Effects of amide constituents from pepper on adipogenesis in 3T3-L1 cells

Several amide constituents (piperlonguminine and retrofractamides A, B, and C) from the fruit of Piper chaba promoted adipogenesis of 3T3-L1 cells. Among them, retrofractamide A was the most active and significantly increased the amount of adiponectin released into the medium and the uptake of 2-deoxyglucose into the cells. Retrofractamide A also increased mRNA levels of adiponectin, peroxisome proliferator-activated receptor gamma 2 (PPAR gamma 2), glucose transporter 4 (GLUT4), and insulin receptor substrate 1 (IRS-1), but did not act as a PPAR gamma agonist different from troglitazone. (C) 2008 Elsevier Ltd. All rights reserved.