Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: In memory of Federica Novelli. 1-Aryl-4,6-diamino-1,2-dihydrotriazine derivatives Anti-influenza A and B viruses activity Anti-RSV activity Host (human) DHFR inhibition a b s t r a c t We have identified a series of 1-aryl-4,6-diamino-1,2-dihydrotriazines, structurally related to the antimalarial drug cycloguanil, as new inhibitors of influenza A and B virus and respiratory syncytial virus (RSV) via targeting of the host dihydrofolate reductase (DHFR) enzyme. Most analogues proved active against influenza B virus in the low micromolar range, and the best compounds (11, 13, 14 and 16) even reached the sub-micromolar potency of zanamivir (EC 50 ¼ 0.060 mM), and markedly exceeded (up to 327 times) the antiviral efficacy of ribavirin. Activity was also observed for two influenza A strains, including a virus with the S31N mutant form of M2 proton channel, which is the most prevalent resistance mutation for amantadine. Importantly, the compounds displayed nanomolar activity against RSV and a superior selectivity index, since the ratio of cytotoxic to antiviral concentration was >10,000 for the three most active compounds 11, 14 and 16 (EC 50~0 .008 mM), far surpassing the potency and safety profile of the licensed drug ribavirin (EC 50 ¼ 5.8 mM, SI > 43).

Host dihydrofolate reductase (DHFR)-directed cycloguanil analogues endowed with activity against influenza virus and respiratory syncytial virus