Echinacea purpurea fresh-plant extract inhibits swine flu viruses in vitro

Echinacea pur­pu­rea

An inter­na­tio­nal group of rese­ar­chers has now shown for the first time that Echinacea pur­pu­rea (pur­ple con­e­flower) deve­lo­ps direct anti­vi­ral effects against cli­ni­cal­ly important influ­en­za viru­s­es in vitro, inclu­ding the new influ­en­za patho­gens (H1N1“swine flu”) [1]. Even after repea­ted tre­at­ment of the influ­en­za virus with the Echinacea fresh-plant extra­ct no build-up of resis­tances could be seen. Fur­ther­mo­re essen­ti­al ele­ments of the mole­cu­lar mecha­nisms of action of the inhi­bi­ti­on could be reve­a­led by the scientists.


It has long been suspec­ted that Echinacea may have direct anti­vi­ral or viro­sta­tic effects [2]. How effec­ti­ve an Ech­nacea fresh plant extra­ct can block the repli­ca­ti­on of rele­vant respi­ra­to­ry tract patho­gens in vitro was part of a very recent stu­dy. [3]. The results of this rese­arch sug­gested taking a clo­ser look at the anti­vi­ral effect ver­sus influ­en­za viru­s­es, giving par­ti­cu­lar con­side­ra­ti­on to the H1N1 strain (swi­ne flu).

In vitro infection model

Tested influenza A viruses

H1N1Puer­to Rico/​8/​34

Five influ­en­za A strains were inves­ti­ga­ted: H3N2 (e.g. “Hong Kong flu” or sea­so­nal influ­en­za), H5N1 (e.g. “bird flu”, human patho­gen), H7N7 (e.g. avi­an influ­en­za, also human patho­gen), H1N1 (human influ­en­za) and H1N1 (“Mexi­co influ­en­za”, swi­ne flu, cur­rent pan­de­mic). Infec­tious­ness tests were con­duc­ted in a plaque assay with renal epi­the­li­al cells (MDCK cells). The cell cul­tures were trea­ted at dif­fe­rent points in time and in vary­ing con­cen­tra­ti­ons with the Echinacea extra­ct, and the ext­ent of infec­tion inhi­bi­ti­on was then tes­ted. A stan­dar­di­sed alco­hol extra­ct of fresh Echinacea pur­pu­rea herb (95%) and root (5%) was used (L.) Moench (Echina­force®, A. Vogel Bio­f­orce AG, Switzerland).


Virus inhi­bi­ti­on At doses of 1.6 µg/​ml and hig­her, the Echinacea extra­ct inhi­bi­ted the infec­tious­ness of all exami­ned influ­en­za viru­s­es by over 99%, inclu­ding the patho­gens of the cur­rent pan­de­mic swi­ne flu. The inhi­bi­ting effect was also retai­ned at high virus con­cen­tra­ti­ons (e.g. 105 PFU/​ml).

Resis­tance Tre­at­ment with Echinacea did not lead to viral resis­tance in any of the cases, not even fol­lo­wing seve­ral tre­at­ment cycles. In con­trast, almost 100% of the viru­s­es were resistant to the con­ven­tio­nal Rx anti­vi­ral sub­s­tance, which was tes­ted in par­al­lel, after the third tre­at­ment cycle. Even the­se influ­en­za strains were inhi­bi­ted over 99.9% by the Echinacea fresh-plant extract.

Mecha­nisms The results of the haem­ag­glu­ti­nin assays (HA), detec­tion of the intracel­lu­lar ribo­nu­cleo­pro­te­in (RNP) repli­ca­ti­on mar­ker and fur­ther ana­ly­ses – e.g. regar­ding the effects of dif­fe­rent incu­ba­ti­on peri­ods – sug­gest that the tes­ted Echinacea extra­ct deve­lo­ps its anti­vi­ral effect by acting direct­ly on the viru­s­es very ear­ly on during the incu­ba­ti­on pro­cess. Even pri­or to the infec­tion of the epi­the­li­al cells, Echinacea modi­fies the viral sur­face pro­te­in haem­ag­glu­ti­nin in such a way that the virus is unable to adhe­re to cel­lu­lar recep­tors. The influ­en­za viru­s­es are the­r­e­fo­re unable to pene­tra­te and repli­ca­te into cells.

Sum­ma­ry In view of the chal­lenges posed by the cur­rent swi­ne flu pan­de­mic, each addi­tio­nal pro­phyl­ac­tic or the­ra­peu­tic opti­on is a desi­ra­ble gain for dise­a­se con­trol from a viro­lo­gi­cal point of view. The fact that an estab­lished medi­cinal plant with a known, mul­ti­ple spec­trum of effect is also dis­co­ver­ed to have a direct anti­vi­ral effect against swi­ne flu and other influ­en­za viru­s­es is sur­pri­sing. In par­ti­cu­lar becau­se the pat­tern of acti­vi­ty resem­bles the aspects of an inna­te immu­ne respon­se. The signi­fi­can­ce of the cli­ni­cal anti­vi­ral effect of Echina­force in pan­de­mic influ­en­za infec­tions now has to be cla­ri­fied. The aut­hors of the sub­mit­ted stu­dy are of the opi­ni­on that Echina­force, as a stan­dard pre­pa­ra­ti­on, is a useful, easi­ly available, afforda­ble and cli­ni­cal­ly rele­vant addi­ti­on to stan­dard influ­en­za con­trol measures.

• Rai­ner H. Buben­zer, (Dezem­ber 2009).
1. Plesch­ka S, Stein M, Schoop R, Hud­son JB: Anti-viral pro­per­ties and mode of action of stan­dar­di­zed Echinacea pur­pu­rea extra­ct against high­ly patho­ge­nic avi­an Influ­en­za virus (H5N1, H7N7) and swi­­ne-ori­­gin H1N1 (S‑OIV). Virol J. 2009 Nov 13;6(1):197ff. (Abs­tract, Publi­ca­ti­on).
2. Hagers Hand­buch der Dro­gen und Arz­nei­stof­fe, Hager­ROM 2006 (Hrsg. W. Bla­schek, S. Ebel, E. Hacken­thal, U. Holz­gra­be, K. Kel­ler, J. Reich­ling und V. Schulz), Sprin­ger, Hei­del­berg, 2006.
3. Shar­ma M, Ander­son SA, Schoop R, Hud­son JB: Induc­tion of mul­ti­ple pro-inflam­m­a­­to­ry cyto­ki­nes by respi­ra­to­ry viru­s­es and rever­sal by stan­dar­di­zed Echinacea, a potent anti­vi­ral her­bal extra­ct. Anti­vi­ral Res. 2009 Aug;83(2):165–70 (Abs­tract).
4. Natio­na­le For­schungs­platt­form für Zoo­no­sen (Inter­na­tio­nal Work­shop): Novel stra­te­gies to fight respi­ra­to­ry viral dise­a­ses. Ber­lin, 12.–13.10.2009.

Bitte Ihre Frage, Anmerkung, Kommentar im folgenden Feld eingeben