Compositional variation of the essential oils of Artemisia afra Jacq. from three provinces in South Africa--a case study of its safety.

Safety of Artemisia afar has been a controversial issue due to its high thujone content. Despite the declaration of the World Health Organization in the 1970s of the plant being unsafe for consumption, it is still commonly used in folklore medication in South Africa, especially in winter. Essential oils were isolated by hydrodistillation from the twigs of A. afra plants from different locations in the Eastern Cape, Free State and KwaZulu-Natal. Analyses of the oils by GC and GCMS revealed compositional variations in the levels of alpha-and beta-thujone, 1,8-cineole and camphor. alpha-Thujone was the major component of the essential oils ofA. afra from Philippolis (Free State) and Keiskammahoek (Eastern Cape) (62-74%), while the camphor content was very low (< or = 0.1-0.6%). The samples from Gqumahshe, Hogsback (Eastern Cape) and Empangeni (KwaZulu Natal) had low a-thujone contents (3.7-20.0%) while 1,8-cineole (13.0-49.5%) and camphor (13.9-21.2%) were the main components of the essential oils. It was further observed that the concentration of alpha-thujone increased significantly in the dry leaves when compared with the fresh leaves. This implies that fresh leaves are better used for infusion than dry leaves. This study reveals that not all A. afra contain high concentrations of alpha- and beta-thujone.