Dithranol (Anthralin)

Anthralin is an anthrone inhibitor of keratinocyte proliferation and a modulator of differentiation.¹ It increases apoptosis and inhibits proliferation of normal human keratinocytes (NHKs) when used at a concentration of 2.5 μM. It also decreases the mitochondrial membrane potential, increases cytochrome c release, and induces perinuclear mitochondrial clustering in NHKs when used at a concentration of 5 μM.² Anthralin (0.25 μM) decreases the expression of β-defensin-2 and S100 calcium-binding protein A9 (S100A9) and increases the expression of IL-6 and IL-8 in IL-17A- and IL-22-stimulated NHKs.¹ It also inhibits leukotriene B₄ production, stimulated by the calcium ionophore A23187 , from human neutrophils (IC₅₀ = 7 μM).³ Topical anthralin (0.1%) induces hair regrowth in a Dundee experimental bald rat (DEBR) model of alopecia areata.⁴

1.Holstein, J., Fehrenbacher, B., Brück, J., et al.Anthralin modulates the expression pattern of cytokeratins and antimicrobial peptides by psoriatic keratinocytesJ. Dermatol. Sci.87(3)236-245(2017) 2.McGill, A., Frank, A., Emmett, N., et al.The anti-psoriatic drug anthralin accumulates in keratinocyte mitochondria, dissipates mitochondrial membrane potential, and induces apoptosis through a pathway dependent on respiratory competent mitochondriaFASEB J.19(8)1012-1014(2005) 3.Schr?der, J.M.Anthralin (1,8-dihydroxyanthrone) is a potent inhibitor of leukotriene production and LTB4-ω oxidation by human neutrophilsJ. Invest. Dermatol.87(5)624-629(1986) 4.Tang, L., Sundberg, J.P., Liu, H., et al.Old wine in new bottles: Reviving old therapies for alopecia areata using rodent modelsJ. Invest. Dermatol. Symp. Proc.8(2)212-216(2003)