IL17F and psoriasis: It is also a strong inhibitor of the IL23/IL17 axis, which plays a significant role in the pathogenesis of psoriasis, as curcumin decreases the level of IL-17A, IL-17F, IL-22, IL-1b, IL-6 and TNF-a cytokines, as demonstrated by PCR analysis [107], in addition to preventing the proliferation and differentiation of keratinocytes [108].