Synthesis, Antiviral Activity, and Mechanisms of Purine Nucleoside Derivatives Containing a Sulfonamide Moiety

Novel
purine nucleoside derivatives containing a sulfonamide moiety
were prepared, as well as their antiviral activities against
potato virus Y (PVY), cucumber mosaic virus (CMV), and tobacco mosaic
virus (TMV) were evaluated. The antiviral mechanisms of the compounds
were investigated. Results showed that most of the compounds had good
antiviral activities. Compound 5 at 500 μg/mL exhibited
excellent curative and protective activities of 52.5% and 60.0% and
of 52.0% and 60.2% for PVY and CMV, respectively, which are higher
than those of ningnanmycin (48.1%, 49.6%; 45.3%, 47.7%), ribavirin
(38.3%, 48.2%; 40.8%, 45.5%), and chitosan oligosaccharide (32.5%,
33.8%; 35.1%, 34.6%). Moreover, compound 5 displayed
good inactivating activity against TMV, with an EC50 value
of 48.8 μg/mL, which is better than that of ningnanmycin (84.7
μg/mL), ribavirin (150.4 μg/mL), and chitosan oligosaccharide
(521.3 μg/mL). The excellent antiviral activity of compound 5 is related to its immune induction effect which can regulate
the physiological and biochemical processes in plants, including defense-related
enzyme activities, defense-related genes, and photosynthesis-related
proteins. These results indicate that purine nucleoside derivatives
containing a sulfonamide moiety are worthy of further research and
development as new antiviral agents.