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See detailDevelopment and validation of a UHPLC−LTQ−Orbitrap MS method for non-anthocyanin flavonoids quantification in Euterpe oleracea juice
Dias, A.L.; Rozet, Eric ULg; Larondelle, Y. et al

in Analytical and Bioanalytical Chemistry (2013)

Euterpe oleracea fruits have gained much attention because of their phenolic constituents that have shown potential beneficial effects for health. The aim of this work was to identify and quantify major ... [more ▼]

Euterpe oleracea fruits have gained much attention because of their phenolic constituents that have shown potential beneficial effects for health. The aim of this work was to identify and quantify major non-anthocyanin flavonoids in fruit juice by an accurate UHPLC−LTQ−Orbitrap MS method. Fruits were processed to juice, lyophilized and defatted. The residue was then extracted with methanol by sonication and the extraction time optimized giving recovery rates > 90%. Solubilization of dried extract was realized using 40% MeOH which showed the best compromise for MS detection. For the UHPLC quantification, a HSS C18 column (1.8µm) was used with a gradient elution of methanol and water both with 0.1% formic acid. Total error and accuracy profiles were used as validation criteria. Seven compounds and their isomers were successfully separated, including the major non-anthocyanin flavonoids. Calibration in the matrix was found to be more accurate than calibration without matrix. Trueness (< 15% relative bias), repeatability and intermediate precision (<13% RSD), selectivity, response function, linearity, LOD (ranged from 0.04 to 0.81 µg/mL) and LOQ (0.15 - 5.78 µg/mL) for 12 compounds were evaluated and the quantification method validated. Its applicability was demonstrated on real samples from different suppliers. Their qualitative and quantitative profiles were similar and some compounds were for the first time quantified. In addition eriodictyol was identified for the first time in this fruit along with 5 other flavonoids for which we proposed a possible structure. [less ▲]

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See detailNON-ANTHOCYANIN POLYPHENOLS QUANTIFICATION IN EUTERPE OLERACEA FRUITS BY A UHPLC−LTQ-ORBITRAP MS METHOD
Dias, Aecio; Rozet, Eric ULg; Chataigné, G et al

Poster (2013, May)

High antioxidant and anti-inflammatory activities have been observed from non-anthocyanin polyphenols of E. oleracea fruits [1-2]. The aim of this work was to quantify major non-anthocyanin polyphenols by ... [more ▼]

High antioxidant and anti-inflammatory activities have been observed from non-anthocyanin polyphenols of E. oleracea fruits [1-2]. The aim of this work was to quantify major non-anthocyanin polyphenols by an accurate UHPLC−LTQ-Orbitrap MS method. Fruits were harvested in Pará state (Brazil), processed to pulp and lyophilised. 0.5g of dry pulp powder was defatted by sonication with petroleum ether. The residue was then extracted five times with 5mL MeOH each time for 30 min (optimized conditions giving recovery rates > 90%). The extract was evaporated to dryness with a RapidVap® evaporator at 35°C. Solubilization of the dried extract was realised using 40% MeOH. For the UHPLC quantification, a HSS C18 column (1.8µm) was used with a gradient elution of MeOH and H2O both with 0.1% HCOOH and the ionisation source (ESI) was operated in NI mode. 26 compounds were identified, among them 7 identified for the first time in this fruit. Total error and accuracy profiles were used as validation criteria. Calibration in the matrix was found to be more accurate than calibration without matrix. Trueness, repeatability, intermediate precision, selectivity, response function, linearity and LOD/LOQ for 12 non-anthocyanin phenolic compounds were evaluated and the quantification method validated. [1] J. Kang et al., Food Chem. 122 (2010) 610–617. [2] J. Kang et al., Food Chem. 128 (2011) 152–157. [less ▲]

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See detailFast microwave assisted extraction of rotenone for its quantification in seeds of yam bean (Pachyrhizus sp.)
Lautié, E.; Rasse, C.; Rozet, Eric ULg et al

in Journal of Separation Science (2013), 36

The aim of this study was to find if fast microwave assisted extraction could be an alternative to the conventional soxhlet extraction for the quantification of rotenone in yam bean seeds by solid phase ... [more ▼]

