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.