title: Seasonal variation in the essential oil of Pilocarpus microphyllus Stapf.
abstract: The essential oils of the leaves and fine stems of Pilocarpus microphyllus, collected on iron mineralized soil of the Serra de Caraj s, Southeast of Par  State, Brazil, during the rainy and dry seasons, were obtained by hydrodistillation and analyzed by GC-MS. The main identified compounds were 2-tridecanone, beta-caryophyllene, 2-pentadecanone, caryophyllene oxide and germacrene D. Their percentage contents varied with the season, the greater values having been detected mainly in the rainy season. For 2-tridecanone and beta-caryophyllene the higher values were observed in the fine stem oils for the former, and in the leaf oils for the latter. For 2-pentadecanone, caryophyllene oxide and germacrene D they were also in the leaf oils. In general, the leaf oils were very distinguishable from those of fine stem oils, even in the same specimen.
authors.affiliation: Universidade Federal do Maranhão, Departamento de Química, São Luis, MA, Brazil.
authors.forename: Francisca S N
authors.initials: FS
authors.lastname: Taveira
authors.forename: Eloisa H A
authors.initials: EH
authors.lastname: Andrade
authors.forename: Waterloo N
authors.initials: WN
authors.lastname: Lima
authors.forename: José G S
authors.initials: JG
authors.lastname: Maia
mesh_terms: D009822:Oils, Volatile / Q000032:analysis* / Q000737:chemistry; D032103:Pilocarpus / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D012621:Seasons
chemical_list: D009822:Oils, Volatile