The use of hairy root cultures to screen for bio-active principles in Cichorium intybus

Hairy roots, formed by plant cells after transformation with the soil bacterium Agrobacterium rhizogenes, have been found to be a suitable technology for the production of secondary metabolites. The aerial part of Cichorium intybus L. (Asteraceae) mainly contains derivatives of hydroxycinnamic acid, including chlorogenic acid and dicaffeoylquinic acids [1, 2]. These acids were identified in the roots by UPLC^TM and showed radical-scavenging properties toward the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in a TLC autographic assay. Their biological effects are of interest for the pharmaceutical, food and cosmetic industries. For this reason hairy root culture of Cichorium intybus L. was developed. In order to increase the production of these compounds, different elicitors and stress factors like methyl jasmonate, UV light, Bion® and iron deficiency were used. We could show that methyl jasmonate at a concentration of 1000µM increases the production of chlorogenic acid and dicaffeoylquinic acid at least up to 400% of the control. Hairy root cultures optimised in this work showed a strong potential for the production of secondary metabolites, especially for chlorogenic and dicaffeoylquinic acid. They provide the advantages of a rapid growth and easy culture conditions; moreover, they give the possibility to enhance the synthesis of secondary metabolites by elicitors or stress factors.

References: 1. Leung, A.J., Foster, S (2003) Encyclopedia of common natural ingredients: Used in food, drugs and cosmetics. Wiley & Sons. New York. 2 Mulinacci, N. et al. (2001) Chromatographia 54:455–461.