Upland pigmented potatoes as valuable functional foods with anti-inflammatory properties: an insight into bioactive compounds interaction

Over the past few decades, challenges within the global agrifood systems have steadily increased, driven primarily by climate change and global population growth, both of which significantly impact food nutritional security. In this scenario, it is of utmost importance to find resilient, sustainable and cost-effective crops providing macro- and micronutrients and, possibly, health-promoting bioactive compounds. Potatoes may represent valuable candidates, being available multiple varieties cultivated in different climates and farming systems and thanks to their high nutritional value, providing energy, carbohydrates, vitamins B, C and some minerals. In particular, upland pigmented varieties, enriched in bioactive compounds known for their health-promoting activity, like carotenoids and anthocyanins (ACNs), could represent interesting crop genetic resources. In the framework of the JPI FACCE SYSTEMIC project, we evaluated the anti-inflammatory activity of three commercial potato varieties cultivated in Starleggia (Valle Spluga, 1560 masl), named Kennebec (white flesh, yellow skin), Desirèe (yellow flesh, red skin) and Bleuet (purple flesh and skin). Extracts from Kennebec, Desirèe and Bleuet whole tubers, analyzed spectrophotometrically and through HPLC-DAD, allowed to define these varieties as chlorogenic acid (CGA)-rich, carotenoid-rich and ACN-rich, respectively. To test their anti-inflammatory activity, human THP-1 macrophages were pre-treated with extracts and then challenged with LPS, which induces pro-inflammatory mediators, such as TNF-α, IL-1β and IL-6. Dose response experiments highlighted that while Kennebec extract reduced LPS-induced inflammation only at supra-physiological doses, Desirèe and Bleuet extracts significantly decreased the LPS-induced pro-inflammatory cytokines at doses near those reachable in plasma after consumption of pigmented potatoes. Surprisingly, the ACN-rich Bleuet raw extract showed a lower anti-inflammatory activity at plasmatic doses compared to the carotenoid-rich Desirèe. Since CGA did not show anti-inflammatory activity at these doses and its content was significantly high in Bleuet extract, we speculated that CGA may interfere with ACN anti-inflammatory activity. Experiments combining pure ACNs or Bleuet ACN fraction with CGA supported this hypothesis. Moreover, by molecular docking we explored their possible interaction with membrane transporters, paving the way for a molecular rationalization of the observed effect. Our findings suggest that upland pigmented potatoes, like Desirèe and Bleuet, may represent an economic challenge as well as opportunity to local growers considering their improved health-promoting profile of bioactive compounds with the ability to counteract inflammatory-related diseases.