Immunosuppressive and cytotoxic properties of Nigella sativa.

In this study the volatile oil of Nigella sativa seeds (NSVO) was investigated for its immunomodulating and cytotoxic properties. A rat model was designed to examine the effect of NSVO on selected immune components. Long-Evans rats were challenged with a specific antigen (typhoid TH) and treated with NSVO; and the changes produced in their serum antibody titre along with the splenocytes and peripheral immune cells were analysed. Antibody titre for the experimental animal was found to be 1280 as compared to the 2560 in the control rats. There was a significant (p < 0.05) decrease in splenocytes and neutrophils counts, but a rise in peripheral lymphocytes and monocytes in the experimental animals. To test the cytotoxicity of NSVO, a panel of five human cancer cell lines and a fibroblast line was used. The MTT assay was employed to estimate the cell mortality. Vinblastine sulphate and mitomycin C were used as the positive control. LC(50) values for NSVO were 155.02 +/- 10.4, 185.77 +/- 2.9, 120.40 +/- 20.5, 384.53 +/- 12.1 and 286.83 +/- 23.3 micro g/ml respectively against the SCL, SCL-6, SCL-37'6, NUGC-4 cancer lines and 3T6 fibroblast line. Results indicate that the NSVO could be considered as a potential immunosuppressive cytotoxic agent. Copyright 2004 John Wiley & Sons, Ltd.