Comparison of stereochemical structures of cholesterol from different sources by HPLC

Yıl 2012, Cilt: 16 Sayı: 3, 201 - 205, 07.03.2014

Basri Satılmış Tayfun Güldür Arzu Karakurt Ebru Büyüktuncel Mevlüt Ertan

Öz

ABSTRACT: It is known that only one stereoisomeric form, nat-cholesterol, naturally occurs.
Nat-cholesterol and its enantiomer, ent-cholesterol, sometimes show enantiospecific interactions
with biological molecules. If cholesterol is naturally found only one form, then the
question of “why does cholesterol show an enantiomeric selectivity?” arises. For this purpose,
stereoisomer analysis of cholesterol obtained from porcine liver and wool wax were
carried out with three different high performance liquid chromatography (HPLC) systems
including reversed-phase, reversed-phase with different cyclodextrins as a mobile phase
modifier, and chiral. Results from HPLC analysis of both cholesterol samples by permethylated
-cyclodextrin and amylose tris-(3,5-dimethylphenylcarbamate) chiral columns showed
that there was no stereoisomer of cholesterol present. However reversed-phase HPLC analysis
of cholesterol samples from porcine liver carried out with various cyclodextrins as
mobile phase modifiers presented a peak which was not observed in the analysis of cholesterol
samples from wool wax. On the other hand, different storage conditions of cholesterol
samples and addition of cyclodextrins as mobile phase modifiers produced almost identical
alterations in chromatograms of fresh samples by reversed-phase HPLC. This could be attributed
to catalytic properties of cyclodextrins. Cyclodextrins may not be suitable as a mobile
phase modifier in the stereoisomer analysis of cholesterol with high performance liquid
chromatography.
KEY WORDS: Cholesterol, stereoisomer, chromatography, chiral, cyclodextrin

Anahtar Kelimeler

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Comparison of stereochemical structures of cholesterol from different sources by HPLC

Öz

Kolesterol molekülünün doğada sadece bir stereoizomerik formda, nat-kolesterol, bulunduğu bilinmektedir. Nat-kolesterol ve enantiomeri olan ent-kolesterol, biyolojik moleküllerle bazen enantiospesifik etkileşimler göstermektedir. Bu durumda, kolesterol doğada bir formda bulunuyorsa “kolesterol neden enantiomerik seçicilik göstermektedir? ” sorusu ortaya çıkmaktadır. Bu amaçla, domuz karaciğeri ve koyun yün yağından elde edilen kolesterolün stereokimyasal analizleri, ters-faz, mobil faz modifiye edici ajan olarak farklı siklodekstrinlerin kullanıldığı ters-faz ve kiral’ den oluşan üç farklı HPLC metodu ile gerçekleştirilmiştir. Her iki kolesterol örneğinin, permetillenmiş -siklodekstrin ve amiloz tris-(3,5-dimetilfenilkarbamat) kiral kolonlar ile yapılan HPLC analizlerinde kolesterol stereoizomeri bulunmamaktadır. Bununla birlikte, domuz karaciğerinden elde edilen kolesterol örneğinin çeşitli siklodekstrinlerin mobil faz modifiye edici olarak kullanıldığı ters-faz HPLC analizlerinde belirlenen bir pik, koyun yün yağından elde edilen kolesterol örneklerinin analizinde gözlenmemektedir. Öte yandan, farklı bekletme koşullarındaki kolesterol örneklerinin ters-faz HPLC analizleri ile yeni hazırlanmış kolesterol örneklerinin siklodekstrinlerin mobil faza eklendiği ters-faz HPLC analizleri sonucunda, kromatogramlarda hemen hemen birbirine eş değişiklikler gözlenmektedir. Bu durum siklodekstrinlerin katalitik özelliklerine dayandırılabilir. Bu nedenle, kolesterolün HPLC ile stereoizomer analizinde mobil faz modifiye edici olarak siklodekstrinlerin kullanılması uygun olmayabilir

Anahtar Kelimeler

ANAHTAR SÖZCÜKLER: kolesterol, stereoizomer, kromatografi, kiral, siklodekstrin

Kaynakça

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