Immobilized svPLA2 coupled with UPLC-Q-TOF/MS and molecular docking for rapid screening of snakebite treatment candidates from Hedyotis diffusa Willd. and Paris polyphylla

Developing candidates from medicinal plants for snakebite treatment is quite promising but still remains challenging. The widespread snake venom phospholipase A 2 (svPLA 2 ) is considered as an important therapeutic target for treating snakebite envenomation. In this study, a ligand fishing based platform was established following the immobilization of svPLA 2 onto Fe 3 O 4 magnetic nanoparticles for the first time. After investigating the enzymatic properties and verifying the ligand fishing efficacy, the developed platform was applied to screen svPLA 2 inhibitors from Hedyotis diffusa Willd . and Paris polyphylla . Three compounds (chlorogenic acid, caffeic acid, 2-hydroxycinnamic acid) from Hedyotis diffusa Willd . aqueous extracts and four compounds (rutin, cynaroside, kaempferol, 2-hydroxycinnamic acid) from Paris polyphylla aqueous extracts were screened and identified as potential inhibitors by coupling with UPLC-Q-TOF/MS. Their inhibitory activity was verified through an enzymatic inhibition assay, and their interaction with svPLA 2 enzyme was confirmed by molecular docking. The results demonstrated the developed platform was feasible for the rapid and accurate screening of svPLA 2 inhibitors from medicinal plant extracts. This study provides a strategy for the future development of next-generation antivenom treatments.