Rapid Structure-Based Annotation and Profiling of Dihydrochalcones in Star Fruit (Averrhoa carambola) Using UHPLC/Q-Orbitrap-MS and Molecular Networking.

Dihydrochalcones are a subclass of flavonoids. There has been growing interest in dihydrochalcones for their health benefits and potential to modulate flavor, but their comprehensive profile in diverse plant species is lacking. Star fruit is a tropical fruit rich in dihydrochalcones. In this study, a systematic annotation using UHPLC/Q-Orbitrap-MS and molecular networking was established to rapidly identify dihydrochalcones in 12 star fruit cultivars. A total of 53 dihydrochalcones were characterized within a short retention time including one novel compound (phloretin-3'-C-(2-O-trans-p-coumaroyl)-β-d-fucopyranoside) and 23 compounds identified from the Averrhoa genus for the first time. 3-Hydroxyphloretin was the most abundant dihydrochalcone in star fruit. All the identified dihydrochalcones had a higher abundance in leaves compared to fruits. This is the first report that systematically investigates dihydrochalcones in star fruit of multiple cultivars, and the results could provide a useful reference for the future development and utilization of plant genetic resources.