In vitro antiviral activity of Rosmarinus officinalis L. aqueous extract against Respiratory Syncytial Virus
Year: 2026
Type: article
Abstract: Respiratory syncytial virus is a significant cause of respiratory illness. It generally infects infants and immunosuppressed persons, causing morbidity and mortality in young children. Currently, no authorized vaccine or proven antiviral treatment is available for RSV. This study evaluates the in vitro cytotoxicity, antiviral, anti-inflammatory and antioxidant effects of the aqueous extract of Rosmarinus officinalis L. The maximum non-toxic dose (MNTD) of the aqueous extract of R. officinalis L. was determined to be 62.5 µg/mL, with an IC50 of 206.6 µg/mL. Cytopathic effects of RSV in HEp-2 were observed microscopically and the viral titer was quantified 10³·⁷⁵ TCID₅₀/mL using the endpoint dilution or the median tissue culture infective dose method. Antiviral activity was evaluated using the pre-treatment, co-treatment and post-treatment methods. The most significant antiviral activity was observed in the co-treatment assay where the aqueous extract inhibited virus growth by 67.28%. The post-treatment method achieved 45.31% virus inhibition whereas the pre-treatment method showed no significant effect. A dose-dependent inhibition resulted in moderate DPPH radical scavenging activity of the plant extract, with an IC50 value of 65.14 µg/mL. The aqueous extract showed significant anti-inflammatory activity at concentrations ranging from 25 to 125 µg/mL, with a concentration-dependent inhibitory effect, yielding inhibition percentages of 8.38% to 68.61%.
Institution: Maharshi Dayanand University
Language: English
Topic: Medicinal Plant Research
Subfield: Plant Science
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W7220385331