The chemical composition of the essential oil of C. ambrosioides was determined by GC and
GC/MS. The GC analysis was carried out using a Hewlett-Packard model 5890 apparatus fitted with a
DB-5 fused silica column (30 m × 0.32 mm, 0.25 µm film thickness). The oven temperature was
programmed from 50 to 200 ºC at 5 ºC/min. The injector and detector (FID) temperatures were fixed at 200 ºC and 250 ºC respectively.