| Summary: | Four new chromones, phomochromenones D–G (<b>1</b>–<b>4</b>), along with four known analogues, diaporchromone A (<b>5</b>), diaporchromanone C (<b>6</b>), diaporchromanone D (<b>7</b>), and phomochromenone C (<b>8</b>), were isolated from the culture of <i>Phomopsis asparagi</i> DHS-48 from Chinese mangrove <i>Rhizophora mangle</i>. Their structures were elucidated on the basis of comprehensive spectroscopic analysis. The absolute configurations of <b>1</b> and <b>4</b> were assigned on the basis of experimental and calculated electronic circular dichroism (ECD) data, and those of enantiomers <b>2</b> and <b>3</b> were determined by a modified Mosher’s method and basic hydrolysis. To the best of our knowledge, phomochromenones D–F (<b>1</b>–<b>4</b>) possessing a 3-substituted-chroman-4-one skeleton are rarely found in natural sources. Diaporchromone A (<b>5</b>) showed moderate to weak immunosuppressive activity against T and/or B lymphocyte cells with IC<sub>50</sub> of 34 μM and 117 μM.
|
|---|