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. 2011 Feb 25;11:16.
doi: 10.1186/1472-6882-11-16.

Inhibitory Activity of a Standardized Elderberry Liquid Extract Against Clinically-Relevant Human Respiratory Bacterial Pathogens and Influenza A and B Viruses

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Inhibitory Activity of a Standardized Elderberry Liquid Extract Against Clinically-Relevant Human Respiratory Bacterial Pathogens and Influenza A and B Viruses

Christian Krawitz et al. BMC Complement Altern Med. .
Free PMC article


Background: Black elderberries (Sambucus nigra L.) are well known as supportive agents against common cold and influenza. It is further known that bacterial super-infection during an influenza virus (IV) infection can lead to severe pneumonia. We have analyzed a standardized elderberry extract (Rubini, BerryPharma AG) for its antimicrobial and antiviral activity using the microtitre broth micro-dilution assay against three Gram-positive bacteria and one Gram-negative bacteria responsible for infections of the upper respiratory tract, as well as cell culture experiments for two different strains of influenza virus.

Methods: The antimicrobial activity of the elderberry extract was determined by bacterial growth experiments in liquid cultures using the extract at concentrations of 5%, 10%, 15% and 20%. The inhibitory effects were determined by plating the bacteria on agar plates. In addition, the inhibitory potential of the extract on the propagation of human pathogenic H5N1-type influenza A virus isolated from a patient and an influenza B virus strain was investigated using MTT and focus assays.

Results: For the first time, it was shown that a standardized elderberry liquid extract possesses antimicrobial activity against both Gram-positive bacteria of Streptococcus pyogenes and group C and G Streptococci, and the Gram-negative bacterium Branhamella catarrhalis in liquid cultures. The liquid extract also displays an inhibitory effect on the propagation of human pathogenic influenza viruses.

Conclusion: Rubini elderberry liquid extract is active against human pathogenic bacteria as well as influenza viruses. The activities shown suggest that additional and alternative approaches to combat infections might be provided by this natural product.


Figure 1
Figure 1
Effect of the elderberry extract on bacterial growth. Visualization of Gram-positive and Gram-negative bacterial strains exposed to different concentrations of Rubini elderberry extract during growth in liquid culture. Every biological experiment was independently repeated at least three times with two replicates per trial. Standard deviation is indicated. The p < 0.05 was observed for all bacterial species tested.
Figure 2
Figure 2
Impact of the elderberry extract on propagation of IV. A) Focus size reduction assay. MDCK cells were infected with the two virus strains as indicated and incubated for 48 h in the presence of the extract (1:100). Foci were detected by immunochemistry. B) Pre-treated MDCK cells were infected with pre-treated virus and were propagated for 48 h in the presence of the extract. As control untreated virus and cells were used for infection. The mean titre of three independent experiments is given as percentage of the control (black) set to 100%. Standard deviation is indicated (KAN-1: p < 0.07, Mass: p < 0.03).

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