Figure 1.

Postulated Mechanisms for effects of polyphenols on macrophage cholesterol efflux. Cholesterol is effluxed out of macrophage foam cells in the first step of reverse cholesterol transport (RCT). Efflux to lipid-free or lipid-poor Apo-A1 particles (which then become mature HDL) occurs via the ATP-binding cassette subfamily A1 (ABCA1) transporter, while efflux directly to mature HDL particles occurs via the ATP-binding cassette subfamily G1 (ABCG1) transporter.²⁷ Resveratrol and anthocyanins promote the efflux pathway via upregulation of liver X receptor (LXR).²¹,²² Uto-Kondo et al demonstrated that two phenolic acids, as well as whole coffee, increased both mRNA and protein levels of ABCG1 and scavenger receptor class B type I (SR-BI), but not ABCA1, by enhancing mRNA stability.²⁶