References of "Tits, Monique"
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See detailApoptosis induction in human cancer cells by sungucine from Strychnos icaja root
Frederich, Michel ULg; Bentires-Ali, M.; Tits, Monique ULg et al

in Naunyn-Schmiedeberg's Archives of Pharmacology (2003), 367(3), 260-265

Sungucine (SG) and isosungucine (ISG) are bisindole alkaloids characterized by a 5'-23 link between the two parts of the compounds, which are till now specific to Strychnos icaja. In this work, SG and ISG ... [more ▼]

Sungucine (SG) and isosungucine (ISG) are bisindole alkaloids characterized by a 5'-23 link between the two parts of the compounds, which are till now specific to Strychnos icaja. In this work, SG and ISG were submitted to the NCI's in vitro 60 human tumor cell line screen, where SG showed interesting selectivity (6X) against the tested leukemia cell lines. In HL60-treated cells, apoptosis was demonstrated by observation of apoptotic bodies formation, and phosphatidylserine exposition at cell surface. In HeLa-treated cells, the analysis of cellular cycle by flow cytometry showed G1 accumulation and a small sub-G1 peak that could be related to DNA fragmentation characteristic of apoptosis. The eventual role of p53 was analyzed using wild-type HCT-116 colon cancer cells. Nevertheless, p53 and Bax expression were not modified in SG-treated cells. The cleavage of PARP by caspase-3 protease proved that apoptosis was also induced in this line. These results demonstrate that SG induces apoptosis, but also necrosis, in human cancer cell lines. [less ▲]

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See detailIndole alkaloids from Strychnos species and their antiplasmodial and cytotoxic activities
Frederich, Michel ULg; Tits, Monique ULg; Angenot, Luc ULg

in Chemistry of Natural Compounds (2003), 39(6, NOV-DEC), 513-519

Strychnos species (Loganiaceae) have been studied in the laboratory of Pharmacognosy of the University of Liege for more than fifty years. Although investigations into the Strychnos genus have been going ... [more ▼]

Strychnos species (Loganiaceae) have been studied in the laboratory of Pharmacognosy of the University of Liege for more than fifty years. Although investigations into the Strychnos genus have been going on for a long time in the case of Asian tetanizing and American curarizing species, the first chemical and pharmacological screening on African species was undertaken in the early nineteen fifties by the late Prof A. Denoel (University of Liege, Belgium), who examined twenty-five species of Strychnos collected in the Belgian Congo [1]. This research programme was also an offshoot of an inventory of medicinal and toxic plants in Rwanda, carried out during the years 1969-1970. The Belgian scientists were lucky to observe the tribe of Banyambo, living along the Akagera river on the border between Rwanda and Tanzania, where hunters prepared in front of them an arrow poison with Strychnos usambarensis roots and leaves as the main ingredients [2]. Strychnos species have several ethnobotanical uses. A few species are well known for their incorporation into arrow and ordeal poisons, but play more a role in ethnomedicine against fever, rheumatism, worms, ulcers, leprosy, snake-bites, and so forth [3]. In fact, among about one hundred and ninety species, only six would contain strychnine (1) (Strychnos nux-vomica L. [4-7], S. ignatii P. Bergius [8, 9], and S. wallichiana Steud ex DC. [7, 10] from Asia, S. lucida R. Br. [7, 11] from Australia, S. icaja Baillon [1, 12] from Africa, and S. panamensis [13-15] from South America). Strychnos alkaloids are in fact an example of molecular and pharmacological biodiversity. More than 300 different Strychnos alkaloids have been isolated to date and theypresent various biological activities in several fields: parasitology (amoebiasis, paludism, etc.) [ 16-18], cancer [ 19-22], neurology (tetanizing or curarizing effects) [14, 23, 24-26], inflammation [27], and so on. [less ▲]

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See detailAnti-inflammatory effect of natural proanthocyanidins: pharmacological evaluation on in vivo models.
Garbacki, Nancy ULg; Tits, Monique ULg; Damas, Jacques ULg

in Pflügers Archiv : European Journal of Physiology (2003), 446

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See detailEffects of prodelphinidins isolated from Ribes nigrum leaves on chondrocyte metabolism and COX activity
Angenot, Luc ULg; Garbacki, Nancy ULg; Damas, Jacques et al

