Drug Designing Through Inhibition of Nucleic Acid Synthesis - Through their detailed studies of antimetabolites or inhibitors (they block key enzymes) of DNA synthesis G. Elison and G. Hitchings (both of USA) were able to develop drugs for treating 'cancer', 'gout', "malaria' and viral infections such as 'herpes'.
They found that there are drugs like '6-mereaptopurine' and 'thioguanine' whicl1 inhibit DNA synthesis leading to inhibition of cell division and therefore are effective in cancer chemotherapy. Another drug developed by them is 'azathioprine' used to fight transplant rejection, or diseases like rheumatoid arthritis, in both cases the drug acting through attacking the immune system (immunosuppressive effect).
Elion and Hitchings also studied the differences in nucleic acid synthesis of prokaryotes and human cells, which led to the development of drugs like 'pyramethamine' for malaria, 'trimethoprim' for bacterial infection and ‘acyclovir’ for herpes virus infection, ‘Azidothymidine (AZT)’ developed recently for AIDS also woks on the principle formulated by Elison and Hitchings.