C-Methylated flavanones from the rhizomes of Matteuccia intermedia and their α-glucosidase inhibitory activity

One new flavanonol , demethylmatteucinol ( 1 ), and nine new flavanone glucoside derivatives, matteflavosides H-J ( 2–4 ) and matteuinterates A-F ( 5 – 10 ), were isolated from the rhizomes of Matteuccia intermedia C.Chr., along with 21 known flavanones ( 11 − 31 ). Notably, all of them contain C -methylation in the A-ring. The structures of the compounds were elucidated by spectroscopic methods and chemical derivatization. The α -glycosidase inhibition assay indicated that compounds 12 – 17 showed potent inhibitory activity with IC 50 values of 12.4–69.7 μM, which suggested their hypoglycemic effect.