Thiazolidines: Potential anti-viral agents against avian influenza and infectious bronchitis viruses

Viral outbreaks are a common cause of morbidity and mortality in livestock and human populations. Lack of good vaccines and poor control measures along with natural viral genetic drifting and shifting are the common causes of new viral strains and outbreaks. The current study reports the synthesis of some 2-aryl substituted thiazolidine-4-carboxylic acids 1a-h and their 3-acetyl 2a and 3-benzoyl derivatives 3a. Two important poultry viruses: Avian influenza virus (AIV; A/Chicken/Italy/1994/H9N2) and infectious bronchitis virus (IBV) were selected, grown in ‎9-11 days old chicken embryonated eggs‎, and subjected to in ovo anti-viral assays. Most of the synthesized compounds were found active against AIV subtype H9N2 and IBV. In the case of AIV, the best results were attained for compound 1d which showed an IC₅₀ value of 3.47 µM, while IBV 1c showed IC₅₀ value of 4.10 µM. The lower IC₅₀ values of these compounds correlate with the high potency of these compounds, especially in comparison with control groups. The standard drugs amantadine and ribavarin were used as positive controls in the case of AIV and IBV, respectively. Better results were obtained with 2-aryl substituted thiazolidine-4-carboxylic acids 1a-h compared to their N-acylated derivatives 2a and 3a against both viruses. In conclusion, this preliminary data support the idea that thiazolidine carboxylic acids could be used as anti-viral drugs against AIV and IBV infections.