The aim of this study was to find if fast microwave assisted extraction could be an alternative to the conventional soxhlet extraction for the quantification of rotenone in yam bean seeds by solid phase extraction and HPLC-UV. For this purpose, an experimental design was used to determine the optimal conditions of the microwave extraction. Then the values of the quantification on three accessions from two different species of yam bean seeds were compared using the two different kinds of extraction. A microwave extraction of 11 min at 55°C using methanol/dichloromethane (50:50) allowed rotenone extraction either equivalently or more efficiently than the 8h soxhlet extraction method and was less sensitive to moisture content. The selectivity, precision, trueness, accuracy and limit of quantification of themethod with microwave extraction were also demonstrated. [less ▲]

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See detailQuantification of rotenone in seeds of different species of yam bean (Pachyrhizus sp.) by a SPE HPLC-UV method
Lautié, E.; Rozet, Eric ULg; Hubert, Philippe ULg et al

in Food Chemistry (2012), 131(4), 1531-1538

This study describes the development of a validated method for the quantification of rotenone in yam bean. The milled seeds were submitted to a Soxhlet dichloromethane extraction which allowed extracting ... [more ▼]

This study describes the development of a validated method for the quantification of rotenone in yam bean. The milled seeds were submitted to a Soxhlet dichloromethane extraction which allowed extracting 90% of the seeds rotenone. Elimination of the lipids was obtained via solid phase extraction. Rotenone was eluted with dichloromethane/methanol and the solution dried under vacuum and solubilised directly in methanol before injection in HPLC. The whole process was realised as much as possible protected from light and at temperatures lower than 40°C which allowed high recovery rates of spiked rotenone. Total error was used as criterion for the validation process and accuracy profiles drawn. The method allows the quantification of rotenone in yam bean seeds from 0.07% up to 1.25% (w/w). This method was applied to the quantification of rotenone in the seeds of several accessions of Pachyrhizus erosus and P. ahipa. The results range from 1.13 to 2.76 mg/g dry material. [less ▲]

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See detailA RAPID VALIDATED UHPLC-PDA METHOD FOR ANTHOCYANINS QUANTIFICATION FROM EUTERPE OLERACEA FRUITS
Dias, A.L.S.; Rozet, Eric ULg; Chataigne, G et al

Poster (2012)

Commercialization of Euterpe oleracea fruit has increased because of its abundance in anthocyanins [1]. Characterizations of these compounds are important for the food industry. The aim is to validate an ... [more ▼]

Commercialization of Euterpe oleracea fruit has increased because of its abundance in anthocyanins [1]. Characterizations of these compounds are important for the food industry. The aim is to validate an UHPLC-PDA method for major anthocyanins quantification in this fruit after fast extraction procedures and samples preparation. Fruits were harvested in Abaetetuba (Brazil) and extracted sequencially by EtOAc, MeOH and MeOH 50% all at 0.1% HCl. A HSS C18 column (1.8µm) was used with a gradient elution of ACN and 5% HCOOH. Total error and accuracy profiles were used as validation criteria. A first EtOAc extraction removes the lipophilic compounds and allows an easier extraction by MeOH and quantification of anthocyanins in this extract. It was found to be faster (17 min) that HPLC-UV methods [2]. Calibration in the matrix was found to be more accurate than calibration without matrix. Trueness (<6.76% relative bias), repeatability (<4.6% RSD), intermediate precision (<5.3% RSD), selectivity (by UHPLC-ESI+-HRMS), response function and linearity for cyanidin-3-glucoside and cyanidin-3-rutinoside were evaluated. The concentration range validated was 1 to 48 µg/mL for both compounds. [less ▲]

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See detailA rapid validated UHPLC–PDA method for anthocyanins quantification from Euterpe oleracea fruits
Dias, A.L.S.; Rozet, Eric ULg; Chataigné, G. et al

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2012), 907

The aim of this work is to develop the first validated UHPLC–PDA method for major anthocyanins quantification in Euterpe oleracea fruits after fast extraction procedures and samples preparation. The ... [more ▼]

