Markus Ganzera

Investigation of Uña De Gato I. 7-Deoxyloganic acid and 15N NMR spectroscopic studies on pentacyclic oxindole alkaloids from Uncaria tomentosa☆

The C-8-(S) isomer of deoxyloganic acid (7-deoxyloganic acid), together with beta-sitosteryl glucoside, five known stereoisomeric pentacyclic oxindole alkaloids and the tetracyclic oxindole isorhyncophylline, were isolated from the inner bark of Uncaria tomentosa. Structures of the isolated compounds were based on 1H and 13C NMR data, mainly 2D NMR experiments, including 1H-13C HMBC and 1H-1H NOESY correlation. Furthermore, the hitherto unreported 15N chemical shifts of the isomeric oxindole alkaloids, using 1H-15N HMBC experiments, were utilized to facilitate their characterization. Uncarine D showed weak cytotoxic activity against SK-MEL, KB, BT-549 and SK-OV-3 cell lines with IC(50) values between 30 and 40 microg/ml, while uncarine C exhibited weak cytotoxicity only against ovarian carcinoma (IC(50) at 37 microg/ml).

The American mayapple revisited : Podophyllum peltatum-still a potential cash crop?

Podophyllum peltatum, was reexamined for its potential use in the commercial production of podophyllotoxin, a lignan used in the semisynthesis of important anticancer drugs. A survey of the natural population of the American mayapple, Podophyllum peltatum, was conducted in order to identify high-yielding genotypes. Plants were collected from the eastern and central United States. The lignan content of leaf blades and rhizome material of the collected specimens was characterized by aqueous extraction followed by HPLC analysis. Podophyllotoxin and α-peltatin appeared most prominently among the lignans obtained. Leaf blades were generally richer in podophyllotoxin than rhizomes. Several high-yielding accessions were identified, the blades of which contained 4.0–5.6% podophyllotoxin. A negative correlation was observed between podophyllotoxin and peltatin content in the blades. The combination of high biosynthetic capacity and preferential accumulation of podophyllotoxin in leaves of mayapple makesthis plant an excellent candidate for agricultural production of podophyllotoxin.RésuméO potencial de utilização do Podophyllum peltatum foi rexaminado para a produção comercial de podofilotoxina, urn composto usado na semisìntese de importantes drogas anticancerìgenas. Urn levantamento da população norte-americana da mayapple, Podophyllum peltatum, foi conduzido com a finalidade de identificar genótipos de alta produtividade. As coletas foram feitas no centroeste dos Estados Unidos e o conteúdo de lignanas do limbo foliar e dos rizomas foi caracterizado por extração aquosa seguida da análise por HPLC. Podofilotoxina e a peltatin apareceram mais proemintes do que as demais lignanas. Geralmente, o limbo foliar apresentou um conteúdo de podofilotoxina mais rico do que os rizomas. Muitas accessões com alta produtividade foram identificadas e cujo o conteúdo de podophyllotoxina no limbo foliar variou entre 4.0–5.6%. Observou-se ainda uma correlação negativaentre apodofilotoxina e o conteúdo de peltatin no limbo foliar. Nas folhas, a combinaú ão entre a capacidade biosintética e o acúmulo preferencial da podofilotoxina, faz com que essa espécie seja considerada uma excelente candidata para a produção agrícola desta lignana.

Analytical techniques for the determination of lactones inPiper methysticum forst

SummaryThe development and comparison of two analytical methods (HPLC in reversed phase and normal phase mode and GC) for the determination of six major lactones inP. methysticum is described in this paper. By all methods, a satisfying separation of these compounds could be achieved. Each method shows distinct advantages to previously published ones, regarding separation quality, time or conditions. Several kava samples were analyzed by these new or modified methods, and the qualitative and quantitative results obtained were comparable. Primary differences in separation times and detection limits were observed, so that each method might be preferable, depending on the requirements.

Separation of Cimicifuga racemosa Triterpene Glycosides by Reversed Phase High Performance Liquid Chromatography and Evaporative Light Scattering Detection

SummaryThe main triterpene glycosides ofCimicifuga racemosa were separated by reversed phase HPLC, using a C-18 column, Evaporative Light Scattering (ELS) detection and a grient system consisting of water, acetonitrile and reagent alcohol. Within 35 min three main glycosides could be separated and quantified in the methanolic root extract with detection limits of 10.5, 15.6 and 31.6 μg·mL−1 respectively. The method was successfully used, to analyzed differentCimicifuga racemosa market products, as well as to distinguish between otherCimicifuga samples from China.

Separation ofPodophyllum lignans by micellar electrokinetic capillary chromatography (MECC)

SummarySeparation of the mainPodophyllum lignans by MECC has been achieved using a phosphate-borate buffer system with the pH of 7.25, containing 25 mM SDS and 15% methanol. Optimum temperature and voltage were found to be 35°C and 20kV, respectively, UV-detection was performed at 220 nm. The method was successfully used to analyse different samples ofPodophyllum peltatum collected in the southern USA, and showed great qualitative and quantitative variations among these populations. The quantitative MECC results for podophyllotoxin were in good agreement to those obtained by HPLC.

Analysis of Sesquiterpene Lactones in Magnolia grandiflora L. by Micellar Electrokinetic Capillary Chromatography

SummaryFive sequiterpene lactones found inMagnolia grandiflora were successfully separated by micellar electrokinetic capillary chromatography (MECC). Separation parameters were studied systematically, and the best results were obtained with a phosphate-borate buffer at pH 7.25, containing the bile salt sodium cholate as surfactant and isopropanol as organic modifier. Optimum temperature, voltage and detection wavelength were 30°C, 20 kV and 210 nm, respectively. This setup allowed a baseline separation of the standard compounds within 12 min, with a detection limit of 4.7 μg·mL−1 or less. A quantitative analysis of differentM. grandiflora samples showed parthenolide as the most dominant sesquiterpene lactone in all specimens, with concentrations ranging from 0.019% in fruits to 0.335% in leaves (w/w).