Structurally Diverse Bisbenzylisoquinoline Alkaloids with Antiadipogenic Activity through Downregulation from the Embryo of Seeds

Six undescribed and six known bisbenzylisoquinoline alkaloids were isolated from the embryo of seeds. Their structures were fully characterized by a combination of H, C NMR, 2D NMR, and HRESIMS analyses, as well as ECD computational calculations. The antiadipogenic activity of 11 alkaloids was observed in a dose-responsive manner, leading to the suppression of lipid accumulation in 3T3-L1 cells. Luciferase assay and Western blot analysis showed that the active alkaloids downregulated peroxisome proliferator-activated receptor gamma (, a key antiadipogenic receptor) expression in 3T3-L1 cells. Analysis of the structure-activity relationship unveiled that a 1,1' configuration in bisbenzylisoquinoline alkaloids led to a notable enhancement in antiadipogenic activity. The resistance level against lipid accumulation highlighted a consistent pattern with the suppressive effect on the expression. These activity results indicate that alkaloids from the embryo of seeds have a potential of antiobesity effects through downregulation.