PDF(Pubmed)
Abstract：
Sulforaphane is a chiral phytochemical with chemopreventive properties. The presence of a stereogenic sulfur atom is responsible for the chirality of the natural isothiocyanate. The key role of sulfur chirality in biological activity is underscored by studies of the efficacy of individual enantiomers as chemoprotective agents. The predominant native (R) enantiomer is active, whereas the (S) antipode is inactive or has little or no biological activity. Here we provide an enantioselective high-performance liquid chromatography (HPLC) protocol for the direct and complete resolution of sulforaphane and its chiral natural homologs with different aliphatic chain lengths between the sulfinyl sulfur and isothiocyanate group, namely iberin, alyssin, and hesperin. The chromatographic separations were carried out on the immobilized-type CHIRALPAK IH-3 chiral stationary phase with amylose tris-[(S)-methylbenzylcarbamate] as a chiral selector. The effects of different mobile phases consisting of pure alcoholic solvents and hydroalcoholic mixtures on enantiomer retention and enantioselectivity were carefully investigated. Simple and environmentally friendly enantioselective conditions for the resolution of all chiral ITCs were found. In particular, pure ethanol and highly aqueous mobile phases gave excellent enantioseparations. The retention factors of the enantiomers were recorded as the water content in the aqueous-organic modifier (methanol, ethanol, or acetonitrile) mobile phases progressively varied. U-shaped retention maps were generated, indicating a dual and competitive hydrophilic interaction liquid chromatography (HILIC) and reversed-phase liquid chromatography retention mechanism on the CHIRALPAK IH-3 chiral stationary phase. Finally, experimental chiroptical studies performed in ethanol solution showed that the (R) enantiomers were eluted before the (S) counterpart under all eluent conditions investigated.
摘要：
萝卜硫素是一种具有化学预防特性的手性植物化学物质。立体异构硫原子的存在是天然异硫氰酸酯手性的原因。对单个对映体作为化学保护剂的功效的研究强调了硫手性在生物活性中的关键作用。主要的天然（R）对映体是有活性的，而（S）对映体无活性或几乎没有或没有生物活性。在这里，我们提供了一种对映选择性高效液相色谱（HPLC）方案，用于直接和完全拆分亚磺酰基硫和异硫氰酸酯基团之间具有不同脂肪链长度的萝卜硫烷及其手性天然同系物，即伊贝林，alyssin,还有Hesperin.色谱分离是在固定化型CHIRALPAKIH-3手性固定相上进行的，其中直链淀粉三-[（S）-甲基苄基氨基甲酸酯]作为手性选择剂。仔细研究了由纯醇溶剂和水醇混合物组成的不同流动相对对映异构体保留和对映选择性的影响。发现了用于拆分所有手性ITC的简单且环境友好的对映选择性条件。特别是,纯乙醇和高含水流动相具有出色的对映体分离效果。对映体的保留因子记录为水性有机改性剂（甲醇，乙醇,或乙腈)流动相逐渐变化。生成了U形保留图，表明CHIRALPAKIH-3手性固定相上的双重竞争性亲水相互作用液相色谱（HILIC）和反相液相色谱保留机制。最后,在乙醇溶液中进行的手性实验研究表明，在所有研究的洗脱剂条件下，（R）对映体在（S）对应物之前被洗脱。
