Sesquiterpenes-Rich Essential Oils ofPolyalthia longifoliaThw. (Annonaceae) from Nigeria

The essential oils of the leaf and stem bark of Polyalthia longifolia Thw. (Annonaceae) have been studied for their constituents by means of GC and GC/MS. The leaf oil was almost exclusively composed of sesquiterpene derivatives, being represented by allo-aromadendrene (19.7%), caryophyllene oxide (14.4%), β-caryophyllene (13.0%), β-selinene (7.9%), α-humulene (7.0%) and ar-curcumene (6.8%). However, α-copaene and α-muurolol (ca. 8.7%), β-selinene (8.6%), viridiflorene (8.1%), α-guaiene (7.8%), allo-aromadendrene (7.4%) and δ-cadinene (7.0%) were the major constituents occurring in the oil of the bark sample. All the other sesquiterpenoid compounds were observed in amount greater than 1%. α-Pinene (0.5%) and camphene (tr), which are the two monoterpenoids present in the leaf oil, could not be detected from the bark essential oil.