Two New Monoterpenes from Tithonia diversifolia and Their Anti-Hyperglycemic Activity

Two new monoterpenes: ((1S,2R,3R,5S)-2-hydroxymethyl-6,6-dimethylbicyclo[3.1.1]heptane-2,3diol (1) and (3R)-6,6-dimethyl-4-methylenebicyclo[3.1.1]heptane-1,3-diol-3-O-β-D-glucopyranoside (2), along with three known compounds, namely, sobrerol (3), (1R,2S,5S)-2,8-p-menth-diol (4) and (lR,5S)-10hydroxyverbenon (5), were isolated from aerial part of Tithonia diversifolia. Their structures were determined on the basis of spectroscopic analyses (IR, HR-ESI-MS/MS, 1D/2D NMR). Under the concentration of 10 μg/mL, compounds 1 and 3 significantly increased glucose uptake in 3T3-L1 adipocytes without significant toxic effects in vitro.