, Pakistan.
authors.forename: S
authors.initials: S
authors.lastname: Siddiqui
authors.forename: S
authors.initials: S
authors.lastname: Faizi
authors.forename: B S
authors.initials: BS
authors.lastname: Siddiqui
authors.lastname: Ghiasuddin
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D001208:Asia; D001419:Bacteria / Q000187:drug effects; D008401:Gas Chromatography-Mass Spectrometry; D036701:Limonins; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D008968:Molecular Conformation; D010946:Plants, Medicinal / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D036701:Limonins; D014315:Triterpenes; C074714:naheedin; C074715:mahmoodin