Two new glycosides from Stachys geobombycis CYWu

Two new compounds geobomlin A (1) and geobomlin B (2) were isolated from the roots of Stachys geobombycis C. Y. Wu. Structural determinations were established principally by two-dimensional NMR and MS data analyses. Geobomlin B showed moderate inhibitory activity against alpha-glucosidase with IC50 = 248.77 mu M. We have also determined the mechanism by which geobomlin B elicit its inhibitory effect on alpha-glucosidase, for which we have established a competitive inhibition mode. Docking studies confirmed our results on geobomlin B alpha-glucosidase inhibitory properties.