Maurice Vanhaelen

Tropine alkaloids production by hairy root cultures of Datura stramonium and Hyoscyamus niger

Abstract Hairy root were induced by inoculation of Agrobacterium rhizogenes in sterile seedlings of Datura stramonium and Hyoscyamus niger . The transformed roots cultures were established and subcultured on a Murashige and Skoog [1] hormone free medium. Several strains of hairy root were obtained from different genotypes of D. stramonium . Determination of hyoscyamine and scopolamine was performed by TLC-densitometry. A high variability of alkaloids production was observed between the different strains. Sucrose concentration as well as mineral composition of the culture medium influence the alkaloidal content of the transformed roots; scopolamine concentration expressed on a dry weight basis reached 0.56% in optimum conditions.

Lawsone accumulation in normal and transformed cultures of henna, Lawsonia inermis

The improvement of axillary shoot formation of Lawsonia inermis L. cultured in vitro depended on the iron concentration in the culture medium. Regenerated shoots were rooted on a hormone-free half-strength Murashige and Skoog medium (1/2 MS) before transfer to greenhouse conditions. Determination of lawsone in the plant material was investigated using a new HPLC method. The results showed that lawsone accumulation in vivo is restricted to the aerial part of the plant. In addition, the possibility of inducing lawsone biosynthesis in root cultures was studied. Hairy root cultures were established by a co-culture method using leaf segments of L. inermis and Agrobacterium rhizogenes NCIB 8196. Of several basal media tested, the production of lawsone (0.13% dry weight) was only observed in hairy roots tissues incubated in the dark and cultured in 1/2 MS or MS media.

Immunodetection of artemisinin in Artemisia annua cultivated in hydroponic conditions

Abstract A highly specific and sensitive ELISA method was developed for the detection and semi-quantitative determination of artemisinin and its structurally related compounds in crude extracts of Artemisia annua. The antibodies were raised in rabbits using a 10-succinyldihydroartemisinin-BSA conjugate as immunogen. The peroxide linkage in the artemisinin molecule was critical in determining the antibody specificity. The working range of the assay was from 0.02 to 10 ng per assay. The cross-reacting material in crude plant extracts was evaluated by chromatographic methods combined with the immunoassay method. The distribution of artemisinin equivalents in five-week-old A. annua plants cultivated in hydroponic conditions was investigated. The highest artemisinin equivalent content (1.12% dry wt) was found in the leaves of the upper parts of the plant.

Countercurrent Chromatography for Isolation of Flavonol Glycosides From Ginkgo Biloba Leaves

Abstract A procedure which combined countercurrent chromatography with gradient elution and preparative high-performance liquid chromatography was developed for the isolation and the purification of the seven predominant flavonol glycosides from Ginkgo biloba leaves.

High-speed countercurrent chromatography separation of taxol and related diterpenoids from Taxus baccata

Abstract Taxol and related taxane diterpenoids were isolated from pre-purified extracts of stem-barks of Taxus bacccata by HSCCC. The described method allowed to obtain a mixture of taxol and cephalomannine without any other interfering constituent and furthermore a partial separation of taxol (40 % of the total recovery) from cephalomannine. In addition, the HPLC and TLC separation conditions of these compounds for the semi-preparative and analytical purposes were improved. The proposed HSCCC method could be adapted to the scaling-up separation of taxol from vew material.

Factors affecting the in vitro rapid germination of Taxus embryos and the evaluation of taxol content in the plantlets

A simple and efficient in vitro method for breaking the dormancy of Taxus baccata L. cv. Stricta seeds was investigated. The highest rate of germination (100%) of embryos isolated from seeds, which had been washed with running tap water for 7 days, was obtained after 7 days of culture on modified Murashige and Skoog or Heller media. The taxol equivalent content in 2-month-old Taxus plantlets was investigated using anti-taxol polyclonal antibodies. The results showed that the taxol equivalent content varied, depending on Taxus species and on the individuals in the same taxon.

Antihepatotoxic Actions of Cochlospermum Tinctorium Rhizomes

The antihepatotoxic activity of the rhizomes of Cochlospermum tinctorium was investigated using carbon tetrachloride- and galactosamine-induced cytotoxicity in primary cultured rat hepatocytes. Because the methanol and ethanol extracts of C. tinctorium rhizomes exhibited antihepatotoxic effects, the former was fractionated in order to elucidate the active constituents. Polyphenol compounds (gallic and ellagic acids) were detected in the active fractions and may account for much of the antihepatotoxic activity. Carotenoids could also be implicated in the activity of the total extracts.

Apocarotenoids from Cochlospermum tinctorium

Abstract Seven carotenoids have been isolated from Cochlospermum tinctorium by means of countercurrent chromatography and HPLC. The two major constituents were identified by spectroscopic methods (UV-VIS, IR, 1 H NMR, 13 C NMR and EIMS) as 6-hydroxy-8′-apo-e-caroten-3-one-8′-oic acid (cochloxanthin) and 4,5-dihydro-6-hydroxy-8′-apo-e-caroten-

Triacylbenzenes and long-chain volatile ketones from Cochlospermum tinctorium rhizome

Abstract The composition of the volatile fraction from Cochlospermum tinctorium rhizome was investigated by GC and GC-MS; among 11 constituents detected, eight were identified as straight chain ketonic compounds. In addition, five triacylbenzenes were isolated from a petrol extract of the rhizome, separated by HPLC and identified by their spectral data.

Large Scale Purification of Apocarotenoids from Cochlospermum Tinctorium by Countercurrent Chromatography

Abstract Carotenoids are well-known for their instability so as usual analytical methods such as HPLC or preparative TLC applied to the separation of the constituents of Cochlospermum tinctorium failed to the isolation of pure pigments for further chemical characterization. Thus high-speed CCC using a horizontal flow-through coil planet centrifuge was used to conveniently and efficiently achieve this separation for quantities up to 500mg of the crude plant extract.