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F Tillequin

Publications and source records attributed to F Tillequin.

At least 19 recordsLinked to original sources
PubMed2002

Chalconoid and stilbenoid glycosides from Guibourtia tessmanii.

Phytochemical studies on the stem bark of Guibourtia tessmanii yielded a dihydrochalcone glucoside, 2',4-dihydroxy-4'-methoxy-6'-O-beta-glucopyranoside dihydrochalcone and a new stilbene glycoside, 3,5-dimethoxy-4'-O-(beta-rhamnopyranosyl-(1-->6)-beta- glucopyranoside) stilbene besides the known pterostilbene. Their structures were established on the basis of one and two dimensional NMR spectroscopic techniques, FABMS and chemical evidence.

Chalcone↗
PubMed2002

Design of selectively activated anticancer prodrugs: elimination and cyclization strategies.

Cancer chemotherapy is associated with severe side effects which may be reduced by selective liberation, at the tumour site, of a cytotoxic agent from a non-toxic prodrug. Several strategies are used to achieve the required selective activation: with enzymes which are present in higher concentration in, or close, to the tumour (beta-glucuronidase, plasmin), with enzymes covalently linked to a macromolecular carrier able to recognize antigen positive cancer cells (ADEPT: Antibody Directed Enzyme Prodrug Therapy) or with reductive processes which are favoured in an hypoxic environment. Most of the prodrugs include a linker (or spacer) between the trigger and the drug (or effector). The design of such linkers is crucial in order to achieve a fast drug liberation under physiological conditions. The linker groups may be classified in two categories based on elimination or cyclization processes. The advantages and the limitations of each strategy are discussed.

Animals↗
PubMed2002

[New antitumor agents in the acronycine series].

The acridone alkaloid acronycine, isolated from several Sarcomelicope species (Rutaceae) was shown to exhibit a promising activity against a broad spectrum of solid tumors. Nevertheless, clinical trials only gave poor results, probably due to the moderate potency of this drug. The isolation of the unstable acronycine epoxide from several New-Caledonian Sarcomelicope led us to a hypothesis of bioactivation of acronycine by transformation of the 1,2-double bond into the corresponding oxirane in vivo. Consequently, we synthesized a series of cis-1,2-dihydroxy-1,2-dihydroacronycine diesters which exhibited interesting antitumor properties with a broadened spectrum of activity and an increased potency when compared with acronycine. The demonstration that acronycine should interact with DNA, by some noncovalent process prompted us to develop benzo[b] acronycine analogs possessing an additional aromatic ring linearly fused on the natural alkaloid basic skeleton. When tested against a panel of cancer cell lines in vitro, cis-1,2-dihydroxy-1,2-dihydrobenzo[b] acronycine diesters exhibited cytotoxic activities within the same range of potency as the most active drugs currently used in cancer chemotherapy. In vivo, cis-1,2-diacetoxy-1,2-dihydrobenzo[b] acronycine (S 23906-1), selected for further preclinical development, demonstrated a marked antitumor activity in human orthotopic models of lung, ovarian and colon cancers xenografted in nude mice.

Acronine↗
PubMed2001

Furomegistines I and II, two furanopyridine alkaloids from the bark of Sarcomelicope megistophylla.

Two alkaloids, furomegistine I (1) and furomegistine II (2), were isolated from the bark of Sarcomelicope megistophylla. Their structures have been elucidated on the basis of MS and NMR data. Both belong to the category of furanopyridine alkaloids and should be considered as oxidation products of a furo[2,3-b]quinoline precursor. The two alkaloids exhibited moderate cytotoxic activity.

Alkaloids↗
PubMed2001

Selective amination of secoiridoid glycosides to give monomeric pyridine, dimeric pyridine, and naphthyridine alkaloids.

