Antiviral, embryo toxic and cytotoxic activities of Astragalus membranaceus root extracts

Antiviral activity of Astragalus membranaceus aqueous and methanol root extracts was determined against Avian influenza H9 virus. Toxicity profile of extracts was evaluated using chicken embryos and BHK-21 cell line. Different concentrations (400, 200, 100, 50, 25. 12.5, 6.25 and 3.12μg/mL) of both aqueous and methanol extracts were mixed with standard virus inoculum (4HAunits) and incubated for 30minutes at 37°C prior to inject the chicken embryos. Chorioallantoic fluid harvested 72 hours post inoculation and evaluated for virus growth using hemagglutination assay. Same concentrations of both extracts without virus were injected in chicken embryos to evaluate embryo toxic activity as well. The cytotoxic activity of aqueous and methanol extracts was determined by MTT colorimetric assay using BHK-21 cells. Three concentrations (400, 200 and 100μg/mL) of aqueous and five concentrations (400, 200, 100, 50 and 25μg/mL) of methanol extract showed antiviral activity. None of the tested concentrations of aqueous and methanol A. membranaceus root extracts caused chicken embryo mortality. Cell survival percentage of aqueous extract was higher than 50 at all of the tested concentrations except 400μg/mL. Two concentrations (400 and 200μg/mL) of methanol extract showed cytotoxicity. It was concluded that aqueous and methanol roots extracts of A. membranaceus have antiviral activity and concentrations which were safe may be used for treatment of Avian influenza H virus infections.