9-Hydroxy chrysarobin or 3-methylanthralin is a pure product of chrysophanic acid reduction. The compound 3-methylanthralin is listed in the Merck Index as an antipsoriatic. Chrysarobin is a mixture of compounds derived from Goa powder, and includes 3-methylanthralin. Goa powder (Araboba) is derived from the wood and bark of Andria Araroba Aguiar (Leguminosae). Literature references describing the isolation of chrysarobin date back to the second part of 1800s. A method of reducing chrysarobin to obtain 3-methylanthralin was known as early as 1931. At present chrysarobin is used in the topical antipsoriatic compositions with natural plant extracts and as a homeopatic product. Pure 3-methylanthralin when tested on mice in vivo was found to play an important role in skin hyperplasia and promotion of skin carcinogenesis by effecting the expression of several gap-junctional proteins connexins (Cxs) and inhibiting glucocorticoid receptor expression in mouse epidermis specifically in keranocytes. Chrysarobin is approved by FDA as an over-the-counter drug. ProZ92 is a trade name a patented botanical formula, topical marketed in Israel which primary anti-psoriatic agents are: 3-methylanthralin, chrysophanol, aloe-emodin and aloe-emodin acetate.