Bioactivity assay coupled with molecular networking for the discovery of antioxidants from purslane

This study presents an innovative integration of bioactivity-guided isolation with molecular networking for discovery of the antioxidants from purslane (Portulaca oleracea L.), which is popular as a medicinal and edible plant worldwide. This strategy led to the isolation and characterization of 31 indoline amide glucosides (IAGs), including 21 previously undescribed ones, namely portuoleramides A-U. Among them, nine compounds showed stronger DPPH radical scavenging activity than vitamin C (EC₅₀ = 24.66 μM), compound 21 is strongest (EC₅₀ = 15.70 μM). Almost all IAGs displayed ABTS radical scavenging capacity, compounds 12, 17, and 21-23 showed the most potent effects with EC₅₀ values range from 5.07 to 5.99 μM. In the t-BHP-induced HaCaT cell model, the majority of IAGs displayed cytoprotective effect. Notably, compound 14 significantly mitigated oxidative damage by modulating intracellular ROS levels. These findings provide a foundational basis for employing purslane-derived antioxidants in the food, cosmetic, and pharmaceutical fields.