Melanin-concentrating hormone-1 receptor antagonism and anti-obesity effects of ethanolic extract from Morus alba leaves in diet-induced obese mice

Ethnopharmacological relevanceIn Korea, Morus alba leaves have been traditionally administered as natural therapeutic agent for the alleviating dropsy and diabetes.Aim of the studyThe present study was performed to evaluate melanin-concentrating hormone receptor subtype 1 (MCH1) antagonism of the ethanol extract of Morus alba leaves (EMA) and its anti-obesity effect in diet-induced obese (DIO) mice.Materials and methodsThe binding affinity of EMA for the MCH1 receptor with europium-labeled MCH (Eu-MCH), the function of recombinant MCH1 receptors expressed in CHO cells, and the anti-obesity effects in DIO mice were evaluated.ResultsMCH1 receptor binding studies showed, EMA exhibited a potent inhibitory activity with IC50 value of 2.3 ± 1.0 μg/ml. EMA (10–100 μg/ml) also inhibited the intracellular calcium mobilization with the recombinant MCH1 receptors expressed in CHO cells. In an anti-obesity study with DIO mice, long-term oral administrations of EMA for 32 consecutive days produced a dose-dependent decrease in body weight and hepatic lipid accumulation.ConclusionsThese results suggest that chronic treatment with EMA exerts an anti-obesity effect in DIO mice, and its direct MCH1 receptor antagonism may contribute to decrease body weight.