In Vivo Approaches to Investigate the Immune Response of Plant-Based Anti Tumour Drug, Elephantopus Scaber L

Inspired by our earlier research reports towards the ability of E. scaber and its phytochemical constituents in regimens for inhibiting tumours with extensive proliferative potencies, the active fraction of E. scaber (ES) was chosen in the present study for investigating its immuno modulatory activity, anti tumour activity and toxicity, in in vivo animal models. The influence of the administration of ES (100 mg/kg, i.p) on the humoral and cellular immune response was investigated in mice. The immuno potentiating effect of ES were evaluated by determining the immune profile of treated mice such as circulating antibodies, anti-SRBC antibody producing cells (PFC), antibody dependent complement mediated cytotoxicity (ACC) of tumour and normal mice, delayed type hypersensitivity reaction (DTH), and the number of peritoneal exudates cells and macrophages. ES significantly increased the production of specific antibody to sheep red blood cell (SRBC) antigen in immunized mice. ES enhanced splenocyte proliferation and showed maximum peak value of spleen cells on day 5. After EAC tumour transplantation, the antibody complement mediated cytotoxicity (ACC) showed a significant cytotoxic activity in the ES treated group on day 10 for an antibody dilution of 1:4. The effects of ES for 7 days elicited a significant dose related increase in 4h and delayed 24h DTH response in mice Elevated delayed type hypersensitivity reaction (DTH), observed in this study suggested the activation of the cellular immune response. Treatment with ES for 7 consecutive days resulted in a two fold increase in number of peritoneal exudate cells and macrophage count. The results of immuno modulatory studies using in vivo models demonstrated the effect of ES to stimulate both the humoral and cell-mediated components of the immune response in the experimental mice. Growth inhibitory effect of ES on EAC tumour cells implanted into the peritoneal cavity of mice were evaluated by determination of animal survival, recorded and expressed as mean survival time (MST) in days and the percentage increase in life span (% ILS).ES (100 mg/kg, i.p) was found effective in prolonging the lifespan of (Ehrlich Ascites Carcinoma) EAC tumour bearing mice and exhibited significant in vivo anti tumour efficacy against EAC tumour cells. The influence of the administration of ES for the short term toxicity studies was investigated in Wistar rats. The short term toxicity studies in the animals treated with ES were judged by monitoring behavioral changes, hematological parameters, serum enzymes activities and other biochemical parameters. The effect of ES on serum enzyme activities, alkaline phosphatase (SAKP), alanine transaminase (SALT), aspartate transaminase (SAST), and other biochemical parameters like serum urea, serum creatinine, serum calcium and serum glutamyl transferase (γ-GT) levels of rats indicated that there was no toxicity even at higher concentrations upto1000 mg/kg. Also haematological profiles such as red blood cell count (RBC), white blood cell count (WBC) and differential count of WBC such as neutrophil, lymphocytes, monocytes and basophils, haemoglobin content, hematocrit (Hct), platelet count and erythrocyte indices such as mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC), also did not show any treatment related effects. The results of the short term toxicity studies indicated that high dose upto 1000 mg/kg of ES was tolerated by rats, without producing any toxic symptoms thus indicating a wide margin of safety of the drug used. In conclusion, our results indicated that ES with its nontoxic nature, is as a good candidate for further investigations in order to develop a natural compound as an immuno modulator and anticancer agent. Our earlier research work reported the presence of sesquiterpene lactones, deoxyelephantopin and isodeoxyelephantopin as the major phytochemical constituents of ES. Hence its constituents can be used as potential therapeutic tools to regulate inflammatory responses/immunological disorders and prevent carcinogenesis.