UPLC-ESI-TQD-MS/MS Identification and Antioxidant, Anti-Inflammatory, Anti-Diabetic, Anti-Obesity and Anticancer Properties of Polyphenolic Compounds of Hawthorn Seeds

Hawthorn seeds are a by-product of fruit processing and due to the scale of processing of this raw material, they can be an important source of bioactive compounds. This work is the first report on the phenolic composition of hawthorn seeds and their antioxidant, anti-inflammatory, antidiabetic, antiobesity and anticancer activities. In the isolated phenolic fraction of six seed species, 23 phenolic compounds were identified using the UPLC-ESI-TQD-MS/MS method, the key ones of which included the B-type procyanidin dimer. The seeds of the tested species showed high antioxidant activity (mainly by scavenging O₂^•− and OH^• radicals), anti-inflammatory (mainly through LOX inhibition), anti-diabetic, anti-obesity and anti-cancer, with the highest activity against colon cancer cells (Dld-1 line), showing no activity against healthy colon epithelial cells (CCD841CoN). This activity was significantly dependent on the analyzed hawthorn species and, according to PCA analysis, on the content of flavan-3-ols. These discoveries provided the theoretical basis for the possibility of industrial use of hawthorn seeds.