Decoction-derived bioactive nanoparticles of Lycopodium japonicum Thunb. attenuate knee osteoarthritis by regulating MAPK/ERK signaling

This study leverages modern nanotechnology and molecular biological approaches to elucidate the scientific rationale underlying the traditional aqueous decoction practice of Lycopodium japonicum Thunb. (LJT) for knee osteoarthritis (KOA), establishing that the spontaneously formed nanoparticles may contribute to the pharmacologically active material foundation, and demonstrating that they confer therapeutic benefits predominantly through modulation of the MAPK/ERK inflammatory pathway, thereby positioning LJT-NPs as a potentially biocompatible, plant-derived nanotherapeutic candidate. LJT constituents were profiled by ultrahigh-performance liquid chromatography coupled with high-resolution mass spectrometry (UPLC-HR-MS) during aqueous decoction, and their self-assembly into supramolecular nanoparticles was observed by transmission electron microscopy (TEM). After optimization, LJT-derived nanoparticles (LJT-NPs) were prepared and biosafety was assessed in vivo . Systems pharmacology predicted the main pathway, and anti-osteoarthritic efficacy was validated in papain-induced KOA rat models and in vitro cellular assays. UPLC-HR-MS analysis indicated that lycopodium alkaloids were the primary components of LJT-NPs. In vivo profiling suggested that this endogenous nanosystem exhibits preliminary biosafety. Systems pharmacology revealed MAPK/ERK as the primary regulatory pathway, and experiments showed attenuated phosphorylation of RAF, MEK, ERK, and ELK1 in vivo and in vitro . Additionally, LJT-NPs ameliorated KOA at low doses via local joint injection. LJT-NPs showed therapeutic potential in KOA models, associated with attenuation of MAPK/ERK pathway hyperactivation. This positions LJT-NPs as a botanical-origin nanotherapeutic candidate with good safety and efficacy profiles. Graphical