The aim of this work is to develop the first validated UHPLC–PDA method for major anthocyanins quantification in Euterpe oleracea fruits after fast extraction procedures and samples preparation. The separation was performed on HSS C18 column (1.8 m) using a gradient elution with acetonitrile and 5% formic acid in a total run time of only 17 min. Total error and accuracy profiles were used as criteria for the validation process. Calibration in the matrix was found to be more accurate than calibration without matrix. Trueness (<6.76% relative bias), repeatability (<4.6% RSD), intermediate precision (<5.3% RSD), selectivity, response function and linearity for major anthocyanins, cyanidin-3-glucoside and cyanidin-3-rutinoside, were evaluated. The concentration range validated was 1–48 g/mL for both compounds. In addition two cyanidin-di-O-glycosides were detected for the fist time in this fruit. We also showed that a first extraction of the fruits with ethyl acetate removes the lipophilic compounds and allows an easier extraction by methanol and quantification of anthocyanins in this extract. [less ▲]

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See detailAPPLICATION OF DESIGN OF EXPERIMENTS AND DESIGN SPACE METHODOLOGY FOR THE HPLC-UV SEPARATION OPTIMIZATION OF APORPHINE ALKALOIDS FROM LEAVES OF Spirospermum penduliflorum THOUARS
Rafamantanana, Mamy; Debrus, Benjamin ULg; Raoelison, Guy et al

in Journal of Pharmaceutical & Biomedical Analysis (2012), 62

Spirospermum penduliflorum Thouars (Menispermaceae) is an endemic species of Madagascar traditionally used as vasorelaxant. Recently, two aporphine alkaloids known to possess antihypertensive activity ... [more ▼]

Spirospermum penduliflorum Thouars (Menispermaceae) is an endemic species of Madagascar traditionally used as vasorelaxant. Recently, two aporphine alkaloids known to possess antihypertensive activity (dicentrine and neolitsine) were isolated and identified from the leaves of this plant. In the present study, a HPLC-UV method allowing the separation of all alkaloids and the quantification of dicentrine in the alkaloidic extract of leaves was developed using design of experiments and design space methodology. Three common chromatographic parameters (i.e. the mobile phase pH, the initial proportion of methanol and the gradient slope) were selected to construct a full factorial design of 36 experimental conditions. The times at the beginning, the apex (i.e. the retention time) and the end of each peak were recorded and modelled by multiple linear equations. The corresponding residuals were normally distributed which confirmed that the models can be used for the prediction of the retention times and to optimize the separation. The optimal separation was predicted at pH 3, with a gradient starting at 32% of methanol and a gradient slope of 0.42%/min. Good agreement was obtained between predicted and experimental chromatograms. The method was also validated using total error concept. Using the accuracy profile approach, validation results gave a LOD and LOQ for dicentrine of 3 µg/ml and 10 µg/ml, respectively. A relative standard deviation for intermediate precision lower than 10% was obtained. This method was found to provide accurate results in the concentration range of 10 µg/ml to 75 µg/ml of dicentrine and is suitable for routine analysis. [less ▲]

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See detailA RAPID UHPLC-DAD-ESI-MSn METHOD FOR ANTHOCYANINS QUANTIFICATION FROM Euterpe oleracea FRUITS HARVESTED AT DIFFERENT TIMES
Dias, A.; Chataigné, G.; Rozet, Eric ULg et al

Poster (2011, June 09)

Euterpe oleracea is a palm tree widely distributed in northern South America. Its greatest occurrence and economic importance happens in the floodplains of the Amazonian delta. The fruits called açai are ... [more ▼]

