Anti-adipogenic activity of Carduus crispus and its constituent apigenin in 3T3-L1 adipocytes by downregulating PPARγ and C/EBPα

Abstract

Carduus crispus, native to Europe and Asia, is a traditional herbal medicine used for treating inflammatory disorders in Korea. Obesity is characterized by a state of chronic inflammation with increased inflammatory markers along with the expression and release of inflammation-related adipokines. Most anti-obesity drugs have been developed based on this concept. Our research for anti-obesity agents derived from C. crispus utilized the 3T3-L1 cell line. The methanol extract was initially screened and exhibited significant inhibition of adipogenesis in 3T3-L1 adipocytes. Among five liquid–liquid partition fractions, the ethyl acetate (EA) fraction showed the most potent suppressive effect compared with hexane, chloroform, n-butanol, and water. The EA fraction was considered for further study because of the presence of abundant polyphenols, including flavonoids. To isolate the active components from the EA fraction, elution–extrusion countercurrent chromatography was used. Among the seven fractions from the EA layer, fraction 6 inhibited lipid accumulation as well as CCAAT/enhancer-binding protein alpha and peroxisome proliferator-activated receptor gamma protein expression levels. The active component apigenin (fraction 6) was confirmed using high-performance liquid chromatography, electrospray ionization mass spectrometry, and one-dimensional nuclear magnetic resonance spectroscopy. The present data suggest that apigenin is one of the main bioactive compounds from C. crispus for inhibiting adipogenesis in 3T3-L1 adipocytes via the activation of AMP-activated protein kinase.