Influenza, common cold – scientific based herbal alternatives

Interview with Prof. Dr. Stephan Pleschka (Germany) and Prof. Dr. Jim Hudson (Canada)

Echinacea pur­pu­rea

Influ­en­za vac­ci­nes, anti­vi­ral medi­ca­ti­ons, natio­nal and inter­na­tio­nal pan­de­mic plans – aren“t we alre­a­dy super­b­ly equip­ped to deal with influ­en­za thre­ats of influ­en­za pan­de­mics or the sea­so­nal influ­en­za? Do we need alternatives?

J. Hud­son Addi­tio­nal opti­ons for action are defi­ni­te­ly desi­ra­ble from the medi­cal view­point. Sim­ply to address more effec­tively the many indi­vi­du­al pro­blem cases, such as vac­ci­na­ting pregnant women and child­ren against influ­en­za or drug into­le­rance and resis­tance. Espe­ci­al­ly for peo­p­le unwil­ling to be vac­ci­na­ted, the­re is curr­ent­ly a need for alter­na­ti­ve approa­ches to pro­vi­de pro­tec­tion against respi­ra­to­ry tract infec­tions. Influ­en­za vac­ci­na­ti­ons and the few anti­vi­ral agents with effects against influ­en­za viru­s­es are far from being opti­mal. This is why alter­na­ti­ve opti­ons are urgen­tly nee­ded – some­thing which has long been reco­gni­zed by health aut­ho­ri­ties worldwide.

Why are extra­cts of medi­cinal plants, e.g. from the herb and roots of Echinacea pur­pu­rea, of such inte­rest in this situation?

S. Plesch­ka Pur­ple con­e­flower in par­ti­cu­lar has been found to have the abili­ty to pre­vent com­mon colds and influ­enz­as and tre­at them in acu­te cases. Our latest rese­arch has now shown that this effect is attri­bu­ta­ble to an anti­vi­ral and anti-inflamm­a­to­ry effect. The tra­di­tio­nal use of Echinacea pur­pu­rea to streng­then or balan­ce the immu­ne sys­tem is ther­eby sub­stan­tia­ted by the latest findings.

What method do you use to demons­tra­te the anti­vi­ral effec­ti­ve­ness of a medi­cinal plant extra­ct against viru­s­es such as H3N2, H5N1, H1N1?

J. Hud­son All stu­dies of this kind start with cell cul­tures. The­se cul­tures were then infec­ted with the rele­vant sel­ec­ted viru­s­es, which were trea­ted at dif­fe­rent times and in dif­fe­rent dosa­ges with Echinacea extra­ct. The results of the “plaque assay” then cle­ar­ly show whe­ther a plant extra­ct can inhi­bit the infec­tious­ness of the viru­s­es. Fur­ther expe­ri­ments are per­for­med to find out whe­ther or not viral resis­tance deve­lo­ps. This was of par­ti­cu­lar inte­rest, sin­ce the tre­at­ment of influ­en­za (e.g. by neu­r­a­mi­ni­da­se inhi­bi­tors) will ine­vi­ta­b­ly lead to resis­tance. Final­ly, we attempt to estab­lish how the obser­ved anti­vi­ral effects can be explai­ned at the mole­cu­lar level.

Plea­se sum­ma­ri­ze the results of your latest research.

S. Plesch­ka To tre­at the cell cul­tures, we used a stan­dar­di­zed alco­ho­lic extra­ct of fresh herb (95%) and roots (5%) of Echinacea pur­pu­rea (L.) Moench (Echina­force®, A. Vogel Bio­f­orce AG, Switz­er­land). Five rele­vant influ­en­za A strains were tes­ted, inclu­ding two clas­si­cal human types, two high­ly patho­ge­nic avi­an flu viru­s­es with pan­de­mic poten­ti­al and the curr­ent­ly pre­va­lent “swi­ne flu virus”. Echinacea from a dose of 1.6 µg/​ml onwards was alre­a­dy found to inhi­bit the infec­tious­ness of the influ­en­za viru­s­es by more than 99%. This con­cen­tra­ti­on is far below the local Echinacea dosa­ge recom­men­ded for oral use. The virus-inhi­bi­ting effect was also main­tai­ned at high viral burdens.

