Triterpenes and lignans from Artemisia caruifolia and their cytotoxic effects on meth-A and LLC tumor cell lines

One new triterpene, 3beta-hydroxy-29-norcycloart-24-one (1), and four new lignans, caruilignans (2-5), together with six known compounds were isolated from the aerial part of Artemisia caruifolia BUCH.-HAM. ex TOXB. Their structures were determined by various spectroscopic means. Most of the isolated lignans were moderately cytotoxic to Meth-A cells with ED50 values of 5-10 microg/ml, but not to Lowis lung carcinoma (LLC) cells. An oxime derivative of 1 showed more potent cytotoxic activity against Meth-A and LLC cells than the original triterpene 1.     

New generation of functionalized bipyrazolic tripods: synthesis and study of their coordination properties towards metal cations

A simple and easily synthesis of new generation of N-donor bipyrazolic tripods by coupling of functionalized pyrazole derivatives and an appropriate primary amine derivative via condensation or nucleophilic substitution reaction is presented. The complexation capacity of these compounds towards bivalent metal ions (Hg²⁺, Cu²⁺, Pb²⁺, Cd²⁺) and alkaline metal ions (Li⁺, Na⁺, K⁺) were investigated using the liquid–liquid extraction process. The percentage limits of extraction were determined by atomic absorption measurements.     

Ruthenium(II) complexes of 2-benzoylpyridine-derived thiosemicarbazones with cytotoxic activity against human tumor cell lines

Reaction of [RuCl(3)(dppb)H(2)O] (dppb=1,4 bis(diphenylphospine)butane) with 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N(4)-methyl (H2Bz4M) and N(4)-phehyl (H2Bz4Ph) derivatives gave [RuCl(dppb)(H2Bz4DH)]Cl (1), [RuCl(dppb)(H2Bz4M)]Cl (2) and [RuCl(dppb)(H2Bz4Ph)]Cl (3). The cytotoxic activity of the studied compounds was tested against the MCF-7, TK-10 and UACC-62 human tumor cell lines. The precursor [RuCl(3)(dppb)H(2)O] exhibits cytocidal activity against the tree cell lines. H2BzDH, H2Bz4M, and [RuCl(dppb)(H2Bz4M)]Cl (2) show a selective cytocidal effect against the UACC-62 cell line which makes them the most promising compounds.     

Synthesis and cytotoxic activity of resveratrol-based compounds

In continuation of our studies on compounds with a resveratrol-based scaffold two compounds with N-containing functional groups have been synthesized and screened for their inhibitory effect on the growth of the human cancer cell lines HT29, 518A2, AsPC-1, BxPC-3, and PC-3. Compound 4, but not 1, demonstrated pronounced in vitro cytotoxicity against all these cancer cell lines, thus making this compound a promising candidate for further preclinical in vivo studies. Correspondence: Thomas Erker, Department of Medicinal Chemistry, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.     

New sorafenib derivatives: synthesis, antiproliferative activity against tumour cell lines and antimetabolic evaluation

Sorafenib is a relatively new cytostatic drug approved for the treatment of renal cell and hepatocellular carcinoma. In this report we describe the synthesis of sorafenib derivatives 4a-e which differ from sorafenib in their amide part. A 4-step synthetic pathway includes preparation of 4-chloropyridine-2-carbonyl chloride hydrochloride (1), 4-chloro-pyridine-2-carboxamides 2a-e, 4-(4-aminophenoxy)-pyridine-2-carboxamides 3a-e and the target compounds 4-[4-[[4-chloro-3-(trifluoromethyl)phenyl]carbamoylamino]-phenoxy]-pyridine-2-carboxamides 4a-e. All compounds were fully chemically characterized and evaluated for their cytostatic activity against a panel of carcinoma, lymphoma and leukemia tumour cell lines. In addition, their antimetabolic potential was investigated as well. The most prominent antiproliferative activity was obtained for compounds 4a-e (IC(50) = 1-4.3 μmol·L-1). Their potency was comparable to the potency of sorafenib, or even better. The compounds inhibited DNA, RNA and protein synthesis to a similar extent and did not discriminate between tumour cell lines and primary fibroblasts in terms of their anti-proliferative activity.     

