New dammarane-type glucosides as potential activators of AMP-activated protein kinase (AMPK) from Gynostemma pentaphyllum

Two novel dammarane-type saponins, damulins A (1) and B (2), that strongly activate AMPK in cultured L6 myotube cells was isolated from Gynostemma pentaphyllum. Damulins A and B also increased β-oxidation and glucose uptake with increasing GluT4 translocation to the plasma membrane in L6 myotube cells. These results indicate that activation of AMPK by damulins A and B may contribute to beneficial effect of G. pentaphyllum on glucose and lipid metabolism.