Poster (2002, October 29)

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See detailAntiplasmodial activity of alkaloids from various Strychnos species
Frederich, Michel ULg; Jacquier, M. J.; Thepenier, P. et al

in Journal of Natural Products (2002), 65(10), 1381-1386

The in vitro antiplasmodial activities of 69 alkaloids from various Strychnos species were evaluated against chloroquine-resistant and chloroquine-sensitive lines of Plasmodium falciparum. The compounds ... [more ▼]

The in vitro antiplasmodial activities of 69 alkaloids from various Strychnos species were evaluated against chloroquine-resistant and chloroquine-sensitive lines of Plasmodium falciparum. The compounds, comprising mainly indolomonoterpenoid alkaloids, exhibited a wide range of biological potencies in the antiplasmodial assays. The most active alkaloids were also tested for cytotoxicity against HCT-116 colon cancer cells to determine their antiplasmodial selectivity. As a result of these studies, structure-activity relationships for these alkaloids have begun to emerge. Alkaloids presenting four types of bisindole skeleton exhibited potent and selective activities against Plasmodium. They were sungucine-type (IC(50) values ranging from 80 nM to 10 microM), longicaudatine-type (IC(50) values ranging from 0.5 to 10 microM), matopensine-type (IC(50) values ranging from 150 nM to 10 microM), and usambarine-type alkaloids. Within the last structural type, isostrychnopentamine (49) and ochrolifuanine A (46) were found to be active against chloroquine-sensitive and -resistant strains (IC(50) values of 100-150 and 100-500 nM, respectively), and dihydrousambarensine (51) exhibited a 30-fold higher activity against the chloroquine-resistant strain (IC(50) = 32 nM) than against the chloroquine-sensitive one. [less ▲]

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See detailApoptosis of HL-60 leukemia cells induced by the bisindole alkaloids sungucine and isosungucine from Strychnos icaja
Lansiaux, A.; Bailly, Christian; Houssier, Claude ULg et al

in Planta Medica (2002), 68(7), 591-595

Sungucine and isosungucine are two bisindole alkaloids isolated from the roots of the African plant Strychnos icaja Baillon. They both exhibit antiplasmodial activities but also show cytotoxic effects ... [more ▼]

Sungucine and isosungucine are two bisindole alkaloids isolated from the roots of the African plant Strychnos icaja Baillon. They both exhibit antiplasmodial activities but also show cytotoxic effects against human cancer cell lines. In order to elucidate their mechanism of action, we have investigated the interaction of the alkaloids with DNA and their capacity to inhibit nucleic acids and protein synthesis in the human HL-60 promyelocytic leukemia cell line. Cell treatment with both sungucine and isosungucine leads to the appearance of a hypo-diploid DNA content peak. Western blotting analysis reveals that the two alkaloids induce cleavage of the poly(ADP-ribose) polymerase (PARP) and promote the cleavage of a caspase-3 DEVD peptide substrate. The activation of the caspase cascade is accompanied with a fragmentation of DNA in cells, as revealed by the TUNEL assay. Altogether, the results shed light on the mechanism of action of these two plant alkaloids and identify signaling factors involved in (iso)sungucine-induced apoptosis in HL-60 cells. [less ▲]

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See detailEffects of prodelphinidins isolated from Ribes nigrum on chondrocyte metabolism and COX activity
Garbacki, Nancy ULg; Angenot, Luc ULg; Bassleer, C. et al

in Naunyn-Schmiedeberg's Archives of Pharmacology (2002), 365(6), 434-441

Articular diseases. such as osteoarthritis, is the clinical expression of the loss of cartilage function. COX inhibitors are widely used in the treatment of such pathologies for their beneficial effects ... [more ▼]

