title: Purification, identification, concentration and bioactivity of (Z)-7-dodecen-1-yl acetate: sex pheromone of the female Asian elephant, Elephas maximus.
abstract: In their natural ecosystems, adult male and female Asian elephants, Elephas maximus, live separately. For several weeks prior to ovulation, female elephants release a substance in their urine which elicits a high frequency of non-habituating chemosensory responses, especially flehmen responses, from male elephants. These responses occur prior to, and are an integral part of, mating. Using bioassay-guided fractionation, quantitatively dependent on these chemosensory responses, a specific sex pheromone was isolated and purified by an alternating series of organic and/or aqueous extractions, column chromatography, gas chromatography and high-performance liquid chromatography. Using primarily 1H-proton nuclear magnetic resonance (NMR) spectrometry and gas chromatography-mass spectrometry (GC-MS) of the urine-derived pheromone and its dimethyl disulfide derivative, we determined the structure of the active compound to be (Z)-7-dodecen-1-yl acetate (Z7-12:Ac). Concentrations of Z7-12:Ac in the female urine increased from non-detectable during the luteal phase to 0.48 microgram/ml (0.002 mM) early in the follicular phase and to 33.0 micrograms/ml (0.146 mM) just prior to ovulation. Bioassays with commercially available authentic synthetic Z7-12:Ac, using 10 Asian male elephants at several locations in the US, demonstrated quantitatively elevated chemosensory responses that were robust during successive tests, and several mating-associated behaviors. Bioassays with Z7-12:Ac with adult male elephants dwelling in more natural social situations in forest camps in Myanmar revealed some differing contextual pre-mating behavioral components. The remarkable convergent evolution of this compound suggests that compounds identified in mammalian exudates that are also present in pheromone blends of insects should be re-evaluated as potential mammalian chemosignals.
authors.affiliation: Department of Chemistry, Biochemistry, and Molecular Biology, Oregon Graduate Institute of Science and Technology, Portland 97291-1000, USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Rasmussen
authors.forename: T D
authors.initials: TD
authors.lastname: Lee
authors.forename: A
authors.initials: A
authors.lastname: Zhang
authors.forename: W L
authors.initials: WL
authors.lastname: Roelofs
authors.forename: G D
authors.initials: GD
authors.lastname: Daves
mesh_terms: D000818:Animals; D001681:Biological Assay; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D007851:Dodecanol / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology / Q000652:urine; D004606:Elephants; D004971:Estrus / Q000378:metabolism / Q000652:urine; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D010060:Ovulation / Q000652:urine; D010675:Pheromones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*
chemical_list: D010675:Pheromones; C001993:7-dodecen-1-yl acetate; D007851:Dodecanol