Topical Thymoquinone in 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. Thymoquinone is the major bioactive ingredient, accounting for 30-48% of the essential oil, has high antioxidant and anti-inflammatory, immune-boosting, cell survival-improving, and energy metabolism-promoting properties, which may explain why they are so beneficial to our health. The anti-inflammatory properties of black seeds and thymoquinone are primarily mediated by COX-2 and PGD2 inhibition. Clinical trials on skin disorders have shown that N. sativa essential oil and crude extract are effective. (Atopic dermatitis, Atopic eczema,Wart, Eczema, Acne vulgaris, Acute cutaneous leshmaniasis, Arsenical keratosis, Psoriasis, Vitiligo, Infant skin infections, Acute radiation dermatitis) It can be applied as an alternative treatment that helps patients with skin-related problems