Abstract:A new cucurbitacin glycoside, named hemsamabilinin B (2), was isolat-ed from Hemsleya amabilis Diels. 2 was hydrolyzed by enzyme on acid to produce 23,24-dihydrocucurbitacin F (3) or D-glucose respectively. On the basis of the spectrosco-pic data of 2 and its acetate (4) (1H NMR, 13CNMR and MS), the structure of 2 wasassigned as 2-0-β-D-glucopyranoside of 3.