Two New Kojic Acids from Noni Juice with Glucose Uptake Activity in Insulin-Resistant HepG2 Cells

Two new kojic acids, nonikojics A and B (1 and 2), were obtained from the water soluble extract of the Noni juice, and their chemical structures were elucidated by comprehensive modern spectroscopic techniques. The effects on glucose uptake of two new compounds were evaluated in insulin-resistant HepG2 cells, and the results indicated that 1 and 2 significantly increased glucose uptake with doses of 50 mu mol/L and thus improved insulin resistance.