Four New Eudesmanes from Caragana intermedia and Their Biological Activities

Four new eudesmanes, namely, 4(15)-eudesmene-1beta,7alpha-diol (1), 4(15)-eudesmene-1beta,7beta-diol (2), 7-trinoreudesma-4(15),8-dien-1beta-ol-7-one (3), and eudesma-4(15),7-dien-1beta-ol (4), as well as three known compounds, 5-epi-eudesma-4(15)-ene-1beta,6beta-diol (5), 4(15)-eudesmene-1beta,6alpha-diol (6), and 4(15)-eudesmene-1beta,5alpha-diol (7), were isolated from the aerial part of Caragana intermedia. The structures were elucidated by spectroscopic and spectrometric analyses including 1D, 2D NMR, HRMS, and IR. The structures of compounds 1, 5, 6, and 7 were confirmed by X-ray crystallographic analysis. Compound 7 showed glucose consumption activity with an IC value of 10.7 microg/mL in a C2C12 muscle cell assay. The MIC value of this compound (100 mg/kg) in a db/db mice model is equivalent to that of metformin in vivo.