Twenty-eight tetraketones (1–28) with variable substituents at C-7 were synthesized and evaluated as tyrosinase inhibitors. Remarkably compounds 25 (IC50= 2.06 μM), 11 (IC50= 2.09 μM), 15 (IC50= 2.61 μM), and 27 (IC50= 3.19 μM) were found to be the most active compounds of the series, even better than both standards kojic acid (IC50= 16.67 μM) and l- mimosine (IC50= 3.68 μM). This study may lead to the discovery of therapeutically potent ...