The Chemical constituents in essential oils of Pterocarpus soyauxii leaf, leaf stalk and stem bark

Abstract

The Nigerian essential oils of fresh Pterocapus soyauxii leaf, leaf stalk and stem bark were isolated by hydro-distillation using the adapted all glass Clevenger’s apparatus designed to British Pharmacopeia specifications. Chemical compositions of the plant parts were characterized using Gas Chromatography-Mass Spectroscopy (GC-MS).
 The leaf essential oil contained 12 compounds, out of which 10 were identified accounting for 93.91% of it. Leafstalk oil had 20 major compounds, which were characterised; they constitute 95.47% of the oil. 11 compounds make up 78.61% of stem bark oil, out of which 7 were characterised, responsible for 76.30% of it.
 Prominent compounds in the leaf oil were cembrene (43.59%), a monocyclic diterpenoid, eremophilene (29.72%), and azulene derivatives (6.62%), which are polycyclic aromatic compounds. Leaf stalk oil was dominated by hexadecane (32.97%), cis- and trans- β-ocimene (11.60 and 7.74% respectively) and heptanol (8.39%). Major compounds in stem bark oil were neophytadiene (22.11%), 2-heptanol (19.27%) and 3,7,11,15-Tetramethyl-2-hexadecene-1-ol (14.35%). Other prominent compounds in the stem bark oil are 4-propyl-cyclohexene (4.83%), 3-Eicosyne (7.63%), 3,7,11-trimethyl-14-(1-methylethyl-[S-(E,Z,E,E)]-1,3,6,10-cyclodecatetraene (5.10%) and methyl-Z-5,8,11,14,17-Eicosapentaenoate (3.01%).
 Notable compounds of biological importance and in appreciable amounts in the oils include phytol (6.93%), squalene (1.14%) and ambrial (1.97%). Fragmentation patterns in the mass spectrum of some unidentified compounds are also presented which are unique features of the oils.
 Interesting classes of compounds in the three oils include monoterpenes, sesquiterpenes, diterpenes, naphthalenes, alcohols and hydrocarbons.