Planta Med 2013; 79 - PB48
DOI: 10.1055/s-0033-1351993

Imupret® inhibits respiratory syncytial virus replication and displays in vitro and in vivo immunomodulatory properties

K Wosikowski 1, S Seifert 1, O Melnykov 2, J Haunschild 1
  • 1Bionorica SE Kerschensteinerstrasse 11 – 15 92318 Neumarkt Germany
  • 2Institute of Otolaryngology of Prof. Al Kolomiychenko NAMS Kiev Ukraine

Imupret® drops are an ethanolic-aqueous extract of seven different plants (Althaeae radix, Matricariae flos, Equiseti herba, Juglandis folium, Millefolii herba, Quercus cortex, Taraxaci herba). They are used for treatment of recurrent and chronic infections of the respiratory tract, especially tonsillitis. We investigated the antiviral and immunomodulatory potential of Imupret® drops both in vitro and in vivo.

Imupret® inhibited in vitro respiratory syncytial virus (RSV) replication (EC50= 6.8 µg/ml) as determined by the plaque reduction assay in MDCK cells. Imupret® increased the percentage of active phagocytic cells (e.g. macrophages) from tonsils of patients with chronic tonsillitis when incubated for 1h with 1:50 and 1:500 dilutions of Imupret®, suggesting activation of antibacterial immunity. Imupret® also increased the number of CD56+ natural killer cells, important effectors of antiviral immunity. In addition, Imupret® significantly induced antibody-dependent cellular cytotoxicity (25 ± 10% lytic activity in cells treated with 1:500 dilution vs. 10 ± 3% in control cells). It also induced the release of IFN-α and IFN-γ. Modulation of cytolytic activity was confirmed in vivo by studying the influence of Imupret® on the immune system of healthy, antigen-challenged Wistar rats. Imupret® significantly increased cytolytic activity of splenocytes from rats treated with 0.3x the human equivalent dose during 5 days (55 ± 16% lytic activity in treated vs. 26 ± 10% in control animals). In addition, the number of antigen-specific antibody producing cells in the spleen increased significantly (164 ± 25 plaque forming cells/106 splenocytes in treated vs. 101 ± 16/106 cells in control animals).

In conclusion, the results show that Imupret® drops inhibit replication of RSV and modulate immune functions relevant for combating bacterial or viral infections which are beneficial for patients suffering from tonsillitis, an infectious disease of mixed viral and bacterial etiology.