Abstract 
Globe artichoke leaves are highly rich in phenolic acids, in particular chlorogenic acid and dicaffeoylquinic acids. The latter are of particular interest since they can exert a stronger antioxidant activity, due to the presence of two adjacent hydroxyl groups on each of their phenolic rings. Plant tissue and cell cultures have been widely exploited for the production of secondary metabolites. We compared the content of 5-O-caffeoylquinic acid (chlorogenic acid) and 1,5-O-dicaffeoylquinic acid in leaf tissues and calli obtained from leaf explants of two globe artichoke genotypes (SAROM and C3-RR) belonging to the varietal type ‘Romanesco’. HPLC analyses highlighted that chlorogenic acid accumulates preferentially in leaf tissue, while dicaffeoyquinic acid in calli. We previously set up a system, based on UV-C exposure of leaf foliar discs, which was found to induce dicaffeoylquinic acid synthesis. Preliminary results demonstrate that UV-C further increases the content of dicaffeoylquinic acid of 1.5-fold also when applied to callus tissue. Globe artichoke callus culture combined with UV-C radiation may thus represent a promising system for the production of dicaffeoylquinic acids.

1,5-O-dicaffeoylquinic acid (Chengdu Biopurify Phytochemicals Ltd., China)