A Simple Synthesis of Alliin and allo-Alliin: X-ray Diffraction Analysis and Determination of Their Absolute Configurations

Abstract

A simple method for the isolation of the bioactive compound alliin from garlic, as well as a method for the synthesis of diastereomerically pure alliin and allo-alliin on a preparative laboratory scale, was developed. The absolute configuration of the sulfur atom in alliin and allo-alliin was assigned on the basis of enzyme reactivity, optical rotatory dispersion, and circular dichroism analyses. A comparison of the results from these analyses, in combination with an X-ray diffraction study on a protected allo-alliin derivative, revealed S and R configurations of the sulfur atoms in alliin and allo-alliin, respectively. In addition, the same (1)H NMR spectrum was observed for synthetic and natural alliin. The absolute configuration of natural alliin was assigned for the first time on the basis of the NMR spectrum and X-ray coordinates.

Influence of different wild-garlic (Allium ursinum) extracts on the gastrointestinal system: spasmolytic, antimicrobial and antioxidant properties

“…The extensive analyses of the recorded 1D and 2D spectra, in two different NMR solvents, allowed a direct quantitation of six different sulphur‐containing compounds (three diastereomeric pairs): alliin and allo ‐alliin, trans ‐isoalliin and trans ‐ allo ‐isoalliin, as well as methiin and allo ‐methiin, differing in the configuration as the sulphur atom. Peak assignment was accomplished through detailed analyses of 2D NMR spectra, alongside a comparison with literature data . Specific signals of all mentioned amino acids were clearly resolved from all other signals, except in the case of alliin and its diastereomer, which were quantified from mutually overlapped multiplets, with the aid of spectral simulation (MestReNova 6.0).…”

“…This also allowed to determine the exact values of the chemical shifts and coupling constants for the isomers (isomer I: 5.9267 ppm, dddd, J = 17.3, 10.5, 7.9, 6.7 Hz, and isomer II: 5.9069 ppm, dddd, J = 17.3, 10.7, 6.7, 6.7 Hz). Assignment of signals used in qNMR experiments was performed in two ways: the signals were chosen based on their correspondence with literature values, and these were verified by a careful inspection of their correlations in 2D spectra recorded in DMSO‐ d 6 . The ratio of the signal integrals (analytes to standard) was used to calculate the amount of the six S ‐alk(en)yl cysteine sulphoxides in the extract samples.…”

“…Peak assignment was accomplished through detailed analyses of 2D NMR spectra, alongside a comparison with literature data. [21][22][23][24][25] Specific signals of all mentioned amino acids were clearly resolved from all other signals, except in the case of alliin and its diastereomer, which were quantified from mutually overlapped multiplets, with the aid of spectral simulation (MestReNova 6.0). Typical 1 H NMR spectra of A1-A5 are provided in the supplementary material ( Figures S6 and S7) file, along with the appropriate expansions.…”

Combined Effects of Amino Acids in Garlic and Buna-Shimeji (Hypsizygus marmoreus) on Suppression of CCl4-Induced Hepatic Injury in Rats

“…ACSO was chemically synthesised according to previous reports [ 25 , 32 ]. l -Arginine was purchased from Daesang Co., Ltd. (Seoul, Korea).…”

Sulfuric Odor Precursor S-Allyl-l-Cysteine Sulfoxide in Garlic Induces Detoxifying Enzymes and Prevents Hepatic Injury

“…S -Allyl- l -cysteine sulfoxide (ACSO), S -methyl- l -cysteine sulfoxide (MCSO), and S -ethyl- l -cysteine sulfoxide (ECSO) were synthesized from the corresponding alk(en)yl bromide and l -cysteine followed by the addition of hydrogen peroxide [25,39]. S -Allyl- l -cysteine (ACS), diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS) were purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan).…”