Qinghao acid

Artemisinic acid, Qinghao acid, Arteannuinic acid Aerial part 40,41... 

Haynes, R. K. Vonwiller, S. C. Catalysed oxygenation of allyhc hydroperoxides derived from Qinghao (artemisinic) acid. Conversion of qinghao acid into dehydroqinghaosu (artemisitene) and qinghaosu (artemisinin). J. Chem. Soc. Chem. Commun., 1990, 451 53. 

Artemisinin is an antimalarial constituent isolated from Qinghao. It is a sesquiterpene lactone with an endoper-oxide bridge, structurally distinct from other classes of antimalarial agents. Several derivatives of the original compound have proved effective in the treatment of Plasmodium falciparum malaria and are currently available in a variety of formulations artesunate (intravenous, rectal, oral), artelinate (oral), artemisinin (intravenous, rectal, oral), dihydroartemisinin (oral), artemether (intravenous, oral, rectal), and artemotil (intravenous). Artemisinic acid (qinghao acid), the precursor of artemisin, is present in the plant in a concentration up to 10 times that of artemisinin. Several semisjmthetic derivatives have been developed from dihydroartemisinin (1). 

These experiments confirm the previous proposal that 20 is the biosynthesis precursor of 1. Their additional studies on the biotransformation of 20 also find that epoxide 19 is the precursor of 10, but not the precursor of 1, and 10 is not the precursor of 1. The other qinghao component 23 also can be biogenetically transferred into 1, but it is not clear whether artemisinic acid (20) converts to 1 through dihydro-artemisinic acid (23) or artemisitene (26) (Scheme 5-8). " ... 

Since then, several laboratories also report in their research that artemisinic acid (20) is confirmed to be the biogenetic intermediate of qinghaosu, and dihydro-artemisinic acid (23) can also be biotransferred to qinghaosu. Furthermore, on incubation with the cell-free extracts of qinghao leaves, 20 can also be transferred into 10 and in turn 10 as well as dihydro-10 can be transferred to qinghaosu. 

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