Several reports have demonstrated the effectiveness of pistachio against oxidative stress and inflammation. In this study, we investigate if polyphenols extracts from natural raw shelled pistachios (NP) or roasted salted pistachio (RP) kernels have anti-inflammatory and antioxidant properties at lower doses than reported previously, in both in vitro and in vivo models. The monocyte/macrophage cell line J774 was used to assess the extent of protection by NP and RP pistachios against lipopolysaccharide (LPS)-induced inflammation. Moreover, antioxidant activity of NP and RP was assessed in an in vivo model of paw edema in rats induced by carrageenan (CAR) injection in the paw. Results from the in vitro study demonstrated that pre-treatment with NP (0.01, 0.1 and 0.5 mg/mL) and RP (0.01 and 0.1 mg/mL) exerted a significant protection against LPS induced inflammation. Western blot analysis showed NP reduced the degradation of IκB-α, although not significantly, whereas both NP and RP decreased the TNF-α and IL-1β production in a dose-dependent way. A significant reduction of CAR-induced histological paw damage, neutrophil infiltration and nitrotyrosine formation was observed in the rats treated with NP. These data demonstrated that, at lower doses, polyphenols present in pistachios possess antioxidant and anti-inflammatory properties. This may contribute toward a better understanding of the beneficial health effects associated with consumption of pistachios.
Keywords: inflammation; oxidative stress; paw edema; pistachio.