AUTHOR=Chen Yue , Ruan Jingya , Sun Fan , Wang Huimei , Yang Shengcai , Zhang Ying , Yan Jiejing , Yu Haiyang , Guo Yuanqiang , Zhang Yi , Wang Tao 

TITLE=Anti-inflammatory Limonoids From Cortex Dictamni

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00073

DOI=10.3389/fchem.2020.00073

ISSN=2296-2646

ABSTRACT=<p>The root barks of perennial herb <italic>Dictamnus dasycarpus</italic> (<italic>Cortex Dictamni</italic>) 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 (<bold>1</bold>), dictamlimonoside B (<bold>2</bold>), and dictamlimonols C–F (<bold>3</bold>–<bold>6</bold>), along with seven known ones (<bold>7</bold>–<bold>13</bold>), were obtained. Their structures were ascertained based on the extensive spectroscopic methods and ECD data analysis. Among them, compound <bold>1</bold> 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 <bold>5</bold>, <bold>7</bold>–<bold>11</bold>, and <bold>13</bold> were found to inhibit LPS-induced nitric oxide (NO) production. Moreover, dictamlimonol D (<bold>5</bold>), fraxinellone (<bold>11</bold>), and dasylactone A (<bold>13</bold>) 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 <italic>Cortex Dictamni</italic> may be beneficial for inflammation.</p>