Mazzini Francesco, Betti Michele, Netscher Thomas, Galli Francesco, Salvadori Piero
Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa 56126, Italy.
Chirality. 2009 May;21(5):519-24. doi: 10.1002/chir.20630.
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.
带有羧基的维生素E衍生物因其抗肿瘤特性最近受到了极大关注。藤黄酸（反式-13'-羧基-δ-生育三烯酚）是从可乐果种子中提取的一种维生素E类似物，其中羧基位于脂肪族侧链末端，根据旋光测量报告其为外消旋体。然而，我们对该酸样品进行的圆二色性测定在208nm处给出了一个正峰，表明它不是外消旋体。为了评估藤黄酸的对映体组成，将其转化为α-生育酚并通过手性HPLC在OD-H柱上进行分析。根据α-生育酚立体异构体的洗脱顺序，藤黄酸样品在色满环的碳2处具有R构型，是对映体纯的。此外，在初步试验中，该酸及其一些衍生物对胶质瘤C6癌细胞显示出显著的抗增殖作用。
