Eriodictyol

Ligand fishing with immobilized enzymes offers a promising approach for screening natural active compounds in complex extracts. Key challenges in enzyme immobilization include maintaining structural integrity and enhancing loading capacity. This study employed hydrogen-bonded organic frameworks (HOFs), eco-friendly porous materials synthesized via hydrogen bonding, to immobilize elastase (ELA) through self-assembly for affinity screening of ELA inhibitors from Coreopsis tinctoria Nutt. The successful fabrication of ELA@HOF was validated using techniques such as SEM, TEM, FT-IR, XRD, XPS, TGA, and BET. HOFs significantly improved enzyme loading capacity (524.4 mg/g), immobilization rate (85.7%), specific activity (25.7 U/mg) and stability (notable acid resistance) compared to conventional methods. ELA@HOF demonstrated remarkable repeatability for ligand fishing which was reusable for 12 cycles. Seven inhibitors of ELA were extracted from extracts of C. tinctoria, which were identified by UPLC-MS combined with comparison with authentic samples as isookanin, taxifolin, marein, 7,3',5'-trihydroxyflavanone, okanin, eriodictyol, and sulfuretin. The ELA inhibitory activity and enzymatic kinetic study were further investigated, revealing a significant level of inhibition. Molecular docking technique was used to simulate the interaction between the ligand and ELA. These findings suggest the great potential of hydrogen-bonded organic frameworks for the rapid screening of active natural compounds.

Pistacia chinensis is used as a decorative tree and currently studied as a source of biofuels. Besides, its parts and extracts are endowed with several therapeutic uses which have been widely explored in traditional medicine and that are related to its rich composition in phytochemicals. Molecular docking and enzymatic inhibition tests were used to study the activity of eriodictyol, a flavonoid extracted from the barks of P. chinensis, against ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and aldose reductase (ALR2). The compound was highlighted as a micromolar inhibitor in vitro (IC₅₀ = 263.76 ± 1.32 µM and 4.21 ± 0.94 µM, respectively) and docking showed that eriodictyol efficiently targets the binding sites of the enzymes. In conclusion, this study unveils the potential of eriodictyol on enzymes that are involved in immunostimulation and in complications of diabetes mellitus.