Comparison of extraction methods for secologanin and the quantitative analysis of secologanin from symphoricarpos albus using ¹H‐NMR

Abstract

In order to develop an efficient large-scale extraction of secologanin from Symphoricarpos albus, different methods have been compared. Ultrasonication with organic solvents and water, microwave-assisted extraction and hot water extraction methods were evaluated for their efficiencies. Among the methods tested, ultrasonication with methanol showed the highest yield of secologanin (3.35 +/- 0.24 mg/g fresh weight). For reliable quantification of secologanin a 1H-NMR method was developed. The experiment was performed by the analysis of the integral of the signal of H-9, which was well separated in the range delta 7.4-7.5 in the 1H-NMR spectrum. The quantity of the compound was calculated from the relative ratio of intensity of the target peak to the known amount of internal standard, 200 microg of gallic acid. This method allows rapid and simple quantification of secologanin in 5 min without any pre-purification steps.

Metabolic Discrimination ofCatharanthus roseusLeaves Infected by Phytoplasma Using 1H-NMR Spectroscopy and Multivariate Data Analysis

“…1) and loganic acid (d 7.09). In the case of secologanin, H-3 is changeable, especially at higher pH values because the aldehyde proton can form the dimethylacetal, and this results in the effect on the chemical shift of H-3 of secologanin (Kim et al, 2004;Tomassini et al, 1995). So, the signal at d 7.49 might be due to the artifact of secologanin.…”

A comparison of metabolite extraction strategies for 1H‐NMR‐based metabolic profiling using mature leaf tissue from the model plant Arabidopsis thaliana

“…Not investigated in this study were the use of high-or lowtemperature extractions, [12,16,18,20,22,27] the use of ultrafiltration to remove high molecular weight impurities, [5] the effect of repeated extraction on the same tissue pellet, [22,33] microwaveassisted extraction, [10] sonication during extraction, [11,16] duration of extraction/homogenization, [15] duration of centrifugation [6] and the removal of metal ions to facilitate absolute quantification by NMR, [28] however the reader is directed to the existing literature on these topics.…”

“…In a study comparing aqueous extractions, high temperature was necessary to denature enzymes in the aqueous-only extracts. [11] Additionally, aqueous environments, especially those containing sugars, are ideally suited for microbial growth. Because these microorganisms consume, produce and excrete a range of metabolites, their presence can complicate interpretation of the metabolite profile of the organism of interest.…”

“…Maharjan and Ferenci reported that methanolic extractions can yield close to 100 metabolites, whereas other extraction solvents yielded between 50 and 80 metabolites from the same tissue. [7] Although methanol has been widely used as an extraction solvent, it has been shown to enolize aldehyde groups [11] and transmethylate sugar esters. [19] Some enzymes, such as phosphatases, [19] can retain appreciable activity in the presence of methanol.…”

“…Systematic comparison of sample preparation methods for metabolite analysis in yeast, [6] E. coli, [7] filamentous fungi, [8,9] chickpea, [10] snowberry, [11] a variety of herbs, [12] earthworm, [13] fish muscle and liver, [14,15] bovine liver, [16] rat brain [17] and human serum [18] has been reported. Limited studies have been performed using Arabidopsis thaliana, [19,20] but these have been targeted to detection by mass spectrometry.…”