Cinnamaldehyde Inhibits the Replication of Porcine Reproductive and Respiratory Syndrome Virus Type 2 In Vitro

Area of Science:

• Veterinary Virology
• Natural Product Chemistry
• Antiviral Research

Background:

• Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses in the swine industry.
• Current vaccines offer limited protection, and no specific treatments exist for PRRSV.

Purpose of the Study:

• To identify natural products with anti-PRRSV activity.
• To investigate the mechanism of action of cinnamaldehyde (CA) against PRRSV.

Main Methods:

• Screening of four natural products for PRRSV inhibition.
• In vitro assays using Marc-145 cells to assess CA's effect on PRRSV infection.
• Analysis of PRRSV N protein inhibition, viral particle interaction, and dsRNA levels.

Main Results:

• Cinnamaldehyde (CA) demonstrated significant inhibition of PRRSV infection, with up to 93% inhibition of the PRRSV N protein at 160 μM.
• CA directly interacts with PRRSV particles, blocking viral binding, entry, replication, and release.
• A significant reduction in double-stranded RNA (dsRNA) levels was observed in CA-treated cells.

Conclusions:

• Cinnamaldehyde (CA) effectively inhibits multiple essential stages of the PRRSV lifecycle in vitro.
• CA's direct interaction with PRRSV and disruption of dsRNA expression contribute to its antiviral effect.
• CA presents a promising natural product for the development of novel strategies for PRRSV prevention and treatment.