Effect of plant extracts against viral infections
While bacterial diseases can be well treated with antibiotics, viral infections such as Influenza (flu) or COVID-19 (caused by the new Coronavirus SARS-CoV-2) are difficult to treat. There are some anti-viral drugs, but their effect is often limited. Various vegetable substances, however, have a quite convincing anti-viral effect, which also makes a therapeutic application is attractive.
A research team led by Andreas Hensel of the Institute for Pharmaceutical biology and Phytochemistry, University of Münster discussed in a recent contribution, the effect of plant extracts against viral infections of the upper throat and some of the most promising drug candidates is presented. In the “journal of phytotherapy” report the researchers on the use of antiviral agents in the field of herbal medicine.
The lack of drugs against virus infections
Currently it’s all about the Coronavirus, but also influenza viruses, rhinoviruses, adenoviruses, and RSV viruses infect the nose and throat. While there are antiviral medications that can cause certain virus infections to a significant reduction in the viral load., the absence of most of the viral Pathogens in the area of the pharynx and upper air-way-specific effective substances, according to the research team.
Tannins with anti-viral effect
Among the promising antiviral candidates from the crop sector, according to the researchers, the tanning agents (tannins) ends. Because tannins interact strongly with proteins, and the protein structure and functionality, in part, substantially change, some have a direct effect on the shell of the virus. Well, the effects of condensed tannins (proanthocyanidins) and tannin-containing extracts against influenza virus was demonstrated, for example.
Green tea, sorrel herb, and rockrose herb
Against Herpes simplex virus (HSV-1) show proanthocyanidins to have a positive effect. The condensed tannins are, according to the researchers, for example, in green tea, to find sorrel herb, or rockrose herb. Although an application was to be considered as a therapeutic agent in the case of overt virus infections are unlikely to be successful, but it is quite conceivable, “to bring dosage forms for application, the highly concentrated tannin extracts used for local application in the oral cavity as a prophylaxis use,” says the research team.
Sweets and chewing gum with tannins?
Proposals for the application of the researchers also. This could be, for example, sorrel candy or chewing gum with Proanthocyanidins in the highest possible concentration. Also gargling and mouth rinsing solutions containing such extracts, are conceivable. Several studies for regular gargling with green tea or green tea extract (for several months) had shown evidence of a preventive effect against influenza viruses.
Antiviral potential of essential Oils
“Besides the tannins also certain essential Oils anti seem to have antiviral potential against enveloped viruses to have”, reports the researchers are more. Here, too, the interaction with viral envelope Proteins stand in the foreground. Most of the studies had been carried out with the main part of the Eukalyptusöls (1,8-Cineol) of Herpes simplex virus (HSV-1 / HSV-2). But also in the case of Influenza in mice, infect have shown a protective effect, which, however, is less on a direct anti-viral effect, but rather to a reduction of the inflammatory reactions in pneumonia the lung is based.
Laurel oil is effective against the Coronavirus
Furthermore, the essential Oil of the Bay Laurel tree have shown promising activity against the Coronavirus SARS-CoV. The essential Oil of the aerial Parts of the tree under pressures of the growth of the virus. “Inhalation applications of Laurel oil would be conceivable here, of the possibly allergenic potential should be considered,” say the researchers. Sage Oil is also rich in 1,8-cineole, have shown a similar effect, but weaker in its effect. In addition to essential Oil the leaves (Salvia officinalis) are included in Sage, but also of condensed tannins, so that these could be used, for example, in gurgel solutions make sense.
“So why in times of a hardly controllable Virus pandemic, not even once unconventional, try something and test”, ask the researchers. The development of lozenges preparations with essential Oils or tannins, as well as appropriate gargling or rinsing solutions are quite a try. “Not as medicines – for that, we need regulatory approvals, but simply as food,” the researchers continue. (fp)