Hydroxypicolinic aldehyde thiosemicarbazone

Anticancer examples, Thiosemicarbazones have been mentioned above in connexion with their antiviral and antitubercular properties. They also have anticancer activity, as already mentioned for 5-hydroxypicolinic aldehyde thiosemicarbazone (4.18) in Section 4.0. Such substances powerfully inhibit ribonucleoside diphosphate reductase, the enzyme which converts ribo- to deoxyribo- nucleotides, leading to inhibition of DNA synthesis. Interaction with the enzymatically-required iron by these drugs in thought to lie at the root of their action (Agrawal, et al,y 1972). 

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