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Updated: May 28, 2026

Quantification of Hypopigmentation Activity In Vitro
Published on: March 6, 2019
Structural requirement of phenylthiourea analogs for their inhibitory activity of melanogenesis and tyrosinase
Pillaiyar Thanigaimalai1, Ki-Cheul Lee, Vinay K Sharma
1College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 305-764, Republic of Korea.
Abstract:
Effect of a series of 1-phenylthioureas 1a-k and 1,3-disubstituted thioureas 2a-k were evaluated against melanin formation in melanoma B16 cell line and mushroom tyrosinase. Inhibitory activity of tyrosinase of 1-phenylthioureas 1a-k is parallel to their melanogenic inhibition. Thus, the melanogenic inhibition in melanoma B16 cells of 1-phenylthioureas could be the result of inhibition of tyrosinase. However, 1,3-diaryl or 1-phenyl-3-alkylthioureas, 2a-k, appears as melanogenic inhibitor without inhibition of tyrosinase. The molecular docking study of 1e and 2b to binding pocket of tyrosinase provided convincing explanation regarding the necessity of direct connection of planar phenyl to thiourea unit without N'-substitution of phenylthioureas 1 as tyrosinase inhibitor and 2 as non-tyrosinase inhibitor.
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