Potent Tyrosinase Inhibitory Activity of Curcuminoid Analogues and Inhibition Kinetics Studies

Natural tyrosinase inhibitors from herbal plants are promising therapeutic agents for skincare and cosmetic products. curcuminoids exhibit weak antityrosinase properties. The structural modification of curcumin, the major curcuminoid Curcuma longa, gave 14 analogues. inhibitory activity natural modified analogues on both L-tyrosine DOPA substrates were evaluated. inhibition kinetics also undertaken. For with potent substrate, isoxazole analogue 12 two reduced analogues, hexahydrocurcumin (16) α,β-unsaturated 17, showed IC50 values 8.3, 14.6 9.4 µM, 20.9-, 11.9- 18.4-fold more active, respectively, than kojic acid, reference compound. dimethylated 5 exhibited strongest against value 8.0 which was 16.6-fold active acid. revealed that could bind free enzyme enzyme–substrate complex. It acted as a competitive–uncompetitive mixed-II type inhibitor. Curcuminoid 17 results indicated mixed-I inhibitor, while noncompetitive inhibitor bound enzymes These might serve new potential prevention treatment skin pigmentation disorders.