How does this pro­no­un­ced anti­vi­ral effec­ti­ve­ness come about?

J. Hud­son All the stu­dies we have con­duc­ted show that the Echinacea extra­ct inhi­bits the sur­face pro­te­in of the influ­en­za viru­s­es – hem­ag­glu­ti­nin – which they need to dock onto the body“s cells. As a result, the infec­tion of the cells, the viral repli­ca­ti­on insi­de the cells and their fur­ther spread do not take place.

What other spe­cial pro­per­ties does the extra­ct have?

J. Hud­son Whe­re­as the influ­en­za virus beca­me resistant to a syn­the­tic anti­vi­ral drug after a few tre­at­ment cycles, no such resis­tance deve­lo­ped during the Echinacea tre­at­ment. And even bet­ter: Echinacea was also able to inhi­bit the infec­tious­ness of the virus that were alre­a­dy resistant to the chemical.

The dis­co­very of the anti­vi­ral acti­vi­ty of Echinacea, espe­ci­al­ly against many typi­cal com­mon cold viru­s­es, is main­ly the result of your many years of rese­arch. How do you rate the dis­co­very that Echinacea also has pro­no­un­ced effects against influ­en­za viruses?

S. Plesch­ka Sin­ce Echinacea is used main­ly during the peri­od bet­ween autumn and spring, expe­ri­ence reports and stu­dies also inva­ria­bly include sea­so­nal influ­en­za in Janu­ary and Febru­ary. To this ext­ent, a direct acti­vi­ty against influ­en­za viru­s­es is cer­tain­ly plausible.

Is a medi­cinal plant like Echinacea only a sup­pli­er of che­mi­cal­ly defi­ned sub­s­tances, which after their sci­en­ti­fic descrip­ti­on, iso­la­ti­on and pos­si­ble che­mi­cal modi­fi­ca­ti­on can then be used medicinally?

J. Hud­son An Echinacea fresh plant extra­ct con­ta­ins a broad ran­ge of dif­fe­rent sub­s­tances with dif­fe­rent che­mi­cal struc­tures. Based on exis­ting know­ledge, howe­ver, the anti­vi­ral, anti-inflamm­a­to­ry and anti­bac­te­ri­al acti­vi­ties descri­bed may be attri­bu­ta­ble to dif­fe­rent clas­ses of acti­ve sub­s­tances. Iso­la­ting an indi­vi­du­al sub­s­tance would always invol­ve a reduc­tion of the spec­trum of action and would the­r­e­fo­re be undesirable.

Moreo­ver, orga­nisms like viru­s­es find it har­der to deve­lop resis­tance to a mix­tu­re con­tai­ning a lar­ge num­ber of sub­s­tances than to a sin­gle che­mi­cal substance.

If Echinacea can build up a direct anti­vi­ral pro­tec­ti­ve shield, e.g. after taking Echina­force drops, doesn“t this effect remain con­fi­ned to the oral cavi­ty and pha­ryn­ge­al space? Sure­ly, an acu­te respi­ra­to­ry dise­a­se like swi­ne flu also affects other parts of the body!?

S. Plesch­ka It is gene­ral­ly assu­med that a lar­ge num­ber of viru­s­es that cau­se acu­te respi­ra­to­ry tract dise­a­ses initi­al­ly infect in the pos­te­ri­or nas­opha­ryn­ge­al space. This appli­es both to the most com­mon cau­sa­ti­ve agents of com­mon colds, the rhi­no­vi­ru­s­es, and to many influ­en­za viru­s­es, inclu­ding the cur­rent swi­ne flu viru­s­es. Only after an infec­tion has beco­me estab­lished in this regi­on do the viru­s­es spread to the nose or deeper air­ways. The pri­ma­ri­ly infec­ted pha­ryn­ge­al space is thus cer­tain­ly rea­ched on oral use of Echinacea extra­ct and the mea­su­red anti­vi­ral effects are rela­ted to the oral use of Echinacea.

No cli­ni­cal stu­dies are yet available for the infec­tion inhi­bi­ting acti­vi­ty of Echina­force in new influ­en­za strains like swi­ne flu virus. Do you nevert­hel­ess recom­mend its use for this condition?

