Isolation and identification of the five major sesquiterpene hydrocarbons of ginger

Forty‐eight different ginger oils from nine countries spanning four continents have been investigated by dual capillary gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). All oils were found to contain the same five major sesquiterpene hydrocarbons. Two of them were isolated in one step from an Indian oil by an efficient reversed phase high performance liquid chromatographic (RP‐HPLC) separation. The other three were isolated by a combination of RP‐HPLC and preparative capillary GC. They were identified by UV, MS, 1H NMR and 13C NMR as α‐zingiberene (1), β‐bisabolene (2), (E,E)‐α‐farnesene (3), β‐sesquiphellandrene (4) and ar‐curcumene (5). The reported absence of some of these compounds in earlier studies could in many cases be explained by unsatisfactory separations, misidentifications and confusion in the nomenclature.