Comparative study of the chemical composition of the essential oils from organs of Annona senegalensis Pers. oulotricha le Thomas subspecies (Annonaceae)

The chemical composition of the essential oils from leaves, stems bark, roots bark, epicarp and mesocarp of Annona senegalensis Pers., oulotricha Le Thomas subspecies (Annonaceae), growing in Brazzaville (Congo), were analyzed by CG and CG-MS. These oils essentially contain sesquiterpenic compounds (58.3-97.7%), dominated by oxygenated sesquiterpenes (21.8-88.3%), with elemol (13.2-35.0%), beta and gamma-eudesmols (3.7-58.3%) as characteristic components. The essential oils from roots and stems bark is distinguished by its high content in diterpenes (17.1 and 11.9% of the total), while the seeds presents a significant amounts of monoterpene hydrocarbons (25.8%) with alpha-pinene (6.2%) and beta-phellandrene (11.5%) as major components accompanied by two oxygenated monoterpenes : bornyle acetate (4.5%) and smallest of 1,8-cineole. However, in the epicarp oil, the presence of about 5.8% of oxygenated monoterpenes as terpinen-4-ol and bornyle acetate in comparable rates (1.7%) was noted. The mesocarp oil is exclusively rich in aliphatic fatty acids (35.8%) which is absent in the other organs, but represented by lauric acid (18.0%), hexadecanoic acid (8.6%), myristic acid (7.2%) and oleic acid (2.0%). Results were compared with same species collected in the democratic republic of Congo and in Cameroon essentially dominated by monoterpenes (84.2 and 87.6%).