Monique Zèches-Hanrot

Alkaloids of Alstonia angustifolia

Abstract Thirty-one alkaloids have been isolated from the leaves and from the stem bark of Alstonia angustifolia from Malaysia. Twenty of them were known compounds: yohimbine, O -acetyl yohimbine, pleiocarpamine, fluorocarpamine, cathafoline, cabucraline, N -1 desmethylquaternine, vincamajine, normacusine B, lochnerine, affinisine, akuammicine, 11-methoxyakuammicine, antirhine, alstonisine, alstonerine, alstophylline, macralstonine, villalstonine and tetrahydrocantleyine. Among the 11 novel alkaloids, three were monomers: 19,20-dehydro-10-methoxytalcarpine, 19,20-dehydro- O -acetyl yohimbine and hydroxystrictamine, and eight were dimers: villalstonine N -4′-oxide, 10-methoxy villalstonine, 10-methoxyvillalstonine N-4′-oxide, 10-methoxymacrocarpamine, 10-methoxymacrocarpamine N -4′-oxide, angusticraline, alstocraline and foliacraline. Structural elucidation of the new alkaloids was based on spectral data analysis including high field 1 H and 13 CNMR.

Isolation of indole alkaloids from Catharanthus roseus by centrifugal partition chromatography in the pH-zone refining mode

Centrifugal partition chromatography (CPC) in the pH-zone refining mode allowed a preparative and efficient isolation of vindoline, vindolinine, catharanthine and vincaleukoblastine from a crude mixture of Catharanthus roseus alkaloids. The separation protocol was tested with a synthetic mixture of vindoline, catharanthine and vincaleukoblastine. The fraction content was analyzed and the results compared with theoretical chromatograms obtained by numerical simulation. The increase in injected sample mass results in an improvement of the purity of the isolated compounds. This observation, confirmed by theory, is of prime importance for the development of preparative pH-zone refining CPC as a preparative separation method.

Preparative separation of anthocyanins by gradient elution centrifugal partition chromatography

Abstract Centrifugal partition chromatography (CPC) allowed purification of anthocyaanins from Champagne vintage by-products (Vitis vinifera) and from blackcurrant (Ribes ni9grum L.). In the first case a 5-1 pilot-CPC used on a preparative multi-gram scale. The biphasic solvent system used was ethyl acetate-1-butanol-water, acidified by TFA (pH 1–3) for both gradient and isocratic normal-phase elutions. Separation selectives which differ for cyanidin and delphinidin glycosides in CPC and cellulose-TLC using the solvent system 1-butanol-acetic acid-water (4:1:5) are discussed.

Dammarane saponins from Zizyphus lotus

Four dammarane-type saponins were isolated by means of centrifugal partition chromatography from the root bark of Zizyphus lotus. Their structures were elucidated using a combination of 1D and 2D 1H and 13C NMR spectra and mass spectroscopy. One of these glycosides is the known jujuboside A. The others are three new dammarane saponins, identified as 3-O-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl (1-->3)-[alpha-L-rhamnopyranosyl(1-->2)]-alpha-L-arabinopyranosyl jujubogenin = jujuboside C, 3-O-alpha-L-rhamnopyranosyl (1-->2)-[beta-D-glucopyranosyl(1-->3)]-beta-D-galactopyranosyl lotogenin = lotoside I, and 3-O-alpha-L-rhamnopyranosyl(1-->2)-[beta-D-glucopyranosyl (1-->3)]-beta-D-glucopyranosyl lotogenin = lotoside II. Lotogenin is a new dammarane derivative identified as (15R, 16R, 20R, 22R)-16 beta, 22-epoxydammar-24-ene-3 beta, 15 alpha, 16 alpha, 20 beta-tetraol.

