LC-HRMS/MS-Guided\nIsolation of Unusual Diarylheptanoids\nfrom the Rhizomes of Alpinia officinarum

LC-HRMS/MS analysis\nfacilitated the precise targeting,\nisolation,\nand identification of unusual dimeric diarylheptanoids from Alpinia officinarum (A. officinarum). The tandem MS data for (4<i>E</i>)-1,7-diphenyl-4-hepten-3-one\n(<b>7</b>) revealed fragment ions at <i>m</i>/<i>z</i> 91, 105, and 117, which are fragmentation patterns specific\nto diarylheptanoids. In the tandem MS data, peaks with <i>m</i>/<i>z</i> values ranging from 450 to 600 that exhibited\nthese specific fragment ions were selected and isolated. Consequently,\ntwo previously undescribed dimeric diarylheptanoids (<b>1</b> and <b>2</b>) and four unusual diarylheptanoids (<b>3</b>–<b>6</b>) along with 10 monomeric diarylheptanoids\n(<b>7</b>–<b>16</b>) were isolated from the rhizomes\nof A. officinarum using various chromatographic\ntechniques. The structures of the isolates were elucidated by an analysis\nof 1D/2D NMR and HRESIMS data, and a combination of DP4+ probability\nanalysis and ECD calculations. To evaluate the anti-inflammatory effects\nof the isolated compounds, their inhibitory activity against nitric\noxide production in LPS-induced RAW 264.7 cells was assessed. Compounds <b>1</b>, <b>7</b>, and <b>9</b> exhibited remarkable\ninhibitory effects with IC<sub>50</sub> values of 14.7, 6.6, and 5.0\nμM, respectively.