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See detailQualitative and quantitative evaluation of bisindole usambarane alkaloids in Strychnos usambarensis roots by high performance liquid chromatography diode-array
Frederich, Michel ULg; Tits, Monique ULg; Angenot, Luc ULg

in Phytochemical Analysis (1998), 9(2), 63-66

A high performance liquid chromatographic method for the simultaneous determination of bisindole usambarane alkaloids from the roots of Strychnos usambarensis using a diode-array detector is proposed, The ... [more ▼]

A high performance liquid chromatographic method for the simultaneous determination of bisindole usambarane alkaloids from the roots of Strychnos usambarensis using a diode-array detector is proposed, The system, consisting of a RP-8 Select B column and a linear gradient elution with acetonitrile and acetate buffer allowed the separation of all the alkaloids in 20 min, Usambarensine was found to be the major tertiary alkaloid present in the roots, In order to demonstrate the possibility of quantifying the bisindole alkaloids in crude roots extracts, the quantitative evaluation of 3',4'-dihydrousambarensine, usambarensine and N-b-methylusambarensine was carried out. (C) 1998 John Wiley & Sons, Ltd. [less ▲]

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See detailThe DNA intercalating alkaloid cryptolepine interferes with topoisomerase II and inhibits primarily DNA synthesis in B16 melanoma cells.
Bonjean, K.; De Pauw, Marie-Claire ULg; Defresne, Marie-Paule ULg et al

in Biochemistry (1998), 37(15), 5136-46

Cryptolepine hydrochloride is an indoloquinoline alkaloid isolated from the roots of Cryptolepis sanguinolenta. It is characterized by a multiplicity of host-mediated biological activities, including ... [more ▼]

Cryptolepine hydrochloride is an indoloquinoline alkaloid isolated from the roots of Cryptolepis sanguinolenta. It is characterized by a multiplicity of host-mediated biological activities, including antibacterial, antiviral, and antimalarial properties. To date, the molecular basis for its diverse biological effects remains largely uncertain. Several lines of evidence strongly suggest that DNA might correspond to its principal cellular target. Consequently, we studied the strength and mode of binding to DNA of cryptolepine by means of absorption, fluorescence, circular, and linear dichroism, as well as by a relaxation assay using DNA topoisomerases. The results of various optical and gel electrophoresis techniques converge to reveal that the alkaloid binds tightly to DNA and behaves as a typical intercalating agent. In DNAase I footprinting experiments it was found that the drug interacts preferentially with GC-rich sequences and discriminates against homo-oligomeric runs of A and T. This study has also led to the discovery that cryptolepine is a potent topoisomerase II inhibitor and a promising antitumor agent. It stabilizes topoisomerase II-DNA covalent complexes and stimulates the cutting of DNA at a subset of preexisting topoisomerase II cleavage sites. Taking advantage of the fluorescence of the indoloquinoline chromophore, fluorescence microscopy was used to map cellular uptake of the drug. Cryptolepine easily crosses the cell membranes and accumulates selectively into the nuclei rather than in the cytoplasm of B16 melanoma cells. Quantitative analyses of DNA in cells after Feulgen reaction and image cytometry reveal that the drug blocks the cell cycle in G2/M phases. It is also shown that the alkaloid is more potent at inhibiting DNA synthesis rather than RNA and protein synthesis. Altogether, the results provide direct evidence that DNA is the primary target of cryptolepine and suggest that this alkaloid is a valid candidate for the development of tumor active compounds. [less ▲]

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See detail3 ',4 ',5 ',6 ' tetradehydrolongicaudatine Y, an anhydronium base from Strychnos usambarensis
Frederich, Michel ULg; Quetin-Leclercq, J.; Biala, R. G. et al

in Phytochemistry (1998), 48(7), 1263-1266

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See detailGlucoindole alkaloids from stem bark of Strychnos mellodora
Brandt, Viviane; Tits, Monique ULg; Angenot, Luc ULg

Conference (1996, May)

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See detailGlucoindole alkaloids from stem bark of Strychnos mellodora
Brandt, V; Tits, Monique ULg; Angenot, Luc ULg

Poster (1996, February)

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See detailGlucoindole Alkaloids from Stem Bark of Strychnos Mellodora
Tits, Monique ULg; Brandt, V.; Wauters, Jean-Noël ULg et al

in Planta Medica (1996), 62(1), 73-4

Three glucoindole alkaloids, dolichantoside (1), strictosidine (2), and palicoside (3), have been identified in the stem bark of Strychnos mellodora (Loganiaceae), collected in Zimbabwe. The chiroptical ... [more ▼]

Three glucoindole alkaloids, dolichantoside (1), strictosidine (2), and palicoside (3), have been identified in the stem bark of Strychnos mellodora (Loganiaceae), collected in Zimbabwe. The chiroptical (CD) data are compared. [less ▲]

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See detailA new HPLC method for the assay of alkaloids in Strychnos nux-vomica and Strychnos ignatii
Gadi Biala, Rose; Tits, Monique ULg; Wauters, Jean-Noël ULg et al

in Fitoterapia (1996), 67(2), 163-165

A reversed-phase high performance liquid chromatographic procedure was developed for the qualitative and quantitative analysis of the alkaloids in S. nux-vomica and S. ignatii.

