Lignanamides from the roots of Limonium gmelinii (Willd.) Kuntze and their anti-diabetic, cytotoxic and anti-inflammatory activities

Nine undescribed lignanamides, limoniumins A−I, together with ten known lignanamides and two known phenolics were isolated from ethyl acetate extract of the roots of Limonium gmelinii (Plumbaginaceae). Their structures were determined by spectroscopic analysis including 1D and 2D NMR and HRESIMS experiments. Limoniumin A is the first hybrid lignanamide of phenylpropanoid and coumarin. All tested lignanamides showed significant inhibitory activity against α-glucosidase stronger than positive control and remarkable inhibitory effect to PTP1B with IC50 values less than 10 μM. In addition, some lignanamides exhibited moderate cytotoxic activity against HeLa and MCF-7 cells and anti-inflammatory activity against COX-2 in a dose-dependent way. [Display omitted] •Nine undescribed lignanamides were isolated and identified from Limonium gmelinii roots.•Compound 1 is the first hybrid lignanamide of phenylpropanoid and coumarin.•This is the first report on lignanamides from the plants of Plumbaginaceae family.•Most compounds showed potent inhibitory activity against PTP1B and α-glucosidase.