Chemical constituents of the volatile fractions from leaves and flowers of Ocimum urticifolium Roth

Volatile fractions from leaves and flowers of the native African plant Ocimum urticifolium Roth were obtained by steam distillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Twenty-seven compounds, representing 89.0 % of the volatile fraction from the leaves were identified, while fifty-five compounds, representing 63.9 % of the volatile fraction were identified in the flower essential oil. The main sesquiterpene constituent found in the leaves was delta-cadinene (17.2 %) together with beta-caryophyllene (14.5 %) and gamma-muurolene (10.5 %). The dominant monoterpene compound of the leaves was (Z)-beta-ocimene (22.7 %), while the biologically active phenylpropanoid elemicine was detected by 8.8 %. The main sesquiterpene compound detected in the flowers was beta-bisabolene (19.2 %) followed by beta-caryophyllene (10.5 %). The major monoterpene in the flowers was linalool (2.3 %) which was found to be present together with (Z)-beta-ocimene (2.4 %) and camphor (1.5 %). High amounts of elemicine (6.4 %) could also be detected in the flower essential oil. A higher number of monoterpene and sesquiterpene constituents were detected in the flowers compared to the leaves. The yield of the essential oil was 0.48 % and 0.21 % (v/w) for flowers and leaves, respectively.