Neolignans with anti-inflammatory activity from Piper kadsura (Choisy) Ohwi

Two novel neolignans, piperkadsurenin A (1) and kadsurenin N (2), along with six known neolignans (3-8) and two lignans (9-10) were isolated from the stems of Piper kadsura (Choisy) Ohwi. Extensive spectroscopic data interpretation and ECD calculations were used to identify the structures of the new compounds 1 and 2. Especially, compound 1 represents the first example of neolignan with cyclopenta[b]pyran framework. The anti-inflammatory efficacy of compounds 1-10 in vitro was systematically assessed through NO production inhibitory assay. Compounds 3 and 7 significantly inhibited LPS-induced NO generation in RAW 264.7 cells, with IC₅₀ values of 34.29 ± 0.82 and 47.5 ± 5.81 μM, respectively.