Articular diseases. such as osteoarthritis, is the clinical expression of the loss of cartilage function. COX inhibitors are widely used in the treatment of such pathologies for their beneficial effects on inflammation but often produce a negative activity on cartilage synthesis. In this study, we determined the effect of different prodelphinidins, the major compounds isolated from Ribes nigrum leaves, on the proteoglycans (PGs), type II collagen (coll. II) and prostaglandin E-2 (PGE(2)) production by differentiated human chondrocytes cultivated in long term (12 days) and in clusters as well as their inhibition potential on COX-1 and COX-2 in vitro. Gallocatechin trimer (GC-GC-GC) showed the higher stimulation of PGs and coll. II production (1 mug ml(-1)) and the synthesis of PGE(2) was significantly reduced by gallocatechin dimer (GC-GC), gallocatechin-epigallocatechin (GC-EGC) and GC-GC-GC at 10 and 100 mug ml(-1). The inhibition of PGE(2) synthesis was confirmed by the in vitro test on purified COX enzymes, showing the selectivity of prodelphinidins on COX-2. However, the prodelphinidins had no effects on COX activity in the whole blood assay. Our studies suggest that the prodelphinidins fractions from R. nigrum may be useful as an additive agent in the prevention of osteoarthritis. [less ▲]

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See detailIn vitro antiplasmodial activity of Tithonia diversifolia and identification of its main active constituent: tagitinin C.
Goffin, Eric ULg; Ziemons, Eric ULg; De Mol, Patrick ULg et al

in Planta Medica (2002), 68(6), 543-5

The antimalarial properties of Tithonia diversifolia, an Asteraceae traditionally used to treat malaria, were investigated in vitro against three strains of Plasmodium falciparum. The ether extract from ... [more ▼]

The antimalarial properties of Tithonia diversifolia, an Asteraceae traditionally used to treat malaria, were investigated in vitro against three strains of Plasmodium falciparum. The ether extract from aerial parts of the plant collected in Sao Tome e Principe, demonstrated good antiplasmodial activity (IC 50 on FCA strain: 0.75 microg/ml). A bioassay guided fractionation of this extract led to the isolation of the known sesquiterpene lactone tagitinin C as an active component against Plasmodium (IC 50 on FCA strain: 0.33 microg/ml), but also possessing cytotoxic properties (IC 50 on HTC-116 cells: 0.706 microg/ml). [less ▲]

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See detailStrychnohexamine from Strychnos icaja, a naturally occurring trimeric indolomonoterpenic alkaloid
Philippe, Geneviève ULg; Prost, E.; Nuzillard, J. M. et al

in Tetrahedron Letters (2002), 43(18), 3387-3390

A reinvestigation of Strychnos icaja roots has resulted in the isolation, from the EtOAC extract, of one tertiary trisindole alkaloid, named strychnohexamine. Its structure has been investigated by means ... [more ▼]

A reinvestigation of Strychnos icaja roots has resulted in the isolation, from the EtOAC extract, of one tertiary trisindole alkaloid, named strychnohexamine. Its structure has been investigated by means of spectroscopic data interpretation (UV. IR. HRESIMS. 1D and 2D NMR). This is the first time that a natural trimeric indolomonoterpenic alkaloid has been isolated directly from a plant species. This compound is one of the largest alkaloids ever discovered. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailIsolation and pharmacological activity of phenylpropanoid esters from Marrubium vulgare
Sahpaz, S.; Garbacki, Nancy ULg; Tits, Monique ULg et al

in Journal of Ethnopharmacology (2002), 79(3), 389-392

The isolation and identification of major phenylpropanoid esters from Marrubium vulgare: (+) (E)-caffeoyl-L-malic acid 1, acteoside 2, forsythoside B 3, arenarioside 4, ballotetroside 5, as well as their ... [more ▼]