Synthesis and characterization of chroman‐containing compounds and their preliminary assessment of cytotoxicity toward two human cancer cell lines

A series of chroman derivatives were synthesized by employing o‐methyl phenol as a precursor. These compounds were fully characterized using IR, NMR spectroscopic techniques, and elemental analysis. Mechanisms for the formation of the chroman moiety of these compounds were also proposed. MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay was used to estimate their cytotoxicity toward two cancer cell lines: human ovarian cancer (A2780) and human cervical cancer (Hela). © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:423–429, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20621     

Concise synthesis of 5-methoxy-6-hydroxy-2-methylchromone-7-O- and 5-hydroxy-2-methylchromone-7-O-rutinosides. Investigation of their cytotoxic activities against several human tumor cell lines

The synthesis of two novel 2-methylchromone-7-O-rutinosides is reported, and the in vitro biological activities of these compounds and their synthetic precursors have been investigated on the basis of their cytotoxicity against several human tumor cell lines. The synthesis features early stage assembly of the acidic labile glycosidic bond between sugar and 2-methylchromone aglycon under phase transfer catalyzed glycosidation conditions, whereas all the other standard glycosylation conditions specific to a wide array of rutinosyl donors bearing different anomeric leaving groups (e.g., SPh, OC(NH)CCl(3), Br, OH groups) failed to furnish any detectable products.     

Synthesis of complex compounds of methyl derivatives of 8-quinolineselenol with metals and their cytotoxic activity

A series of 2-methyl-, 4-methyl-, and 2,4-dimethyl-8-quinolineselenolates of zinc, cadmium, mercury, nickel, palladium, platinum, arsenic, antimony, and bismuth has been synthesized and their cytotoxicity has been studied on HT-1080 (human fibrosarcoma), MG-22A (mouse hepatoma), B16 (mouse melanoma), and Neuro 2A (mouse neuroblastoma) tumor cells. Mercury complexes were distinguished by high cytotoxicity on all the cell lines. Palladium complexes possessed somewhat lower activity and were significantly less toxic in relation to normal NIH 3T3 mouse embryo fibroblasts. All the studied metal 2-methyl-8-quinolineselenolates displayed high cytotoxicity on B16 melanoma, arsenic 4-methyl-8-quinolineselenolate acted most effectively on HT-1080 and MG-22A cells. Di(4-methyl-8-quinolyl) diselenide also possessed high cytotoxicity on these same cells. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 59–66, January, 2006.     

Design,synthesis and cytotoxic activity of vitamin E bearing selenium compounds against human breast cancer cell line (MCF-7)

A new series of vitamin E/selenated pyridine, vitamin E/selenated pyridazine, vitamin E/selenated coumarine and vitamin E/selenated nicotine moieties were synthesized and their cytotoxic activity is investigated using the human breast cancer cell line. The newly synthesized compounds were characterized using spectroscopic tools (IR, ¹H NMR, ¹³C NMR, and mass spectroscopy) as well as microanalysis. Our study reveals that compound vitamin E/selenated nicotine moiety has the highest cytotoxic effect than the other synthesized compounds.     

Polyphenols from Eriobotrya japonica and their cytotoxicity against human oral tumor cell lines

Three new flavonoid glycosides, together with 15 known flavonoids, have been isolated from the leaves of Eriobotrya japonica, and characterized as (2S)- and (2R)-naringenin 8-C-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosides, and cinchonain Id 7-O-beta-D-glucopyranoside, respectively, based on spectral analyses including two dimensional (2D) NMR techniques. Higher proanthocyanidin fraction in the water-soluble portion of the extract was characterized as a procyanidin oligomer mixture mainly composed of undecameric procyanidin. These polyphenols have also been assessed for cytotoxic activity against two human oral tumor (human squamous cell carcinoma and human salivary gland tumor) cell lines. Selective cytotoxicity of the procyanidin oligomer between tumor and normal gingival fibroblast cells, and its possible mechanism, were also described.     

