Metabolite Profiling of Young Safflower (Carthamus tinctorius L.) Shoots at Different Harvest Times

Safflower (Carthamus tinctorius L.) is an oilseed plant species within the Asteraceae family. It is cultivated on a large scale and is widely used in traditional herbal medicine. However, information on changes in the metabolite profiles of young safflower shoots at different harvest times remains limited. Comprehensive metabolite profiling of Carthamus tinctorius L. young shoots harvested at 11, 18, and 21 days after sowing was performed using LC–Q-Orbitrap HRMS. A total of 76 compounds were tentatively identified, representing several major phytochemical groups, including amino acids and related compounds, carbohydrates, other glycosides, phenylpropanoid glycosides, apocarotenoids, hydroxycinnamic acid amides, flavonoids, lignans, and lipids. Exploratory principal component analysis and hierarchical clustering revealed clear differences in metabolite profiles among the three harvest times. Most of the semi-quantified metabolites showed lower contents at the later harvest times, although distinct patterns were observed for individual metabolites. Post-column ABTS profiling indicated that antioxidant activity was predominantly associated with quercetin and luteolin derivatives. Overall, the results demonstrate marked, harvest-time-associated differences in the phytochemical profiles of young safflower shoots.