Indole alkaloid glucosides from the roots of <i>Isatis indigotica</i>

<div><p></p><p>Five new indole alkaloid glucosides named isatindigotindolosides A-E (<b>1–5</b>), along with three known analogs (<b>6–8</b>), were isolated from an aqueous extract of the <i>Isatis indigotica</i> roots. Their structures including the absolute configurations were determined based on comprehensive spectroscopic data analysis, combined with chemical methods and electronic circular dichroism spectra calculations. In the preliminary assays, compounds <b>1</b>, <b>6</b> and <b>7</b> showed antiviral activity against influenza virus A/Hanfang/359/95 (H3N2) with IC<sub>50</sub> values of 14.6–33.3 μM. Compound <b>1</b> also exhibited inhibitory effect against nitric oxide (NO) production in microglial cell BV2 with an inhibition ratio of 93.0% at 10 μM.</p></div>