Effect of a plant polyphenol-rich extract on the lung protease activities of influenza-virus-infected mice.
Influenza infection was induced in white mice by intranasal inoculation of the virus A/Aichi/2/68 (H3N2). The lung protease and the protease-inhibitory activities were followed for 9 days after infection. The intranasal application of a polyphenol-rich extract (PC) isolated from Geranium sanguineum L. induced a continuous rise in the anti-protease activity but did not cause substantial changes in the lung protease activity of healthy mice. Influenza virus infection triggered a slight reduction in protease activity in the lungs at 5 and 48 h post infection (p.i.) and a marked increase at 24 h and 6 day p.i.. Protease inhibition in the lungs was reduced at 24 and 48 h p.i. and an increase was observed at 5 h and 6 and 9 days p.i.. PC treatment brought both activities to normal levels. The restoration of the examined parameters was consistent with a prolongation of mean survival time and reduction of mortality rate, infectious virus titre and lung consolidation. PC reinstated superoxide production by alveolar macrophages and increased their number in virus-infected mice. The favourable effect on the protease and the protease-inhibitory activities in the lungs of influenza-virus-infected mice apparently contributes to the overall protective effect of PC in the murine experimental influenza A/Aichi infection. The antiviral effect of the individual constituents was evaluated.
Serkedjieva
Julia
J
Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria. jserkedjieva@microbio.bas.bg
Toshkova
Reneta
R
Antonova-Nikolova
Stefka
S
Stefanova
Tsvetanka
T
Teodosieva
Ani
A
Ivanova
Iskra
I
D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D005260:Female; D005419:Flavonoids / Q000494:pharmacology*; D031315:Geranium; D053122:Influenza A Virus, H3N2 Subtype; D008168:Lung / Q000201:enzymology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009976:Orthomyxoviridae Infections / Q000188:drug therapy* / Q000201:enzymology; D010636:Phenols / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D059808:Polyphenols; D011480:Protease Inhibitors / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism
D000998:Antiviral Agents; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D011480:Protease Inhibitors; D013481:Superoxides