Investigation of the potential anti-influenza activity of five plants grown in Sudan and used folklorically for respiratory infections

Abstract

Respiratory tract infections caused by influenza viruses have challenged clinicians due to shortages of ideal antiviral therapy or rapid development of resistance to available drugs. The development of new medications, especially from natural sources, is particularly important to combat the highly mutagenic influenza virus. This study was conducted to test the activity of some medicinal plants used traditionally in Sudan for the treatment of respiratory tract infections and other various diseases. Balanites aegyptiaca, Cordia africana, Aristolochia bracteolata, Boscia senegalensis, and Leptadenia 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 ranges of 0.25-20 mg/ml and 10-35 mg/ml, respectively. The toxicities of all extracts were evaluated against Madin-Darby canine kidney cells, and the cytotoxic concentration for all extracts was 80 mg/ml. Plants' extracts at a concentration of 2.5-20 mg/ml prevented hemagglutinin-assisted viral adsorption to RBCs using hemagglutination inhibition assay. The proven anti-influenza activity of the tested plants could explain their folkloric use. It would be valuable to standardize the plants' extracts and conduct in vivo studies so as to develop a safe and effective herbal formula for influenza.