Alkaloids from stem bark and leaves of Peschiera buchtieni

Abstract During an investigation of the stem bark and leaves of Peschiera buchtieni , 34 alkaloids were isolated. Eight new alkaloids were obtained from the stem bark, N -methyl-pericyclivine, 18,19( R )-dihydroxycoronaridine, chloromethylene affinisinium, demethylaccedinisine, 18-hydroxyaffinisine, buchtienine, 3-hydroxytetrahydroolivacine and demethylceridimine. The known alkaloids from the stem bark were coronaridine, voaphylline, coronaridine hydroxyindolenine, heyneanine, eglandine, eglandulosine, 19-epi-heyneanine, voachalotine, ochropamine, olivacine, ibogamine, affinisine, N -oxyaffinisine, vallesamine, ( E )-isositsirikine, voaphylline hydroxyindolenine, normacusine B, janetine, 3,14-dihydroolivacine, 3′( R / S )-hydroxy- N -demethyl-tabernamine, 4′,17β-dihydrotchibangensine, ceridimine and N -demethyltabernamine. Apodine, voacristine, voacristine hydroxyindolenine and olivacine were identified in leaves.

Lotusine G: a new cyclopeptide alkaloid from Zizyphus lotus

In addition to six cyclopeptide alkaloids lotusines A-F, a new compound lotusine G, was isolated from the root bark of Zizyphus lotus by centrifugal partition chromatography.

Purification of Rosmarinic Acid by Strong Ion‐Exchange Centrifugal Partition Chromatography

Abstract Ion‐Exchange centrifugal partition chromatography using benzalkonium chloride as a strong exchanger (SIXCPC) was successfully used to purify rosmarinic acid from a crude extract that was produced by callus culture. The purification process was carried out on a gram scale using the ternary biphasic system CHCl3: n‐BuOH∶water 4.5:1:4.5 v/v/v in the ascending mode (mobile aqueous phase and stationary organic phase). Two particular points are discussed: the influence of benzalkonium chloride on ternary solvent system stability and the advantage of injecting the analytes as sodium salts rather than molecular acids.

Indolomonoterpenic alkaloids from Strychnos icaja roots

In the course of our search for new antiplasmodial alkaloids from Strychnos icaja, we have isolated five alkaloids: three monomers, protostrychnine and genostrychnine, previously described in Strychnos nux-vomica, pseudostrychnine, already found in the leaves of the plant, a new bisindolic alkaloid, named strychnogucine C, and the first naturally occurring trimeric indolomonoterpenic alkaloid: strychnohexamine. This latter trimeric alkaloid presented an antiplasmodial activity against the FCA Plasmodium falciparum line near 1 microM.

Fractionation of low-molecular-mass heparin by centrifugal partition chromatography in the ion-exchange displacement mode

Centrifugal partition chromatography in the ion-exchange displacement mode allowed a preparative and efficient fractionation of low-molecular-mass heparins from enoxaparin sodium. Amberlite LA2--a lipophilic liquid secondary amine--was chosen as a weak anion exchanger. The biphasic system methyl isobutyl ketone-water was selected. Protonated LA2 (10%, v/v) was added to the organic stationary phase. Hydroxide (Na+, OH-) was chosen as a displacer in the aqueous mobile phase. The observed pH and concentration profiles are typical of displacement chromatography, as supported by numerical simulation. The Dubois test for the analysis of sugar content and an analysis of sulfur content (and consequently sulfatation rate) were carried out to monitor the effectiveness of the procedure. Moreover, the fractions were analyzed by high-performance size-exclusion chromatography and the 1H NMR spectra confirmed the fractionation of the sample of enoxaparin sodium.

Alkaloids from leaves and stem bark of Ervatamia peduncularis

Chemical study of the leaves and stem bark of Ervatamia peduncularis afforded two novel bisindole alkaloids, pedunculine and peduncularidine, together with seven known alkaloids, coronaridine, coronaridine hydroxyindolenine, eglandine, heyneanine, eglandulosine, heyneanine hydroxyindolenine and N(1)-methyl-aspidos-permidine. Structural elucidation of the new alkaloids was based on their spectral data.