Sesquiterpene-rich volatile constituents of Ipomoea obscura (L.) Ker-Gawl.

The hydro-distilled essential oil from flowering aerial parts of Ipomoea obscura (L.) Ker-Gawl. (Convolvulaceae) was investigated by using gas chromatography equipped with a flame ionisation detector GC-FID and gas chromatography coupled with a mass spectrometry (GC/MS). Forty-two components, representing 97.1% of the total oil, were identified. The major constituents of the essential oil were α-bulnesene (23.8%), α-humulene (13.7%) and seychellene (11.2%). The other minor constituents were α-guaiene (8.3%), β-caryophyllene (7.1%), γ-terpinene (4.2%), hexadecanoic acid (3.0%) and β-elemene (2.7%). The oil was found to be rich in sesquiterpene hydrocarbon type constituents (78.4%).