Inhibitory effects of sumac (Rhus SPP.) fruit extracts and pentagalloyl glucose on mushroom tyrosinase enzyme

Several plant phenolics inhibit the tyrosinase enzyme which is involved in the biosynthesis of melanin. We recently reported that winged sumac (Rhus coriaria) fruit contains polyphenols including pentagalloyl glucose (PGG) (1) and the new galloyl derivative, galloyl malic acid dimethyl ester (2). Here, two sumac fruit extracts (R. coriaria and R. copallinum) were evaluated for anti-tyrosinase and anti-melanogenesis properties. The total polyphenolic content for the R. coriaria and R. copallinum extracts were 20.94 and 18.18% gallic acid equivalents, respectively. In the tyrosinase enzyme inhibitory assay, PGG (IC₅₀=570.3µM) was comparable to the positive controls, kojic acid and arbutin (IC₅₀=440µM and 1.7 mM, respectively). Our results demonstrate the inhibitory effects of sumac fruit extracts and PGG on tyrosinase enzyme, showing their anti-melanin formation potential.