Effect of nanosized gold particle addition to supported metal oxide catalyst in methanol oxidation.

Gold has rarely been utilized as a catalytic component because of its poor affinity to chemical species. It is however known that nanosized gold particles promote the dissociation of oxygen or hydrogen. In this study, alumina-supported metal oxide catalysts were prepared by impregnation method and applied to methanol oxidation. The dispersion form and size of the gold particles were observed by transmission electron microscopy (TEM). In the results, the maximum catalytic activity was obtained over the ZnO/Al2O3 catalyst, and the optimum loading was 4 wt%. Furthermore, nano-sized gold particles at various loadings were added to ZnO/Al2O3 catalyst by deposition method. The gold particles on Au/ZnO/Al2O3 catalyst were well dispersed and the catalyst activity was remarkably increased compared to ZnO/Al2O3 catalyst. The role of gold particles in the increased catalytic activity is discussed and a possible mechanism is presented.

Requirement of Smad4-mediated signaling in odontoblast differentiation and dentin matrix formation.

Dentin is the major part of tooth and formed by odontoblasts. Under the influence of the inner enamel epithelium, odontoblasts differentiate from ectomesenchymal cells of the dental papilla and secrete pre-dentin which then undergo mineralization into dentin. Transforming growth factor-beta (TGF-ß)/bone morphogenetic protein (BMP) signaling is essential for dentinogenesis; however, the precise molecular mechanisms remain unclear. To understand the role of TGF-ß/BMP signaling in odontoblast differentiation and dentin formation, we generated mice with conditional ablation of Smad4, a key intracellular mediator of TGF-ß/BMP signaling, using Osr2 or OC-Cre mice. Here we found the molars of Osr2CreSmad4 mutant mice exhibited impaired odontoblast differentiation, and normal dentin was replaced by ectopic bone-like structure. In Osr2CreSmad4 mutant mice, cell polarity of odontoblast was lost, and the thickness of crown dentin was decreased in later stage compared to wild type. Moreover, the root dentin was also impaired and showed ectopic bone-like structure similar to Osr2CreSmad4 mutant mice. Taken together, our results suggest that Smad4-dependent TGF-ß/BMP signaling plays a critical role in odontoblast differentiation and dentin formation during tooth development.

Alkyl and carboxylalkyl esters of 4'-demethyl-4-deoxypodophyllotoxin: synthesis, cytotoxic, and antitumor activity.

Esters of 4'-demethyl-4-deoxypodophyllotoxin (DDPT) with alkanoic acids and alkanedioic acids were prepared and tested for cytotoxic and antitumor activity. Among 19 esters, esters of propanoic acid, tetradecanedioic acid, 13-carboxyundecanoic acid, and hexadecanedioic acid improved the antitumor activity compared with that of the starting compounds, DDPT.

Cytotoxic 2',5'-dihydroxychalcones with unexpected antiangiogenic activity.

A series of 2',5'-dihydroxychalcones were synthesized and evaluated for cytotoxicity against tumor cell lines and human umbilical venous endothelial cells (HUVEC). It was found that chalcones with electron-withdrawing substituents on the B ring exhibited potent cytotoxicity against a variety of tumor cell lines while compounds with electron-releasing groups were less potent in general. Those compounds with B ring replaced by extended or heteroaromatic rings exhibited significant bioactivity. Several compounds were shown to have marked cytotoxic selectivity towards HUVECs. Especially, among the synthesized compounds, 2-chloro-2',5'-dihydroxychalcone (2-3) showed the highest selectivity index up to 66 in comparison to HCT116 cells. This compound also exhibited strong inhibitory effects on the HUVEC tube formation in an in vitro model. When administered into BDF1 mice bearing Lewis lung carcinoma cells at 50 mg kg(-1) day(-1), 2-3 was found to inhibit the growth of tumor mass by 60.5%.

2,3-dibenzylbutyrolactones and 1,2,3,4-tetrahydro-2-naphthoic acid gamma-lactones: structure and activity relationship in cytotoxic activity.