Treatment of the secoiridoids oleuropein (4), ligstroside (5) and methyloleoside (6) by beta-D-glucosidase in the presence of ammonium chloride led exclusively to monomeric pyridine alkaloids 7, 1, and 8. Dimeric 3,4,5-trisubstituted pyridines were obtained from methyloleoside (6) when ammonium chloride was generated in the reaction mixture by successive additions of ammonia and hydrochloric acid. The use of ammonium acetate permitted conversion of secoiridoids 4 and 5 into the naphthyridine alkaloid jasminine (3).

Alkaloids↗
PubMed2001

Homarine, a common metabolite in edible Mediterranean molluscs: occurrence, spectral data and revision of a related structure.

Homarine was isolated from nine edible species of marine molluscs belonging to classes Gastropoda, Bivalvia, and Cephalopoda. A thorough chromatographic, NMR and MS study provided evidence that homarine is a common and abundant metabolite of all these species. This study casts doubt on a previous assertion that 1,1'-dimethyl-[2,2']-bipyridinium is a metabolite of the Bivalve Callista chione.

Animals↗
PubMed2001

Induction of cyclin E and inhibition of DNA synthesis by the novel acronycine derivative S23906-1 precede the irreversible arrest of tumor cells in S phase leading to apoptosis.

S23906-1 is a diester derivative of 1,2-dihydrobenzo[b]acronycine with an unknown mechanism of action. This cytotoxic compound was 20-fold more potent than acronycine in inhibiting the proliferation of six tumor cell lines. Using a clonogenic assay of cell survival, the HT29 human colon carcinoma cell line was 100-fold more sensitive to S23906-1 than acronycine. Cell cycle analysis, by flow cytometry, showed that S23906-1 induced a partially reversible arrest of HT29 cells in G2+M at 1 microM and below and an irreversible arrest in S phase at 2.5 microM and above. These cell cycle effects were followed by cell death through apoptosis, quantified by annexin-V labeling. Inhibition of DNA synthesis was observed by complete prevention of bromodeoxyuridine (BrdU) incorporation after only 4 h of incubation with 5 microM S23906-1. Interestingly, under the same experimental conditions, a significant increase of cyclin E protein level was observed without any modification of cyclins D1, D2, D3, or A. This overexpressed cyclin E protein was not complexed with Cdk2, as shown by western blotting for Cdk2 in immunoprecipitates of cyclin E. Similar inhibition of BrdU incorporation and elevation of cyclin E protein were observed after treatment with cytosine arabinoside, which reversibly inhibited progression into S phase, but not after DNA damage induced by cisplatin. S23906-1 thus has a novel mechanism of action. A cell line resistant to S23906-1 showed that overexpression of cyclin E was implicated in the novel cytotoxic activity of this compound.

Acronine↗
PubMed2001

Synthesis and cytotoxic activity of benzophenanthrolinone analogues of acronycine.

Condensation of either 2-bromobenzoic acid (4) or 2-chloro-3-nitrobenzoic acid (5) with suitable aminoquinolines 6-8 afforded phenylquinolylamines 9-13. Acid mediated cyclization gave the corresponding 12H-benzo[b][1,7]phenanthrolin-7-ones 14 and 15, and 12H-benzo[b][1,10]phenanthrolin-7-ones 16-18. Compounds 14, 16, and 17 were subsequently N-methylated to 6-demethoxyacronycine and acronycine analogues 19-21, whereas reduction of the aromatic nitro group of 18 gave the amino derivative 22. Unsubstituted 12H-benzo[b][1,10]phenanthrolin-7-ones 16, 17, 20, and 21 were devoid of significant cytotoxic activity, whereas 18 and 22, bearing a nitrogen substituent at position 11, were significantly active. Unsubstituted 12H-benzo[b][1,7]phenanthrolin-7-ones 14 and 19, which include a pyridine nitrogen in the same 4-position as the pyran oxygen of acronycine exhibited cytotoxic activities within the same range of magnitude as acronycine itself.

Acronine↗
PubMed2001

1-Oxo-2-hydroxy-1,2-dihydroacronycine: a useful synthon in the acronycine series for the introduction of amino substituents at 6-position and for the conversion into isopropylfuroacridones.