J. Hud­son We cer­tain­ly still have a way to go befo­re the effect against H1N1 viru­s­es we have dis­cus­sed will also be con­firm­ed in cli­ni­cal stu­dies. Howe­ver, we are alre­a­dy awa­re, from num­e­rous stu­dies, of the gene­ral­ly bene­fi­ci­al actions of Echinacea extra­ct in influ­en­za-like infec­tions. And it is clear that the­se bene­fits deri­ve both from lon­ger-term immun­mo­du­la­ting effects and the nor­ma­liza­ti­on of pro-inflamm­a­to­ry signal sub­s­tances that exa­cer­ba­te sym­ptoms. The anti­vi­ral com­po­nent is a valuable addi­ti­on to this mul­ti­mo­dal spec­trum of action. In our view, the­r­e­fo­re, the use of Echinacea extra­ct for pro­phyl­ac­tic and the­ra­peu­tic pur­po­ses can be recom­men­ded on the basis of exis­ting know­ledge. Espe­ci­al­ly sin­ce the medi­cinal plant extra­ct Echina­force is available over the coun­ter wit­hout a pre­scrip­ti­on and is not affec­ted by the dis­tri­bu­ti­on and ratio­ning pro­blems expe­ri­en­ced with vac­ci­nes or syn­the­tic drugs. Streng­thening the body“s own immu­ne respon­se is cer­tain­ly advan­ta­ge­ous in such times.

Correspondence to:

Prof. Dr. Ste­phan Pleschka
Insti­tut für Medi­zi­ni­sche Virologie
Jus­tus-Lie­big Universität
Frank­fur­ter Stras­se 107
35392 Gies­sen – Germany
e‑mail: [email protected]


Prof. Dr. James Hudson
Depart­ment of Patho­lo­gy and Labo­ra­to­ry Medicine
Uni­ver­si­ty of Bri­tish Columbia
2733 Hea­ther Street
Van­cou­ver V5Z 1M5 – Canada.
e‑mail: [email protected]

© Bio­f­orce AG, Switz­er­land, 2010

Pro­fes­sor Jim Hud­son is con­side­red to be one of the fore­most viro­lo­gists in Wes­tern Cana­da and is curr­ent­ly Pro­fes­sor Eme­ri­tus at the Uni­ver­si­ty of Bri­tish Colum­bia. He has published over 130 papers in peer-review­ed jour­nals and writ­ten a num­ber of books, inclu­ding “Anti­vi­ral Com­pounds from Plants”.
His rese­arch inte­rests include elu­ci­da­ting the mole­cu­lar mecha­nisms of action of her­bal medi­ci­nes and seve­ral col­la­bo­ra­ti­ve pro­jects with Insti­tu­tes in deve­lo­ping count­ries in Afri­ca and Asia.
Other key acti­vi­ties include natu­ral­ly occur­ring phy­to­me­di­ci­nes as anti-viral and anti-micro­bi­al sub­s­tances and how the appro­pria­te use of her­bal medi­ci­nes can bene­fit human health.

© Plesch­ka, Ger­ma­ny, 2009

Pro­fes­sor Ste­phan Plesch­ka is a well-known viro­lo­gist at the 400-years-old Jus­tus Lie­big-Uni­ver­si­ty in Giessen/​Germany. Important sci­en­ti­fic acti­vi­ties in viro­lo­gy and micro­bio­lo­gy are:
* Iden­ti­fi­ca­ti­on, cha­rac­te­riza­ti­on and assess­ment of viral host fac­tors which are rele­vant for both reco­gni­ti­on and the tar­ge­ted bin­ding of influ­en­za virus to host cells and for human infections.
* Rele­van­ce of viral and cel­lu­lar fac­tors and mecha­nisms regu­la­ting viral mul­ti­pli­ca­ti­on in infec­ted cells and thus influence the viral replication.
* Viral spread and con­se­cu­ti­ve immu­ne reac­tions of infec­ted hosts inclu­ding infec­tion syn­dro­mes in dif­fe­rent ani­mal models.
In addi­ti­on to his rese­arch in patho­ge­ne­sis of influ­en­za and new the­ra­peu­tic approa­ches, other rele­vant work appli­es to bio­lo­gy of tumors, seve­ral lung dise­a­ses and the inna­te immunity.

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