Abstract: The conditions for microwave-assisted extraction of total flavones from leaves of Moriga oleifera were optimized by response surface analysis.On the basis of single-factor experiments,the relationship between main extraction conditions including ethanol concentration,microwave power,extraction time and liquid-solid ratio were modeled using a 4 factor,3 level Box-Behnken experimental design.The established model was analyzed by response surface methodology to obtain the optimal extraction conditions.The optimal extraction conditions were as follows:ethanol concentration of 58%,microwave power of 397 W,extraction time of 8 min and liquid-solid ratio of 59:1 (mL/g).Under these conditions,the yields of total flavones were 3.45%,which was consistent with the predicted value.Total flavones from M.oleifera leaves were investigated for its hypoglycemic activity by measuring 24 hours glucose up take in cultured HepG2 cells.Overall,our results suggested that the total flavones can enhance the glucose consumption in HepG2 cells under high glucose condition;moreover,flavones extracted by microwave exhibited higher efficiency in glucose depletion than those extracted from reflux extraction.

Key words: Moriga oleifera leaves, total flavones, microwave-assisted extraction, response surface methodology, hypoglycemic activity in vitro