Anti-diabetic effect of ethanol extract of Cyclolepis genistoides D. Don (Palo azul), made in Paraguay

Abstract

Extract of Cyclolepis genistoides D. Don (vernacular name Palo azul; Palo) are traditionally consumed in the Republic of Paraguay in South America for the treatment of diabetes and kidney disease, and is sold in Japan as dietary supplement. This study aimed to elucidate the mechanism of anti-diabetes activity of Palo, especially focused on insulin resistance. Palo promoted adipocytes differentiation and regulated adipokine profiles in 3T3-L1 adipocytes by modulation of PPARγ, a major regulator of adipose differentiation. Human adipocyte showed almost similar profile with 3T3-L1 against Palo treatment. Furthermore, Palo treatment (250 or 1000 mg/kg) was performed with C57BL/6J mice for 14 weeks, being fed high-fat-diet (HFD60) simultaneously. Palo 250 mg/kg exhibited a tendency to decrease subcutaneous adipose volume along with increase of PPARγ and its target, adiponectin mRNA expression. In addition, as the other insulin targeted cell, effect on muscle differentiation was examined. Palo increased differentiation of C2C12 mouse muscle myoblasts by increase of IGF-1, myogenin, and myosine heavy chain (MHC) as well as 5'-AMP-activated protein kinase (AMPK) activation. Palo subsequently promoted myotube formation under differentiation condition. From the above, it was clarified that Palo acts variously on the differentiation and maturation of both adipocytes and muscle cells, and from the viewpoint of the regulatory mechanism for adipocytes, PPARγ-inducing action was shown to be a mechanism that acts across species.