Four new isoquinoline alkaloids from Dactylicapnos lichiangensis and their anti-inflammatory activity.

Four undescribed protoberberine isoquinoline alkaloids (1-4), along with twenty-six known alkaloids (5-30) were isolated from the aerial parts of Dactylicapnos lichiangensis. The structures and absolute configurations of 1-4 were established through comprehensive spectroscopic analysis and quantum chemical calculations. Compounds 1, 2 and 4 were evaluated for their anti-inflammatory activity. In vitro assays showed dose-dependent inhibition of nitric oxide production in LPS-stimulated macrophages, and significant suppression of TNF-α and IL-6 secretion.