Potential AMPK activators of cucurbitane triterpenoids from Siraitia grosvenorii Swingle.

AMP-activated kinase (AMPK) as a key controller in the regulation of whole-body energy homeostasis, plays an important role in protecting the body from metabolic diseases. Recently, improved glucose, lipid utility and increased insulin sensitivity were observed on several diabetic rodent models treated with crude mogrosides isolated from the fruit of Siraitia grosvenorii Swingle, but the precise active compounds responsible for the anti-diabetic activity of this plant have not been clearly identified. In our current work, acid hydrolysis of crude mogrosides provided five new cucurbitane triterpenoids (1-4, 8), along with three known ones (5-7). The main aglycone mogrol (7) and compounds 4 and 8 were found to be potent AMPK activators in the HepG2 cell line. This result suggested AMPK activation by the mogroside aglycones 7 and 8 was proved to contribute at least partially to the anti-hyperglycemic and anti-lipidemic properties in vivo of S. grosvenorii.