Molecular networking-enabled metabolomics of Reichardia tingitana (Asteraceae): extensive MS/MS annotation and NQO1 induction–linked chemoprotective activity

Reichardia tingitana belongs to the family Asteraceae, which is one of the biggest families of the Egyptian flora. Only two Reichardia species, Reichardia picroides (L.) and Reichardia tingitana (L.), were recorded in the Egyptian flora. In this work, we aimed to explore the metabolome of R. tingitana. An LC-MS/MS ESI (+/−) analysis approach synchronised with a feature-based molecular network (FBMN) was adopted to provide a comprehensive overview of the metabolome variety of R. tingitana. A total of 82 metabolites were putatively annotated (MSI Level 2), encompassing phenolic acids, flavonoids, terpenes, lipids, benzofurans, lignans, chlorophyll derivatives and purines. Five of these metabolites were individually isolated, and their structures were elucidated using NMR spectroscopy. The non-polar extract caused a 3.9-fold induction of chemopreventive NQO1 protein expression in the Hepa1c1c7 model, compared to vehicle control. Also loliolide (18) showed a 1.4-fold induction in NQO1 protein expression, compared to control.