Disclosed is an AMPK activating material used for improving and treating metabolic syndrome, in which AMPK (AMP-activated protein kinase) is a main enzyme for regulating an energy sensor and lipid/glucose metabolism in the body. The activation of AMPK inhibits the synthesis of fat and cholesterol, and accelerates the reduction of body fat and blood glucose, thereby improving obesity, diabetes, and hyperlipidaemia. The disclosed AMPK activating material contains, as active ingredients having an improving and treating effect on metabolic syndrome, including obesity, diabetes, and hyperlipidaemia, a novel compound 2α,3β,12β-trihydroxydammar-20(22)-E,24-diene-3-O-[β-D-glucopyranosyl-(1→)-β-D-glucopyranoside], named Damulin A, and a novel compound 2α,3β,12β-trihydroxydammara-20,24-diene-3-O-[β-D-glucopyranosyl-(1→)-β-D-glucopyranoside], named Damulin B. Herein, the contents of damulin A and damulin B (as active indicator ingredients for AMPK activation) can be increased by treating a Gynostemma pentaphyllum extract with high temperature/high pressure. Accordingly, the novel Gynostemma pentaphyllum extract with a significantly increased AMPK activating capability can be used for improving or treating metabolic syndrome, such as obesity, diabetes, and hyperlipidaemia.