Thermic aromatic nucleophilic displacement of the methoxy group at C-6 of (+/-)-1-oxo-2-hydroxy-1,2-dihydroacronycine (2) by an amine is a reaction that gives a facile entry to acronycine derivatives bearing an amino substituent at this position. The introduction of the amino substituents was confirmed with a long-range 1H-15N correlation NMR spectrum at natural abundance. Under basic conditions, compound 2 can also be rearranged to the corresponding isopropylfuroacridone 12, in 80% yield.

Acronine↗
PubMed2001

Synthesis and cytotoxic activity of benzopyranoxanthone analogues of benz.

Condensation of 3-hydroxy-2-naphthalenecarboxylic acid with phloroglucinol afforded 1,3-dihydroxy-12H-benzo[b]xanthen-12-one. Construction of an additional dimethylpyran ring onto this skeleton, by alkylation with 3-chloro-3-methyl-1-butyne followed by Claisen rearrangement, gave access to a series of benzo[b]pyrano[2,3-i]xanthen-6-ones and benzo[b]pyrano[3,2-h]xanthen-7-ones related to psorospermine and benzo[b]acronycine. In contrast with what is observed in the pyridoacridone and benzopyridoacridone series, the linear benzo[b]-pyrano[2,3-i]xanthen-6-one derivatives were more potent than their angular benzo[b]pyrano[3,2-h]xanthen-7-one isomers. cis-3,4-Diacetoxy-5-methoxy-2,2-dimethyl-3,4-dihydro-2H,6H-benzo[b]pyrano[2,3-i]xanthen-6-one, the most active among the new compounds, was more potent than acronycine in inhibiting the proliferation of L1210 murine leukemia cells.

Animals↗
PubMed2001

Marked antitumor activity of a new potent acronycine derivative in orthotopic models of human solid tumors.

S 23906-1 is a novel acronycine derivative selected on the basis of its potency in vitro. We investigated the antitumor activity of S 23906-1 against several murine transplantable tumors (C38 colon carcinoma, P388 leukemia, B16 melanoma, and Lewis lung carcinoma) and in orthotopic models of human lung (NCI-H460 and A549), ovarian (IGROV1 and NIH:OVCAR-3), and colorectal cancers (HCT116 and HT-29). Against established C38 colon carcinoma, S 23906-1 administered twice i.v. from 1.56-6.25 mg/kg markedly inhibited tumor growth. Treatment at the optimal dose (6.25 mg/kg) induced tumor regression in all of the mice. Acronycine was 16-fold less potent and only moderately active at the maximum tolerated dose, 100 mg/kg. Against other murine tumors of the former National Cancer Institute panel, S 23906-1 was either only moderately active or totally inactive. When evaluated in human orthotopic models, S 23906-1 given p.o. or i.v. demonstrated a marked antitumor activity against human carcinomas. In the two human lung cancer models, S 23906-1 increased the survival of the animals in a dose-dependent manner and induced treated versus control values of 162% (NCI-H460) and 193% (A549). Vinorelbine was less active, with treated versus control values of 119% and 174%, respectively. A significant survival benefit was also observed against the two i.p. ovarian tumors in which S 23906-1 was as active as paclitaxel, inducing 80% long-term survivors in the NIH:OVCAR-3 model. Lastly, S 23906-1 inhibited the growth of primary HT-29 and HCT116 colon tumors grafted onto the cecum as efficiently as irinotecan and eradicated the formation of lymph node, hepatic, and pulmonary metastases in the aggressive HCT116 model. The novel spectrum of activity of S 23906-1 compared with existing anticancer agents warrants further preclinical investigation.

Acronine↗
PubMed2000

Two major flavonoids from Ballota nigra.

Two lactoylate flavonoids, luteolin-7-lactate and luteolin-7-glucosyl-lactate were isolated from Ballota nigra. They should be used for the chemical standardization of this drug of medicinal interest.

