New depside and rosmarinic acid derivatives from Perilla frutescens and their anti-inflammatory activity

Two new depside derivatives 1 and 2 as well as a new pair of rosmarinic acid enantiomers 3a/b were isolated from the leaves of Perilla frutescens (L.) britt. The chemical structures of these compounds were identified based on detailed spectroscopic and physicochemical analyses (HR-ESI-MS, NMR) and comparison of literature data. Compounds 3a/b were obtained by chiral separation, and their absolute configurations were determined by comparison of experimental and calculated ECD spectra. Compounds 3a/b exhibited potential inhibitory activity on nitric oxide (NO) production induced by lipopolysaccharide in RAW264.7 cells with IC₅₀ values of 15.92 ± 3.32 μM and 48.72 ± 4.12 μM.