Lignan analysis in seed oils from fourSesamum species: Comparison of different chromatographic methods

Abstract

Different chromatographic methods, thin‐layer chromatography (TLC), gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS) and normal‐ and reversed‐phase high‐performance liquid chromatography (HPLC), were compared for their ability to separate the different lignans present in fourSesamum species,viz., S. indicum Linn.,S. alatum Thonn., S. radiatum Schum & Thonn. andS. angustifolium (Oliv.) Engl. The advantages and limitations of each method are discussed, and a combination of methods is suggested for qualitative analyses. Two‐dimensional TLC was found to be a valuable qualitative technique and one‐dimensional TLC is useful for preparative purposes. GC is a good supplement for qualitative analysis, but it had many limitations as a quantitative tool—it involves many preparative steps, no suitable internal standard was found to be commercially available and the various lignans had markedly different response factors. GC/MS is a necessary techniqee to confirm the identity of the lignans present. HPLC is a one‐step technique suitable for quantitative analyses, and is fast and simple because it involves direct injection of oil solutions. Reversed‐phase HPLC was unable to separate sesamolin and sesangolin, but a normal‐phase silica column provided satisfactory separation for these two lignans. 2‐Episesalation ofS. alatum, however, did not elute from the normalphase column. Once lignans are identified, a relevant HPLC method can be used for quantitative analyses. Sesamin was present in large amounts inS. radiatum, in considerable amounts inS. indicum andS. angustifolium, and in small amounts inS. alatum. Sesamolin occurred in considerable amounts inS. indicum andS. angustifolium, but only in small amounts in the other two wild species studied.Sesamum alatum was characterized by high amounts of 2‐episesalatin, andS. angustifolium was characterized by high levels of sesangolin.

Bioactive lignans from sesame (Sesamum indicum L.): evaluation of their antioxidant and antibacterial effects for food applications

“…In the present study, sesamin and sesamolin were purified, from sesame oil, after saponification and preparative HPLC. The retention times for sesamin and sesamolin are similar to the retention times reported in literature (Amarowicz et al 2001;Kamal-Eldin et al 1994). The lignans were also characterized by GC-MS as given under "Materials and methods".…”

Extraction of sesamin from sesame oil using macroporous resin

“…Manufacturers' information regarding the characteristics of the resins are reported in Table 2. -Eldin et al (1994) reported a HPLC method to determine concentrations of lignans and lignan glycosides in sesame. But the accuracy was affected by the baseline shift and these methods were not satisfactory.…”

“…Compared with n-hexane/ chloroform (2:1) (Kamal-Eldin et al, 1994) and other solvents listed in Table 3, cyclohexane was the best choice due to its reasonable recovery and relative standard deviation.…”

On‐line LC‐NMR‐MS characterization of sesame oil extracts and assessment of their antioxidant activity

“…thinlayer chromatography (TLC), gas chromatography/mass spectrometry (GC/MS) and normal-and reversed-phase high-performance liquid chromatography (HPLC) [24]. The amounts of 6-episesaminol, sesamin, sesaminol, sesamol and sesamolin determined in sesame oil extract, sesame deodorizer distillate extract, and sesaminol-enriched sesame extract are provided in Tab.…”