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See detailQuantitative Densitometric Evaluation of Harpagoside in the Secondary Roots of Harpagophytum procumbens D.C.
Poukens-Renwart, Pascale; Tits, Monique ULg; Angenot, Luc ULg

in Journal of Planar Chromatography- Modern TLC (1996), 9(May/June), 199-202

Harpagophytum procumbens D.C. (Devil's Claw) secondary roots are used in Europe as a home remedy for lack of appetite, dyspeptic complaints, and in supportive therapy for degenerative disorders of the ... [more ▼]

Harpagophytum procumbens D.C. (Devil's Claw) secondary roots are used in Europe as a home remedy for lack of appetite, dyspeptic complaints, and in supportive therapy for degenerative disorders of the locomotor system. The main characteristic iridoid glucoside of the plant is harapagoside. An HPTLC method has been developed for the quantitative determination of harpagoside in the secondary roots and extracts of this plant. The mobile phase used is an optimized version of one described in the literature.It furnished the most homogenous spots for quantitative densitometric evaluation ( at lambda= 286 nm, the wavelenght of maximum absorption for harapgoside).The results have been compared with those obtained afetr visualization with sulfuric acid-vanillin reagent and those obtained using a previously published HPLC method; To check that separation was complete, the spectra of harpagoside obtained from Devil's Claw extracts before and after visualization were superimposed on thos of harpagoside standard. [less ▲]

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See detailUtilisation de prodelphinidines pour le traitement de l'arthrose
Franchimont, Paul; Bassleer, Corine; Angenot, Luc ULg et al

Patent (1994)

The subject of the invention is the use of prodelphinidins for obtaining medicaments intended for the treatment of articular pathologies associated with the destruction of the cartilage, and more ... [more ▼]

The subject of the invention is the use of prodelphinidins for obtaining medicaments intended for the treatment of articular pathologies associated with the destruction of the cartilage, and more particularly of arthrosis. [less ▲]

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See detailActivité antiinflammatoire du mucilage de bleuet
Bodart, Patricia; Tits, Monique ULg; Angenot, Luc ULg

Poster (1994, May)

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See detailOn the occurrence of (iso-)dolichantoside in Strychnos mellodora
Quarré, Marie-Noëlle; Tits, Monique ULg; Wauters, Jean-Noël ULg et al

Poster (1994, March)

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See detailAntiinflammatory activity of centaurea cyanus flowers
Bodart, Patricia; Goldsztajn, V.; Tits, Monique ULg et al

Poster (1994, March)

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See detailAntiinflammatory activity of Centaurea cyanus flowers
Bodart, Patricia; Damas, Jacques ULg; Goldsztajn, V. et al

in Journal de Pharmacie de Belgique (1994, February), 59(1), 73

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See detailSelective Antiprotozoal Activity of Some Strychnos Alkaloids
Wright, Colin; Allen, David; Cai, Ya et al

in Phytotherapy Research (1994), 8

The in vitro activities of 28 Strychnos alkaloids have been determined against three species of protozoa and the most active compounds were then assessed for in vitro cytotoxic activity against KB cells ... [more ▼]

The in vitro activities of 28 Strychnos alkaloids have been determined against three species of protozoa and the most active compounds were then assessed for in vitro cytotoxic activity against KB cells. 3',4'-dihydrousambarensine was the most active against Plasmodium falciparum and was relatively nontoxic to KB cells (cytotoxic/antiplasmodial ratio, 1474). Usambarensine displayed the most selectivity against Entamoeba histolytica while "',4'-dihydrousambarensine was the most selective compound against Giardia intestinalis although the cytotoxic/antiprotozoal ratios (20.4 and 6.6 respectively) were less favourable than the above.The four strychnobiline-type alkaloids were found devoid of activity against E. histolytica and G. intestinalis but to have weak antiplasmodial properties (7-13 times less active than chloroquine). None of the compounds containing only one indole ring system displayed antiprotozoal properties. [less ▲]

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See detailSemi-Quantitative Salicin Analysis According the German Pharmacopoeia (DABX): Avoidance of Picein Interference
Poukens-Renwart, Pascale; Tits, Monique ULg; Angenot, Luc ULg

in Planta Medica (1993), 59(Supplement Issue), 629-630

The semi-quantitative determination of salicin by TLC described in the German Pharmacopoeia (DABX) does not separate salicin from picein, another phenolic glycoside of some willow species. In this paper ... [more ▼]

The semi-quantitative determination of salicin by TLC described in the German Pharmacopoeia (DABX) does not separate salicin from picein, another phenolic glycoside of some willow species. In this paper we propose to combine the use of both an adequate mobile phase and a suitable reagent (vanillin reagent instead of sulfuric acid-thymol) for an unambiguous determination of the amount of salicin.. [less ▲]

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See detailDensitometric Determination of Salicin in Willow Stem Bark
Poukens-Renwart, Pascale; Tits, Monique ULg; Angenot, Luc ULg

in Journal of Planar Chromatography (1993), 6(november-december), 434-437

Most of the salicin present in willow stem bark occurs as labile glycosides (e.g. salicin, salicortin, 2-O'-acetylsalicortin, 3-O'-acetylsalicortin, tremulacin and fragilin). On alkaline hydrolysis, these ... [more ▼]

Most of the salicin present in willow stem bark occurs as labile glycosides (e.g. salicin, salicortin, 2-O'-acetylsalicortin, 3-O'-acetylsalicortin, tremulacin and fragilin). On alkaline hydrolysis, these acylated derivatives decompose to salicin; in this way, the total amount of salicin can be determined. A HPTLC method has been developed for the quantitative determination of salicin in stem bark before and after alkaline hydrolysis. The mobile phase used for the separation is a modification of one described in the literature. a double or triple migration is necessary to separate salicin from other components of the extract. The results have been compared with those obtained after bidimensional chromatography using two phases described for the quantitative evaluation of salicin. to check that separation was complete, the spectrum of salicin obtained from willow extracts was superimposed on that of a salicin standard.Quantification was performed at lambda = 270nm, the wavelenght of maximum absorption in the IV spectrum of salicin. [less ▲]

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