Effects of laccase-catalyzed rutin polymer fraction on adipogenesis inhibition in 3T3-L1 adipocytes

Rutin was enzymatically polymerized by laccase and the rutin polymer fraction (RPF) was collected by ultrafiltration with a molecular cut off of 3 kDa. The RPF contained a range of oligomer size varying from hexamer (m/z 3650) to octamer (m/z 4866). The Fourier transform infrared spectrum indicated that various linkages such as hydrogen bonds (OH), aromatic groups (CC), and ether bonds (CO) were involved in rutin polymer formation. RPF more effectively suppressed triglyceride accumulation compared to the rutin monomer in 3T3-L1 adipocytes at all tested concentrations (p < 0.05). The anti-adipogenic effect of RPF was mediated by down-regulation of the expression of adipogenic transcriptional factors including peroxisome proliferator-activated receptor (PPARγ), CCATT/enhancer binding protein (C/EBPα), sterol regulatory binding protein (SREBP1C) and fatty acid synthase (FAS) while up-regulating lipolysis and adiponectin expression in 3T3-L1 adipocytes. These results suggest that RPF has a potential protective effect in the development of obesity and that enzyme-catalyzed polymerization could be useful in improving flavonoids bioactivity.