Abstract: A novel flavone glycoside, 3′″-carbonyl-2″-β-L-quinovosyl icariside Ⅱ was isolated from a Chinese medicinal plant, Epimedium koreanum Nakai. The ¹H and ¹³C NMR chemical shifts of the compound were completely assigned using a combination of 1D(¹H, ¹³C NMR, NOE and DEPT) and 2D NMR(¹H-¹H COSY，HSQC, HMBC and NOESY) techniques and by referring to ¹H and ¹³C NMR spectra of icariside Ⅱ, 2″-rhamnosyl icariside Ⅱ and icariin. The structure of the compound was determined to be 4′-Methylether, 3-O-[3-one-β-L-quinovosyl-(1→2)-α-L-rhamnopyranoside], 5, 7-dihydroxy-2-(4-hydroxyphenyl)-8-(3-methyl-2-butenyl)-4H-1-benzopyran-4-one.

Key words: NMR, assignment, 2D NMR, 3′″-carbonyl-2″-β-L-quinovosyl icariside Ⅱ