Young Geun Shin

High-performance liquid chromatographic analysis of ginseng saponins using evaporative light scattering detection

Abstract Ginseng saponins were analysed using HPLC with evaporative light scattering detection (ELSD). A LiChrosorb NH 2 column was used to separate ginseng saponins in white and red ginseng. The complete separation of ginsenoside Rb 1 , Rb 2 , Rc, Rd, Re, Rf, Rg 1 , Rg 2 , Rg 3 and Rh 1 was achieved within 35 min with an amino-bonded column using an acetonitrile-water-2-propanol gradient system. The ELSD drift tube temperature was set at 145°C and the nitrogen flow was set at 40 mm rotameter units. The detection limits ( S / N =3) of the ginsenosides ranged from 35 to 155 ng.

Determination of betaine in Lycium chinense fruits by liquid chromatography-electrospray ionization mass spectrometry.

A rapid and sensitive high-performance liquid chromatography-electrospray mass spectrometric method has been developed for the determination of betaine in Lycium chinense fruits. Betaine was analyzed on a system consisting of a NH2 stationary phase and a mobile phase of water-acetonitrile (25:75) by isocratic elution for 40 min. Betaine was identified and quantitated by electrospray ionization mass spectrometry with selected ion monitoring of the protonated ion [Betaine+H]+ and clustered ions [nBetaines+H]+. The limit of detection for betaine by this method was ca. 0.2 ng/ml and the relative standard deviations of the assay (intra- and inter-day) were less than 8.1%.

High performance liquid chromatographic determination of ginsenosides using photoreduction fluorescence detection

Abstract A high performance liquid chromatographic method using photoreduction fluorescence detection was described for the analysis of ginsenosides. Ginsenosides were separated on an amino column using acetonitrile and aqueous 2-tert-butylanthraquinone(t-BAQ) solution. Column effluent was passed through a 45cm-PTFE capillary tube coiled around a 10W-UV lamp to reduce t-BAQ to a highly fluorescent dihydroxy anthracene derivative which was detected by a fluorescence detector. The detection limit for the ginsenoside Rg1 by this method was found to be about 130ng. This method is less influenced by other UV-absorbing compounds compared to the conventional HPLC-UV detection method.

Analysis of alkaloids in the seeds ofZizyphus jujuba by high performance liquid chromatography

A high performance liquid chromatographic method was developed for the separation and determination of seven alkaloids in “sanjoin” (the seeds ofZizyphus jujuba, Rhamnaceae), a plant with potent sedative activity. A reverse phase system of Lichrosorb RP-Select B column and 0.05 M potassium phosphate buffer (pH=3.5)-acetonitrile with gradient elution was employed. Two known alkaloids, juzirine and lysicamine, were newly isolated fom “sanjoin”.

Photoreactivity of anthraquinones for the analysis of ginsenosides using photoreduction fluorescence detection-HPLC

The photoreactivity of twelve anthraquinone derivatives was examined to evaluate its usefulness as a photo-reagent for the analysis of ginsenosides using photoreduction fluorescence (PRF) detection method. Among the tested compounds, 2-tert-butylanthraquinone (TBAQ), 2-chloroanthraquinone (CAQ) and anthraquinone (AQ) showed good characteristics as photoreagents. The detection limits of ginsenoside Rg1 by PRF-HPLC method using TBAQ, CAQ or AQ as a photo-reagent were found to be ca. 35 ng, 50 ng and 50 ng, respectively.

Chemical constituent ofAloe capensis

A C-glycosyl chromone, named as 7-O-methylaloesinol, was newly isolated from the leaf exudate ofAloe capensis and identified as 8-C-β-D-glucopyranosyl β-2-[2-(R)-hydroxypropyl]-7-methoxy-5-methyl-4H-1-benzopyran-4-one by chemical and spectral evidence.

Determination of aloesin in plasma by high-performance liquid chromatography as fluorescent 9-anthroyl derivative.

A sensitive high-performance liquid chromatographic (HPLC) method for the determination of aloesin in plasma was developed. After solid-phase extraction from plasma and derivatization of aloesin and compound AD-1, which was prepared from aloesin as a internal standard, with 9-anthroylnitrile in the presence of quinuclidine, the derivatives were separated on a Inertsil ODS-3 column using acetonitrile/methanol/water (3∶1∶6) as a mobile phase, and detected fluorimetrically at 460 nm with excitation at 360 nm. The detection limit of aloesin was 3.2 ng/ml in plasma (S/N=3).

The New Observation of Intramolecular Acyl Transfer from Aglycon to Sugar of C-Glycoside. The Regioselective and Single Step Acylation of 2′-Hydroxyl Group of Free C-Glucopyranoside.

Abstract A new intramolecular acyl transfer from aglycon to sugar moiety in C -glucopyranoside has been observed. This unusual acyl transfer reaction has been extended to the regioselective and direct acylations of 2′-hydroxyl group of free C -glucopyranoside and one step syntheses of four natural C -glycosylchromones from aloesin glucopyranoside have also been achieved by this method.

Chemical constituents inAloe barbadensis

Two compounds were newly isolated from the leaves ofAloe barbadensis Mill. Their structures were identified as 3,4-dihydro-3,9-dihydroxy-8-methoxy-3-methyl-1(2H)-anthracenone(1) and 10-β-D-glucopyranosyl-1,8,10-trihydroxy-3-(hydroxymethyl)-(R)-9(10)-anthracenone(2) by chemical and spectral evidences.