ABSTRACT
Respiratory tract infections caused by influenza viruses have challenged clinicians due to shortages of ideal antiviraltherapy or rapid development of resistance to available drugs. The development of new medications, especially fromnatural sources, is particularly important to combat the highly mutagenic influenza virus. This study was conducted totest the activity of some medicinal plants used traditionally in Sudan for the treatment of respiratory tract infectionsand other various diseases. Balanites aegyptiaca, Cordia africana, Aristolochia bracteolata, Boscia senegalensis, andLeptadenia arborea were extracted by water and methanol and tested against influenza virus strain A/WSN/33(H1N1)using zanamivir as a standard. The effective concentrations for methanol and water extracts were found in the rangesof 0.25–20 mg/ml and 10–35 mg/ml, respectively. The toxicities of all extracts were evaluated against Madin–Darbycanine kidney cells, and the cytotoxic concentration for all extracts was 80 mg/ml. Plants’ extracts at a concentrationof 2.5–20 mg/ml prevented hemagglutinin-assisted viral adsorption to RBCs using hemagglutination inhibitionassay. The proven anti-influenza activity of the tested plants could explain their folkloric use. It would be valuableto standardize the plants’ extracts and conduct in vivo studies so as to develop a safe and effective herbal formula forinfluenza.