Copper‑containing amine oxidase purified from Lathyrus sativus as a modulator of human neutrophil functions

: Over the last few decades, copper‑containing amine oxidase (Cu‑AO) from vegetal sources, and belonging to the class of diamine oxidase, has been documented to exhibit beneficial effects in both in vivo and ex vivo animal models of inflammatory or allergic conditions, including asthma‑like reaction and myocardial or intestinal ischemia‑reperfusion injuries. The aim of the present study was to assess the potential of vegetal Cu‑AO as an anti‑inflammatory and an antiallergic agent and to clarify its antioxidant properties. In cell‑free systems, the reactive oxygen species and reactive nitrogen species scavenging properties of Cu‑AO that is purified from Lathyrus sativus were investigated. Its effect on the formyl‑methionyl‑leucyl‑phenylalanine peptide (fMLP)‑activated cellular functions of human neutrophils were subsequently analyzed. The obtained results demonstrated that Cu‑AO is not a scavenger of superoxide or nitric oxide, and does not decompose hydrogen peroxide. However, it inhibits the fMLP‑dependent superoxide generation, elastase release and cell migration, and interferes with the process of calcium flux, supporting the idea that plant Cu‑AO can interact with human neutrophils to modulate their inflammatory function. Therefore, the importance of these properties on the possible use of vegetal Cu‑AO to control inflammatory conditions, particularly intestinal inflammation, is discussed in the current study.