Alnus hirsuta is a deciduous, broad-leaved tree that thrives in damp locations, and the bark of the Alnus species has been used in traditional oriental medicine as a remedy for hemorrhage, fever, diarrhea, and alcoholism. Two diarylheptanoids, 1,7-bis-(3,4-dihydroxyphenyl)-heptane-3-one-5-O-${eta}$-D-xylopyranoside (Compound I) and 1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-${eta}$-D-xylopyranoside (Compound II), were isolated from the stem bark of A. hirsuta. In the present study, the investigations of two diarylheptanoids on insulin signaling were performed in insulin-responsive human hepatocarcinoma (HepG2) cells co-treated with high glucose. As the results, the insulin metabolic effect of glucose uptake was inhibited by high glucose. However, treatment of Compound I enhanced the glucose uptake ability in HepG2 cells, whereas, Compound II did not affect glucose incorporation noticeably. In addition, we demonstrated that treatment of HepG2 cells with Compound I improved the mRNA expression level of insulin receptor (IR) and insulin receptor substrate-1 (IRS-1).