A. Kamaleldin et al., LIGNAN ANALYSIS IN SEED OILS FROM 4 SESAMUM SPECIES - COMPARISON OF DIFFERENT CHROMATOGRAPHIC METHODS, Journal of the American Oil Chemists' Society, 71(2), 1994, pp. 141-147
Different chromatographic methods, thin layer chromatography (TLC), ga
s chromatography (GC), gas chromatography/mass spectrometry (GC/MS) an
d normal- and reversed-phase high-performance liquid chromatography (H
PLC), were compared for their ability to separate the different Lignan
s present in four Sesamum species, viz., S. indicum Linn., S. alatum T
honn, S. radiatum Schum and Thonn. and S. angustifolium (Oliv.) Engl.
The advantages and limitations of each method are discussed, and a com
bination of methods is suggested for qualitative analyses. Two-dimensi
onal TLC was found to be a valuable qualitative technique and one dime
nsional TLC is useful for preparative purposes. GC is a good supplemen
t for qualitative analysis, but it had many limitations as a quantitat
ive tool-it involves many preparative steps, no suitable internal stan
dard was found to be commercially available and the various lignans ha
d markedly different response factors. GC/MS is a necessary technique
to confirm the identity of the lignans present. HPLC is a one-step tec
hnique suitable for quantitative analyses, and is fast and simple beca
use it involves direct injection of oil solutions. Reversed-phase HPLC
was unable to separate sesamolin and sesangolin, but a normal phase s
ilica column provided satisfactory separation for these two lignans. 2
-Episesalatin of S. alatum, however, did not elute from the normal-pha
se column, Once lignans are identified, a relevant HPLC method can be
used for quantitative analyses. Sesamin was present in large amounts i
n S. radiatum, in considerable amounts in S. indicum and S angustifoli
um, and in small amounts in S. alatum. Sesamolin occurred in considera
ble amounts in S. indicum and S. angustifolium, but only in small amou
nts in the other two wild species studied. Sesamum alatum was characte
rized by high amounts of 2-episesalatin, and S. angustifolium was char
acterized by high levels of sesangolin.