Synthesis and Anti-Inflammatory Effect of Sinomenine 4-Hydroxy Esters

In order to find more active anti-neuroinflammatory sinomenine derivatives, 17 sinomenine 4-hydroxy esters were designed and prepared. All synthesized derivatives were structurally confirmed by ESI-MS and PMR. Their anti-neuroinflammatory effects were evaluated using LPS-stimulated BV-2 microglia cells. Among them, four compounds presented more than 80% of cell viability. Compound 8 showed remarkable inhibition of nitric oxide (NO) release by the Griess method. Furthermore, esters 5–9 were tested to check their suppressive effects on xylene-induced ear edema. It was observed that 8 was more active and less toxic than 5–7 with shorter aliphatic chains.