Immune response modulatory effect of Emilia sonchifolia (L.) DC: an in vivo experimental study.

Background: This study was performed in order to provide a scientific basis for the conventional use of Emilia sonchifolia in the traditional Indian Ayurvedic medicine possibly through modulation of the host immune defense.

Methods: Emilia sonchifolia methanolic extract (25 mg/kg body weight) was administered intraperitoneally in mice, and hematological parameters, relative organ weights, bone marrow cellularity, and α-esterase activity were assessed. Humoral immune response was evaluated by hemagglutinating antibody (HA) titer and plaque forming cell (PFC) assay. Blastogenesis assays of lymphoid organs were done in the presence and absence of various mitogens such as phytohemagglutinin, concanavalin A, pokeweed mitogen, and lipopolysaccharide. Cytotoxic T lymphocyte (CTL) production was assessed by Winn's neutralization test. The levels of cytokines interleukin-2 (IL-2) and interferon-γ (IFN-γ) were evaluated by ELISA.

Results: Emilia sonchifolia significantly enhanced the total white blood cell count (9995±535 cells/mm3), bone marrow cellularity, α-esterase activity, and weight of lymphoid organs (p<0.001). The effect on humoral immune response was evident from the enhanced HA titer and increased number of PFCs (p<0.001). The blastogenic effects of mitogens were also stimulated to significant levels by E. sonchifolia treatment. Emilia sonchifolia treatment augmented cell-mediated immune response by enhancing the killing activity of CTLs and by enhanced production of IL-2 and IFN-γ.

Conclusions: From these results, it was very evident that E. sonchifolia, an indigenous medicinal plant, is a potent immune response modulator, and the present report is so far the first study to demonstrate the immunoregulatory activity of E. sonchifolia.