Efficacy and Safety of Thymoquinone Ointment as a Potential New Therapeutic Modality of Psoriasis Vulgaris.

Psoriasis is a systemic chronic relapsing immune-mediated disease which often requires a long-term therapy. Psoriasis occurs in around 2-3% of the total global population. In Egypt, the prevalence of psoriasis ranges between 0.19% and 3%.

Besides, it could have profound implications on the patients' psychological state and quality of life.

It is presented by erythematous, scaly plaques over the preferred sites. The pathogenesis of this highly complex disease is still far from being fully understood. Keratinocytes' hyperproliferation and immune system dysfunctions are well recognized contributors, with numerous treatments targeting these unique immunologic dysfunctions.

Topical therapy for psoriasis is a current trending subject as it implies good compliance for the patient, few adverse systemic reactions and a targeted effect. Numerous substances are now being tested, from natural to synthetic compounds and already known substances in improved formulas such as vesicular systems.

Nigella sativa belongs to the Ranunculaceae family is an annual plant which distributed in southern Europe and some parts of Asia, including Syria, Turkey, Saudi Arabia, Pakistan, and India. Different active pharmaceutical ingredients have been identified in the N. sativa seeds, including saponins, flavonoids, cardiac glycosides, thymoquinone, thymol, limonene, carvacrol, p-cymene, alpha-pinene, 4-terpineol, longifolene, t-anethole benzene, isoquinoline, and pyrazole alkaloids, as well as unsaturated fatty acid such as linoleic acid, oleic acid, and palmitic acid.