Green synthesis of silver nanoparticles using <i>Padina tetrastromatica</i> against malaria and deciphering the mechanism through machine learning driven metabolomics and network pharmacology

Malaria remains a major public health challenge due to drug and insecticide resistance, underscoring the need for novel therapies with distinct mechanisms of action. In this study, silver nanoparticles were green-synthesized using the brown marine algae Padina tetrastromatica (Ag-PT) and evaluated through integrated in vitro, in vivo, metabolomics, network pharmacology, and in silico approaches. Ag-PT showed potent antiplasmodial activity, with significantly lower IC₅₀ values and superior parasite suppression compared to chemically synthesized silver nanoparticles (Ag-NP). Untargeted metabolomics revealed that Ag-PT treatment specifically restored malaria-induced disruptions in fatty acid, arginine, and arachidonic acid metabolism. This included elevating precursors of specialised pro-resolving mediators (SPMs) such as DHA, 14-HDHA, and 18-HEPE, and replenishing L-arginine to improve nitric oxide synthesis and vascular function. Integration with network pharmacology identified COX-2 (PTGS2) as a key hub gene. Molecular docking and dynamics confirmed strong binding of the Ag-PT phytochemical eriodictyol to COX-2, suggesting inhibition that shifts arachidonic acid metabolism toward anti-inflammatory SPM production. Collectively, these findings reveal that Ag-PT offers a multifaceted therapeutic strategy by simultaneously targeting the parasite while modulating host inflammatory and metabolic pathways. This integrated therapeutic strategy highlights the potential of eco-friendly, plant-based nanomedicines as a next-generation intervention for malaria management.