Monday, March 14, 2011

Anti-HIV Drugs from King Alfred's Cakes

King Alfred the Great has a lot to answer for. Bothering those poor Danes for one, when all they had in mind was a bit of pillaging. And improving the literacy of the Anglo Saxons for another. One point point where he is undoubtedly blameless though is the legend of him burning some poor woman's cakes. The story goes while fleeing Vikings, he took refuge in the house of cowherd. His wife bade him watch over bread she had cooking on the hearth, but the king was preoccupied with other things and allowed the cakes to burn. While this story dates from 300 years after his reign (1) and is therefore dubious to say the least, it does lend a picaresque name to the fungus Daldinia concentrica: King Alfred's Cakes.
King Alfred's Cakes, Daldinia concentrica
One look at this inedible ascomycete is enough to understand where the name comes from. Its shiny black, tough looking outer surface is suprisingly brittle, showing concentric rings from previous years' growth in cross section (2). It can be seen all year round on dead and dying tree braches, Ash in particular (although in some areas, such as Scotland it is found more on birch(3)), growing up to 5 cm in diameter.
King Alfred's Cakes, Daldinia concentrica
D. concentrica has proved itself rich in unique secondary metabolites (4). In one study alone, Quang et al. (5) discovered four new compunds as well as isolating eleven known compounds. One of the more intriguing metabolites produced by the fungus is a lactone called Concentricolide, first isolated in 2006 (6). This was shown to have anti-HIV-1 properties by blocking binding of infected T helper cells with healthy cells, preventing the killing of the healthy cells. This significant inhibitory effect on the cytopathy caused by HIV-1 is very promising and the recent synthesis of Concentricolide (7) as well as an approved patent (8) for its use bodes well for its role in treating this disease.

  1. Smyth 1995, King Alfred the Great
  2. Sterry 2004, Collins Complete Guide to Irish Wildlife p. 288
  3. Whalley and Watling 1982, Transactions of the British Mycological Society 78 pp. 47-53
  4. Qin et al. 2006, Helvetica Chimica Acta 89 pp. 450-455
  5. Quang et al. 2002, Journal of Natural Products 65 pp. 1869-1874
  6. Qin et al. 2006, Helvetica Chimica Acta 89 pp. 127-133
  7. Fang and Liu 2009, Heterocycles 78 pp. 2107-2113
  8. Liu et al. 2010, Kunming Institute of Botany, Concentricolide and its Derivatives, Process for Preparing Them, Pharmaceutical Composition Comprising the Same and its Use, Patent Number US 7,659,308 B2

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