@article {Wen2008,
	title = {{Naturally occurring pentacyclic triterpenes as inhibitors of glycogen phosphorylase: Synthesis, structure-activity relationships, and X-ray crystallographic studies}},
	journal = {J. Med. Chem.},
	volume = {51},
	number = {12},
	year = {2008},
	pages = {3540{\textendash}3554},
	abstract = {Twenty-five naturally occurring pentacyclic triterpenes, 15 of which were synthesized in this study, were biologically evaluated as inhibitors of rabbit muscle glycogen phosphorylase a (GPa). From SAR studies, the presence of a sugar moiety in triterpene saponins resulted in a markedly decreased activity (7, 18-20) or no activity (21, 22). These saponins, however, might find their value as potential natural prodrugs which are much more water-soluble than their corresponding aglycones. To elucidate the mechanism of GP inhibition, we have determined the crystal structures of the GPb-asiatic acid and GPb-maslinic acid complexes. The X-ray analysis indicates that the inhibitors bind at the allosteric activator site, where the physiological activator AMP binds. Pentacyclic triterpenes represent a promising class of multiple-target antidiabetic agents that exert hypoglycemic effects, at least in part, through GP inhibition.},
	isbn = {0022-2623},
	doi = {10.1021/jm8000949},
	author = {Wen, X A and Sun, H B and Liu, J. and Cheng, K G and Zhang, P and Zhang, L Y and Hao, J and Ni, P Z and Zographos, S E and Leonidas, D D and Alexacou, K M and Gimisis, T. and Hayes, J.M. and Oikonomakos, N G}
}