Euterpe oleracea is a palm tree widely distributed in northern South America. Its greatest occurrence and economic importance happens in the floodplains of the Amazonian delta. The fruits called açai are an interesting source of different anthocyanins. Lately they have gained popularity in North America and in the European countries in the food industry and in the health sector due to their extremely high antioxidant capacity and potential anti-inflammatory activities [1]. Some studies have characterized chemically açaí pulps and have reported anthocyanin profiles which differ both qualitatively and quantitatively. Among other reasons, these differences may be associated with the stages of ripening of the fruits, since açai fruits are generally harvested in different maturation stages. The evaluation of the anthocyanin profile of açai fruits during different maturation stages is thus important for the post-harvest industry. In addition a rapid separation by UHPLC and an unambiguous identification by MSn are very useful for an effective quality control of the fruits. Thus, the aim of this study was to characterize the anthocyanin profiles of açai fruits at different stages of maturity. The fruits were harvested during the peak harvesting season, between July and October 2009, in the floodplains of the eastern Amazonian region (State of Pará, Brazil). A protocol of solid-liquid extraction of phenolic compounds was developed. Characterisation of the anthocyanins present in the fruits of Euterpe oleracea was conducted by UHPLC–DAD–ESI–MSn analysis, in positive ionization mode. All identified compounds was separated in 10 minutes of a total run time of 21 min instead of 55 min in the previously developed HPLC method. Six anthocyanins were identified in the extracts namely: cyaniding-3-glucoside, cyaniding-3-rutinoside, pelargonidin-3-glucoside, peonidin-3-glucoside, peonidin-3-rutinoside and cyanidin. The first two compounds were the major constituents in all maturity stages, with similar proportions, except for the first maturity stage for which the anthocyanins were under the limit of quantification. However, in the last maturity stage, cyanidin-3-glucoside became less abundant than cyanidin-3-rutinoside. On the other hand, cyanidin decreased with maturation. For the other compounds, proportions were similar along maturation. Hence, this work was important as it provides valid information on variation of anthocyanin profiles of açai fruits during maturation. This may contribute to the selection of an optimal maturity stage for harvesting as well as it will allow a rapid quality control of the fruits. [1]: Heinrich, M., et al., Açai (Euterpe oleracea Mart.)- A phytochemical and pharmacological assessment of the species’ health claims. Phytochem. Lett. (2010), doi: 10.1016/j.phytol.2010.11.005 [less ▲]

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See detailAn improved HPLC-UV method for the simultaneous quantification of triterpenic glycosides and aglycones in leaves of Centella asiatica (L.) Urb (APIACEAE).
Rafamantanana, M. H.; Rozet, Eric ULg; Raoelison, G. E. et al

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2009), 877(23), 2396-402

The simultaneous quantification of madecassoside, asiaticoside, madecassic acid and asiatic acid in Centella asiatica by HPLC-UV is proposed. Asiaticoside was used as reference for the quantification of ... [more ▼]

The simultaneous quantification of madecassoside, asiaticoside, madecassic acid and asiatic acid in Centella asiatica by HPLC-UV is proposed. Asiaticoside was used as reference for the quantification of heterosides and asiatic acid for aglycones. The evaluation of the extraction efficiency of the four molecules led to use Soxhlet extraction for 8 h. The method was validated and was found to be accurate in the concentration range of 1.0-3.0 mg/ml for asiaticoside and 0.5-2.0 mg/ml for asiatic acid with CV <3% for all investigated compounds. LOD and LOQ were, respectively, 0.0113 and 1.0 mg/ml for asiaticoside and 0.0023 and 0.5 mg/ml for asiatic acid. This method was shown to be convenient for routine analysis of samples of C. asiatica. [less ▲]

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See detailA validated method for the quantification of pimarane and trachylobane diterpenes in the leaves of Croton zambesicus by capillary gas chromatography
Block, S.; Brkic, D.; Hubert, Philippe ULg et al

in Phytochemical Analysis [=PCA] (2005), 16(5, SEP-OCT), 342-348

A sensitive and accurate method, combining Soxhlet extraction, solid-phase extraction and capillary gas chromatography, is described for the quantitative determination of four new diterpenes (ent ... [more ▼]

A sensitive and accurate method, combining Soxhlet extraction, solid-phase extraction and capillary gas chromatography, is described for the quantitative determination of four new diterpenes (ent-trachyloban-3 beta-ol, ent-18-hydroxy-trachyloban-3-one, ent-trachyloban-3-one and isopimara-7,15-dien-3 beta-ol) from the leaves of Croton zambesicus. This is the first method describing the quantification of trachylobane diterpenes in a crude extract. It has been fully validated in order to be able to compare the diterpene composition in other samples of C. zambesicus, which is an important source of trachylobanes. Copyright (c) 2005 John Wiley [less ▲]

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See detailDevelopment and validation of a high performance liquid chromatographic method for quantitative determination of aporphine alkaloids from different samples of Cassytha filiformis
Stevigny, C.; Wautier, M. C.; Jiwan, J. L. H. et al

in Planta Medica (2004), 70(8), 764-770

A sensitive and accurate procedure based on an alkaloid extraction coupled to an HPLC-UV-MS determination has been developed for the separation and quantification of the major aporphines in Cassytha ... [more ▼]

