Molecular Networking Reveals Antioxidant Properties and Phenolic Profiles of Four Rosaceae Seeds

For centuries, four Rosaceae species-Malus sieboldii, Sorbus commixta, Duchesnea indica, and Prunus sargentii-have been prized for their pharmacological properties. In this study, solvent extracts from the seeds of these species were prepared, and their total polyphenol and flavonoid contents were measured. Antioxidant capacity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays, as well as ferric reducing antioxidant power (FRAP) and Fe²⁺ chelation tests. Compounds in the extracts were identified through molecular networking with the Global Natural Products Social Molecular Networking (GNPS) platform. Among all samples, D. indica extract contained the highest polyphenol and flavonoid concentrations (335.63 ± 0.03 mg gallic acid equivalents (GAE) per gram of extract and 230.14 ± 2.90 mg rutin equivalents (RE) per gram of extract, respectively). It also exhibited the strongest antioxidant activity in DPPH, ABTS, and FRAP assays, with statistically significant outcomes. Liquid chromatography/mass spectrometry analysis and molecular networking revealed a diverse metabolite profile corresponding to seven biosynthetic pathways in the extracts. Notably, D. indica extract was rich in shikimates, phenylpropanoids, and ellagic acid derivatives, which have potent antioxidant effects. These results suggest a strong relationship between the extract's chemical profile and its biological activity, offering promising opportunities to use D. indica seeds as functional ingredients across various fields.