Pomegranate juice and its main polyphenols exhibit direct effects on amine oxidases from human adipose tissue and inhibit lipid metabolism in adipocytes

Pomegranate juice (PJ) is a beverage with potential beneficial effects due to its high content of polyphenols. The objective of this study is to explore at a molecular level the direct properties of PJ and its two main polyphenolic components, punicalagin and ellagic acid, on adipocyte functions. Increasing doses of PJ were tested using radiometric methods to determine amine oxidase activities in human adipose tissue preparations. The influences on lipogenic and lipolytic activity were also assessed by radiochemical and colorimetric assays. The results showed a dose-dependent capacity of PJ to inhibit the monoamine oxidase and the semicarbazide-sensitive amine oxidase activities present in human adipose tissue. PJ also inhibited lipogenesis and lipolysis in mouse and human adipose cells, while punicalagin and ellagic acid inhibited lipolysis rather than lipogenesis. However, the combination of punicalagin and ellagic acid resulted in a synergistic action in impairing MAO activity or basal glucose incorporation into lipids.