P. Thepenier

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.

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.

Further alkaloids from strychnos longicaudata and strychnos ngouniensis

Abstract Twenty four alkaloids have been isolated and identified from the root and stem barks of Strychnos longicaudata Gilg and Strychnos ngouniensis Pellegrin. Among these, 17 alkaloids are isolated for the first time; the novel bisindole series represented by longicaudatine includes now two other compounds: longicaudatines F and Y; besides ngouniensine, its epimer epingouniensine has been isolated along with two glucosyl-ngouniensines. Other new alkaloids include tubotaiwinal and several bases possessing the akuammicine skeleton.

Alkaloids of Strychnos johnsonii

Abstract Twenty-three alkaloids have been identified in the root bark and stem bark of Strychnos johnsonii from Zaire. They are demethoxycarbonyl-3,14-dihydro-gambirtannine, angustine, dihydro-cycloakagerine, O -ethylakagerine, O -ethylakagerine lactone, dihydro decussine, normalindine, oxojanussine, tetrahydroalstonial, ajmalicinial, norepimalindine, norharman, harman, akagerine, akagerine lactone, janussines A and B, tetrahydro akagerine, demethoxycarbonyl-3,14,15,16,17,18-hexahydro-gambirtannine, dihydrocorynantheol, anthirine lactone, anthirine and isoanthirine.

Nuclear magnetic resonance monitoring of centrifugal partition chromatography in pH-zone-refining mode

The coupling of centrifugal partition chromatography to NMR spectroscopy as detection and analysis method is investigated. Separation of a test mixture of three N-2,4-dinitrophenyl amino acids was performed in pH-zone-refining elution mode. The NMR and chromatography instrumentation was very similar to the one of the LC-NMR technique.

Alcaloïdes des feuilles du Cinchona ledgeriana

Abstract Five monomeric and seven quasi-dimeric indole alkaloids were isolated from the leaves of Cinchona ledgeriana , five are known; the structures of two novel quasi-dimeric alkaloids have been elucidated by chemical correlation.

Alkaloids from roots of Strychnos potatorum

Twenty-four compounds have been isolated and identified in the root bark of Strychnos potatorum. They are: Harmane carboxamide, cantleyine, 18,19-dihydrousambarensine, polyneuridine, norharmane, akuammidine, nor-C-flurorocurarine, ochrolifuanine A, bisnordihydrotoxiferine, ochrolifuanine E, normacusine B, normavacurine, henningsamine, 11-methoxyhenningsamine, dihydrolongicaudatine, dihydrolongicaudatine Y, antirhine, (20R- and (20S-dihydroantirhine, 11-methoxy-12-hydroxydiaboline, diaboline, 11-methoxydiaboline, desacetylretuline and diaboline N-oxide. The alkaloids in italic are novel.

Alkaloids from roots of Strychnos matopensis

Abstract Twenty-six alkaloids have been identified in the root bark of Strychnos matopensis from Zaire. They are Wieland-Gumlich aldehyde (WGA), desoxy WGA, N -formyldesoxy WGA, nor - C -fluorocurarine, N -desacetylretuline, N -desacetylisoretuline, isorosibiline, (16R)-isositsirikine, 1 1-methoxy diaboline, diaboline, matopensine, 16-methoxy isomatopensine, 16-ethoxy isomatopensine, 18-hydroxy matopensine, 18,18′- bis -hydroxy matopensine, matopensine N -oxide, strychnofuranine, bisnordihydrotoxiferine, bisnor-C-alkaloid H, bisnor-C-curarine, bisnor-C-alkaloid D, longicaudatine, longicaudatine F, longicaudatine Y, longicaudatine Z and N -oxylongicaudatine. The new compounds are N -formyldesoxy-Wieland-Gumlich aldehyde, the derivatives of matopensine, strychnofuranine and longicaudatine Z. Strychnofuranine is made up of two geissoschizal units with C-16 and C-17 being condensed into a furan ring.