Elderberry fruit extract may help fight H1N1 flu

A new in vitro study in the July 2009 issue of Photochemistry suggests that certain elderberry flavonoids may be more effective than Tamiflu and Amantadine in treating H1N1 flu.

B Roschek and colleagues from HerbalScience Group LLC in Florida tested an elderberry fruit (Sambucus nigra L.) extract in vitro and found the preparation inhibited human Influenza A (H1N1) infection with the half maximal inhibitory concentration (IC50) at 252 micrograms per mL.

Flavonoids from the elderberry extract were found to bind to directly to H1N1 virions and block the ability of the virus to infect host cells.

The scientists were able to identify two binding compounds as 5,7,3',4'-tetra-O-methylquercetin and 5,7-dihydroxy-4-oxo-2-(3,4,5-trihydroxyphenyl)chroman-3-yl-3,4,5-trihydroxycyclohexanecarboxylate.

They further synthesized the methylquercetin and dihydromyricetin, a derivative from the second compound and found their IC50 at 0.13 microg/mL (0.36 microM) for H1N1 infection inhibition and 2.8 microg/mL (8.7 microM) respectively.

In comparison, the IC50 for Tamiflu against H1N1 viruses is 0.32 microM and the IC50 for Amantadine against the influenza is 27 microM.

The researchers concluded that the H1N1 inhibition activites of the elderberry flavonoids are comparable to the anti-influenza activities of Oseltamivir (Tamiflu) and Amantadine.

The Centers for Disease Control and Prevention has advised that antiflu drugs should not be used as preventatives and they should be only used to treat those who have been infected with H1N1 because the drugs can make the virus drug-resistant.

Roche the manufacturer of Tamiflu says on its website that the most common side effects with the medication are mild to moderate nausea and vomiting.

The U.S. government expects the H1N1 virus outbreak or pandemic will potentially kill tens of thousands of people in the winter time.

Epidemiological studies found that most vulnerable to the H1N1 infection are people who have underlying health conditions. For most people, the flu is mild and would not cause any harm.

By David Liu davidl at foodconsumer dot org