45ESSENTIAL OIL COMPOSITIONS OF LEAF, STEM BARK AND ROOT OF ALSTONIA BOONEI DE WILD (APOCYANACEAE)In our quest for active metabolites in natural products which are lesser known, we studied chemical composition of the essential oils using GC and GC-MS, from leaf, stem bark and root parts of Alstonia boonei [Apocynaceae], a Nigerian herb utilized as antimalaria in ethno-medicine. The oils were obtained by hydro-distillation, using an all-glass apparatus adapted to British Pharmacopeia specifications and gave good yields of 0.05 to 1.26%. Eleven, thirteen and twelve compounds were identified respectively in leaf, stem bark and root oils, representing 95.16%, 97.22% and 100% of each oil respectively. Most abundant compounds are (Z)-9-octadecenoic acid in leaf and stem bark, and methyl (7E)-7-octadecenoate in root essential oils. Dominant compounds (%) in leaf are acids (72.20), esters (13.82) and hydrocarbons (6.32); in stem bark are acids (56.20), esters (30.83) and halo-compounds (8.20); in root are esters (85.40), acids (13.36) and hydrocarbons (0.69). Acids and esters dominate the essential oils of Alstonia boonei. Presence of hetero compounds [S,Cl,P,I,N] are unique features of the oils. We present the volatile contents of A. boonei leaf, stem bark and root which have not been earlier reported in literaturefunkemoronkola@yahoo.comResearch312012Essential oils,hydro-distillation,antimalaria, GC and GC-MS, ethno-medicineD.O. Moronkola,O.F. KunleOlabisi Onabanjo University, Department of Chemical Sciences, P.M.B. 2002, Ago-Iwoye, Ogun-State, Nigeria.,National Institute for Pharmaceutical Research and Development, Abuja, Nigeria