The leaves of Nyctanthus arbortristis L. (NA) are reported to be useful in rheumatism, menorrhagia, dysentry, asthma and allergic reactions. They were proven experimentally to have antibacterial, antiinflammatory and anthelmintic activity. The aim of the present study was to investigate the effect of methanolic leaves extraxt (MNA) on immune cells by using in-vitro and in-vivo models. The MNA was examined for the ability to induce secretory and cellular responses in murine peritoneal macrophages. Macrophages treated with the extract exhibited increased acid phosphatase and myeloperoxidase activity as well as significant increase in the production of nitric oxide (NO), hydrogen peroxide (H2O2), and superoxide (O2
–). Hence, in vivo studies were carried out to confirm the immunomodulatory potential of MNA in mice. Oral administration of MNA at doses of 250 and 500mg/kg, significantly increased in total leukocyte count and in weight of spleen indicating an uplift of innate immunity. It has significantly increased carbon clearance index and ovalbumin induced delayed type hypersensitivity (DTH) reactions. It also produced a significant increase in serum globulin content and specific antibody titer against ovalbumin. Treatment with MNA increased the number of bone marrow cells positive for nonspecific esterase and peroxidase activity. Leaves of NA showed the presence of carbohydrates and glycosides (iridoids glucosides and flavanol glycosides), which suggest the major role of glycosides for the immunostimulant activity.
In conclusion MNA has shown to stimulate both innate and adaptive immune response either through stimulation of macrophages or through stimulating the release of factors that are involved in proliferation of bone marrow cells.
