Antitumor activity of diethynylfluorene derivatives of gold(I)

A list of diethynylfluorenes and their gold(I) derivatives have been studied for their antitumor activity as a function of their structure–activity relationships. End-capping the fluoren-9-one unit with gold(I) moieties could significantly strengthen the cytotoxic activity in vitro on three human cancer cell lines with induction of reactive oxygen species generation on Hep3B hepatocellular carcinoma cells and exhibit attractive antitumor activity from in vivo nude mice Hep3B xenograft model with limited adverse effects on vital organs including liver and kidney.     

Synthesis and biological activity of cyclic ADP-carbocyclic-ribose analogs: structure-activity relationship and conformational analysis of N-1-carbocyclic-ribose moiety

Several cyclic ADP-carbocyclic-ribose analogs 3-10 modified in the N-1-carbocyclic-ribose moiety were synthesized. Their Ca2+-releasing activity was estimated in sea urchin eggs to show that the 3"-deoxy analog 6 shows 5 times more potent activity than cADPcR, but the 2",3"-didieoxy-2",3"-unsunsaturated analog 3 has very weak activity. We also calculated their stable conformation and found that 3 and 6 were significantly different in their stable conformation.     

An evaluation of the biologic activity and vitamin D receptor binding affinity of the photoisomers of vitamin D3 and previtamin D3

Skin is in the site of previtamin D3 and vitamin D3 synthesis and their isomerization in response to ultraviolet irradiation. At present, little is known about the function of the photoisomers of previtamin D3 and the vitamin D3 in skin cells. In this study we investigated the antiproliferative activity of the major photoisomers and their metabolites in the cultured human keratinocytes by determining their influence on 3H-thymidine incorporation into DNA. Our results demonstrated at both 10(-8) and 10(-6) M in a dose-dependent manner. Lumisterol, tachysterol3, 5,6-trans-vitamin D3, and 25-hydroxy-5,6-trans-vitamin D3 only induced significant inhibition at 10(-6) M. 25-Hydroxytachysterol3 was approximately 10- to 100-fold more active than tachysterol3. 7-Dehydrocholesterol was not active even at 10(-6) M. The dissociation constants of vitamin D receptor (VDR) for 25-hydroxytachysterol3, 25-hydroxy-5,6-trans-vitamin D3, and 5,6-trans-vitamin D3 were 22, 58, and 560 nM, respectively. The dissociation constants for 7-dehydrocholesterol, tachysterol, and lumisterol were greater than 20 microM. In conclusion, vitamin D3, its photoisomers and the photoisomers of previtamin D3 have antiproliferative activity in cultured human keratinocytes. However, the antiproliferative activity did not correlate with their binding affinity for VDR. The results suggest that some of the photoproducts may be metabolized to their 25-hydroxylated and 1 alpha,25-dihydroxylated counterparts before acting on VDR. Alternatively, a different receptor may recognize these photoproducts or another mechanism may be involved in modulating the antiproliferative activity of the photoisomers examined.     

Synthesis of 3'-deoxy-3'-C-methyl nucleoside derivatives

2',3'-Dideoxy-3'-C-methyl nucleosides bearing the five naturally occurring nucleic acid bases were synthesized. Additionally, the 3'-deoxy-3'-C-methyl nucleoside analogues bearing 5-aminoimidazole-4-carboxamide as well as 1,2,4-triazole-3-carboxamide moieties were prepared. The synthesis of the corresponding 2',3'-dideoxy-3'-C-methyl triazole derivative was also accomplished. The dideoxynucleoside derivatives were prepared by radical deoxygenation from their 3'-deoxy-3'-C-methyl parent ribonucleosides. When evaluated for their antiviral activity in cell culture experiments, none of these compounds showed any significant antiviral activity.     

3-(2-Aminocarbonylphenyl)propanoic acid analogs as potent and selective EP3 receptor antagonists. Part 1: Discovery and exploration of the carboxyamide side chain

A series of 3-(2-aminocarbonyl-4-phenoxymethylphenyl)propanoic acid analogs were synthesized and evaluated for their EP3 antagonist activity in the presence of additive serum albumin. Several compounds were biologically evaluated for their in vivo efficacy with respect to the PGE₂-induced uterine contraction in pregnant rats as well as their pharmacokinetics. The discovery process of these potent and selective EP3 antagonists and their structure activity relationship are also presented.     

