The avian influenza A virus (AIV) is naturally prevalent in aquatic birds, infecting different avian species and transmitting from birds to humans. Both AIVs, the H5N1 and H7N9 viruses, have the potential to infect humans, causing an acute influenza disease syndrome in humans, and are a possible pandemic threat. AIV H5N1 is highly pathogenic, whereas AIV H7N9 has comparatively low pathogenicity. A clear insight into the disease pathogenesis is significant to understand the host’s immunological response, which in turn facilitates the design of the control and prevention strategies. In this review, we aim to provide comprehensive details on the pathogenesis and clinical features of the disease. Moreover, the innate and adaptive immunological responses to AIV and the recent studies conducted on the CD8⁺ T cell immunity against AIVs are detailed upon. Further, the current status and advancement in the development of AIV vaccines, along with the challenges, are also discussed. The information provided will be helpful in combating the transmission of AIV from birds to humans and, thus, preventing severe outbreaks leading to pandemics worldwide.

The current work involves the use of dehydroacetic acid based chalcone derivatives for the synthesis of spirooxindole grafted pyrrolidine moieties. All the synthesized compounds have been characterized using spectroscopic techniques such as NMR (¹H-NMR and ¹³C-NMR), IR, mass and elemental analysis. Molecular mechanics studies were performed to comprehend the regioselectivity in the product formation. Molecular docking of the synthesized compounds was performed with few bacterial proteins of Bacillus subtilis and Pseudomonas aeruginosa responsible for biofilm formation followed by molecular dynamics simulations with the potential lead compound. Further, to corroborate the results obtained via in silico study, anti-biofilm activity etc. of the synthesized compounds (4a–e) was checked for effectiveness against biofilm formation. Taken together, this study opens up to explore these compounds’ multiple roles in diverse fields in the arena of medical sciences.

A facile one-pot sequential four-component synthesis of highly substituted trispiro heterocyclic system involving [3 + 2]-cycloaddition of azomethine ylides as the key step is described. The protocol provides a mild reaction condition, high yield of the products, high regioselectivity, and operational simplicity to assemble complex structural entity in a single operation. The structure of the product was confirmed by spectroscopic techniques, elemental and high-resolution mass spectrum analysis. Graphical Abstract

An expedient one-pot sequential five component synthesis of highly substituted pyrazolo-N-methyl-piperidine grafted spiro-indenoquinoxaline pyrrolidine heterocycles involving [3 + 2]-cycloaddition of azomethine ylides as the key step is described. The protocol provides a mild reaction condition, high yield of the products, high regioselectivity and operational simplicity to assemble complex structural entity in a single operation. The structure of the product was confirmed by spectroscopic techniques and elemental analysis.

A facile and expedient one-pot sequential five-component synthesis of highly substituted trispiro-pyrrolidine heterocycles is described. The key step involves [3 + 2]-cycloaddition of azomethine ylide. This multicomponent reaction (MCR) strategy provides a mild reaction condition, high yield of the products, high regioselectivity, and operational simplicity to assemble complex structural entity in a single operation. The structure of product was confirmed by IR, ¹H-NMR, ¹³C-NMR, and high-resolution mass spectroscopic analysis. A theoretical insight is provided through MM2 calculation for the formation of the observed products. Graphical Abstract