Comparative investigation of sesquiterpene components of essential oils originating from intact plants and hairy root chamomile cultures

The importance of chamomile (Chamomilla recutita) inflorescence is widely known in classical and folk medicine, with the largest group of its effective constituents forming the essential oil (chamazulene, a-bisabolol, α-farnesene, trans-β-farnesene, spathulenol, cis/trans-en-in-dicycloethers). Among cultivated species, the Hungarian BK-2 contains more chamazulene in its essential oil than the German Degumil type, which is mainly cultivated for its a-bisabolol. Both components have important antiinflammatory activities.

Wild populations can be easily distinguished from cultivated ones by their high amount of bisaboloides, particularly the flower of Hungarian Szabadkígyós wild type, which contained on average 48 % of the biologically active (-)-a-bisabolol. The population of Szabadkígyós has good salt tolerance which is important owing to global warming, because the proportion of saline areas is increasing worldwide.

To keep the genome of Szabadkígyós having high (-)-a-bisabolol content, Szőke and research team used biotechnological methods.

Sterile plantlets, were infected by Agrobacterium rhizogenes strains #A-4, #15834, #R-1601. The hairy root clones possessing the best growing and biosynthetical potential were multiplied for phytochemical investigations. Pharmacologically important compounds of their essential oils were followed in great detail. The amount of in vitro cultured terpenoids and polyin compounds was compared with that of in vivo plants.

GC-MS studies showed that sterile chamomile cultures generated the most important terpenoid and polyin compounds characteristics of the mother plant. Berkheyaradulene, geranyl-isovalerat and cedrol as new components were identified in these sterile cultures. The main component of hairy root cultures (D/400, D/1, D/100 and Sz/400) was tr-b-farnesene and in addition one new compound: a-selinene was identified. Hairy root culture originated from chamomile collected in Szabadkígyós was intensive increased the essential oil content and pharmacological active compounds: (-) -α-bisabolol and β-eudesmol was also synthetized in large quantity. Furthermore, in vitro organized cultures were made from this population to obtain propagation material containing numerous active substances.