A new ent-kaurane diterpenoid glycoside from Isodon japonica var. glaucocalyx

A new ent-kaurane diterpenoid glycoside (1), named glaucocalyxin G, has been isolated from the n-butanol-soluble fraction of the dried whole plants of Isodon japonica var. glaucocalyx along with two known compounds, namely arjunglucoside (2) and kaempferol-3-O-rutinoside (3). The structures of the isolated compounds were assigned on the basis of their (1)H and (13)C NMR spectra including two-dimensional NMR techniques such as HMQC, HMBC, and NOESY experiments and comparison with the literature data.