ABSTRACT
Thymoquinone [TQ] was demonstrated as the major active component of Nigella sativa seed oil. It was reported that thymoquinone has an anti-inflammatory and immune-stimulatory effects. On the other hand, cortisone is one of the steroid hormones that used as an anti-inflammatory and immune-suppressor drug. In the present study, the effects of both thymoquinone and cortisone were studied on the histological structure of both duodenum and superior mesenteric lymph nodes of rats. It was noticed that there was an increase of the duodenum mucosal mucus-secreting cells and some nuclear changes in the nuclei of the Brunner's gland cells. There was an increase in number of macrophages, plasma cells and lymphocytes in the superior mesenteric lymph nodes. These findings were discussed according the anti-inflammatory and the immunestimulatory effects of thymoquinone as a point of view, and the anti-inflammatory and immune-suppressing effects of cortisone on another point of view. It was concluded that thymoquinone has an anti-inflammatory and immune sthnulatory effects on rat duodenum and superior mesenteric lymph nodes. However, more investigations are still in need to recommend the replacement of this natural ingredient instead of cortisone with its side effects