Design,synthesis, biological activities and DFT calculation of novel 1,2,4-triazole Schiff base derivatives

Series of 1,2,4-triazole Schiff bases (2a-2d, 2f-2h and 3a-3h) have been designed and synthesized. The structure of title compounds was confirmed on the basis of their spectral data and elemental analysis. All the target compounds were screened for their in vitro antifungal activity and antibacterial activity. Two of the tested compounds (2a and 2b) exhibited significant antifungal activity against most fungi, especially compound 2a showed better antifungal activity than triadimefon. Meanwhile, the antibacterial activity assay also indicated compound 2a exhibited excellent antibacterial activities comparable to chloramphenicol. The SAR manifested no substitution at position 5 of the triazole ring caused an increase in activity, and 3-phenoxy phenyl group introduced in 1,2,4-triazole scaffold can enhance the antibacterial activity. The DFT calculation indicated triazole ring, S atom and benzene ring in both of the 2a and 3a make a major contribution to the activity.     

Chloropyrimidines as a new class of antimicrobial agents

In the course of our investigations of pyrimidines as antimycotic agents, we have identified a sub-class, with significant in vitro activity against mycobacteria. The salient feature of these pyrimidine derivatives (3a-o and 7a,b) is their appended aryl, heteroaryl and alkylthio substituent at position 6 and also alkylthio substituent at position 2. The rational design, synthesis, and evaluation of the in vitro antibacterial activity against six pathogenic bacteria including virulent and non-virulent strains of Mycobacterium tuberculosis is described. Some of the synthesized compounds (3c, 3h, 3i, 3o) have displayed only potent in vitro antimycobacterial activity with MIC of 0.75 microg/mL except 3i which also demonstrated activity against Escherichia coli at 12.5 microg/mL concentration. Only two compounds, 3a and 3b, demonstrated antibacterial activity against Pseudomonas aeruginosa and E. coli with MIC 12.5 microg/mL. All the synthesized compounds were also evaluated for their antimycotic activity against five pathogenic fungi but only some of them 3j-n and 7a,b were found most potent against Aspergillus fumigatus and Trichophyton mentagrophytes.     

Enhancement of human monocyte function against Candida albicans by the colony-stimulating factors (CSF): IL-3, granulocyte-macrophage-CSF, and macrophage-CSF

The effect of IL-3, granulocyte-macrophage (GM)-CSF and macrophage (M)-CSF on Candida albicans growth inhibition by human peripheral blood monocytes was investigated. By using a radiolabel microassay developed in our laboratory that makes use of the incorporation of [3H]glucose into residual C. albicans, we demonstrated that rGM-CSF and rIL-3 effectively enhanced human monocyte-mediated anticandidal activity. Incubation for 24 h with either GM-CSF or IL-3 significantly enhanced monocyte antifungal responses down to 0.01 U/ml. M-CSF, at higher concentrations of 10 U/ml, could also enhance monocyte function but to a smaller degree. None of the CSF interfered directly with fungal growth, even up to 1000 U/ml. Because IFN-gamma is also a known monocyte activator, its effect on monocytes was also assessed. Monocytes were first cultured in medium for several days and then further incubated with each of the cytokines. Monocytes aged in medium were found to lose their spontaneous anticandidal activity. Such aged monocytes did not develop anticandidal activity in response to IFN-gamma but did in response to GM-CSF or IL-3. To further elucidate this difference, fresh monocytes were continuously cultured with or without cytokines for 1 to 5 days before assessing their anticandidal activity. Monocytes cultured in IFN-gamma progressively lost their activity by 2 days but monocytes in GM-CSF or IL-3 maintained their high level of anticandidal activity throughout the whole length of culture. Therefore, GM-CSF and IL-3 not only enhanced fresh monocyte anticandidal activity, but maintained monocyte function for a longer period. These results suggest that GM-CSF and IL-3 may act on monocytes via a different pathway than does IFN-gamma.     

Structure-antioxidant activity relationships of flavonoids isolated from the resinous exudate of Heliotropium sinuatum

Relationships between the structural characteristics of flavonoids isolated from the resinous exudate of Heliotropium sinuatum and their antioxidant activity were studied. Radical formation energies, DeltaH of dehydrogenation and spin densities were calculated using DFT methods (B3LYP/6-31G*). Results show that studied flavonoids can be divided into two sets according to their activity. It has been found that antioxidant activity depends both on substitution pattern of hydroxyl groups of the flavonoid skeleton and the presence of an unsaturation at the C2-C3 bond. A good tendency between DeltaH of dehydrogenation and antioxidant activity was established.     

Association of the human Lewis blood group Le(a-b-c-d-) with the failure of expression of alpha-3-L fucosyltransferase

Two unrelated individuals are reported who lack alpha-3-L-fucosyltransferase activity in their serum and saliva. Both were blacks, one from the United States and the other from South Africa. No other of the tested members of their families lacked this enzyme. A survey of more than 2000 serum samples from both black and white South African blood donors, black United States donors and white United Kingdom donors failed to disclose another example of a serum deficient in alpha-3-L-fucosyltransferase activity. The two individuals lacking in alpha-3-L-fucosyltransferase activity both had the Lewis blood group phenotype Le(a-b-c-d-). No other persons with this phenotype have been reported. The absence of Lec activity in the two individuals who are deficient in alpha-3-L-fucosyltransferase is consistent with the interpretation that alpha-3-linked L-fucose is an essential part of the antigenic determinant recognised by the anti-Lec reagent used in this investigation.     

