Abstract
The immunosuppressive activity of the Methanol extract of bark of Madhuca longifolia (Koenig) consisting of a mixture of saponins, flavonoids, tannins, steroids, phenol and glycosides was studied on the immune responses in mice. Methanol extract of Madhuca longifolia (MLL) was administered orally at doses of 50, 100 and 150 mg/kg/day to healthy mice divided into four groups consisting of six animals each. The assessment of immunomodulatory activity was carried out by testing the humoral (antibody titre) and cellular (foot pad swelling) immune responses to the antigenic challenge by sheep RBCs. Furthermore, the effect on hematological parameters as well as relative organ weight was determined. On oral administration MML showed a significant decrease delayed type hypersensitivity (DTH) response whereas the humoral response to sheep RBCs was unaffected. Thus MLL significantly suppressed the cellular immunity by decreasing the footpad thickness response to sheep RBCs in sensitized mice. With a dose of 100 and 150 mg/kg/day the DTH response was $7.66{\pm}2.75$ and $6.41{\pm}1.21$ respectively in comparison to corresponding value of $14.50{\pm}2.38$ for untreated control group. These differences in DTH response were statistically significant (P < 0.05). The study demonstrates that MLL shows preferential suppression of the components of cell-mediated immunity and shows no effect on the humoral immunity.