Investigating the Antiviral Mechanism of Kaempferol Against Grouper Iridovirus: Combined Evaluation of In Vitro Activity and In Vivo Efficacy

Singapore grouper iridovirus (SGIV) is one of the major pathogens that pose significant threats to the aquaculture industry. Kaempferol is a flavonoid compound extracted from Illicium verum Hook.f. (star anise), a material that is both edible and used in traditional medicine. In this study, we evaluated the antiviral effects of kaempferol against SGIV in vitro and in vivo, and elucidated the antiviral mechanism. Our study found that kaempferol could effectively resist SGIV infection in vitro and in vivo. Kaempferol might destroy the SGIV envelope and interfere with the attachment, invasion, and replication stages of SGIV infection. Transcriptomic analysis showed that differentially expressed genes regulated by kaempferol were enriched in ribosome, NF-κB, and phospholipase D signalling pathways. Further screening of immunity-related genes and pathway analysis revealed that antiviral immune responses were mainly governed by the JAK-STAT, PI3K-Akt, and TNF signalling pathways. This study demonstrated that kaempferol exhibited significant antiviral effects against SGIV through multiple mechanisms and had the potential to become an anti-SGIV fishery drug. These findings provide a theoretical basis for the development of effective drugs for the prevention and treatment of SGIV.