Synthesis and antiviral evaluation of unnatural beta-L-enantiomers of 3'-fluoro- and 3'-azido-2',3'-dideoxyguanosine derivatives

3'-fluoro-2',3'-dideoxy- (3) and 3'-azido-2',3'-dideoxy- (4) beta-L-ribofuranonucleoside derivatives of guanine have been synthesized and their antiviral properties examined. All these derivatives were regioselectively and stereospecifically prepared by glycosylation of 2-N-acetyl-6-O-(diphenylcarbamoyl)guanine 5 with a suitable peracylated L-xylo-furanose sugar 6, followed by appropriate chemical modifications. The prepared compounds were tested for their activity against HIV and HBV viruses, but they did not show significant activity.     

Adaptation to phenylacetamide as a growth substrate by an acetanilide-utilizing mutant of Pseudomonas aeruginosa

Mutants able to utilize phenylacetamide as sole nitrogen source were isolated from the acetanilide (N-phenylacetamide)-utilizing Pseudomonas aeruginosa mutant strain AI3 and from its parent strain L10. Growth properties of the mutants (Ph strains) on amide media and the physicochemical properties of their amidases in cell free extracts indicated that their phenylacetamidase activities were attributable to alterations in their amidases. Differences in amide hydrolase specificities between the AI3-and the L10-Ph mutants were observed. The AI3 group had a high level of activity towards 4-nitrophenylacetamide, activity towards phenylacetyl-4-nitroaniline but, unlike strain AI3, no activity towards acetyl-4-nitroaniline; the L10 group had a low activity towards 4-nitrophenylacetamide, no activity towards phenylacetyl-4-nitroaniline but retained the low level of activity towards acetyl-4-nitroaniline exhibited by strain L10. Confirmation of the association between these altered specificition of alterations in amidases was obtained from analysis of the properties of phenylacetamidases purified from an AI3-Ph mutant (pH5) and an L 10-Ph mutant (Ph14). The original mutation in the amidase gene of strain AI3 appeared responsible for the differences between the two groups of Ph mutants and the binding interactions with acetanilide that it determined were eliminated in AI3-Ph mutants.     

Comparative distribution of glyceraldehyde 3-phosphate dehydrogenase activity in human, guinea-pig, rabbit and mouse erythrocytes

1. Guinea-pig erythrocytes contain half the activity of the enzyme glyceraldehyde-3-phosphate dehydrogenase (G3PD) present in human cells. About 60% of their total activity is membrane-bound. 2. Rabbit erythrocytes also contain half the amount of the enzyme of human red cells. The distribution of G3PD in rabbit cells, however, is similar to that of human cells with 70% of the enzyme being membrane-bound. 3. Mouse erythrocytes contain about two-thirds of G3PD activity present in human cells. All their enzyme activity is present in membrane-free hemolysate. 4. Non-human erythrocyte membrane proteins, in addition, have relatively greater amount of band 2.1, lack band 2.2, have a more heterogenous band 3 than its human counterpart, and have overlapping bands 4.1 and 4.2.     

Deoxyribonucleic acid polymerase III of Escherichia coli. Characterization of associated exonuclease activities.

Purified DNA polymerase III has two distinct exonuclease activities: one initiates hydrolsis at the 3 termini, and the other at the 5 termini of single-stranded DNA. Both exonucleases have the same relative mobility on polyacrylamide gels as the polymerase activity. Molecular identity of the three activities is further indicated by their comparative rates of thermal inactivation and their sensitivity to ionic strength. The 3-5 exonuclease activity hydrolyzes only single-standed DNA. The rate of hydrolysis is twice the optimal rate of polymerization. The products are 5-mononucleotides, but the 3-5 activity is unable to cleave free dinucleotides or the 5-terminal dinucleotide of a polydeoxynucleotide chain. The 3-5 activity will not degrade 3-phosphoryl-terminated oligonucleotides such as d(pTpTpTp). The 5-3 activity catalyzes the hydrolysis of single-stranded DNA at 1/15 the rate of the 3-5 exonuclease. The 5-3 exonuclease requires the presence of a 5 single-stranded terminus in order to initiate hydrolysis, but will thereafter proceed into a double-stranded region. Although the limit products found during hydrolysis of substrates designed to assay specifically the 5-3 activity are predominantly mono- and dinucleotides, these products probably arise from the subsequent hydrolysis of oligonucleotides by the 3-5 hydrolytic activity. This interpretation is supported by (a) the relatively greater activity of the 3-5 exonuclease, (b) the inability of the enzyme to degrade d(pTpTpTp), and (c) the release of the 5 terminus of a single-stranded DNA molecule as an oligonucleotide. The 5-3 exonuclease attacks ultraviolet-irradiated duplex DNA which has first been incised by the Micrococcus luteus endonuclease specific for thymine dimers in DNA.     

