| Summary: | The dried vine stems of <i>Spatholobus suberectus</i> are commonly used in traditional Chinese medicine for treating gynecological and cardiovascular diseases. In this study, five new compounds named spasuberol A (<b>2</b>), homovanillyl-4-oxo-nonanoate (<b>5</b>), spasuberol C (<b>6</b>), spasuberoside A (<b>14</b>), and spasuberoside B (<b>15</b>), together with ten known compounds (<b>1</b>, <b>3</b>, <b>4</b>, <b>7</b>−<b>13</b>), were isolated from the dried vine stems of <i>S. suberectus</i>. Their chemical structures were analyzed using spectroscopic assays. This is the first study interpreting the detailed structural information of <b>4</b>. The anti-inflammatory activity of these compounds was evaluated by reducing nitric oxide overproduction in RAW264.7 macrophages stimulated by lipopolysaccharide. Compounds <b>1</b> and <b>8</b>−<b>10</b> showed strong inhibitory activity with half maximal inhibitory concentration (IC<sub>50</sub>) values of 5.69, 16.34, 16.87, and 6.78 μM, respectively, exhibiting higher activity than the positive drug <span style="font-variant: small-caps;">l</span>-<i>N</i><sup>6</sup>-(1-iminoethyl)-lysine (<span style="font-variant: small-caps;">l</span>-NIL) with an IC<sub>50</sub> value of 19.08 μM. The IC<sub>50</sub> values of inhibitory activity of compounds <b>2</b> and <b>4</b>−<b>6</b> were 46.26, 40.05, 45.87, and 28.29 μM respectively, which were lower than <span style="font-variant: small-caps;">l</span>-NIL, but better than that of positive drug indomethacin with an IC<sub>50</sub> value of 55.44 μM. Quantitative real-time polymerase chain reaction analysis revealed that assayed compounds with good anti-inflammatory activity, such as <b>1</b>, <b>6</b>, <b>9</b>, and <b>10</b> at different concentrations, can reduce the messenger RNA (mRNA) expression of some pro-inflammatory cytokines such as tumor necrosis factor α (TNF-α), nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX-2). The anti-inflammatory activity and the possible mechanism of the compounds mentioned in this paper were studied preliminarily.
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