Synthesis and cytotoxicity of 3,4-diaryl-2(5H)-furanones

Synthesis and cytotoxic activities of 4,5-diarylisoxazoles

A series of 4,5-diarylisoxazoles related to combretastatin A-4 (CA-4) were synthesized and evaluated for cytotoxicity against three human cancer cell lines. Among them, compound 6e showed better cytotoxic activity than CA-4 in HeLa and HepG2 cell lines assayed with IC(50) value as low as 0.022 and 0.065nM, respectively.

Naphthalene combretastatin analogues: synthesis, cytotoxicity and antitubulin activity

Synthesis and evaluation of new combretastatin analogues with varied modifications on the bridge and the aromatic rings, have shown that the 2-naphthyl moiety is a good surrogate for the 3-hydroxy-4-methoxyphenyl (B-ring) of combretastatin A-4. Other bicyclic systems, such as 6(7)-quinolyl and 5-indolyl, can replace the B-ring, but they produce less potent analogues in the cytotoxicity and tubulin polymerization inhibition assays. Other modifications are detrimental for the potency of the studied analogues. The 2-naphthyl combretastatin 53 and the related 6-quinolyl combretastatin 106 analogues are the most potent among the derivatives of this type, whereas 92 and 95 are the most potent among the naphthalene derivatives with a heterocycle in the bridge. Previous and new results in this family of combretastatin analogues are discussed.

Synthesis and cytotoxicity of epoxide and pyrazole analogs of the combretastatins

Twenty-six epoxide and corresponding pyrazole derivatives, of the structurally related chalcones and combretastatin A-4 (CA-4), were synthesized and tested for in vitro cytotoxicity. These molecules were synthesized by epoxidation of the relevant chalcones, followed by reaction with hydrazine. The structures of epoxides 3 and 7, and pyrazole 17, were confirmed by X-ray diffraction studies. The relatively coplanar conformation of a 3',3'',4',4'',5',5''-hexamethoxypyrazole 17 was in good agreement with the shape for 3',3'',4',4'',5'-pentamethoxypyrazole 16, which was determined from molecular mechanics optimization. In vitro cytotoxicity of each class of compounds was obtained using a 72 h continuous exposure MTT assay against two murine cancer cell lines; B16 melanoma and L1210 leukemia. The effect of substitution in the A-ring is addressed: three methoxy groups versus two, generally increased cytotoxicity across both cell lines. In the majority of cases, the pyrazoles are generally more active than the epoxides, with the most active, 5-(3''-amino-4''-methoxyphenyl)-3-(3',4',5'-trimethoxyphenyl)pyrazole 21, possessing an IC(50) value of 5 and 2.4 microM (B16 and L1210, respectively). Due to their planar conformations, the pyrazoles are typically less active than the corresponding chalcones, which adopt angular conformations similar to CA-4. B-ring modifications confirmed that in general the amino compounds are more active than the corresponding nitro compounds. Varying the number and orientation of methoxy groups on the A-ring did not produce any significant differences in toxicity in the cell lines studied.

New naphthylcombretastatins. Modifications on the ethylene bridge

Compounds with three aromatic systems, carrying a 2-naphthalene and a 3,4,5-trimethoxyphenyl moieties bonded to five-membered, six-membered or fused heterocycles display potent cytotoxic effect and inhibition of tubulin polymerization, in agreement with their structural similarity to combretastatins and their heterocyclic analogues.

Furanones as potential anti-bacterial coatings on biomaterials

A major barrier to the long-term use of medical devices is development of infection. Staphylococcus epidermidis is one of the most common bacterial isolates from these infections with biofilm formation being their main virulence factor. Currently, antibiotics are used as the main form of therapy. However with the emergence of staphylococcal resistance, this form of therapy is fast becoming ineffective. In this study, the ability of a novel furanone antimicrobial compound to inhibit S. epidermidis adhesion and slime production on biomaterials was assessed. Furanones were physically adsorbed to various biomaterials and bacterial load determined using radioactivity. Slime production was assessed using a colorimetric method. Additionally, the effect of the furanone coating on material surface characteristics such as hydrophobicity and surface roughness was also investigated. The results of this study indicated that there was no significant change in the material characteristics after furanone coating. Bacterial load on all furanone-coated materials was significantly reduced (p<0.001) as was slime production (p<0.001). There is a potential for furanone-coated biomaterials to be used to reduce medical device-associated infections.

Examination of the 1,4-disubstituted azetidinone ring system as a template for combretastatin A-4 conformationally restricted analogue design

A series of novel 1,4-diaryl-2-azetidinones was prepared by stereospecific Staudinger reaction as conformationally restricted analogues of combretastatin A-4 because molecular modeling studies suggested close geometric similarities. They were evaluated for cytotoxicity against a number of human tumor and normal cell lines. Strong potencies were observed, with the best compounds exhibiting IC(50)'s of 25-74 nM against human neuroblastoma IMR 32 cell growth and a variety of other cell lines. Compounds inhibited tubulin polymerization with potencies commensurate with their cytotoxic activity and a more soluble anilino-containing analogue was very effective in inhibiting the growth of AR42J rat pancreatic tumors transplanted into in nude mice. Further studies on this interesting group of compounds as anti-cancer agents appear warranted.

Synthesis and anti-tumor activity of novel combretastatins: combretocyclopentenones and related analogues

A series of 2-(3,4,5-trimethoxyphenyl)-3-arylcyclopent-2-ene-1-ones (8a-8e) and their related analogues, including pentenone 9a, pentenol 10a, pentene 12a, and furane 15, were synthesized and evaluated for cytotoxicity against murine and human tumor cell lines. Compounds 8a-c, 8e and 9a showed strong cytotoxicity with IC(50) values in the range of 8-34ng/mL. Compound 8e exhibited significant anti-tumor activity in BDF1 mice bearing Lewis lung carcinoma cells with an inhibition ratio of 59%.