Anti-inflammatory properties of different potato varieties in THP-1 macrophages

Chronic inflammation is a prolonged inflammatory condition, which represents a risk factor of various types of diseases, including cancer, diabetes, cardiovascular and autoimmune diseases. Dietary strategies to reduce acute inflammation and prevent its degeneration towards the chronic state are attracting great interest. Many phytonutrients found in pigmented plants are naturally-occurring anti-inflammatory and anti-oxidant compounds. Among these, anthocyanins (ACNs) were found to counteract many inflammation-related diseases, including obesity-related inflammation, whereas consumption of carotenoids has been inversely correlated to the incidence of many chronic diseases, including obesity, diabetes and cancer. Based on these premises, we have deemed it interesting to evaluate the possible anti-inflammatory properties of pigmented upland potato varieties enriched in different combinations of phytonutrients as possible source of beneficial bioactive compounds. Tubers of three commercial potato varieties namely Bleuet (purple skinned and fleshed tubers), Desiree (red-skinned and yellow-fleshed tubers) and Kennebec (yellow-skinned and white-fleshed tubers) from upland cultivation site (Starleggia, Valle Spluga, Lombardy, 1.560 masl) were checked as ACN-rich, carotenoid-rich and chlorogenic acid (CGA)-rich respectively, and their phytonutrient composition have been characterized by HPLC-DAD and spectrophotometric analysis. Thereafter, THP-1 cells, differentiated in M1-macrophages via PMA-treatment, were pre-treated with equivalent extracts from the three different cultivars and then challenged with LPS. The dose-dependent effects on gene expression and/or protein levels of TNFα, IL-1β, iNOS, COX-2, NO and PGE2 were evaluated. Our results show that the three extracts have different effects on the analyzed inflammation markers, with the ACN-rich extract being most effective in reducing LPS-induced inflammation, followed by the carotenoid-rich and CGA-rich varieties. In conclusion, these potato varieties may exert a significant anti-inflammatory activity, representing possible functional foods to counteract chronic inflammation.