Profiling chicory sesquiterpene lactones by high resolution mass spectrometry

Sesquiterpene lactones (SLs) are the main determinants of radicchio bitterness and the control of their concentrations is a key point for the market value of this product. An innovative analytical approach based on two complementary mass spectrometers, Orbitrap-HRMS and MS/MS, was used for quantitative analysis of SLs in aerial part of four different varieties of chicory. Data highlighted the presence of eight SLs: 11β,13-dihydrolactucin, lactucin, 8-deoxy-lactucin, dihydro-8-deoxylactucin, dihydrolactucopicrin, lactucopicrin, lactuside C (jaquinellin glucoside) and dihydro-lactucopicrin oxalate. Significant varietal differences were found. The highest amount of SLs was found in the radicchio “Treviso Precoce” variety (189.71 μg/g), the lowest amount in “Treviso Tardivo” variety (45.78 μg/g). Lactucopicrin was the most abundant compound with concentration ranged between 99.36 in “Treviso Precoce” and 13.50 μg/g in “Treviso Tardivo” while dihydro-lactucopicrin oxalate was the less abundant in all analyzed varieties with an average concentration of about 1% on the total amount of SLs.