New Ent-Kaurane-Type Diterpene Glycosides and Benzophenone from Ranunculus muricatus Linn.

Two new ent-kaurane diterpene glycosides, ranunculosides A (1) and B (2), and a new benzophenone, ranunculone C (3), were isolated from the aerial part of Ranunculus muricatus Linn. The chemical structures of compounds 1-3 were established to be (2S)-ent-kauran-2β-ol-15-en-14-O-β-d-glucopyranoside, (2S,4S)-ent-kauran-2β,18-diol-15-en-14-O-β-d-glucopyranoside, and (R)-3-[2-(3,4-dihydroxybenzoyl)-4,5-dihydroxy-phenyl]-2-hydroxylpropanoic acid, respectively, by spectroscopic data and chemical methods. The absolute configuration of 1 was determined by the combinational application of RP-HPLC analysis and Mosher's method.