Nitric oxide induced by Indian ginseng root extract inhibits Infectious Bursal Disease virus in chicken embryo fibroblasts in vitro

Ganguly, Bhaskar; Umapathi, Vijaypillai; Rastogi, Sunil Kumar

Methanol: chloroform: water:: 12:5:3 (MCW) extract of roots of Withania somnifera roots obtained and characterized as described previously [12] was used in the present study at a concentration of 160 μg/mL pre-determined to be non-cytotoxic to CEF (data not shown). Nitric oxide assay Griess test CEF monolayers were grown in 6-well cell culture plates and upon reaching 80-90% confluence, they were infected with IBDV with or without MCW extract treatment. 0.75 mL of the culture medium was withdrawn from each group at 0, 2, 4, 6, 24 and 48 h and transferred to five wells (150 μL each) of a 96-well plate. The volume withdrawn from the 6-well plate was made up with medium of matching MCW extract concentration. To each well of the 96-well plate, 100 μL of Griess reagent was added and allowed 30 min for color development, following which the plate was read at 570 nm. Concentrations of nitric oxide were expressed in terms of sodium nitrite-equivalents, obtained by using a sodium nitrite standard curve.