EVALUATION OF ANTIVIRAL ACTIVITY AGAINST NEWCASTLE DISEASE VIRUS AND EMBRYOTOXICITY OF ESSENTIAL OIL AND ETHANOLIC EXTRACT OF TRACHYSPERMUM AMMI

Abstract

Background: Trachyspermum ammi (Ajwain) is a medicinal plant known for its therapeutic properties. Given its bioactivity, it presents a promising candidate for treating viral diseases such as Newcastle disease, a highly contagious and economically significant viral illness of poultry caused by the Newcastle disease virus (NDV). Objective: The present study aimed to evaluate the antiviral activity and embryo toxicity of the essential oil and ethanolic extract of T. ammi against NDV using an in ovo model. Methods: Ten serial dilutions (100 to 0.19 µg/mL) of both T. ammi essential oil and ethanolic extract, and five concentrations (40 to 20 µg/mL) of the standard antiviral drug ribavirin were prepared. Each concentration was mixed with a fixed titer (4 HA units) of virulent NDV. The mixtures were inoculated into nine-day-old specific pathogen-free (SPF) chicken embryos, which were then incubated for 72 hours. Antiviral activity was assessed post-incubation using a hemagglutination test, while embryo toxicity was calculated based on the percentage of embryo survival. Main Outcome Measures: The primary outcomes were the minimum concentration of each substance that achieved complete inactivation of NDV (antiviral activity) and the concentration at which embryo mortality occurred (embryo toxicity). Results: The essential oil of T. ammi demonstrated complete inactivation of NDV across a wide concentration range, from 0.78 µg/mL to 100 µg/mL. The ethanolic extract of T. ammi showed complete antiviral activity from 1.5 µg/mL to 100 µg/mL. The Embryo toxicity for both the essential oil and the ethanolic extract was observed only at the highest tested concentration of 100 µg/mL. Ribavirin exhibited strong antiviral activity at all tested concentrations (20-40 µg/mL) but was found to be embryo-toxic at the higher concentrations of 40, 30, and 25 µg/mL. Conclusion: This experiment demonstrates that both the essential oil and ethanolic extract of Trachyspermum ammi possess significant antiviral potential against NDV, with a favorable safety profile showing embryo toxicity only at a high concentration. Their efficacy and lower toxicity compared to ribavirin suggest that T. ammi is a promising candidate for further investigation in the development of natural antiviral agents against Newcastle disease