Evaluation of the immunomodulatory effect of Emblica officinalis (amla) fruit pulp extracts in mice

Abstract

The immunomodulatory activity of alcoholic and aqueous extracts of Emblica offictnalis was investigated on the basis of their effects on humoral, cell mediated and cellular immune mechanism in mice. The extracts were also qualitatively tested for the presence of various active principles in it. One hundred and forty four mice taken for the study were divided into two in which one group was tested with alcoholic extract while the other with aqueous extract. The extracts were fed at two dose levels ie, l00mg and 200 mg/kg bodyweight for 19 days. The controls in both groups received vehicle alone (five percent gum acacia). Various physiological, biochemical, haematological and immunological parameters like bodyweight, organ weight, total leukocyte count, differential leukocyte count, serum total protein, serum globulin, Haemagglutination (HA) titre, Delayed Type of Hypersensitivity (DTH), Macrophage Migration Index (MMI) and NitroBlue Tetrazolium (NBT) dye reduction test were performed for evaluating the immunomodulatory potential of the extract. Both the extracts were found to increase the bodyweight and spleen weight significantly when fed at a higher dose rate of 200mglkg for 19 days. The total leukocyte count was increased to a maximum of 13.9O±2.05 and 12.77±<>.78 xI03/cu.mm respectively in aqueous and alcoholic extract treated groups on 1~ day of experiment, compared to control groups (7.l8±<>.72 and 7.IS± 0.72). Lymphocytic leukocytosis was seen after drug treatment. Serum total protein and globulin levels were also increased by the administration of extracts of Emblica. The drug administration increased the globulin concentration to 1.88±<>.42 and 1.97±0.21goA» on 19th day for alcoholic and aqueous extract treated groups respectively which was significantly higher than the control groups. The increase in HA antibody titre indicated the augmentation of humoral immune response to SRBC by Emblica officina/is. Administration of Amla extracts

significantly increased cell mediated immune response as evidenced by increase in DTH response. Both the extracts were found to increase the macrophage migration area to 10.93±2.21 and 11.87±3.54 mm' in aqueous and alcoholic extract treated group respectively on 19th day of experiment compared to the controls (5.33±1.61 and 4.78±2.18). Thus a 1.5 to 2.5 fold increase in MMI could be noticed. The results of NBT test gave a maximum of 53.28 percent increase in respiratory burst activity of macrophage in aqueous extract treated group while the alcoholic extract treated group had a maximum of 46.04 percent increase from their controls. The phytochemical study of the Emblica extracts revealed the presence of active principles like tannins, flavonoids, glycosides, phenols, diterpenes, triterpenes and saponins in it. Thus the present study establishes the positive immunomodulatory activity of dried Emblica officinalis fruit pulp extracts, in a concentration dependent manner acting via humoral, cell mediated and cellular immune response.