Synthesis and biological evaluation of novel sinomenine derivatives as anti-inflammatory and analgesic agent

Sinomenine (SIN) has long been known as an anti-inflammatory drug, while poor efficiency and large-dose treatment had limited its further application. A series of novel SIN derivatives 1-26 were designed and synthesized to improve its anti-inflammatory activity. The anti-inflammatory activity evaluation showed most of the derivatives exhibited enhanced anti-inflammatory activity in vitro compared to SIN. Compound 17 significantly inhibited LPS-induced secretion of pro-inflammatory factors NO (IC₅₀ = 30.28 ± 1.70 μM), and suppressed the expression of iNOS, IL-6 and TNF-α in RAW264.7 cells. Moreover, compound 17 showed excellent anti-inflammatory in mouse paw edema. Immunohistochemistry results revealed that compound 17 exerted anti-inflammatory activity by inhibiting the pro-inflammatory cytokine TNF-α. Furthermore, compound 17 exhibited an analgesic effect in vivo. The results attained in this study indicated that compound 17 had the potential to be developed into an anti-inflammation and analgesic agent.