Anti-Allergic Compounds from the Deep-Sea-Derived Actinomycete Nesterenkonia flava MCCC 1K00610

Abstract

A novel cyclic ether, nesterenkoniane (<b>1</b>), was isolated from the deep-sea-derived actinomycete <i>Nesterenkonia flava</i> MCCC 1K00610, together with 12 known compounds, including two macrolides (<b>2</b>, <b>3</b>), two diketopiperazines (<b>4</b>, <b>5</b>), two nucleosides (<b>6</b>, <b>7</b>), two indoles (<b>8</b>, <b>9</b>), three phenolics (<b>10</b>-<b>12</b>), and one butanol derivate (<b>13</b>). Their structures were established mainly on detailed analysis of the NMR and MS spectroscopic data. All 13 compounds were tested for anti-allergic activities using immunoglobulin E (IgE) mediated rat mast RBL-2H3 cell model. Under the concentration of 20 μg/mL, <b>1</b> exhibited moderate anti-allergic activity with inhibition rate of 9.86%, compared to that of 37.41% of the positive control, loratadine. While cyclo(d)-Pro-(d)-Leu (<b>4</b>) and indol-3-carbaldehyde (<b>8</b>) showed the most potent effects with the IC₅₀ values of 69.95 and 57.12 μg/mL, respectively, which was comparable to that of loratadine (IC₅₀ = 35.01 μg/mL). To the best of our knowledge, it is the first report on secondary metabolites from the genus of <i>Nesterenkonia</i>.