Dibenzyl-g-butyrolactone and 1,2,3,4-tetrahydro-2-naphthoic acid gamma-lactone (TNL) derivatives were synthesized and evaluated for cytotoxic activity against some cancer cell lines. It was found that TNL derivatives with a shorter distance between C-4 in ring A and C'-2 in ring C were more cytotoxic, while dibenzyl-gamma-butyrolactones with a longer one were nearly inactive. In TNL series, presence of 3,4-dioxy group in ring A and 2-methoxy group in ring C was essential for the enhancement of the activity.

Antiangiogenic activity of Bupleurum longiradiatum on human umbilical venous endothelial cells.

The ethyl acetate fraction of Bupleurum longiradiatum was found to have an inhibitory effect on the tube-like formation of human umbilical venous endothelial (HUVE) cells. The active compounds, isolated from the fraction, were identified as acetylbupleurotoxin (P1) and bupleurotoxin (P2). The compounds P1 and P2 completely inhibited the tube-like formation of HUVE cells at 30 microg/ml, below the cytotoxic concentration. But, they did not exhibit antitumor activity on BDF1 mice bearing Lewis lung carcinoma cells despite their antiangiogenic activity.

Synthesis and cytotoxicity of 2,5-dihydroxychalcones and related compounds.

A series of 2, 5-dihydroxychalcones and related compounds were synthesized, and their cytotoxicities against tumor cell lines and human umbilical venous endothelial cells (HUVEC) evaluated. It was found that chalcones, with electron-withdrawing substituents on an A ring, exhibited significant cytotoxicities. Among the synthesized compounds, 2'-chloro-2, 5-dihydroxychalcone (9) was most potent, with an IC50 value as low as 0.31 microg/mL. This compound also exhibited a significant cytotoxic selectivity toward HUVEC.

Synthesis and cytotoxicity of some rigid derivatives of methyl 2,5-dihydroxycinnamate.

Eight rigid compounds designed as esterase-stable analogues of methyl 2,5-dihydroxycinnamate (1) were synthesized. These derivatives include 2-(2',5'-dihydroxybenzylidene)cyclopentenone (3a), 2-(2',5'-dihydroxybenzylidene)cyclohexanone (3b), 2,6-bis(2',5'-dihydroxybenzylidene)cyclohexanone (4b), 2,6-bis(2',5'-dihydroxybenzylidene)cyclopentenone (4a), (E)-3-(2',5'-dihydroxybenzylidene)pyrrolidin-2-one (5), (E)-5-(2',5'-dihydroxybenzylidene)-1,2-isothiazolidine-1,1-dioxide (6), 4-(2',5'-dihydroxyphenyl)-5H-furan-2-one (7), and 3-(2',5'-dihydroxyphenyl)cyclopent-2-ene-1-one (8). Among the eight compounds, the furanone 7 and cyclopentenone 8 showed the most potent cytotoxicity with IC50 values of 0.39-0.98 microg/mL. Compound 8 was further brominated, phenylated and methylated at the alpha position to give three corresponding analogues, including 2-bromo-3-(2',5'-dihydroxyphenyl)cyclopent-2-ene-1-one (24), 3-(2',5'-dihydroxyphenyl)-2-phenylcyclopent-2-ene-1-one (27), and 3-(2',5'-dihydroxyphenyl)-2-methylcyclopent-2-ene-1-one (28). Among the three, the most enhanced activity was observed with the phenylated compound 27.

Synthesis, cytotoxicity and antitumor activity of 2,3-diarylcyclopent-2-ene-1-ones.

Two series of 2,3-diarylcyclopent-2-ene-1-ones including 2-aryl-3-(2,5-dihydroxyphenyl)cyclopent-2-ene-1-ones (2a-2f) and 3-aryl-2-3',4',5'-trimethoxyphenyl)cyclopent-2-ene-1-one (3a-3j) were synthesized and evaluated for the cytotoxicity against three tumor cell lines; B16F10, HCT116 and A431. It was found that the 3,4,5-trimethoxy substituent was optimal for the bioactivity of compounds in series 2. Meanwhile, compounds in series 3 exhibited the most potent cytotoxicity with 3-aryl ring being 4-methoxyphenyl (compound 3f), (3-hydroxy-4-methoxy)phenyl (compound 3e), or (3-amino-4-methoxy)phenyl (compound 3j).

