- A step-by-step crystallization for preparing thio alkyl/alkenyl cysteine sulfoxide method
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The invention discloses a method for preparing thioalkyl/alkenyl cysteine sulfoxide by fractional crystallization, belonging to the technical field of compound preparation. The method comprises the following steps: adding cysteine or cysteine salts, a sodium hydroxide solution and an R group (alkyl or alkenyl)-derived material into absolute ethanol in sequence for reaction to synthesize coarse ACSs, re-crystallizing ACSs, purifying, oxidizing to form ACSOs, and fractionally crystallizing to obtain natural dextrorotatory ACSOs, wherein the R group-derived material is replaced to synthesize different types of ACSOs in allium; enantiomers in racemes are separated by adopting the fractional crystallization method to obtain natural dextrorotatory ACSOs with optical activity. Compared with a conventional extraction method, the method has the characteristics that the yield and the purity are high, a conventional complicated extraction process is avoided, the product has the optical activity, and the physical property is close to that of natural extract; the product is used in the fields of health products, pharmaceuticals and the like, the effects of resisting bacteria and cancers, reducing blood fat and the like of ACSOs are brought into play, or the product serves as an intermediate such as an active ingredient-diallyl thiosulfinate for synthesizing allium.
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Paragraph 0061; 0062
(2017/05/26)
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- Determination of S-methyl-, S-propyl-, and S-propenyl-L-cysteine sulfoxides by gas chromatography-mass spectrometry after tert-butyldimethylsilylation.
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A gas chromatographic-mass spectrometric method for the determination of S-methyl-L-cysteine sulfoxide (1), S-propyl-L-cysteine sulfoxide (2), and S-propenyl-L-cysteine sulfoxide (3), specific marker compounds in the genus Allium, is described. The target amino acids were converted to the tert-butyldimethylsilyl derivatives. The products were silylated on the amino and carboxyl groups and on an additional oxygen atom and were separated on a nonpolar capillary column. That incorporation of three tert-butyldimethylsilyl groups had occurred was verified by mass spectrometry, which gave an m/z 302 fragment as base peak (amino acid side chain eliminated ion) and m/z 436 (1), 464 (2), or 462 (3) as major peaks (tert-butyl function eliminated ion), by electron impact ionization. The detection limits for 1 and 2 under selected ion monitoring at m/z 436 (1) and m/z 464 (2), respectively, were determined to be 0.3 and 1.8 ng per injection. To clean up the analytes from the solvent extract of onion, as a representative food material, onion, the sample solution was subjected to combined solid phase extraction. The eluate from a Sep-Pak C(18) cartridge was applied to a Bond Elut SCX cartridge (H(+) form), followed by washing with 0.1 M hydrochloric acid and elution with 0.5 M ammonia. From a simulated matrix solution containing 5% sucrose, 1 and 2 were extracted quantitatively, and the detection yield was approximately 75%. The contents of 1, 2, and 3 in commercial onion were estimated to be 0.3, 3.1, and 3.0 mg, respectively, per gram of fresh weight.
- Tsuge, Kouichiro,Kataoka, Mieko,Seto, Yasuo
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p. 4445 - 4451
(2007/10/03)
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- Differential inhibition of human platelet aggregation by selected Allium thiosulfinates
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Thiosulfinates (TSs) have been implicated as a principle source of the antiplatelet property of raw onion and garlic juice. The in vitro responses of human platelets to dosages of four TSs were measured using whole blood aggregometry and compared by regression analysis. Of the compounds evaluated, methyl methane-TS (MMTS), propyl propane-TS (PPTS), and 2-propenyl 2-propene-TS (allicin) are present in freshly cut Allium vegetables, whereas ethyl ethane-TS (EETS) has not been detected. All TSs were synthesized using a model reaction system. PPTS and allicin had the strongest antiplatelet activity at 0.4 mM, inhibiting aggregation by 90 and 89%, respectively. At the same concentration, EETS and MMTS were significantly weaker, inhibiting 74 and 26%, respectively. Combinations of TSs were not additive in their inhibition of aggregation, indicating that the antiplatelet potential of Allium extracts cannot be easily predicted by quantifying organosulfur components. EETS, PPTS, and allicin were significantly more potent platelet inhibitors than aspirin at nearly equivalent concentrations.
- Briggs, William H.,Xiao, Hang,Parkin, Kirk L.,Shen, Cunxi,Goldman, Irwin L.
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p. 5731 - 5735
(2007/10/03)
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- In vitro biogeneration of pure thiosulfinates and propanethial-S-oxide
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A model reaction system was developed for generating, pure thiosulfinates and propanethial-S-oxide (PTSO) using an isolated alliinase (EC 4.4.1.4) and isolated or synthetic alk(en)yl-L-cysteine sulfoxides (ACSO). Reaction yields ranged from 30 to 60% after 3 h at 21-23°C, and organosulfur reaction products were extracted into CHCl3 to yield product preparations of controlled composition. A pure thiosulfinate or PTSO was derived from a single ACSO, and a preparation containing a mixture of four thiosulfinate species was derived from reaction mixtures employing binary ACSO substrate systems. Identities of homologous thiosulfinates and PTSO were confirmed by 1H NMR. This approach has the potential to be used as a preparative tool for yielding pure thiosulfinates and PTSO to facilitate the study of chemical and biological properties of this group of compounds or as a means to study the dynamics of organosulfur chemistry in preparations from Allium spp.
- Shen, Cunxi,Parkin, Kirk L.
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p. 6254 - 6260
(2007/10/03)
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