The present invention provides an AGE inhibitor and a health functional food for inhibiting an occurrence of diabetic complications. Particularly, the present invention comprises a compound selected from the group consisting of mulberrofuran G, mulberrofuran K, kuwanon G, kuwanon Z, oxyresveratrol, 2`,4`,5,7-tetrahydroxyflavanone, morusignin L and dihydromorin isolated from Morus Bark as an active ingredient. The compounds disclosed above inhibit the production of AGE which is a causative substance of diabetic complications. Thus, the compounds could be used as an AGE inhibitor and a health functional food for inhibiting diabetic nephropathy, diabetic retinopathy and diabetic neuropathy.