Herbal medication is becoming very popular in today’s world as people seek for natural remedies and avoid synthetic ones. These are widely used as immuno- modulatory agents. Nigella sativa is one of them and its extract contains a major component thymoquinone (TQ), which has immuno-modulatory activities. The objectives of current study were to evaluate the immunomodulatory effects of Nigella sativa extract in ethanol on the polymorphonuclear (PMN)/leukocyte phagocytosis and lymphocyte proliferation in goats. For this purpose, whole blood was analyzed with Phagotest^® by flow cytometry and lymphocyte proliferation using WST-1^® test kit. All doses of D4 and D8 dilutions of Nigella sativa exerted an inhibitory effect on phagocytosis activity, maximal effect was observed with 10 µl (highest dose). In contrast, all doses of the D6 dilution of Nigella sativa enhanced the phagocytosis activity in a dose-dependent manner. The maximum stimulating effect (median: 8%) was observed at the highest dose (l0 µl), which was significantly (P<0.05) different from other doses. Various doses of all tested dilutions (D4, D6, D8) of Nigella sativa stimulated lymphocyte proliferation. The maximum stimulating effect (median: 8%) was observed by the lowest dose (0.5 µl) of D4 dilution of Nigella sativa, which was significantly (P<0.05) different from other doses tested. Thus, ethanolic dilutions of Nigella sativa seed extract may be considered as an immuno- modulatory agent to cure immune mediated disorders.

Key words: Flow cytometry, Goats, lymphocyte proliferation, Nigella sativa, Polymophonuclear phagocytosis