GC-MS analysis of the volatile constituents of Orthosiphon pallidus Royle, ex Benth.

The hydro-distilled essential oil from aerial parts of Orthosiphon pallidus Royle, ex Benth (Lamiaceae) was investigated by using gas chromatography equipped with a flame ionisation detector (GC-FID) and gas chromatography coupled with a mass spectrometry (GC-MS). Fifty-two compounds, representing 98.4% of the total oil constituents, were identified. The major constituents were β-caryophyllene (17.4%) and 7-epi-α-selinene (15.2%). The other minor constituents were terpinolene (6.9%), β-pinene (6.8%), β-elemene (5.1%), α-humulene (4.9%), α-copaene (4.8%), epi-cubebol (4.5%) and zonarene (3.9%). The oil was found to be rich in sesquiterpene hydrocarbon type constituents. Lamiaceae[Formula: see text].