Alkamides from Tropaeolum tuberosum inhibit inflammatory response induced by TNF-α and NF-κB

Ethno-pharmacological relevance: Tropaeolum tuberosum, commonly known as "Mashua", is one of the plants most frequently used by Andean (Peruvian-Bolivian) people as food and medicine. It is used as a remedy against a wide range of diseases, especially those related with inflammation. Objectives: This study aims to identify compounds active against inflammatory related conditions. Materials and methods: A bioassay-guided isolation of anti-inflammatory compounds from black and purple tubers of T. tuberosum was performed measuring TNF-a and NF-kappa B production in THP-1 monocytic cells. Results: The bioassay-guided isolation led to one active compound from purple T. tuberosum, N-oleoyldopamine (1), and another active compound from black T. tuberosum, N-(2-Hydroxyethyl)-72,10Z,13Z,16Z-docosatetraenamide (2). Both compounds displayed anti-TNF-alpha activity with IC50 values of 3.12 +/- 0.19 mu M and 1.56 +/- 0.15 mu M, respectively. Also, both compounds suppressed NF-kappa B with IC50 of 3.54 +/- 0.02 mu M and 1.77 +/- 0.07 mu M, respectively. Conclusions: We identified bioactive compounds from purple and black Tropaeolum tuberosum responsible for their anti-inflammatory activity: N-oleoyldopamine (1) and N-(2-Hydroxyethyl)-7Z,10Z,13Z,16Z-docosatetraenamide (2). This is the first report which isolates these compounds from T. tuberosum and describes their anti-inflammatory activities.