Since we have so many gum maple trees here, I think this is of interest to Missourians. Biochemists have found a high percentage of shikimic acid, a major ingredient in the antiviral drug Tamiflu, in the fruit ("gum balls") of the gum maple or "sweet gum tree". Tamiflu is used to fight influenza outbreaks and is one of the principle defenses against bird flu pandemics.
Do not rush out to harvest your gumballs, however, shikimic acid is not effective against flu by itself. It is the first stage in a complex chemical process leading to Oseltamivir, which is the actual antiviral agent. Shikimic acid availability is the limiting factor on the production of anti-virals like Tamiflu. The acid is found in all plants as a principle component of tannins, lignans, and other useful compounds. Very few plants have high percentages of the important acid, however. Shikimic acid is currently harvested from the star anise tree which grows in China. 90% of the yearly star anise crop goes to shikimic acid production.
For the home herbalist, known herbal antivirals like St. John's Wort and echinacea are better bets than sweet gum.
