Chemical markers of pulp, shreds and inflorescence axis of Artocarpus heterophyllus Lam. and their xanthine oxidase inhibitory activity

To understand the chemical markers and their xanthine oxidase (XO) inhibitory activities in the pulp, shreds and inflorescence axis of A. heterophyllus , an investigation guided by UHPLC-OE-MS tracking, in vitro activity screening and molecular docking was carried out. The inflorescence axis exhibited an XO inhibition rate of 31.87%, significantly higher than that of the pulp (6.69%) and shreds (3.75%), which was closely associated with its abundant content of flavonoids. Further analysis identified flavonoids such as luteolin ( Fl2 ), kaempferol ( Fl3 ), quercitrin ( Fl4 ) and 8-prenylluteone ( Fl16 ) serve as potential contributors to the XO inhibitory activity. Molecular docking with XO revealed binding energies below − 5.0 kcal/mol for above compounds. 8-Prenylluteone ( Fl16 ) showed the strongest interaction, with the lowest binding energy of -8.8 kcal/mol, suggesting its enhanced activity was attributed to the isopentenyl side chain attached to the flavonoid skeleton. This study provided a new perspective for discovering XO inhibitors from A. heterophyllus by-products.