A newly series of 4-(phenylurenyl) chalcone (4a–j) and 4′-(phenylurenyl/thiourenyl) chalcone (9a–l) derivatives were synthesized and their inhibitory effects on the diphenolase activity of banana tyrosinase were evaluated. Tyrosinase has been purified from banana on an affinity gel comprised of Sepharose 4B-l-tyrosine-p-aminobenzoic acid. The result showed that 4a–j inhibited the PPO enzyme activity. Conversely, 9a–h and 9i–l showed ...
