Disclosed is a pharmaceutical composition containing obovatol represented by Formula 1 and its derivatives. The obovatol and its derivatives effectively increase the activity of AMPK (AMP-activated protein kinase) that plays an important role in diabetes and metabolic syndrome, and thus may be variously used in treating diabetes and metabolic syndrome. ##STR00001## (In Formula 1, R.sup.1, R.sup.2 and R.sup.3 are the same as defined above).