title: Natural aromatic steroids as potential molecular fossils from the fruiting bodies of the ascomycete Daldinia concentrica.
abstract: The identification of aromatic steroid hydrocarbons bearing a methyl group at positions 1, 2, 3, 4, or 6 in sediments and petroleum has been puzzling since possible steroidal precursors have not yet been reported in living organisms. Two new aromatic steroids, (17beta,20R,22E,24R)-19-norergosta-1,3,5,7,9,14,22-heptaene (1) and (17beta,20R,22E,24R)-1-methyl-19-norergosta-1,3,5,7,9,14,22-heptaene (2), were isolated from the ascomycete Daldinia concentrica, of which compound 2 bears an unusual methyl group at position 1. We propose that the origin of these compounds is derived from the transformation undergone by their precursor due to microbial action. Compounds 1 and 2 could be the long-sought, biological precursor steroids for organic matter in Earth's subsurface.
authors.affiliation: Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650204, People's Republic of China.
authors.forename: Xiang-Dong
authors.initials: XD
authors.lastname: Qin
authors.forename: Ji-Kai
authors.initials: JK
authors.lastname: Liu
mesh_terms: D001203:Ascomycota / Q000737:chemistry*; D002681:China; D005580:Fossils; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: C497303:(17beta,20R,22E,24R)-1-methyl-19-norergosta-1,3,5,7,9,14,22-heptaene; C497302:(17beta,20R,22E,24R)-19-norergosta-1,3,5,7,9,14,22-heptaene; D013256:Steroids