A sensitive and accurate procedure based on an alkaloid extraction coupled to an HPLC-UV-MS determination has been developed for the separation and quantification of the major aporphines in Cassytha filiformis. The extraction step and the liquid chromatography conditions were optimized in order to improve the selectivity of the method. The HPLC mobile phase consisted of a mixture of water containing 10 mM ammonium acetate adjusted to pH 3 with acetic acid-acetonitrile (90: 10, v/v) (A) and acetonitrile (B) used in a gradient mode (0 to 40%). The stationary phase was an RP-select B (5 mum) column. The method was completely validated using cassythine, one of the major aporphines in our samples, as reference standard and successfully applied to the determination of these pharmacologically interesting aporphines in seven different batches of C. filiformis. The detection and quantitation limits of cassythine were found to be 13 and 20 mug/mL, respectively. The results showed variations in the total alkaloid content in samples from 0.11 to 0.43%. [less ▲]

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See detailQuantification of aporphines in cassytha filiformis bu HPLC/UV : validation and application
Stevigny, C.; Wautier, M. C.; Chiap, Patrice ULg et al

Poster (2004)

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See detailCytotoxic aporphine alkaloids from Cassytha filiformis.
Stevigny, C.; Block, S.; De Pauw, Marie-Claire ULg et al

in Planta Medica (2002), 68(11), 1042-4

Purification of a cytotoxic crude alkaloid extract of Cassytha filiformis led to the isolation of four known aporphine alkaloids: neolitsine, dicentrine, cassythine (= cassyfiline) and actinodaphnine ... [more ▼]

Purification of a cytotoxic crude alkaloid extract of Cassytha filiformis led to the isolation of four known aporphine alkaloids: neolitsine, dicentrine, cassythine (= cassyfiline) and actinodaphnine. Their structures were determined by analysis of spectroscopic data. All isolated alkaloids were tested for their cytotoxic activities on cancer and non-cancer cell lines in vitro. Neolitsine was the most active against HeLa and 3T3 cells (IC 50 :21.6 microM, and 21.4 microM, respectively). Cassythine and actinodaphnine showed the highest activity against Mel-5 (IC 50 : 24.3 microM and 25.7 microM, respectively) and HL-60 (IC 50 : 19.9 microM and 15.4 microM, respectively). This is the first report on the cytotoxic activity of C. filiformis extract and of neolitsine and cassythine. Furthermore, the complete NMR data of cassythine and actinodaphnine are given here for the first time. [less ▲]

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See detailStimulation of topoisomerase II-mediated DNA cleavage by three DNA-intercalating plant alkaloids: cryptolepine, matadine, and serpentine.
Dassonneville, L.; Bonjean, K.; De Pauw, Marie-Claire ULg et al

in Biochemistry (1999), 38(24), 7719-26

Cryptolepine, matadine, and serpentine are three indoloquinoline alkaloids isolated from the roots of African plants: Cryptolepis sanguinolenta, Strychnos gossweileri, and Rauwolfia serpentina ... [more ▼]

Cryptolepine, matadine, and serpentine are three indoloquinoline alkaloids isolated from the roots of African plants: Cryptolepis sanguinolenta, Strychnos gossweileri, and Rauwolfia serpentina, respectively. For a long time, these alkaloids have been used in African folk medicine in the form of plant extracts for the treatment of multiple diseases, in particular as antimalarial drugs. To date, the molecular basis for their diverse biological effects remains poorly understood. To elucidate their mechanism of action, we studied their interaction with DNA and their effects on topoisomerase II. The strength and mode of binding to DNA of the three alkaloids were investigated by spectroscopy. The alkaloids bind tightly to DNA and behave as typical intercalating agents. All three compounds stabilize the topoisomerase II-DNA covalent complex and stimulate the cutting of DNA by topoisomerase II. The poisoning effect is more pronounced with cryptolepine than with matadine and serpentine, but none of the drugs exhibit a preference for cutting at a specific base. Cryptolepine which binds 10-fold more tightly to DNA than the two related alkaloids proves to be much more cytotoxic toward B16 melanoma cells than matadine and serpentine. The cellular consequences of the inhibition of topoisomerase II by cryptolepine were investigated using the HL60 leukemia cell line. The flow cytometry analysis shows that the drug alters the cell cycle distribution, but no sign of drug-induced apoptosis was detected when evaluating the internucleosomal fragmentation of DNA in cells. Cryptolepine-treated cells probably die via necrosis rather than via apoptosis. The results provide evidence that DNA and topoisomerase II are the primary targets of cryptolepine, matadine, and serpentine. [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 detailCharacterization of non pigmented B16 melanoma cell-derived cytotoxic factors.
Siwek, B.; De Pauw, Marie-Claire ULg; Quetin-Leclercq, J. et al

in Chemico-Biological Interactions (1997), 103(1), 59-73

We analyzed and tried to characterize substance(s) responsible for cytotoxic activities detected in culture media conditioned by non pigmented B16 melanoma cells (NPB16). The different cytological tests ... [more ▼]

