Rational design of curcumin-borneol hybrids for rheumatoid arthritis pathological intervention via AKT/mTOR/HIF-1α pathway modulation

A traditional medicine-inspired strategy provides a logical framework for constructing carrier-free hybrids. • Precise structural modifications successfully circumvent the inherent bioaccessibility limitations of natural products. • The covalent integration of diverse functional modules enables synergistic therapeutic efficacy against arthritis. • The therapeutic action is closely associated with the modulation of protein kinase B and hypoxia-inducible factor signaling. Curcumin (Cur) possesses potent anti-inflammatory activity but faces clinical challenges due to poor aqueous dispersibility, insufficient membrane affinity, and low bioavailability. Borneol (Bor), a classic “envoy” component in Traditional Chinese Medicine (TCM), exhibits prominent membrane-penetrating properties. Inspired by the “monarch-envoy” compatibility theory, we rationally designed carrier-free hybrids by covalently conjugating Cur (“monarch”) with Bor (“envoy”). Systematic characterization confirmed the successful synthesis and controllable optimization of key properties, including enhanced dispersibility, improved cellular uptake, and favorable biocompatibility. Using rheumatoid arthritis (RA) as a disease model, we identified SCBMS as the optimal formulation owing to its superior dispersibility and uptake, which directly translated into the most potent anti-RA efficacy. The hybrids exerted synergistic multifunctional effects—including robust anti-inflammatory and antioxidant activities—effectively reducing the arthritis index and ameliorating synovial hyperplasia and joint destruction in vivo . Mechanistically, our results indicate a close correlation between the therapeutic effects and the downregulation of the AKT/mTOR/HIF-1α signaling pathway, supporting the involvement of this pathway in the observed anti-RA activity. This study provides a generalizable framework for developing functional hybrids guided by TCM principles and validates their translational potential. Download: Download high-res image (152KB) Download: Download full-size image