The antiatherogenic properties of pomegranate juice (PJ) were attributed to its antioxidant potency and to its capacity to decrease macrophage oxidative stress, the hallmark of early atherogeneis. pomegranate juice polyphenols and sugar-containing polyphenolic anthocyanins were shown to confer pomegranate juice its antioxidant capacity. In the present study, we questioned whether pomegranate juice simple or complex sugars contribute to the antioxidative properties of pomegranate juice in comparison to white grape juice (WGJ) sugars.
Whole pomegranate juice decreased cellular peroxide levels in J774A.1 macrophage cell-line by 23% more than pomegranate juice polyphenol fraction alone. Thus, we next determined the contribution of the pomegranate juice sugar fraction to the decrease in macrophage oxidative state. Increasing concentrations of the pomegranate juice sugar fraction resulted in a dose-dependent decrement in macrophage peroxide levels, up to 72%, compared to control cells. On the contrary, incubation of the cells with WGJ sugar fraction at the same concentrations resulted in a dose-dependent increment in peroxide levels by up to 37%. The two sugar fractions from pomegranate juice and from WGJ showed opposite effects (antioxidant for pomegranate juice and pro-oxidant for WGJ) also in mouse peritoneal macrophages (MPM) from control as well as from streptozotocin-induced diabetic Balb/C mice.
pomegranate juice sugar consumption by diabetic mice for 10 days resulted in a small but significant decrement in their peritoneal macrophage total peroxide levels and an increment in cellular glutathione content, compared to MPM harvested from control diabetic mice administrated with water. In contrast, WGJ sugar consumption by diabetic mice resulted in a 22% increment in macrophage total peroxide levels and a 45% decrement in cellular glutathione content.
Paraoxonase 2 activity in macrophages increases under oxidative stress conditions. Indeed, macrophage paraoxonase 2 activity was decreased after pomegranate juice sugars supplementation, but increased after WGJ sugars supplementation.
We conclude that pomegranate juice sugar fraction, unlike WGJ sugar fraction, decreases macrophage oxidative state under normal and under diabetic conditions. These antioxidant/antiatherogenic effects could be due to the presence of unique complex sugars and/or phenolic sugars in pomegranate juice.
