Analysis of the Essential Oil from Twigs of Hemizygia welwitschii (Lamiaceae)

ABSTRACT The composition of the essential oil from Hemizygia welwitschii twigs was analyzed by means of GLC, LSC and GC/MS. The portion investigated so far consisted of 51% sesquiterpene hydrocarbons, 17% monoterpene hydrocarbons, 17% oxygen-containing sesquiterpenes, 6% oxygencontaining monoterpenes and 2% oxygen-containing, straight chain aliphatic compounds. The main components were β-caryophyllene (35%) and trans-α-bergamotol (11%); this is the first reported occurrence of the latter compound in Lamiaceae. The composition of the oil of H. welwitschii has not been reported previously. Additionally, 30–40% diterpenes were detected in the total oil.