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

Abstract

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.