A new pyrrolopyrazine alkaloid from the fruit of <i>Lycium chinense</i>

A new pyrrolopyrazine alkaloid, named lycipyrazine A (<b>1</b>), alone with seven known alkaloids (<b>2</b>-<b>8</b>), were isolated from the fruit of <i>Lycium chinense.</i> The structure of new compound <b>1</b> was determined using extensive 1D and 2D spectroscopic analyses, while its absolute configuration was determined by comparison of its experimental and calculated ECD spectra. Their <i>α</i>-glucosidase inhibitory activity was screened using acarbose as a positive control. Compound <b>4</b> showed strong inhibitory activity against <i>α</i>-glucosidase (IC₅₀ = 3.04 ± 0.38 μM). This study enriched the structural diversity of alkaloids in <i>L. chinense</i> and provided further clues for searching new antidiabetic agents from natural sources.