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Updated: May 26, 2026

Quantification of Hypopigmentation Activity In Vitro
Published on: March 6, 2019
Structure-activity relationship of naphthaldehydethiosemicarbazones in melanogenesis inhibition
Pillaiyar Thanigaimalai1, Eeda Venkateswara Rao, Ki-Cheul Lee
1College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 305-764, Republic of Korea.
Abstract:
2-(Naphthalen-1-ylmethylene)hydrazinecarbothioamide (14, IC(50)=1.1μM) was discovered as a highly potent inhibitor of melanogenesis. To define the role of hydrogens (at N1 and N3) and sulfur in 14, a series of analogs 15a-p were synthesized and evaluated for anti-melanogenic activity using melanoma B16 cells under the stimulus of α-MSH. It was observed that replacement of either of these hydrogens at N1 or N3 by substituents increases the activity significantly. Conversely, concomitant substitutions decrease the inhibitory potency. In addition, the presence of sulfur in thiosemicarbazone is essential for the activity.
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