Immunostimulatory and anti-inflammatory properties of Silene succulenta Forssk

Background and objectives Immunomodulation using medicinal plants is a useful alternative to classical conventional chemotherapy for several diseases, including cancer and autoimmune disorders. Therefore, the aim of this study was to investigate the immunomodulatory properties of Silene succulenta Forssk. extract that is a common herb growing in Egypt. Materials and methods S. succulenta was collected from Mediterranean coast region of Egypt, dried in shade, ground, and extracted using methanol. The effect of the plant extract on immune cells was tested using murine splenocytes and human peripheral blood mononuclear cells (PBMCs) proliferation colorimetric assays. A bioassay-directed fractionation was applied to identify the most active fraction and gas chromatography–mass spectrometry (GC–MS) was used to analyze it. The effect of the plant extract and its active fraction on human interleukin-2 (IL-2) was determined using enzyme-linked immunosorbent assay. Furthermore, the effect on macrophage nitric oxide production ability, macrophage viability, and HL-60-differentiated cells to neutrophil ROS production was tested. Results and conclusion Our results demonstrated that S. succulenta extract induced murine splenocytes and PBMCs proliferation in a concentration-dependent manner. Through bioassay-directed fractionation, we identified hexane subfraction as the active fraction of the extract and identified 18 compounds using GC–MS with major components of palmitic acid (33.19%) and phthalic acid, di(6-methylhept-2-yl) ester (20.22%). The extract and its active fraction induced human IL-2, whereas they inhibited macrophage nitrite-production ability, and neutrophil reactive oxygen species production level. We concluded that S. succulenta possesses several immunostimulatory and anti-inflammatory properties that can be utilized to treat several diseases.