Anti-inflammatory Limonoids From .

The root barks of perennial herb () were reported to be rich in anti-inflammation activity constituents, limonoids. Then, the investigation of anti-inflammation therapeutic limonoids from this plant was developed in the present study. Through the combination of various chromatographies isolation, six new limonoids, named dictamlimonol A (), dictamlimonoside B (), and dictamlimonols C-F (-), along with seven known ones (-), were obtained. Their structures were ascertained based on the extensive spectroscopic methods and ECD data analysis. Among them, compound was the first 7,19-epoxy limonoid found in natural products. The anti-inflammatory effects of all limonoids were evaluated in lipopolysaccharide (LPS)-treated RAW 264.7 cell lines. Compounds , -, and were found to inhibit LPS-induced nitric oxide (NO) production. Moreover, dictamlimonol D (), fraxinellone (), and dasylactone A () were found to reduce the LPS-induced expressions of interleukin-6 (IL-6), tumor necrosis factor (TNF-α), inducible nitric oxide synthase (iNOS), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and cyclooxygenase-2 (COX-2) at the protein levels in a dose-dependent manner. These findings support that the administration of may be beneficial for inflammation.