Isolation of lanosterol and dihydrolanosterol from the unsaponifiable matter of lanolin by urea complexation and countercurrent chromatography in heart-cut recycling mode

Rüttler, Felix; Hammerschick, Tim; Schlag, Sarah; Vetter, Walter

doi:10.1016/j.jchromb.2022.123470

Cited by 4 publications

(1 citation statement)

References 41 publications

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“…The present CCC system features four coils in two bobbins which can be driven independently, and HC-CCC can be implemented by installing switching valves and wiring [ 45 ]. Previous applications in our group used bobbin 1 (coil 1 + 2) in the 1st dimension and bobbin 2 (coil 3 + 4) in the 2nd dimension [ 44 , 45 , 46 ]. In the present research, coils 2 + 3 (present in different bobbins, 236 mL) were used in the 1st dimension and coil 1 + 4 (also present in different bobbins, 235 mL) in the 2nd dimension.…”

Section: Resultsmentioning

confidence: 99%

Profiling and Isolation of Ten Rare Branched-Chain Alkylresorcinols in Quinoa

Hammerschick

Vetter

2023

Molecules

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Alkylresorcinols (∑ARs) are bioactive lipid compounds predominantly found in cereals. These amphiphilic compounds exist in a high structural diversity and can be divided into two main groups, i.e., 5-alkylresorcinols (ARs) and 2-methyl-5-alkylresorcinols (mARs). The pseudocereal quinoa has a very unique AR profile, consisting not only of straight-chain alkyl chains but also iso- and anteiso-branched isomers. Here, we describe a method for the isolation of such methyl-branched ARs and mARs from quinoa. The enrichment of the ∑AR fraction from the lipid extracts by centrifugal partition chromatography (CPC) was followed by ∑AR profiling using countercurrent chromatography (CCC) and GC/MS analysis of CCC fractions. A total of 112 ∑ARs could be detected, 63 of which had not been previously described in quinoa. Due to this high number of ∑ARs, the direct isolation of individual ARs was not possible using conventional CCC. Instead, the more powerful heart-cut mode was applied to enrich the target compounds. A final purification step—the separation of CCC-co-eluting mARs from ARs —was performed via silver ion chromatography. Altogether, ten rare branched-chain ∑ARs (five iso-branched mARs and five anteiso-branched ARs, including mAR19:0-i and AR20:0-a) were isolated with purities up to 98% in the double-digit mg range.

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Section: Resultsmentioning

confidence: 99%

Profiling and Isolation of Ten Rare Branched-Chain Alkylresorcinols in Quinoa

Hammerschick

Vetter

2023

Molecules

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Sample preparation of free sterols from vegetable oils by countercurrent chromatography in co-current mode

et al. 2023

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Countercurrent chromatography (CCC) is a preparative instrumental method where both the mobile and stationary phases are liquids and which are predominantly used for the isolation of natural products. In this study, we widened the scope of CCC by using it as an instrumental method for the direct enrichment of the free sterol fraction from plant oils to which they contribute with ~ 1%. For the enrichment of sterols in a narrow band, we employed the so-called co-current CCC (ccCCC) mode in which both liquid phases of the solvent system (here: n-hexane/ethanol/methanol/water (34:11:12:2, v/v/v/v)) are moved at different flow rates in the same direction. Different from previous applications of ccCCC, the lower and predominant “stationary” phase (LPs) was pumped twice as fast as the mobile upper phase (UPm). This novel reversed ccCCC mode improved the performance but also required a higher demand of LPs compared to UPm. Therefore, the exact phase composition of UPm and LPs was determined by gas chromatography and Karl Fischer titration. This step enabled the direct preparation of LPs which considerably reduced the waste of solvents. Internal standards (phenyl-substituted fatty acid alkyl esters) were synthesised and utilised to frame the free sterol fraction. This approach allowed a fractionation of free sterols based on the UV signal and compensated run-to-run variations. The reversed ccCCC method was then applied to the sample preparation of five vegetable oils. In addition to free sterols, free tocochromanols (tocopherols, vitamin E) were also eluted in the same fraction as free sterols. Graphical Abstract

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Quantitative data of up to thirty sterols in vegetable oils and fats

Schlag,

Vetter

2023

Eur Food Res Technol

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Sterols are known for a plethora of 250 different structures. Between 5 and 10% of them usually occur with varying abundance ratios (~ four orders of magnitude) and total amounts (0.4–1000 mg/100 g oil) in samples. Yet, quantitative data are mostly restricted to the few major sterols which are available as reference standards. Here, we developed a gas chromatography with mass spectrometry method operated in selected ion monitoring mode (GC/MS-SIM) that enabled the quantitation of 30 (silylated) sterols although only ten were available as reference standards. This could be obtained by studying the full-scan mass spectra of these ten sterol standards and 20 additional sterols measured in seven oils. In the next step, sterols were assigned to different groups. Values for quantification were then selected on the premise that response factors were constant within a sterol group. The deviation of the response factors within one sterol group was frequently below ± 10% and otherwise about ± 11–12%. Using mean response factors for all sterols, the novel GC/MS-SIM quantification method was superior to GC/FID which was exemplarily applied to two oils. Between eight and 21 of the 30 studied sterols and pentacyclic triterpenols were detected and quantified in 18 vegetable oils and two vegetable fats. The much higher number of sterols that could be quantified resulted in higher sterol amounts and the method and data may be useful for food authentication.

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Isolation of lanosterol and dihydrolanosterol from the unsaponifiable matter of lanolin by urea complexation and countercurrent chromatography in heart-cut recycling mode

Cited by 4 publications

References 41 publications

Profiling and Isolation of Ten Rare Branched-Chain Alkylresorcinols in Quinoa

Profiling and Isolation of Ten Rare Branched-Chain Alkylresorcinols in Quinoa

Sample preparation of free sterols from vegetable oils by countercurrent chromatography in co-current mode

Quantitative data of up to thirty sterols in vegetable oils and fats

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