Pomegranate phytosterol (β-sitosterol) and polyphenolic antioxidant (punicalagin) addition to statin, significantly protected against macrophage foam cells formation.

To assess the anti-atherogenic effects on macrophage cholesterol biosynthesis rate, and on cellular oxidative stress by the combination of simvastatin with a potent polyphenolic antioxidant (punicalagin), or with a phytosterol (β-sitosterol), or with pomegranate juice (POM, that contains both of them). Simvastatin (15 μg/ml) decreased J774A.1 macrophage cholesterol biosynthesis rate by 42% as compared to control cells. The addition to the statin of either punicalagin (15 or 30 μM), or β-sitosterol (50 or 100 μM), increased the inhibitory effect of the statin up to 62% or 57%, respectively. Similarly, the combination of POM and simvastatin, resulted in an inhibitory effect up to 59%. While simvastatin inhibited the rate limiting enzyme HMGCoA-reductase, punicalagin, β-sitosterol or POM inhibited macrophage cholesterol biosynthesis downstream to mevalonate. Simvastatin (15 μg/ml) also modestly decreased macrophage reactive oxygen species (ROS) formation by 11%. In the presence of punicalagin (15 or 30 μM) however, a remarkable further inhibition was noted (by 61% or 79%, respectively). Although β-sitosterol alone showed some pro-oxidant activity, the combination of simvastatin, β-sitosterol and punicalagin, clearly demonstrated a remarkable 73% reduction in ROS production. Similarly, simvastatin + POM decreased the extent of ROS formation by up to 63%. These improved antioxidant effects of the combinations could be related to various anti-oxidative properties of the different compounds, including free radicals scavenging capacity, upregulation of paraoxonase 2, and stimulation of reduced glutathione. The combination of simvastatin with potent antioxidant and phytosterol (such as present in pomegranate) could lead to attenuation of macrophage foam cell formation and atherogenesis.