New constituents from Crinum latifolium with inhibitory effects against tube-like formation of human umbilical venous endothelial cells.

Six compounds (1-6) were isolated from the methanol extract of Crinum latifolium by bioassay-guided separation. Among the six isolates, compounds 2 and 6 were new metabolites. Their structures were established as 4-senecioyloxymethyl-3,4-dimethoxycoumarin (2) and 5,6,3'-trihydroxy-7,8,4'-trimethoxyflavone (6) based on spectroscopic analyses. Compound 2 was found to be strongly inhibitory against the in vitro tube-like formation of human umbilical venous endothelial cells (HUVECs) while manifesting no cytotoxicity in tumor cell lines (B16F10, HCT116). Significant inhibitory activity (inhibition percentage, 53.5%) was still observed at concentrations as low as 1 microg/mL. Compound 6 showed a modest inhibitory effect on the tube-like formation of HUVECs. Other compounds, including cycloartenol (1), 4',7-dihydroxy-3'-methoxyflavan (3), 4',7-dihydroxyflavan (4), and 2',4',7-trihydroxydihydrochalcone (5) were found to be nearly inactive.

Inhibitory effect of Adonis amurensis components on tube-like formation of human umbilical venous cells.

Antiangiogenic activity-guided fractionation and isolation carried out on the methanol extract of Adonis amurensis led to the identification of three compounds, namely cymarin, cymarol, and cymarilic acid. Amongst the three compounds, cymarilic acid was isolated from this plant for the first time. This compound showed no significant cytotoxicity against tumor cell lines but was found to be strongly inhibitory toward tube formation induced by human umbilical venous endothelial (HUVE) cells. Cymarin and cymarol exhibited potent cytotoxicity against a human solid tumor cell line A549 (human lung carcinoma), while being inactive on murine leukemic cells (L1210).

Antitumor activity of unsaturated fatty acid esters of 4'-demethyldeoxypodophyllotoxin.

Unsaturated fatty acid esters of 4'-demethyldeoxypodophyllotoxin (DDPT) were prepared and tested for antitumor activity. The esters showed increased in vivo antitumor activity despite the lower in vitro activity than DDPT. Especially, the ester (DFE12) of all-cis-11,14-eicosadienoic acid was much better (IR, 83%) than VP-16 (IR, 60%) without loss of body weight. Unsaturated fatty acids could be evaluated to be good carrier vehicles of DDPT.

Prodrugs of 4'-demethyl-4-deoxypodophyllotoxin: synthesis and evaluation of the antitumor activity.

A series of prodrugs of 4'-demethyl-4-deoxypodophyllotoxin (DDPT) including carbamates (3-8), a carbonate (9) and water-soluble amino acid derivatives (10-17) were prepared and tested for their antitumor activity. The carbamate 6 (2-hydroxyethylcarbamoyl-DDPT), carbonate 9 (2-chloroethyloxycarbonyl-DDPT), and most of amino acid prodrugs (12-17) showed enhanced antitumor activity.

Antiangiogenic activity of lupeol from Bombax ceiba.

In the search for antiangiogenic agents from medicinal plants used in Vietnam, a methanol extract of the stem barks of Bombax ceiba was found to exhibit a significant antiangiogenic activity on in vitro tube formation of human umbilical venous endothelial cells (HUVEC). Bioactivity-guided fractionation and isolation carried out on this extract afforded lupeol as an active principle. At 50 and 30 microg/mL lupeol showed a marked inhibitory activity on HUVEC tube formation while it did not affect the growth of tumor cell lines such as SK-MEL-2, A549, and B16-F10 melanoma.

Synthesis and cytotoxic activity of A-ring modified betulinic acid derivatives.