Polyoxometalates functionalized by bisphosphonate ligands: synthesis, structural, magnetic, and spectroscopic characterizations and activity on tumor cell lines

We report the synthesis and characterization of eight new Mo, W, or V-containing polyoxometalate (POM) bisphosphonate complexes with metal nuclearities ranging from 1 to 6. The compounds were synthesized in water by treating Mo(VI), W(VI), V(IV), or V(V) precursors with biologically active bisphosphonates H(2)O(3)PC(R)(OH)PO(3)H(2) (R = C(3)H(6)NH(2), Ale; R = CH(2)S(CH(3))(2), Sul and R = C(4)H(5)N(2), Zol, where Ale = alendronate, Sul = (2-Hydroxy-2,2-bis-phosphono-ethyl)-dimethyl-sulfonium and Zol = zoledronate). Mo(6)(Sul)(2) and Mo(6)(Zol)(2) contain two trinuclear Mo(VI) cores which can rotate around a central oxo group while Mo(Ale)(2) and W(Ale)(2) are mononuclear species. In V(5)(Ale)(2) and V(5)(Zol)(2) a central V(IV) ion is surrounded by two V(V) dimers bound to bisphosphonate ligands. V(6)(Ale)(4) can be viewed as the condensation of one V(5)(Ale)(2) with one additional V(IV) ion and two Ale ligands, while V(3)(Zol)(3) is a triangular V(IV) POM. These new POM bisphosphonates complexes were all characterized by single-crystal X-ray diffraction. The stability of the Mo and W POMs was studied by (31)P NMR spectroscopy and showed that all compounds except the mononuclear Mo(Ale)(2) and W(Ale)(2) were stable in solution. EPR measurements performed on the vanadium derivatives confirmed the oxidation state of the V ions and evidenced their stability in aqueous solution. Electrochemical studies on V(5)(Ale)(2) and V(5)(Zol)(2) showed reduction of V(V) to V(IV), and magnetic susceptibility investigations on V(3)(Zol)(3) enabled a detailed analysis of the magnetic interactions. The presence of zoledronate or vanadium correlated with the most potent activity (IC(50)~1-5 μM) against three human tumor cell lines.     

Synthesis and cytotoxic activity of certain new arylazothiazole containing compounds

2‐Amino‐5‐arylazo‐4‐(2‐chlorophenyl)thiazoles ( 2a‐e ) were prepared by the coupling of aryldiazonium chlorides with 2‐amino‐4‐(2‐chlorophenyl) thiazole ( 1 ). The thioureas 3a‐e were obtained by condensing the arylazothiazoles 2a‐c with the appropriate isothiocyanates. Reaction of 2d with aromatic aldehydes afforded the chalcone analogues 4a‐c . The pyridone derivatives 5a,b were synthesized by reacting the ketone 2d with different aromatic aldehydes, ethyl cyanoacetate and ammonium acetate. On the other hand, 5b was also prepared by cyclizing 4c with ethyl cyanoacetate and ammonium acetate. Furthermore, 6‐chloroimidazo[2,l‐b]‐thiazole 7 was obtained from the acid derivative 6b by treatment with POC1₃. While, the imidazo[2,l‐b]‐thiazolones 9a‐d were produced by the cyclization of the chloroacetyl derivatives 8a‐d with DMAP/pyri‐dine. Representative examples of the prepared compounds were tested for in vitro antitumor activity against two human tumor cell lines. Some compounds showed activity against brain tumor cell lines.     

Asymmetric synthesis and cytotoxic activity of isomeric phytosphingosine derivatives

New phytosphingosine analogues have been conceived, synthesised and their cytotoxicity in B16 murine melanoma cells tested. These compounds embed an isomeric substitution pattern resulting from a formal permutation of the C-2 and C-4 substituents along the aliphatic skeleton of the original sphingoid base. Five different stereoisomers have been accessed through regio- and stereocontrolled opening of the oxirane of long chain epoxyamine precursors. The corresponding N-hexyl and N-octanoyl derivatives have also been prepared. In cell viability experiments all the primary amines were found to be more active than the natural phytosphingosine with IC(50) in the low μM range for the most potent compounds.     