We analyzed and tried to characterize substance(s) responsible for cytotoxic activities detected in culture media conditioned by non pigmented B16 melanoma cells (NPB16). The different cytological tests used showed that ultrafiltrated conditioned media (CM U1 fraction) contained several cytotoxic factors with a Mw lower than 1000 Da. These factors seemed to act either directly or indirectly on cell membranes, mitochondria, on the cell cycle and on protein and DNA synthesis. A cytotoxic activity could be found even after high dilution of CM U1. These cytotoxic factors were rapidly released by B16 cells in culture, independently of cell confluence. Their activities in the treated cells were also very fast and the cytotoxic effects were irreversible after only a few hours of treatment. These factors were not intermediate products during melanogenesis, neither polyamines, nor proteases. At least one of them seemed to be a small acidic and basic stable peptide without disulfide bounds but not heat stable. The synthesis of at least one of these cytotoxic factors was inhibited by cycloheximide and the cytotoxic activity was partially destroyed by pronase and trypsin, but not by pepsin. The cytotoxicity was not modified by copper complexants or free radical inhibitors (bovine serum albumin (BSA), tyrosine, superoxyde dismutase (SOD), catalase, vitamin E). Furthermore the levels of glutathione peroxydase activity and reduced glutathione did not change after treatment by CM U1 as compared to controls. [less ▲]

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See detailIn Vitro Cytotoxic Activity of Two Potential Anticancer Drugs Isolated from Strychnos: Strychnopentamine and Usambarensine
Bonjean, K. A.; Gillet, Marie-Claire ULg; Quetin-Leclercq, J. et al

in Anticancer Research (1996), 16(3A, May-Jun), 1129-37

The cytotoxicity and the selective antiprotozoal activity of some Strychnos alkaloids, namely strychnopentamine (SP) and usambarensine (US) (7) led us to analyze and compare their effects with emetine (EM ... [more ▼]

The cytotoxicity and the selective antiprotozoal activity of some Strychnos alkaloids, namely strychnopentamine (SP) and usambarensine (US) (7) led us to analyze and compare their effects with emetine (EM) by using mouse B16 melanoma cells cultivated in vitro. We observed by cytological analysis and proliferation rate studies that these substances induce analogous cytotoxic effects in B16 cells, but at different concentrations i.e. formation of lamellar bodies in the cytoplasm, the which contain pre-melanosomes in the case of SP and US, vacuoles and blebs. At concentrations near their respective IC50, SP and US, but not EM, decreased colony formation. We showed by incorporation of labelled precursors that SP and US first inhibit RNA synthesis while EM initially acts on protein synthesis. These alkaloids increased melanin synthesis. Furthermore, only EM and SP caused hemolysis of sheep red blood corpuscles. This could explain why the rate of antiplasmodial activity is higher for SP and EM. [less ▲]

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See detailAntimalarial Activity of Cryptolepine and some otrher Anhydronium Bases
Wright, C. W.; Phillipson, J. D.; Awe, S. O. et al

in Phytotherapy Research (1996), 10

Eight naturally occurring anhydronium bases and the synthetic quaternary compound Nb-methylharmalane were tested against Plasmodium falciparun (strain K1) in vitro. Cryptolepine was found to have similar ... [more ▼]

Eight naturally occurring anhydronium bases and the synthetic quaternary compound Nb-methylharmalane were tested against Plasmodium falciparun (strain K1) in vitro. Cryptolepine was found to have similar activity to that of chloroquine but alstonine, 5,6-dihydroflavopereirine, matadine, Nb-methylharmalane, melinonine F, normelinonine F, strychnoxanthine and serpentine were found to have little activity. Cryptolepine, given orally to mice infected with Plasmodium berghei berghei was found to have moderate antimalarial activity; parasitemia was suppressed by 80% at 50 mg/kg/day. [less ▲]

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