Configuration of the vitamin E analogue garcinoic acid extracted from Garcinia Kola seeds.

Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa 56126, Italy.
Chirality (Impact Factor: 1.72). 05/2009; 21(5):519-24. DOI: 10.1002/chir.20630
Source: PubMed

ABSTRACT Vitamin E derivatives bearing a carboxylic group have recently gained great attention because of their antitumoral properties. Garcinoic acid (trans-13'-carboxy-delta-tocotrienol) is a vitamin E analog extracted from Garcinia Kola seeds in which the carboxylic group is at the end of the aliphatic side chain and reported to be a racemate based on the optical rotation measurements. However, CD determination of a sample of the acid analyzed by us gave a positive peak at 208 nm, indicating that it is not a racemate. To assess the enantiomeric composition of garcinoic acid, it was thus transformed to alpha-tocopherol and analyzed by chiral HPLC on column OD-H. On the basis of the elution order of alpha-tocopherol stereoisomers, the garcinoic acid sample resulted to be enantiopure with R configuration at carbon 2 of the chroman ring. Moreover, in a preliminary test, the acid and some of its derivatives showed a marked antiproliferative effect on glioma C6 cancer cells.

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