Journal Article↗
PubMed2000

Synthesis and cytotoxic and antitumor activity of benzo[b]pyrano[3, 2-h]acridin-7-one analogues of acronycine.

Benzo¿băcronycine (6-methoxy-3,3,14-trimethyl-3, 14-dihydro-7H-benzo¿bpyrano¿3,2-hăcridin-7-one, 4), an acronycine analogue with an additional aromatic ring linearly fused on the natural alkaloid basic skeleton, was synthesized in three steps, starting from 3-amino-2-naphthalenecarboxylic acid (5). Eight 1, 2-dihydroxy-1,2-dihydrobenzo¿băcronycine esters and diesters (17-24) were obtained by catalytic osmic oxidation, followed by acylation. All these compounds were significantly more cytotoxic than acronycine, when tested against L1210 leukemia cells in vitro. The potency of the cyclic carbonate 24 was in the range of the most active drugs currently used in cancer chemotherapy. Two selected diesters (17 and 24) were evaluated in vivo against P388 leukemia and colon 38 adenocarcinoma implanted in mice. Both compounds were markedly active at doses 16-fold lower than the dose of acronycine itself. Against colon 38 adenocarcinoma, compounds 17 and 24 were highly efficient, inhibiting tumor growth by more than 80%. Diacetate 17 was the most active, inhibiting tumor growth by 96% at 6.25 mg/kg, with two of seven mice being tumor-free on day 43.

Acridines↗
PubMed2000

Phenylpropanoids from Ballota nigra L. inhibit in vitro LDL peroxidation.

From the European plant Ballota nigra L. various polyphenols including phenylpropanoid derivatives were isolated. There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherogenesis. The goal of this study was to test whether the major polyphenolic compounds extracted from Ballota nigra, four phenylpropanoid glycosides, verbascoside, forsythoside B, arenarioside, and ballotetroside and one non-glycosidic phenylpropanoid, caffeoyl-L-malic acid, inhibit Cu(2+)-induced LDL peroxidation. The effectiveness of these compounds was compared to the activity of quercetin, a well-known polyphenol inhibitor of Cu(2+)-induced LDL oxidation. Antioxidant efficacious doses (ED 50) of arenarioside and ballotetroside were 1.8 microM and 7.5 microM respectively, while in the same conditions, the ED 50 of forsythoside B and verbascoside were similar (1 microM) and those of quercetin and of caffeoyl-L-malic acid were 2.3 microM and 9.5 microM respectively. Spectrophotometric studies show that quercetin is a Cu(2+) chelator while phenylpropanoid glycosides and caffeoyl-L-malic acid are not Cu(2+) chelators. Therefore, phenylpropanoid glycosides are strong inhibitors of Cu(2+)-induced LDL oxidation, independent of any capacity to act as Cu(2+) chelators.

Caffeic Acids↗
PubMed2000

Sesquiterpene lactone and friedelane derivative from drypetes molunduana.

A new sesquiterpene lactone, drypemolundein A and a new friedelane derivative, drypemolundein B, along with seven known compounds have been isolated from the whole stems of Drypetes molunduana Pax and Hoffm. Their structures were established on the basis of one- and two-dimensional NMR, homo- and hetero-nuclear spectroscopic evidence.

Lactones↗
PubMed2000

Efficient synthesis of octandrenolone and related dipyranoacetophenones.

Octandrenolone (1) was prepared in high yield by condensation of 2', 4',6'-trihydroxyacetophenone with 3-chloro-3-methylbut-1-yne in the presence of a catalytic amount of copper(I) iodide. Methylation of 1 afforded O-methyloctandrenolone (2). Oxidation of 2 with m-chloroperoxybenzoic acid followed by hydrolysis gave the racemic trans-(+)-1-(9,10-dihydro-9,10-dihydroxy-5-methoxy-2,2,8, 8-tetramethyl-2H,8H-benzo[1,2-b:3,4-b']dipyran-6-yl)ethanone (3), which confirmed the structure of the natural product previously isolated from Melicope erromangensis.

Acetophenones↗