Antiviral activity and antioxidant activity of Cistanche deserticola polysaccharides against pseudorabies viruses

Pseudorabies is an acute, highly contagious infectious disease caused by the pseudorabies virus (PRV). Since 2011, several pathogenic mutant strains of PRV have emerged, and the efficacy of existing vaccines has been inadequate in providing full protection, leading to considerable economic losses in the pig industry. Cistanche deserticola polysaccharides (CDP) exhibits a range of biological activities. However, its antiviral effects remain under-explored. In this study, we demonstrated that CDP possesses antiviral activities against PRV/XJ5, notably, at the concentration of 1000 μg/mL, the inhibitory rate of PRV-infected PK15 B6 cells attained about 90 %. CDP inhibited the adsorption, entry, and replication of PRV/XJ5 in PK15 B6 cells in a dose-dependent manner when introduced at various stages of the viral life cycle. Levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were observed to reduce by almost 50 % at the highest recorded concentration. While simultaneously enhancing superoxide dismutase (SOD) activity, thereby mitigating oxidative stress induced by PRV/XJ5. Additionally, high dose of CDP (200 mg/kg) was found to offer complete protection against PRV in mouse model when the mice were inoculated with lethal doses of PRV via nasal drops. These results suggested that CDP may serve as promising antiviral agent for the prevention and management of PRV variant infections.