New A-ring modified betulinic acid derivatives having small steric hindrance were prepared and tested for cytotoxic activity on 3 cancer cell lines: 10 compounds showed stronger cytotoxic activity than betulinic acid. Especially, the compounds bearing 1-ene-3-oxo with electron-withdrawing groups at C2 showed strong cytotoxicity.

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

A series of 3,4-diaryl-2(5H)-furanone derivatives were synthesized and evaluated for their cytotoxicity in a small panel of cancer cell lines. Four out of 10 compounds in this series, for example 3-(3,4,5-trimethoxyphenyl)-4-(4-methoxyphenyl)-, 3-(3,4,5-trimethoxyphenyl)-4-(3-hydroxy-4-methoxyphenyl)-, 3-(3,4,5-trimethoxyphenyl)-4-(3-amino-4-methoxyphenyl)-, and 3-(3,4,5-trimethoxyphenyl)-4-(2-naphthyl)-2(5H)-furanones, were found to have potent cytotoxic activities with ED50 values of less than 20 nM in most of the cell lines tested.

Deoxypodophyllotoxin; the cytotoxic and antiangiogenic component from Pulsatilla koreana.

The petroleum ether fraction of Pulsatilla koreana (Ranunculaceae) was found to have an inhibitory effect on the tube-like formation of human umbilical venous endothelial (HUVE) cells and strong cytotoxic activity against five tumor cell lines. The active component isolated from the fraction was deoxypodophyllotoxin (DPT). The cytotoxic activity against the tumor cells comprising the A549, SK-OV-3, SK-MEL-2, HCT15, and B16F10 cell lines, expressed as ED50, ranged from 6 to 18 ng/ml. 3 ng/ml of DPT, a concentration considerably below the cytotoxic concentration, completely inhibited the tube-like formation of HUVE cells. Furthermore, DPT exhibited an inhibition ratio of 60 % on BDF1 mice bearing Lewis lung carcinoma cells. The inhibitory effect on the tube-like formation was suggested to play an important role in antitumor activity.

Water soluble prodrugs of the antitumor agent 3-[(3-amino-4-methoxy)phenyl]-2-(3,4,5-trimethoxyphenyl)cyclopent-2-ene-1-one.

Fourteen prodrugs of the antitumor agent 3-[(3-amino-4-methoxy)phenyl]-2-(3,4,5-trimethoxyphenyl)cyclopent-2-ene-1-one (1) were prepared to improve its water solubility and potency. These prodrugs include alpha-amino acid (1a-1h), aliphatic amino acid (1i-1l), phosphoramidate (1m), and phosphate (1n) derivatives. All of the prodrugs showed improved water solubility. A number of the amino acid prodrugs (1a, 1b, 1d-1f, 1h, 1j, and 1k) exhibited more potent antitumor activity compared to the parent compound (1). The phosphate prodrug 1n also offered a potent antitumor activity, but the phosphoramidate 1m did not show any antitumor activity in vivo. None of the prodrugs exhibited significant toxicities in mice. These results indicate that the design and preparation of the amino acid prodrugs (1a, 1b, 1d-1f, 1h, 1j, and 1k) and phosphate prodrug (1n) are beneficial for enhancing the antitumor activity of 1. The similar approaches may be used to improve water solubility and bioactivity of other poorly soluble aromatic amines.

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%.

Preliminary structure-antiangiogenic activity relationships of 4-senecioyloxymethyl-6,7-dimethoxycoumarin.

Through a systematic modification of the novel angiogenesis inhibitor 4-senecioyloxymethyl-6,7-dimethoxycoumarin (1) we found that a 6,7-dimethoxy moiety is important for bioactivity of 1. Replacement of the lactone functionality in coumarin 1 by an amide decreased its activity. By substitution of the senecioyl chain with various cinnamoyl groups we discovered 6d, bearing a 4-methoxycinnamoyl instead of senecioyl side chain, with inhibitory activity in HUVEC tube formation assay enhanced by one order of magnitude compared to 1. We have also synthesized compound 12, an analogue of 6d, with equipotency and improved water solubility.