Bound phenolics from fresh lotus seeds exert anti-obesity effects in 3T3-L1 adipocytes and high-fat diet-fed mice by activation of AMPK

Polyphenols are found in free and bound forms in foods, both of which exert a wide range of pharmacological and therapeutic effects. Here, 3T3-L1 pre-adipocytes and high-fat diet (HFD)-induced mice were used to investigate the potential anti-obesity effect of bound phenolics extracted from lotus seeds (LBP). Phenolic compounds including protocatechuic, caffeic and ellagic acids were identified in LBP. In vitro results showed LBP significantly decreased intracellular lipid accumulation; while oral administration of LBP was found to retard body weight gain and improve plasma lipid profile in HFD-induced mice. Moreover, LBP increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) accompanied with down-regulation of adipogenic/lipogenic genes (Pparγ, C/ebpα, aP2, Srebp-1c, Acc1, Fas, Lpl) expression; and up-regulation of lipolytic genes (Hsl, Pgc-1α, Sirt1, Cpt1α) and adipokine adiponectin expression. Taken together, these observations suggested lotus seeds bound phenolics may alleviate obesity, in part by modulating the AMPK signaling pathway.