First synthesis of the antifungal oidiolactone C from trans-communic acid: cytotoxic and antimicrobial activity in podolactone-related compounds

The synthesis of the fungicide oidiolactone C starting from diterpenic trans-communic acid was carried out with an overall yield of 11.7%. The key step in the process consists of a new bislactonization reaction catalyzed by Pd(II), which gives rise to the podolactone-type tetracyclic skeleton from a norlabdadienedioic acid. We also carried out a study of the structure-biological activity of different natural podolactones and their synthetic precursors. Thus, the highest cytotoxic activity was found in dienic dilactones with ether-type substitutions on C-17, whereas the closure of the gamma-lactone ring is not critical for presenting a maximal antimicrobial activity.     

Synthesis of bengamide E analogues and their cytotoxic activity

A series of bengamide E analogues were prepared from the corresponding polyketide chain and amino acids via amide coupling reactions. Opening of the polyketide chain lactone ring with α-aminolactams was successfully achieved under microwave irradiation in the presence of sodium 2-ethyl hexanoate. A cytotoxic activity evaluation against a panel of cancer cell lines (KB, HepG-2, Lu-1, MCF-7, HL-60 and Hela) indicated that the 2′R analogues were generally more cytotoxic than the 2′S analogues. Additionally, several analogues exhibited selective inhibition against various cancer cell lines: compounds 32a and 32b selectively inhibited MCF-7 cells, while 33b and 35b were more sensitive toward Lu-1 and HepG-2, respectively. Notably, some of the synthetic analogues possess cytotoxic activities with IC₅₀ values less than 1 µM.     

RCM-based synthesis of a variety of beta-C-glycosides and their in vitro anti-solid tumor activity

The synthesis of a number of biologically relevant C-glycosides has been carried out through the use of an esterification-ring-closing metathesis (RCM) strategy. The required acid precursors were readily prepared via a number of standard chemical transformations followed by dehydrative coupling of these acids with several olefin alcohols 1 to yield the precursor esters 3 in excellent yield. Methylenation of the esters 3 was followed by RCM and in situ hydroboration-oxidation of the formed glycals to furnish the protected beta-C-glycosides 6 in good overall yield. Several examples were converted to the corresponding C-glycoglycerolipids 17 and subsequently screened against solid-tumor cell lines for in vitro differential cytotoxicity.     

Synthesis of tetracyclic dioxygenated isoquinolines and their cytotoxic activity

An efficient synthesis of new dioxygenated isoquinolines is reported. The novelty of this approach derives from its use of tricyclic-nitril (3) as a building block in a synthetic sequence of seven steps for the preparation of the tetracyclic isoquinoline (14) and its derivatives. The isoquinoline 16 was 10-fold more active against leukemia L₁₂₁₀ than the corresponding tetrahydroisoquinoline 14.     

Semisynthesis of isetexane diterpenoid analogues and their cytotoxic activity

Isetexane diterpene analogues were semisynthesized from demethylsalvicanol isolated from Perovskia abrotanoides (Labiatae). The structure and cytotoxic activity relationships (SAR) of the natural parent diterpene, demethylsalvicanol, and its semisynthetic analogues were studied by using P388 murine leukemia cells.     

Total synthesis and cytotoxic activity of dechlorogreensporones A and D

The first and convergent total syntheses of polyketide natural products dechlorogreensporones A and D have been accomplished in 17 longest linear steps with 2.8% and 5.4% overall yields, respectively, starting from known methyl 2-(2-formyl-3,5-dihydroxyphenyl)acetate and commercially available R-(+)-propylene oxide and 1,2-epoxy-5-hexene. Our synthesis exploited key Mitsunobu esterification and (E)-selective ring-closing metathesis (RCM) to assemble the macrocycles as well as a Jacobsen hydrolytic kinetic resolution to install the stereogenic centers. Both synthetic compounds were found to display significant cytotoxic activity against seven human cancer cell lines with the IC₅₀ ranges of 6.66–17.25?μM.