Antidiabetic property of fractions and pure compounds from <i>Andrographis paniculata</i>

Chlorophyll-free fractions of <i>Andrographis paniculata</i> were investigated for glucose uptake and lipid reduction in 3T3-L1 adipocytes. At 25 µg/ml, the acid fraction concentration enhanced glucose uptake by 82%. Basic and neutral fractions at 100 µg/ml enhanced glucose uptake by 82% and 78%, respectively. The three fractions showed improved glucose uptake compared to the crude extract (25% uptake at 50 μg/ml). GC-MS analysis of the fractions revealed the presence of chemicals with antidiabetic activities. The neutral fraction was prioritised for pure compound isolation to provide known andrographolide (<b>1</b>), 14-deoxyandrographolide (<b>2</b>), and a novel compound, 3-<i>epi</i>-11,12-didehydro-14-deoxyandrographolide (<b>5</b>). At a concentration of 1 µM, compounds <b>2</b> and <b>5</b> are as effective as 10 mM metformin in glucose uptake. They also reduce lipid accumulations in 3T3-L1 adipocytes by decreasing the size and number of lipid droplets. The activities of fractions and compounds support the use of <i>A. paniculata</i> in treating type 2 diabetes.