Caffeoylquinic acids and flavones profile in Cynara cardunculus L. seedlings under controlled conditions as affected by light and water-supply treatments

Cynara cardunculus L. is an Asteraceae member widely diffused in the Mediterranean Basin, rich in phenolic acids (caffeoylquinic acids and derivatives), flavones (luteolin, apigenin and their conjugates), anthocyanins, inulin and vitamin C. Thanks to their numerous biological activities, these compounds are in high demand for food and no-food applications. To match such request, in this research we evaluated the effect of three water-supply (100%, 75% and 50% of plant requirement) and light (24 h, 12 h and 0 h) treatments on the polyphenols profile of C. cardunculus seedlings, with the aim of developing a production system under controlled conditions. Overall, the 100% of plant water requirement increased the amount of caffeoylquinic acids (+28%), luteolines (+27%) and total measured polyphenols (+26%) respect to water-stressed plants (75% and 50% of plant requirement), with cultivated cardoon showing a higher concentration than the globe artichoke. Concerning the light treatment, the trend 0 < 12< 24 h was found for all phytochemical compounds. In particular, 24 h of light strongly induced the biosynthesis of caffeoylquinic acids (+119%), luteolines (+273%) and total measured polyphenols (+129%) compared to 0 h of light. In both experiments, the most abundant compounds were 5-O-caffeoylquinic acid and 1,5-O-dicaffeoylquinic acid. Regardless of experiment, the genetic background showed a significant role, since the responses were genotype-dependent. From these results clearly emerged the possibility of producing polyphenols-enriched C. cardunculus seedlings in controlled conditions.