Plants have been getting short shrift around here lately. It’s time to fix that.
Sitting in the spice rack of many an Asian home, and a very few American homes, is the unusual looking fruit of an ordinary-looking plant with an unexpected use. Here is that plant:
Delicious or deadly? Both -- depending on your perspective. Image by Shu Suehiro, licensed under the Creative Commons Attribution 3.0 Unported License. Click for link.
And here is its fruit:
Science? Art? My favorite intersection. The shiny objects are the seeds. Image by Bryan Arthur, distributed under the under the Creative Commons Attribution ShareAlike 3.0 License. Click image for link.
The plant is star anise, Illicium verum.
If you know it at all, it is as a spice. As its name implies, its flavor is licorice-y, and indeed the plant makes the same flavoring chemical found in true anise, fennel, and licorice: anethole. It can be used on its own in Asian cooking, but is more commonly known for its inclusion in Chinese five spice powder and Japanese seven spice powder. If you’ve never tried one of these blends, do yourself a favor take some for a spin.*
And now for the use you probably didn’t know about: star anise is the raw ingredient used to make oseltamivir, more familiarly known as Tamiflu. The actual raw ingredient is shikimic acid, and many plants, including the North American Sweetgum (with the beautiful genus name Liquidambar) also make it. But star anise is particularly good at making it. The yields are high.
It seems odd to think of a modern drug depending on a botanical source, but tamiflu is seemingly still very much in that category. In 2005, shortages in Chinese star anise production caused a shortage of Tamiflu.
Nonetheless, it takes some fairly heavy organic chemistry gymnastics to get from shikimic acid to oseltamivir. The wikipedia entry notes, in rather understated language,
Some of the steps in the synthesis require careful handling and relatively mild reaction conditions, as they involve the use of potentially explosive azide chemistry.
Hooo-kay. Having taken organic chemistry, I really do believe that organic chemists earn every penny of their six-figure incomes. You’ll also easily realize, if you compare the structures of shikimic acid and oseltamivir, that the Chinese health minister’s suggestion that people in China cook their pork with star anise to ward off influenza is absolute rubbish. They look totally different. And if it takes a 10-step process involving “potentially explosive azide chemistry” to get to oseltamivir from shikemic acid, it ain’t gonna happen in my stomach. Nor can you get swine flu from pork (duh). Still, pork + star anise could well = tasty.
Star anise’s price still rises and falls with flu outbreaks, even though 99.6% of last year’s seasonal flu was resistant to Tamiflu (a sobering and staggering rise from only 12% the year before) and the same thing could easily happen to pandemic H1N1 flu. Still, so far only 39 of 10,000 pandemic H1N1 flu samples tested positive for resistance to Tamiflu in October. And doctors still turn to Tamiflu to fight this flu. Just a few weeks ago, the U.S. Government decided to release the last of its children’s Tamiflu stockpile due to this flu’s disproportionate ability to kill the young — even, disturbingly, some who were apparently otherwise completely healthy prior to infection.
But it’s hard to believe with hundreds of thousands of doses of Tamiflu flowing into all regions of the U.S. that the drug will last long against the virus. Between this and newly developing E. coli-based shikimic acid production techniques, star anise’s run as a flu-fighter will probably be short lived.
Next time: The Curious Taxonomy of Star Anise
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*Chefs are cooking with five-spice powder more and more as they experiment with traditional ingredients in new cuisines. I often make crispy tofu-ginger fritters with five-spice powder, and I also recently found a recipe in Cooking Light for pumpkin pie with five-spice powder. I bet it’d also be good as a replacement for cinammon in snickerdoodles, since cinnamon is one of the ingredients (in my commercial “Asian Gourmet” blend they are, “cinnamon, anise, fennel, ginger, clove, and licorice root”. I note with amusement that makes six.)
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Comment on this pingback by this blog’s author: it is unlikely that it would make sense for Tamiflu to taste like licorice. In my understanding, changing even a single chemical bond or atom of an molecule can radically alter the molecule’s properties, including taste. — j.f.
Heh, blending two of your interests, Jen?
I second Jen’s statement that star anise is a beautifully flavored thing. Mark Bittman’s soy-poached chicken uses star anise (and more soy sauce than you can shake a stick at). That’s an amazing recipe. And if anyone needs to borrow some star anise, it’s hard to use up!