In vitro and in vivo activities of Melia azedarach L. aqueous leaf extracts on murine lymphocytes.

The effect of Melia azedarach L. aqueous leaf extracts (Ma) on in vitro lymphocyte proliferation and humoral and cellular immune responses in vivo was studied. Proliferation of spleen and lymph node T cells was impaired when these cells were incubated in the presence of the extract using different mitogens as stimuli. Furthermore, treatment of mice with the extracts not only diminished the production of antibodies but also exerted an inhibition on graft vs host and delayed type hypersensitivity reactions. These results suggest that Ma extracts exert a marked immunomodulatory effect on the mouse immune system.