Elaboration a ROS-responsive darutigenol prodrug nanoassemblies for inflammatory arthritis treatment

Darutigenol (DL) is an active diterpenoid extracted from the traditional Chinese medicine Sigesbeckia glabrescens (Makino) Makino, widely employed in the treatment of rheumatoid arthritis (RA) for centuries in China. However, the anti-inflammatory mechanism of DL requires further exploration. In this study, we discovered that DL could scavenge reactive oxygen species (ROS) and nitric oxide (NO), and reduce the secretion of proinflammatory cytokines, inducing the M1-to-M2 polarization of macrophages in vitro. In vivo, DL was demonstrated to exert an anti-inflammatory effect via the JAK1, 3/STAT3 and MAPK pathways. It also showed efficacy in repairing cartilage damage via downregulating the proteins MMP2/MMP9 and inhibiting angiogenesis through the CXCL12/CXCR7 system in synovial tissues. However, the application and therapeutic effect of DL was constrained by its poor water solubility and low bioavailability. To address these limitations, ROS-responsive prodrug nanoassemblies were employed, which could be passively transported to the joint inflammation site and decomposed in the inflammatory environment to release DL. The therapeutic effect of prodrug nanoassemblies was superior to that of DL, with negligible toxicity to organs. In summary, we clarified the anti-RA mechanism of DL and constructed an efficient and safe drug delivery system, which provided a strategy for the further application and development of active compounds in traditional Chinese medicine.