Indazole-Type Alkaloids from <i>Nigella sativa</i> Seeds Exhibit Antihyperglycemic Effects via AMPK Activation in Vitro

Six rare naturally occurring indazole-type alkaloids including two new compounds, 17-<i>O</i>-(β-d-glucopyranosyl)-4-<i>O</i>-methylnigellidine (<b>1</b>) and nigelanoid (<b>2</b>), and four known compounds (<b>3</b>–<b>6</b>) were isolated from a defatted extract of <i>Nigella sativa</i> (black cumin) seeds. 17-<i>O</i>-(β-d-Glucopyranosyl)-4-<i>O</i>-methylnigellidine (<b>1</b>) increased glucose consumption by liver hepatocytes (HepG2 cells) through activation of AMP-activated protein kinase (AMPK). Also, this is the first report of compounds <b>4</b> and <b>6</b> from a natural source