Evaluation of immunomodulatory activities of essential oils by high content analysis

•An original approach for the study of immunomodulatory activities is proposed here.•The developed cell based assay leads to the evaluation of different features by HCS.•The effect of five essential oils is monitored through different features.•The in vitro immunomodulatory effect of Mint EO is described for the first time. Nowadays, research concerning immunomodulatory products are of great interest, particularly in the treatment of inflammatory diseases or the prevention of infectious diseases. These activities are usually evaluated on cell cultures, by tracking different factors requiring dedicated manipulation. Evaluation of the immunomodulatory activities of essential oils and pure compounds using several technics adapted to high content analysis is described in this study. This approach allows a multiparametric evaluation on a single cell batch, in order to obtain an overall response. The developed method is based on the simultaneous evaluation of phagocytosis, production of iNOS and secretion of IL-6, induced by contact of RAW 264.7 cells with LPS. The results highlight the immunomodulatory activities of cinnamon and clove essential oils. They also provide information, particularly concerning the inhibitory activity of mint essential oil, which inhibits the LPS-induced phagocytosis of RAW 264.7 cells by 42%, at 100 μg/ml. This work presents for the first time the adaptation of high content analyses for the monitoring of immunomodulatory activities of essential oils. This protocol could be adjustable to other cell types and supplemented by the evaluation of additional parameters.