Abstract
Background: Long-term use of drugs currently used for the treatment of inflammation is associated with serious adverse effects. Nigella sativa, an herb exclusively used in traditional medicine, is reported to inhibit both cyclooxygenase (COX) and 5-lipoxygenase pathways of arachidonic acid metabolism.

Aims and Objectives: To evaluate anti-inflammatory activity of N. sativa seed fixed oil in different models of inflammation in rats and to compare it with control and aspirin.

Materials and Methods: Albino Wistar rats of either sex weighing 180-200 g were used in this study. N. sativa seed fixed oil was used to evaluate anti-inflammatory by carrageenin-induced hind paw edema, cotton pellet granuloma, and formaldehyde induced arthritis method by oral administration in healthy albino rats. The study was conducted with prior approval of Institutional Animal Ethics Committee.

Results: In the model of acute inflammation, i.e., carrageenin-induced paw edema in rats, N. sativa showed anti-inflammatory activity which was statistically significant as compared to control (P < 0.001) but less than aspirin. In cotton pellet induced granuloma method, N. sativa significantly decreased the formation of granulomatous tissue, as compared to control (P < 0.001). N. sativa showed significant anti-inflammatory activity comparable to aspirin in formaldehyde induced arthritis model of chronic inflammation (P > 0.05).

Conclusion: The result of this study suggests that N. sativa seed fixed oil possesses significant anti-inflammatory activity in rats.

Key words: Anti-inflammatory; Fixed Oil; Formaldehyde Induced Arthritis; Nigella sativa; Paw Edema