Anti-inflammatory activity of polyphenolic extracts from Lactuca sativa (var. Maravilla de Verano) under different fertilization systems

In this study, we report the anti-inflammatory potential of polyphenols extracted from green lettuce (var. Maravilla de Verano) [1], cultivated under different fertilization treatments, in macrophages, treated with Lipopolysaccharide from Escherichia coli. Among all fertilization treatments, those including 120 t manure ha–1 (treatment C) or 150 kg N ha–1 (treatment K) exerted the highest inhibitory effect on nitric oxide release. C and K extracts significantly decreased nitric oxide and cytokines release, inducible nitric oxide synthase and cycloxygenase-2 expression and nitrotyrosine formation. UHPLC-MS analyses, showed that the levels of total phenolic acids and flavonols in the extracts from lettuce treatment without any fertilization (A) were significantly higher than those present in the extracts from the treatments including both mineral (K) and organic fertilization (C, G and E). Plants under mineral fertilization (K) showed levels of free quercetin significantly higher than those subjected to all other treatments. These results could explain the higher antinflammatory potential of lettuce K extract