The isolation and identification of major phenylpropanoid esters from Marrubium vulgare: (+) (E)-caffeoyl-L-malic acid 1, acteoside 2, forsythoside B 3, arenarioside 4, ballotetroside 5, as well as their anti-inflammatory activity are reported for the first time, We evaluated the inhibitory effects of these five compounds on cyclooxygenase (Cox) catalysed prostaglandin biosynthesis activity. Only the glycosidic phenylpropanoid esters showed an inhibitory activity towards the Cox-2 enzyme and three of them: acteoside 2, forsythoside B 3, arenarioside 4, exhibited higher inhibitory potencies on Cox-2 than on Cox-1. These results are of interest, as Cox-2 is mainly associated with inflammation and the Cox-1 inhibition with adverse side effects often observed with non-steroidal anti-inflammatory drugs. The occurence of these phenylpropanoid esters could also explain some other pharmacological properties of M. vulgare. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. [less ▲]

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See detailNew 3-deoxyanthocyanidins from leaves of Arrabidaea chica
Devia, B.; Llabres, Gabriel ULg; Wouters, J. et al

in Phytochemical Analysis [=PCA] (2002), 13(2, Mar-Apr), 114-120

Two new 3-deoxyanthocyanidins, 6,7,3',4'-tetrahydroxy-5-methoxyflavylium and 6,7,4'-trihydroxy-5-methoxyflavylium, and the pigment carajurin, which has been previously identified, were isolated from dried ... [more ▼]

Two new 3-deoxyanthocyanidins, 6,7,3',4'-tetrahydroxy-5-methoxyflavylium and 6,7,4'-trihydroxy-5-methoxyflavylium, and the pigment carajurin, which has been previously identified, were isolated from dried leaves of Arrabidaea chica, a creeper native to the American tropics. The structures of the components were elucidated by H-1- and C-13-NMR spectroscopy and HPLC-MS, including X-ray crystallographic analysis for carajurin. Copyright (C) 2002 John Wiley Sons, Ltd. [less ▲]

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See detail5',6'-Dehydroguiachrysine and 5',6'-Dehydroguiaflavine, Two Curarizing Quaternary Indole Alkaloids from the Stem Bark of Strychnos Guianensis
Penelle, J.; Christen, P.; Molgo, J. et al

in Phytochemistry (2001), 58(4), 619-26

Two new quaternary indole alkaloids 5',6'-dehydroguiachrysine (1) and 5',6'-dehydroguiaflavine (2) were isolated from Strychnos guianensis stem bark. Their structures were determined by analysis of ... [more ▼]

Two new quaternary indole alkaloids 5',6'-dehydroguiachrysine (1) and 5',6'-dehydroguiaflavine (2) were isolated from Strychnos guianensis stem bark. Their structures were determined by analysis of spectral data. Their inhibitory effects on neuromuscular transmission are also reported and compared to that of other quaternary alkaloids. [less ▲]

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See detailReversal of Chloroquine and Mefloquine Resistance in Plasmodium Falciparum by the Two Monoindole Alkaloids, Icajine and Isoretuline
Frederich, Michel ULg; Hayette, Marie-Pierre ULg; Tits, Monique ULg et al

in Planta Medica (2001), 67(6), 523-7

Eight naturally occurring monoindole alkaloids were evaluated in vitro for their ability to inhibit Plasmodium falciparum growth and, in drug combination, to reverse the resistance of a chloroquine ... [more ▼]

Eight naturally occurring monoindole alkaloids were evaluated in vitro for their ability to inhibit Plasmodium falciparum growth and, in drug combination, to reverse the resistance of a chloroquine-resistant strain of Plasmodium falciparum. None of these indole alkaloids has significant intrinsic antiplasmodial activity (IC(50) > 10 microM or 5 microg/ml). Nevertheless, three alkaloids (icajine, isoretuline and strychnobrasiline) did reverse chloroquine resistance at concentrations between 2.5 and 25 microg/ml (IF of 12.82 for isoretuline on W2 strain). The Interaction Factor (IF) equals 2, < 2, or > 2 for additive, antagonistic or synergistic effects of alkaloids on chloroquine inhibition, respectively. Icajine and isoretuline were also assessed in vitro for their mefloquine potentiating activity on a mefloquine-resistant strain of Plasmodium falciparum. Only icajine proved to be synergistic with mefloquine (IF = 15.38). [less ▲]

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