Synthesis and in vivo antihyperglycemic activity of 5-(1H-pyrazol-3-yl)methyl-1H-tetrazoles

A series of 5-[(5-aryl-1H-pyrazol-3-yl)methyl]-1H-tetrazoles 3a-h have been synthesized and evaluated for their in vivo antihyperglycemic activity. Some of the synthesized compounds have shown significant glucose lowering activity in male Sprague-Dawley rats in sucrose loaded model. These compounds were also evaluated for their peroxisome proliferator activated receptor gamma agonistic property, but none of them displayed any significant activity.     

The effect of 1-adamantyl radicals on curare-like activity]

In the series of polymethylene bis-ammonium salts R(CH3)2N(CH2)NN(CH3)2R . 2I--(R=CH3 or Ad) a study was made of the significance of hydrophobic 1-adamantyle radicals (1--Ad) for curare-like activity. Administration of 1-ad radicals into the cation groups of depolarizing agents (n-9--11) altered their mechanism of action and diminished their activity. Attachmeni of 1-Ad radicals to the both quarternary nitrogen atoms of the antidepolarizing agents (n=5 and 6) sharply increased their curare-like activity. The data obtained pointed to the presence of hydrophobic zones in the cholinoreceptors of skeletal muscles.     

Synthesis and antibacterial evaluation of ureides of Baylis-Hillman derivatives

The synthesis of several 1-(2-cyano-3-aryl-allyl)-3-aryl-urea(thiourea) constructed from the reaction between allylamines generated from Baylis-Hillman acetates and substituted isocyanates and isothiocyanates has been described. Further, their cyclization in the presence of a base led to the formation of 5-arylmethyl-4-imino-3-aryl-3,4-dihydro-1H-pyrimidin-2-ones. All compounds were tested for their antibacterial activity. Few of the compounds showed superior activity or were equipotent to the standard antibacterial agents.     

Activation by some T-independent antigens and B cell mitogens of the alternative pathway of the complement system.

A number of T-independent antigens and B cell mitogens were examined for their ability to activate C3 via the alternative pathway of the complement system. Loss of hemolytically active C3, generation of anaphylatoxin activity, and immunoelectrophoretic conversion of C3 and factor B, were checked in normal and C4-deficient guinea pig serum, and, in some cases, in normal human serum. As judged by their activity in these assays, 10 lipopolysaccharides of different origin and constitution, pneumococcus type III polysaccharide, levan, dinitrophenylated aminoethyl-dextran, dinitrophenylated (D-glutamic acid, D-lysin) copolymer, polymerized flagellin, and pokeweed mitogen were all capable of initiating the alternative pathway, but differed with respect to their potency, their relative activity in the presence or absence of C4, and their ability to inhibit C3-turnover at high concentrations. Polyvinylpyrrolidone of intermediate molecular weight (4 x 10(4) daltons) was only active if the most sensitive assay was used (anaphylatoxin generation). Other species of polyvinylpyrrolidone, depolymerized pneumococcal polysaccharide, aminoethyl-dextran, [D-glutamic acid, D-lysin] copolymer, phytohemagglutinin and concanavalin A failed to activate C3. C3-consumption by concanavalin A was due to nonspecific binding.     

Opposite roles of domains 2+3 of Escherichia coli EF-Tu and Bacillus stearothermophilus EF-Tu in the regulation of EF-Tu GTPase activity

The effect of noncatalytic domains 2+3 on the intrinsic activity and thermostability of the EF-Tu GTPase center was evaluated in experiments with isolated domains 1 and six chimeric variants of mesophilic Escherichia coli (Ec) and thermophilic Bacillus stearothermophilus (Bst) EF-Tus. The isolated catalytic domains 1 of both EF-Tus displayed similar GTPase activities at their optimal temperatures. However, noncatalytic domains 2+3 of the EF-Tus influenced the GTPase activity of domains 1 differently, depending on the domain origin. Ecdomains 2+3 suppressed the GTPase activity of the Ecdomain 1, whereas those of BstEF-Tu stimulated the Bstdomain 1 GTPase. Domain 1 and domains 2+3 of both EF-Tus positively cooperated to heat-stabilize their GTPase centers to attain optimal activity at a temperature close to the optimal growth temperature of either organism. This can be explained by a stabilization effect of domains 2+3 on alpha-helical regions of the G-domain as revealed by CD spectroscopy.