title: Precocene I and Other Constituents of the Essential Oil of Platostoma africanum.
abstract: The essential oil from the herb PLATOSTOMA AFRICANUM was analysed by means of GLC, LSC and GC-MS. So far a large number of its components were identified, among which were 16 sesquiterpene hydrocarbons (43%), seven phenylpropane derivatives (16%), seven oxygen-containing, straight-chain aliphatic compounds (11%), and six oxygen-containing sesquiterpenes (5%). Monoterpenes were present in small amounts only. An estimated 10% of the total oil was made up of diterpenes. The main component of the oil was germacrene-D (19%). An unusual component was found to be the chromene derivative precocene I (11%), which is an insect anti-juvenile hormone. This is, as far as we know, the first detection of a chromene in the family Lamiaceae. The composition of the oil of P. AFRICANUM has not been reported previously. The method of isolation affected the yield, composition, and odour of the oil.
authors.affiliation: Division of Pharmacognosy, Center for Bio-Pharmaceutical Sciences, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: O A
authors.initials: OA
authors.lastname: Onayade
authors.forename: A
authors.initials: A
authors.lastname: Looman
authors.forename: J J
authors.initials: JJ
authors.lastname: Scheffer
authors.forename: A B
authors.initials: AB
authors.lastname: Svendsen